The compounds 2',3',4',6'-tetra-O-acetyl-β-d-gluco­pyranosyl N'-cyano-N-phenyl­carbamimido­thio­ate (C22H25N3O9S, 5a), 2',3',4',6'-tetra-O-acetyl-β-d-galacto­pyranosyl N'-cyano-N-phenyl­carbamimido­thio­ate, (C22H25N3O9S, 5b), 2',3',4',6'-tetra-O-acetyl-β-d-galacto­pyranosyl N'-cyano-N-methyl­carbamimido­thio­ate (C17H23N3O9S, 5c), and 2',3',4',6'-tetra-O-acetyl-β-d-galacto­pyranosyl N'-cyano-N-p-tolyl­carbamimido­thio­ate (C23H27N3O9S, 5d) all crystallize in P212121 with Z = 4. For all four structures, the configuration across the central (formal) C=N(CN) double bond of the carbamimido­thio­ate group is Z. The torsion angles C5—O1—C1—S (standard sugar numbering) are all close to 180°, confirming the β position of the substituent. Compound 5b involves an intra­molecular hydrogen bond N—H⋯O1; in 5c this contact is the weaker branch of a three-centre inter­action, whereas in 5a and 5d the H⋯O distances are much longer and do not represent significant inter­actions. The C—N bond lengths at the central carbon atom of the carbamimido­thio­ate group are almost equal. All C—O—C=O torsion angles of the acetyl groups correspond to a synperiplanar geometry, but otherwise all four mol­ecules display a high degree of conformational flexibility, with many widely differing torsion angles for equivalent groups. In the crystal packing, 5a, 5c and 5d form layer structures involving the classical hydrogen bond N—H⋯Ncyano and a variety of ‘weak’ hydrogen bonds C—H⋯O or C—H⋯S. The packing of 5b is almost featureless and involves a large number of borderline ‘weak’ hydrogen bonds. In an appendix, a potted history of wavelength preferences for structure determination is presented and it is recommended that, even for small organic crystals in non-centrosymmetric space groups, the use of Mo radiation should be considered.

The asymmetric unit of the title compound is composed of two independent ion pairs of 4-(di­methyl­amino)­pyridin-1-ium 8-hy­droxy­quinoline-5-sulfonate (HDMAP+·HqSA−, C7H11N2+·C9H6NO4S−) and neutral N,N-di­methyl­pyridin-4-amine mol­ecules (DMAP, C7H10N2), co-crystallized as a 1:1:1 HDMAP+:HqSA−:DMAP adduct in the monoclinic system, space group Pc. The compound has a layered structure, including cation layers of HDMAP+ with DMAP and anion layers of HqSA− in the crystal. In the cation layer, there are inter­molecular N—H⋯N hydrogen bonds between the protonated HDMAP+ mol­ecule and the neutral DMAP mol­ecule. In the anion layer, each HqSA− is surrounded by other six HqSA−, where the planar network structure is formed by inter­molecular O—H⋯O and C—H⋯O hydrogen bonds. The cation and anion layers are linked by inter­molecular C—H⋯O hydrogen bonds and C—H⋯π inter­actions.

The X-ray crystal structure data of 12-α-fluoro-3β-hy­droxy­olean-28,13β-olide methanol hemisolvate, 2C30H47FO3·CH3OH, (1), and 12-α-fluoro-3β-hy­droxy­taraxer-28,14β-olide methanol hemisolvate, 2C30H47FO3·CH3OH, (2), are described. The fluoro­lactonization of oleanolic acid using SelectfluorTM yielded a mixture of the six-membered δ-lactone (1) and the unusual seven-membered γ-lactone (2) following a 1,2-shift of methyl C-27 from C-14 to C-13.

In the title mol­ecule, C11H11BrO3, the di­hydro­indene moiety is essentially planar but with a slight twist in the saturated portion of the five-membered ring. The meth­oxy groups lie close to the above plane. In the crystal, π-stacking inter­actions between six-membered rings form stacks of mol­ecules extending along the a-axis direction, which are linked by weak C—H⋯O and C—H⋯Br hydrogen bonds. A Hirshfeld surface analysis was performed showing H⋯H, O⋯H/H⋯O and Br⋯H/H⋯Br contacts make the largest contributions to inter­molecular inter­actions in the crystal.

Two new [1-(phenyl­sulfon­yl)-1H-indol-2-yl]methanamine derivatives, namely, N-(3-meth­oxy­phen­yl)-N-{[1-(phenyl­sulfon­yl)-1H-indol-2-yl]meth­yl}acetamide, C24H22N2O4S, (I), and N-(2,5-di­meth­oxy­phen­yl)-N-{[1-(phenyl­sulfon­yl)-1H-indol-2-yl]meth­yl}benzene­sulfonamide, C29H26N2O6S2, (II), reveal a nearly orthogonal orientation of their indole ring systems and sulfonyl-bound phenyl rings. The sulfonyl moieties adopt the anti-periplanar conformation. For both compounds, the crystal packing is dominated by C—H⋯O bonding [C⋯O = 3.312 (4)–3.788 (8) Å], with the structure of II exhibiting a larger number, but weaker bonds of this type. Slipped π–π inter­actions of anti­parallel indole systems are specific for I, whereas the structure of II delivers two kinds of C—H⋯π inter­actions at both axial sides of the indole moiety. These findings agree with the results of Hirshfeld surface analysis. The primary contributions to the surface areas are associated with the contacts involving H atoms. Although II manifests a larger fraction of the O⋯H/H⋯O contacts (25.8 versus 22.4%), most of them are relatively distal and agree with the corresponding van der Waals separations.

The crystal structures of two inter­mediates, 4-amino-3,5-di­fluoro­benzo­nitrile, C7H4F2N2 (I), and ethyl 4-amino-3,5-di­fluoro­benzoate, C9H9F2NO2 (II), along with a visible-light-responsive azo­benzene derivative, diethyl 4,4'-(diazene-1,2-di­yl)bis­(3,5-di­fluoro­benzoate), C18H14F4N2O4 (III), obtained by four-step synthetic procedure, were studied using single-crystal X-ray diffraction. The mol­ecules of I and II demonstrate the quinoid character of phenyl rings accompanied by the distortion of bond angles related to the presence of fluorine substituents in the 3 and 5 (ortho) positions. In the crystals of I and II, the mol­ecules are connected by N—H⋯N, N—H⋯F and N—H⋯O hydrogen bonds, C—H⋯F short contacts, and π-stacking inter­actions. In crystal of III, only stacking inter­actions between the mol­ecules are found.

Single crystals of the mol­ecular compound, {Cu20Ir6Cl8(C21H24N2)6(C4H4N2)3]·3.18CH3OH or [({Cu10Ir3}Cl4(IMes)3(pyrazine))2(pyrazine)]·3.18CH3OH [where IMes is 1,3-bis­(2,4,6-trimethylphen­yl)imidazol-2-yl­idene], with a unique heterometallic cluster have been prepared and the structure revealed using single-crystal X-ray diffraction. The mol­ecule is centrosymmetric with two {Cu10Ir3} cores bridged by a pyrazine ligand. The polymetallic cluster contains three stabilizing N-heterocyclic carbenes, four Cl ligands, and a non-bridging pyrazine ligand. Notably, the Cu—Ir core is arranged in an unusual shape containing 13 vertices, 22 faces, and 32 sides. The atoms within the trideca­metallic cluster are arranged in four planes, with 2, 4, 4, 3 metals in each plane. Ir atoms are present in alternate planes with an Ir atom featuring in the peripheral bimetallic plane, and two Ir atoms featuring on opposite sides of the non-adjacent tetra­metallic plane. The crystal contains two disordered methanol solvent mol­ecules with an additional region of non-modelled electron density corrected for using the SQUEEZE routine in PLATON [Spek (2015). Acta Cryst. C71, 9–18]. The given chemical formula and other crystal data do not take into account the unmodelled methanol solvent mol­ecule(s).

The structures of seven gold(III) halide derivatives of general formula LAuX3 (L = methyl­pyridines or di­methyl­pyridines, X = Cl or Br) are presented: tri­chlorido­(2-methyl­pyridine)­gold(III), [AuCl3(C6H7N)], 1 (as two polymorphs 1a and 1b); tri­bromido­(2-methyl­pyridine)­gold(III), [AuBr3(C6H7N)], 2; tri­bromido­(3-methyl­pyridine)­gold(III), [AuBr3(C6H7N)], 3; tri­bromido­(2,4-di­meth­yl­pyridine)­gold(III), [AuBr3(C7H9N)], 4; tri­chlorido­(3,5-di­methylpyridine)­gold(III), [AuCl3(C7H9N)], 5; tri­bromido­(3,5-di­methyl­pyridine)­gold(III), [AuBr3(C7H9N)], 6, and tri­chlorido­(2,6-di­methyl­pyridine)­gold(III), [AuCl3(C7H9N)], 7. Additionally, the structure of 8, the 1:1 adduct of 2 and 6, [AuBr3(C6H7N)]·[AuBr3(C7H9N)], is included. All the structures crystallize solvent-free, and all have Z' = 1 except for 5 and 7, which display crystallographic twofold rotation symmetry, and 4, which has Z' = 2. 1a and 2 are isotypic. The coordination geometry at the gold(III) atoms is, as expected, square-planar. Four of the crystals (1a, 1b, 2 and 8) were non-merohedral twins, and these structures were refined using the ‘HKLF 5’ method. The largest inter­planar angles between the pyridine ring and the coordination plane are observed for those structures with a 2-methyl substituent of the pyridine ring. The Au—N bonds are consistently longer trans to Br (average 2.059 Å) than trans to Cl (average 2.036 Å). In the crystal packing, a frequent feature is the offset-stacked and approximately rectangular dimeric moiety (Au—X)2, with anti­parallel Au—X bonds linked by Au⋯X contacts at the vacant positions axial to the coordination plane. The dimers are connected by further secondary inter­actions (Au⋯X or X⋯X contacts, `weak' C—H⋯X hydrogen bonds) to form chain, double chain (`ladder') or layer structures, and in several cases linked again in the third dimension. Only 1b and 7 contain no offset dimers; these structures instead involve C—H⋯Cl hydrogen bonds combined with Cl⋯Cl contacts (1b) or Cl⋯π contacts (7). The packing patterns of seven further complexes LAuX3 involving simple pyridines (taken from the Cambridge Structural Database) are compared with those of 1–8.

The di­hydro­imidazole ring in the title mol­ecule, C20H20N2O3S, is slightly distorted and the lone pair on the tri-coordinate nitro­gen atom is involved in intra-ring π bonding. The methyl­sulfanyl substituent lies nearly in the plane of the five-membered ring while the ester substituent is rotated well out of that plane. In the crystal, C—H⋯O hydrogen bonds form inversion dimers, which are connected along the a- and c-axis directions by additional C—H⋯O hydrogen bonds, forming layers parallel to the ac plane. The major contributors to the Hirshfeld surface are C⋯H/H⋯C, O⋯H/H⋯O and S⋯H/H⋯S contacts at 20.5%, 14.7% and 4.9%, respectively.

In the title compound, bis­[aqua­(2,2'-bi­pyridine)­fluorido­tin(II)] hexa­fluorido­tin(IV), [SnF(C10H8N2)(H2O)]2[SnF6], an ionic mixed-valent tin(II)–tin(IV) compound, the bivalent tin atom is the center atom of the cation and the tetra­valent tin atom is the center atom of the anion. With respect to the first coordination sphere, the cation is monomeric, with the tin(II) atom having a fourfold seesaw coordination with a fluorine atom in an equatorial position, a water mol­ecule in an axial position and the two nitro­gen atoms of the chelating 2,2'-bi­pyridine ligand in the remaining axial and equatorial positions. The bond lengths and angles of this hypervalent first coordination sphere are described by 2c–2e and 3c–4e bonds, respectively, all of which are based on the orthogonal 5p orbitals of the tin atom. In the second coordination sphere, which is based on an additional, very long tin–fluorine bond that leads to dimerization of the cation, the tin atom is trapezoidal–pyramidally coordinated. The tetra­valent tin atom of the centrosymmetric anion has an octa­hedral coordination. The differences in its tin–fluorine bond lengths are attributed to hydrogen bonding, as the two of the four fluorine atoms are each involved in two hydrogen bonds, linking anions and cations together to form strands.

In the crystal structure of the title compound, C26H36N2O4, the tripodal mol­ecule exists in a conformation in which the substituents attached to the central arene ring are arranged in an alternating order above and below the ring plane. The heterocyclic unit is inclined at an angle of 79.6 (1)° with respect to the plane of the benzene ring. In the crystal, the mol­ecules are connected via N—H⋯O bonds, forming infinite supra­molecular strands. Inter­strand association involves weak C—H⋯O and C—H⋯π inter­actions, with the pyridine ring acting as an acceptor in the latter case.

The crystal structure of hexa­glycinium tetra-μ-iodido-octa­iodido­triplumbate, (C2H6NO2)6[Pb3I12] or (GlyH)6[Pb3I12], is reported. The compound crystallizes in the triclinic space group Poverline{1}. The [Pb3I12]6− anion is discrete and located around a special position: the central Pb ion located on the inversion center is holodirected, while the other two are hemidirected. The supra­molecular nature is mainly based on C—H⋯I, N—H⋯I, O—H⋯I and N—H⋯O hydrogen bonds. Dimeric cations of type (A+⋯A+) for the amino acid glycine are observed for the first time.

The title compound, poly[bis­(β-alaninium) [[di­bromido­plumbate]-di-μ-di­bromido]] {(C2H8NO2)2[PbBr4]}n or (β-AlaH)2PbBr4, crystallizes in the monoclinic space group P21/n. The (PbBr4)2− anion is located on a general position and has a two-dimensional polymeric structure. The Pb center is holodirected. The supra­molecular network is mainly based on O—H⋯Br, N—H⋯Br and N—H⋯O hydrogen bonds.

In the title mol­ecule, C25H29N5O, the di­hydro­quinoxaline unit is not quite planar (r.m.s. deviation = 0.030 Å) as there is a dihedral angle of 2.69 (3)° between the mean planes of the constituent rings and the mol­ecule adopts a hairpin conformation. In the crystal, the polar portions of the mol­ecules are associated through C—H⋯O and C—H⋯N hydrogen bonds and C—H⋯π(ring) and C=O⋯π(ring) inter­actions, forming thick layers parallel to the bc plane and with the n-octyl groups on the outside surfaces.

The cyclic peptide cyclo(Val-Leu-Leu-d-Phe-Pro)2 (peptide 1) was specifically designed for structural chemistry investigations, drawing inspiration from Gramicidin S (GS). Previous studies have shown that Pro residues within 1 adopt a down-puckering conformation of the pyrrolidine ring. By incorporating fluoride-Pro with 4-trans/cis-isomers into 1, an up-puckering conformation was successfully induced. In the current investigation, introducing hy­droxy­prolines with 4-trans/cis-isomer configurations (tHyp/cHyp) into 1 gave cyclo(Val-Leu-Leu-d-Phe-tHyp)2 methanol disolvate monohydrate, C62H94N10O12·2CH4O·H2O (4), and cyclo(Val-Leu-Leu-d-Phe-cHyp)2 monohydrate, C62H94N10O12·H2O (5), respectively. However, the puckering of 4 and 5 remained in the down conformation, regardless of the geometric position of the hydroxyl group. Although the backbone structure of 4 with trans-substitution was asymmetric, the asymmetric backbone of 5 with cis-substitution was unexpected. It is speculated that the anti­cipated influence of stress from the geometric positioning, which was expected to affect the puckering, may have been mitigated by inter­actions between the hydroxyl groups of hy­droxy­proline, the solvent mol­ecules, and peptides.

This study presents the synthesis, characterization and Hirshfeld surface analysis of the title mononuclear complex, [PdCl2(C12H14N4)]·C3H7NO. The compound crystalizes in the P21/c space group of the monoclinic system. The asymmetric unit contains one neutral complex Pd(HLc-Pe)Cl2 [HLc-Pe is 2-(3-cyclo­pentyl-1,2,4-triazol-5-yl)pyridine] and one mol­ecule of DMF as a solvate. The Pd atom has a square-planar coordination. In the crystal, mol­ecules are linked by inter­molecular N—H⋯O and C—H⋯N hydrogen bonds, forming layers parallel to the bc plane. A Hirshfeld surface analysis showed that the H⋯H contacts dominate the crystal packing with a contribution of 41.4%. The contribution of the N⋯H/H⋯N and H⋯O/O⋯H inter­actions is somewhat smaller, amounting to 12.4% and 5%, respectively.

This study presents the synthesis, characterization and Hirshfeld surface analysis of 1-[6-bromo-2-(3-bromo­phen­yl)-1,2,3,4-tetra­hydro­quinolin-4-yl]pyrrolidin-2-one, C19H18Br2N2O. In the title compound, the pyrrolidine ring adopts a distorted envelope configuration. In the crystal, mol­ecules are linked by inter­molecular N—H⋯O, C—H⋯O and C—H⋯Br hydrogen bonds, forming a three-dimensional network. In addition, pairs of mol­ecules along the c axis are connected by C—H⋯π inter­actions. According to a Hirshfeld surface study, H⋯H (36.9%), Br⋯H/H⋯Br (28.2%) and C⋯H/H⋯C (24.3%) inter­actions are the most significant contributors to the crystal packing.

Propane-1,3-diaminium squarate dihydrate, C3H12N22+·C4O42−·2H2O, results from the proton-transfer reaction of propane-1,3-di­amine with squaric acid and subsequent crystallization from aqueous medium. The title compound crystallizes in the tetra­gonal crystal system (space group P4bm) with Z = 2. The squarate dianion belongs to the point group D4h and contains a crystallographic fourfold axis. The propane-1,3-diaminium dication exhibits a C2v-symmetric all-anti conformation and resides on a special position with mm2 site symmetry. The orientation of the propane-1,3-diaminium ions makes the crystal structure polar in the c-axis direction. The solid-state supra­molecular structure features a triperiodic network of strong hydrogen bonds of the N—H⋯O and O—H⋯O types.

In the title compound, C33H29ClN2O2, the two piperidine rings of the di­aza­bicyclo moiety adopt distorted-chair conformations. Inter­molecular C—H⋯π inter­actions are mainly responsible for the crystal packing. The inter­molecular inter­actions were qu­anti­fied and analysed using Hirshfeld surface analysis, revealing that H⋯H inter­actions contribute most to the crystal packing (52.3%). The mol­ecular structure was further optimized by density functional theory (DFT) at the B3LYP/6–31 G(d,p) level and is compared with the experimentally determined mol­ecular structure in the solid state.

In the structure of the title salt, {[Ba(μ3-C3H2N3O2)2(μ-H2O)(H2O)]·H2O}n, the barium ion and all three oxygen atoms of the water mol­ecules reside on a mirror plane. The hydrogen atoms of the bridging water and the solvate water mol­ecules are arranged across a mirror plane whereas all atoms of the monodentate aqua ligand are situated on this mirror plane. The distorted ninefold coord­ination of the Ba ions is completed with four nitroso-, two carbonyl- and three aqua-O atoms at the distances of 2.763 (3)–2.961 (4) Å and it is best described as tricapped trigonal prism. The three-dimensional framework structure is formed by face-sharing of the trigonal prisms, via μ-nitroso- and μ-aqua-O atoms, and also by the bridging coordination of the anions via carbonyl-O atoms occupying two out of the three cap positions. The solvate water mol­ecules populate the crystal channels and facilitate a set of four directional hydrogen bonds. The principal Ba–carbamoyl­cyano­nitro­somethanido linkage reveals a rare example of the inherently polar binodal six- and three-coordinated bipartite topology (three-letter notation sit). It suggests that small resonance-stabilized cyano­nitroso anions can be utilized as bridging ligands for the supra­molecular synthesis of MOF solids. Such an outcome may be anti­cipated for a broader range of hard Lewis acidic alkaline earth metal ions, which perfectly match the coordination preferences of highly nucleophilic nitroso-O atoms. Thermal analysis reveals two-stage dehydration of the title compound (383 and 473 K) followed by decomposition with release of CO2, HCN and H2O at 558 K.

The mol­ecular structure of the tripodal carbamoyl­methyl­phosphine oxide compound diethyl {[(5-[2-(di­eth­oxy­phosphor­yl)acetamido]-3-{2-[2-(di­eth­oxy­phos­phor­yl)acetamido]­eth­yl}pent­yl)carbamo­yl]meth­yl}phospho­nate, C25H52N3O12P3, features six intra­molecular hydrogen-bonding inter­actions. The phospho­nate groups have key bond lengths ranging from 1.4696 (12) to 1.4729 (12) Å (P=O), 1.5681 (11) to 1.5811 (12) Å (P—O) and 1.7881 (16) to 1.7936 (16) Å (P—C). Each amide group adopts a nearly perfect trans geometry, and the geometry around each phophorus atom resembles a slightly distorted tetra­hedron.

The two mol­ecules in the asymmetric unit of the title compound, C23H24N2O2S, have a structural overlap with an r.m.s. deviation of 0.82 Å. The piperidine rings adopt a distorted boat conformation. Intra- and inter­molecular C—H⋯O hydrogen bonds are responsible for the cohesion of the crystal packing. The inter­molecular inter­actions were qu­anti­fied and analysed using Hirshfeld surface analysis. The mol­ecular structure optimized by density functional theory (DFT) at the B3LYP/6–311++G(d,p)level is compared with the experimentally determined mol­ecular structure in the solid state.

The asymmetric unit of the title salt, C7H8N3+·C7H5O6S−, comprises two 1,3-di­hydro-2H-benzimidazol-2-iminium cations and two 2-hy­droxy-5-sulfobenzoate anions (Z' = 2). In the crystal, the mol­ecules inter­act through N—H⋯O, O—H⋯O hydrogen bonds and C—O⋯π contacts. The hydrogen-bonding inter­actions lead to the formation of layers parallel to (overline{1}01). Hirshfeld surface analysis revealed that H⋯H contacts contribute to most of the crystal packing with 38.9%, followed by H⋯O contacts with 36.2%.

The benzimidazole moiety in the title mol­ecule, C19H25N5O, is almost planar and oriented nearly perpendicular to the triazole ring. In the crystal, C—H⋯O hydrogen bonds link the mol­ecules into a network structure. There are no π–π inter­actions present but two weak C—H⋯π(ring) inter­actions are observed. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (62.0%), H⋯C/C⋯H (16.1%), H⋯N/N⋯H (13.7%) and H⋯O/O⋯H (7.5%) inter­actions. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated via the dispersion energy contributions in the title compound.

Coordination compounds of polydentate nitro­gen ligands with metals are used extensively in research areas such as catalysis, and as models of complex active sites of enzymes in bioinorganic chemistry. Tris(2-pyridyl­meth­yl)amine (TPA) is a tripodal tetra­dentate ligand that is known to form coordination compounds with metals, including copper, iron and zinc. The related compound, tris­[(6-bromo­pyridin-2-yl)meth­yl]amine (TPABr3), C18H15Br3N4, which possesses a bromine atom on the 6-position of each of the three pyridyl moieties, is also known but has not been heavily investigated. The mol­ecular structure of TPABr3 as determined by X-ray diffraction is reported here. The TPABr3 molecule belongs to the triclinic, Poverline{1} space group and displays interesting intermolecular Br⋯Br interactions that provide a stabilizing influence within the molecule.

This work describes the X-ray structure of orange–red crystals of 2-meth­oxy-5-nitro­aniline, C7H8N2O3. The compound displays concentration-dependent UV-Vis spectra, which is attributed to dipole-induced aggregation, and light absorption arising from an inter­molecular charge-transfer process that decreases in energy as the degree of aggregation increases. The crystals display π-stacking where the dipole moments align anti­parallel. Stacked mol­ecules inter­act with the next stack via hydrogen bonds, which is a state of maximum aggregation. Light absorption by charge transfer can be compared to colored inorganic semiconductors such as orange–red CdS, with a band gap of 2.0–2.5 eV.

The synthesis of the title compound, [Zn(C4H6N2)6](NO3)2, is described. This complex consists of a central zinc metal ion surrounded by six 1-methyl­imidazole ligands, charge balanced by two nitrate anions. The complex crystallizes in the space group Poverline{3}. In the crystal, the nitrate ions are situated within the cavities created by the [Zn(N-Melm)6]2+ cations, serving as counter-ions. The three oxygen atoms of the nitrate ion engage in weak C—H⋯O inter­actions. In addition to single-crystal X-ray diffraction analysis, the complex was characterized using elemental analysis, 1H NMR, 13C NMR, and FTIR spectroscopy.

A new pyridine-fused seleno­diazo­lium salt, 3-(phenyl­selan­yl)[1,2,4]selena­diazolo[4,5-a]pyridin-4-ylium chloride di­chloro­methane 0.352-solvate, C12H9N2Se2+·Cl−·0.352CH2Cl2, was obtained from the reaction between 2-pyridyl­selenenyl chloride and phenyl­seleno­cyanate. Single-crystal structural analysis revealed the presence of C—H⋯N, C—H⋯Cl−, C—H⋯Se hydrogen bonds as well as chalcogen–chalcogen (Se⋯Se) and chalcogen–halogen (Se⋯Cl−) inter­actions. Non-covalent inter­actions were explored by DFT calculations followed by topological analysis of the electron density distribution (QTAIM analysis). The structure consists of pairs of seleno­diazo­lium moieties arranged in a head-to-tail fashion surrounding disordered di­chloro­methane mol­ecules. The assemblies are connected by C—H⋯Cl− and C—H⋯N hydrogen bonds, forming layers, which stack along the c-axis direction connected by bifurcated Se⋯Cl−⋯H—C inter­actions.

Crystallization of 5-nona­noyl-8-hy­droxy­quinoline in the presence of InCl3 in aceto­nitrile yields a dinuclear InIII complex crystallizing in the space group Poverline{1}. In this complex, [In2(C18H22NO2)2Cl4(H2O)2], each indium ion is sixfold coordinated by two chloride ions, one water mol­ecule and two 8-quinolino­late ions. The crystal of the title complex is composed of two-dimensional supra­molecular aggregates, resulting from the linkage of the Owater—H⋯O=C and Owater—H⋯Cl hydrogen bonds as well as bifurcated Carene—H⋯Cl contacts.

When reacted in dry, degassed toluene, [Ir(COD)Cl]2 (COD = cyclo­octa-1,5-diene) and 2 equivalents of 2-(di-tert-butyl­phosphinito)anthra­quinone (tBuPOAQH) were found to form a unique tri-iridium compound consisting of one monoanionic dinuclear tri-μ-chlorido complex bearing one bidentate tBuPOAQ ligand per iridium, which was charge-balanced by an outer sphere [Ir(toluene)(COD)]+ ion, the structure of which has not previously been reported. This product, which is a toluene solvate, namely, (η2:η2-cyclo­octa-1,5-diene)(η6-toluene)­iridium(I) tri-μ-chlorido-bis­({3-[(di-tert-butyl­phosphan­yl)­oxy]-9,10-dioxoanthracen-2-yl}hydridoiridium(III)) toluene monosolvate, [Ir(C7H8)(C8H12)][Ir2H2(C22H24O3P)2Cl3]·C7H8 or [Ir(toluene)(COD)][Ir(κ-P,C-tBuPOAQ)(H)]2(μ-Cl)3]·toluene, formed as small orange platelets at room temperature, crystallizing in the triclinic space group Poverline{1}. The cation and anion are linked via weak C—H⋯O inter­actions. The stronger inter­molecular attractions are likely the offset parallel π–π inter­actions, which occur between the toluene ligands of pairs of inverted cations and between pairs of inverted anthra­quinone moieties, the latter of which are capped by toluene solvate mol­ecules, making for π-stacks of four mol­ecules each. The related ligand, 2-(di-tert-butyl­phosphinometh­yl)-anthra­quinone (tBuPCAQH), did not form crystals suitable for X-ray diffraction under analogous reaction conditions. However, when the reaction was conducted in chloro­form, yellow needles readily formed following addition of 1 atm of carbon monoxide. Diffraction studies revealed a neutral, dinuclear, di-μ-chlorido complex, di-μ-chlorido-bis­(carbon­yl{3-[(di-tert-butyl­phosphan­yl)­oxy]-9,10-dioxoanthracen-2-yl}hydridoiridium(I)), [Ir2H2(C23H26O2P)2Cl2(CO)2] or [Ir(κ-P,C-tBuPCAQ)(H)(CO)(μ-Cl)]2, Ir2C48H54Cl2O6P2, again crystallizing in space group Poverline{1}. Offset parallel π–π inter­actions between anthra­quinone groups of adjacent mol­ecules link the mol­ecules in one dimension.

The mol­ecule of the title compound, [Ni(C5H7O2)2(C8H9N3)(H2O)]·C2H5OH, has triclinic (Poverline{1}) symmetry. This compound is of inter­est for its anti­microbial properties. The asymmetric unit comprises two independent complex mol­ecules, which are linked by N—H⋯O and O—H⋯O hydrogen bonds along [111]. Hirshfeld surface analysis indicates that 71.7% of inter­mol­ecular inter­actions come from H⋯H contacts, 17.7% from C⋯H/H⋯C contacts and 7.6% from O⋯H/H⋯O contacts, with the remaining contribution coming from N⋯H/H⋯N, C⋯N/N⋯C, C⋯C and O⋯O contacts.

Reaction of 4-methyl­pyridine N-oxide and Co(NCS)2 in ethanol as solvent accidentally leads to the formation of single crystals of Co(NCS)2(4-methyl­pyridine N-oxide)(ethanol) or [Co(NCS)2(C6H7NO)(C2H6O)]n. The asymmetric unit of the title compound consists of one CoII cation, two crystallographically independent thio­cyanate anions, one 4-methyl­pyridine N-oxide coligand and one ethanol mol­ecule on general positions. The cobalt cations are sixfold coordinated by one terminal and two bridging thio­cyanate anions, two bridging 4-methyl­pyridine N-oxide coligands and one ethanol mol­ecule, with a slightly distorted octa­hedral geometry. The cobalt cations are linked by single μ-1,3(N,S)-bridging thio­cyanate anions into corrugated chains, that are further connected into layers by pairs of μ-1,1(O,O)-bridging 4-methyl­pyridine N-oxide coligands. The layers are parallel to the bc plane and are separated by the methyl groups of the 4-methyl­pyridine N-oxide coligands. Within the layers, intra­layer hydrogen bonding is observed.

In the racemic title compound, C28H30O2, the naphthyl ring systems subtend a dihedral angle of 68.59 (1)° and the mol­ecular conformation is consolidated by a pair of intra­molecular C—H⋯π contacts. The crystal packing features a weak C—H⋯π contact and van der Waals forces. A Hirshfeld surface analysis of the crystal structure reveals that the most significant contributions are from H⋯H (73.2%) and C⋯H/H⋯C (21.2%) contacts.

The title compound, [Sn(C6H5)Cl3(C12H8N2)], which was obtained by the reaction between 1,10-phenanthroline and phenyl­tin trichloride in methanol, exhibits intra­molecular hydrogen-bonding inter­actions involving the chlorine and hydrogen atoms. Crystal cohesion is ensured by inter­molecular C—H⋯Cl hydrogen bonds, as well as Y—X⋯π and π-stacking inter­actions involving three different aromatic rings with centroid–centroid distances of 3.6605 (13), 3.9327 (14) and 3.6938 (12) Å]. Hirshfeld surface analysis and the associated two-dimensional fingerprint plots reveal significant contributions from H⋯H (30.7%), Cl⋯H/H⋯Cl (32.4%), and C⋯H/H⋯C (24.0%) contacts to the crystal packing while the C⋯C (6.2%), C⋯Cl/Cl⋯C (4.1%), and N⋯H/H⋯N (1.7%) inter­actions make smaller contributions.

The title compound, [Cd(C14H16N3S)Cl] or [CdLCl] (1), where LH = 2-[bis­(pyridin-2-ylmeth­yl)amino]­ethane-1-thiol, was prepared and structurally characterized. The Cd2+ complex crystallizes in P21/c with a distorted trigonal–bipyramidal metal coordination geometry. Supra­molecular inter­actions in 1 include parallel offset face-to-face inter­actions between inversion-related pyridyl rings and potential hydrogen bonds with chlorine or sulfur as the acceptor. Additional cooperative pyrid­yl–pyridyl inter­actions with roughly 45° tilt angles and centroid–centroid distances of less than 5.5 Å likely also contribute to the overall solid-state stability. Hirshfeld surface analysis indicates that H⋯H (51.2%), Cl⋯H/H⋯Cl (13.9%), C⋯H/H⋯C (12.3%) and S⋯H/H⋯S (11.8%) inter­actions are dominant in the solid state.

Reaction of copper(I)chloride with 2,3-di­methyl­pyrazine in ethanol leads to the formation of the title compound, poly[[μ-chlorido-μ-(2,3-di­methyl­pyrazine)-copper(I)] ethanol hemisolvate], {[CuCl(C6H8N2)]·0.5C2H5OH}n or CuCl(2,3-di­methyl­pyrazine) ethanol hemisolvate. Its asymmetric unit consists of two crystallographically independent copper cations, two chloride anions and two 2,3-di­methyl­pyrazine ligands as well as one ethanol solvate mol­ecule in general positions. The ethanol mol­ecule is disordered and was refined using a split model. The methyl H atoms of the 2,3-di­methyl­pyrazine ligands are also disordered and were refined in two orientations rotated by 60° relative to each other. In the crystal structure, each copper cation is tetra­hedrally coordinated by two N atoms of two bridging 2,3-di­methyl­pyrazine ligands and two μ-1,1-bridg­ing chloride anions. Each of the two copper cations are linked by pairs of bridging chloride anions into dinuclear units that are further linked into layers via bridging 2,3-di­methyl­pyrazine coligands. These layers are stacked in such a way that channels are formed in which the disordered solvent mol­ecules are located. The topology of this network is completely different from that observed in the two polymorphic modifications of CuCl(2,3-di­methyl­pyrazine) reported in the literature [Jess & Näther (2006). Inorg. Chem. 45, 7446–7454]. Powder X-ray diffraction measurements reveal that the title compound is unstable and transforms immediately into an unknown crystalline phase.

The title compound, (C9H8NO)[CuCl3(C7H5NO4)]·2H2O, was prepared by reacting CuII acetate dihydrate, solid 8-hy­droxy­quinoline (8-HQ), and solid pyridine-2,6-di­carb­oxy­lic acid (H2pydc), in a 1:1:1 molar ratio, in an aqueous solution of dilute hydro­chloric acid. The CuII atom exhibits a distorted CuO2NCl3 octa­hedral geometry, coordinating two oxygen atoms and one nitro­gen atom from the tridentate H2pydc ligand and three chloride atoms; the nitro­gen atom and one chloride atom occupy the axial positions with Cu—N and Cu—Cl bond lengths of 2.011 (2) Å and 2.2067 (9) Å, respectively. In the equatorial plane, the oxygen and chloride atoms are arranged in a cis configuration, with Cu—O bond lengths of 2.366 (2) and 2.424 (2) Å, and Cu—Cl bond lengths of 2.4190 (10) and 2.3688 (11) Å. The asymmetric unit contains 8-HQ+ as a counter-ion and two uncoordinated water mol­ecules. The crystal structure features strong O—H⋯O and O—H⋯Cl hydrogen bonds as well as weak inter­actions including C—H⋯O, C—H⋯Cl, Cu—Cl⋯π, and π–π, which result in a three-dimensional network. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing involving the main residues are from H⋯Cl/Cl⋯H inter­actions, contributing 40.3% for the anion. Weak H⋯H contacts contribute 13.2% for the cation and 28.6% for the anion.

The title mol­ecule, C25H23BrN2O2, adopts a cup shaped conformation with the distinctly ruffled imidazolidine ring as the base. In the crystal, weak C—H⋯O hydrogen bonds and C—H⋯π(ring) inter­actions form helical chains of mol­ecules extending along the b-axis direction that are linked by additional weak C—H⋯π(ring) inter­actions across inversion centres. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (51.0%), C⋯H/H⋯C (21.3%), Br⋯H/H⋯Br (12.8%) and O⋯H/H⋯O (12.4%) inter­actions. The volume of the crystal voids and the percentage of free space were calculated to be 251.24 Å3 and 11.71%, respectively, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated by the dispersion energy.

A host–guest supra­molecular inclusion complex was obtained from the co-crystallization of A1/A2-bromo­but­oxy-hy­droxy difunctionalized pillar[5]arene (PilButBrOH) with adipo­nitrile (ADN), C47H53.18Br0.82O10·C6H8N2. The adipo­nitrile guest is stabilized within the electron-rich cavity of the pillar[5]arene host via multiple C—H⋯O and C—H⋯π inter­actions. Both functional groups on the macrocyclic rim are engaged in supra­molecular inter­actions with an adjacent inclusion complex via hydrogen-bonding (O—H⋯N or C—H⋯Br) inter­actions, resulting in the formation of a supra­molecular dimer in the crystal structure.

The title compound, a hydrate of 3,5-di­amino-1,2,4-triazole (DATA), C2H5N5·H2O, was synthesized in the presence of sodium perchlorate. The evaporation of H2O from its aqueous solution resulted in anhydrous DATA, suggesting that sodium perchlorate was required to precipitate the DATA hydrate. The DATA hydrate crystallizes in the P21/c space group in the form of needle-shaped crystals with one DATA and one water mol­ecule in the asymmetric unit. The water mol­ecules form a three-dimensional network in the crystal structure. Hirshfeld surface analysis revealed that 8.5% of the inter­molecular inter­actions originate from H⋯O contacts derived from the incorporation of the water mol­ecules.

The reaction of Zn(ClO4)2·6H2O with Na3SbS4·9H2O in a water/aceto­nitrile mixture leads to the formation of the title compound, (μ-tetra­thio­anti­monato-κ2S:S')bis­[(1,4,8,11-tetra­aza­cyclo­tetra­decane-κ4N)zinc(II)] perchlorate 0.8-hydrate, [Zn2(SbS4)(C10H24N4)2]ClO4·0.8H2O or [(Zn-cyclam)2(SbS4)]+[ClO4]−·0.8H2O. The asymmetric unit consists of two crystallographically independent [SbS4]3– anions, two independent perchlorate anions and two independent water mol­ecules as well as four crystallographically independent Zn(cyclam)2+ cations that are located in general positions. Both perchlorate anions and one cyclam ligand are disordered and were refined with a split mode using restraints. The water mol­ecules are partially occupied. Two Zn(cyclam)2+ cations are linked via the [SbS4]3– anions into [Zn2(cyclam)2SbS4]+ cations that are charged-balanced by the [ClO4]− anions. The water mol­ecules of crystallization are hydrogen bonded to the [SbS4]3– anions. The cations, anions and water mol­ecules are linked by N—H⋯O, N—H⋯S and O—H⋯S hydrogen bonds into a three-dimensional network. Powder X-ray diffraction proves that a pure sample had been obtained that was additionally investigated for its spectroscopic properties.

Two new phenyl­sulfonyl­indole derivatives, namely, N-{[3-bromo-1-(phenyl­sulfon­yl)-1H-indol-2-yl]meth­yl}-N-(4-bromo-3-meth­oxy­phen­yl)benzene­sulfonamide, C28H22Br2N2O5S2, (I), and N,N-bis­{[3-bromo-1-(phenyl­sulfon­yl)-1H-indol-2-yl]meth­yl}benzene­sulfonamide, C36H27Br2N3O6S3, (II), reveal the impact of intra­molecular π–π inter­actions of the indole moieties as a factor not only governing the conformation of N,N-bis­(1H-indol-2-yl)meth­yl)amines, but also significantly influencing the crystal patterns. For I, the crystal packing is dominated by C—H⋯π and π–π bonding, with a particular significance of mutual indole–indole inter­actions. In the case of II, the mol­ecules adopt short intra­molecular π–π inter­actions between two nearly parallel indole ring systems [with the centroids of their pyrrole rings separated by 3.267 (2) Å] accompanied by a set of forced Br⋯O contacts. This provides suppression of similar inter­actions between the mol­ecules, while the importance of weak C—H⋯O hydrogen bonding to the packing naturally increases. Short contacts of the latter type [C⋯O = 3.389 (6) Å] assemble pairs of mol­ecules into centrosymmetric dimers with a cyclic R22(13) ring motif. These findings are consistent with the results of a Hirshfeld surface analysis and together they suggest a tool for modulating the supra­molecular behavior of phenyl­sulfonyl­ated indoles.

The title compound, catena-poly[[tri­aqua­sodium]-di-μ-aqua-[tri­aqua­sodium]-μ-(ethane-1,2-di­yl)bis­[(3-meth­oxy­prop­yl)phosphinodi­thiol­ato]], [Na2(C10H22O2P2S4)(H2O)8]n, crystallizes in the triclinic space group P1. The dianionic [CH3O(CH2)3P(=S)(S—)CH2CH2P(=S)(S—)(CH2)3OCH3]2− ligand fragments are joined by a dicationic [Na2(H2O)8]2+ cluster that includes the oxygen of the meth­oxy­propyl unit of the ligand to form infinite chains.

The crystal structure of the title organic–inorganic hybrid salt, (C13H12N3)2[CdCl4], (I), has been reported with four mol­ecules in the asymmetric unit in a monoclinic cell [Vassilyeva et al. (2021). RSC Advances, 11, 7713–7722]. While using two different aldehydes in the oxidative cyclization–condensation involving CH3NH2·HCl to prepare a new monovalent cation with the imidazo[1,5-a]pyridinium skeleton, a new polymorph was obtained for (I) in space group P1 and a unit cell with approximately half the volume of the monoclinic form. The structural configurations of the two crystallographically non-equivalent organic cations as well as the geometry of the moderately distorted tetra­hedral CdCl42– dianion show minor changes. In the crystal, identically stacked cations and tetra­chloro­cadmate anions form separate columns parallel to the a axis. The loose packing of the anions leads to a minimal separation of approximately 9.53 Å between the metal atoms in the triclinic form versus 7.51 Å in the monoclinic one, indicating that the latter is packed slightly more densely. The two forms also differ by aromatic stacking motifs. Similar to the monoclinic polymorph, the triclinic one excited at 364 nm shows an intense unsymmetrical photoluminescent band with maximum at 403 nm and a full width at half maximum of 51 nm in the solid state.

In the title compound, C10H8N2·2C6H5NO3, 4-nitro­phenol and 4,4'-bi­pyridine crystallized together in a 2:1 ratio in the space group P21/n. There is a hydrogen-bonding inter­action between the nitro­gen atoms on the 4,4'-bi­pyridine mol­ecule and the hydrogen atom on the hydroxyl group on the 4-nitro­phenol, resulting in trimolecular units. This structure is a polymorph of a previously reported structure [Nayak & Pedireddi (2016). Cryst. Growth Des. 16, 5966–5975], which differs mainly due to a twist in the 4,4'-bi­pyridine mol­ecule.

Two different multi-component crystals consisting of papaverine [1-(3,4-di­meth­oxy­benz­yl)-6,7-di­meth­oxy­iso­quinoline, C20H21NO4] and fumaric acid [C4H4O4] were obtained. Single-crystal X-ray structure analysis revealed that one, C20H21NO4·1.5C4H4O4 (I), is a salt co-crystal composed of salt-forming and non-salt-forming mol­ecules, and the other, C20H21NO4·0.5C4H4O4 (II), is a salt–co-crystal inter­mediate (i.e., in an inter­mediate state between a salt and a co-crystal). In this study, one state (crystal structure at 100 K) within the salt–co-crystal continuum is defined as the ‘inter­mediate’.

The title compound, [Zn2(C22H18ClN4O)Cl3], is a dinuclear zinc(II) complex with three chlorido ligands and one penta­dentate ligand containing quinolin-8-olato and bis­(pyridin-2-ylmeth­yl)amine groups. One of the two ZnII atom adopts a tetra­hedral geometry and coordinates two chlorido ligands with chelate coord­ination of the N and O atoms of the quinolin-8-olato group in the ligand. The other ZnII atom adopts a distorted trigonal–bipyramidal geometry, and coordinates one chlorido-O atom of the quinolin-8-olato group and three N atoms of the bis­(pyridin-2-ylmeth­yl)amine unit. In the crystal, two mol­ecules are associated through a pair of inter­molecular C—H⋯Cl hydrogen bonds, forming a dimer with an R22(12) ring motif. Another inter­molecular C—H⋯Cl hydrogen bond forms a spiral C(8) chain running parallel to the [010] direction. The dimers are linked by these two inter­molecular C—H⋯Cl hydrogen bonds, generating a ribbon sheet structure in ac plane. Two other inter­molecular C—H⋯Cl hydrogen bonds form a C(7) chain along the c-axis direction and another C(7) chain generated by a d-glide plane. The mol­ecules are cross-linked through the four inter­molecular C—H⋯Cl hydrogen bonds to form a three-dimensional network.

In the title compound, C25H17NO3, the torsion angle associated with the phenyl benzoate group is −173.7 (2)° and that for the benz­yloxy group is −174.8 (2)° establishing an anti-type conformation. The dihedral angles between the ten-membered cyanona­phthalene ring and the aromatic ring of the phenyl benzoate and the benz­yloxy fragments are 40.70 (10) and 87.51 (11)°, respectively, whereas the dihedral angle between the aromatic phenyl benzoate and the benz­yloxy fragments is 72.30 (13)°. In the crystal, the mol­ecules are linked by weak C—H⋯O inter­actions forming S(4) chains propagating parallel to [010]. The packing is consolidated by three C—H⋯π inter­actions and two π–π stacking inter­actions between the aromatic rings of naphthalene and phenyl benzoate with centroid-to-centroid distances of 3.9698 (15) and 3.8568 (15) Å, respectively. Inter­molecular inter­actions were qu­anti­fied using Hirshfeld surface analysis. The mol­ecular structure was further optimized by density functional theory (DFT) at the B3LYP/6–311+ G(d,p) level, revealing that the energy gap between HOMO and LUMO is 3.17 eV. Mol­ecular docking studies were carried out for the title compound as a ligand and SARS-Covid-2(PDB ID:7QF0) protein as a receptor giving a binding affinity of −9.5 kcal mol−1.

In the title salt, C6H16N22+ ·H2P2O72−, the complete dication is generated by a crystallographic centre of symmetry with the methyl groups in equatorial orientations. The complete dianion is generated by a crystallographic twofold axis with the central O atom lying on the axis: the P—O—P bond angle is 135.50 (12)°. In the crystal, the di­hydrogen diphosphate anions are linked by O—H⋯O hydrogen bonds, generating (001) layers. The organic cations bond to the inorganic layers by way of N—H⋯O and C—H⋯O hydrogen bonds. A Hirshfeld surface analysis shows that the most important contributions for the crystal packing are from O⋯H/H⋯O (60.5%) and H⋯H (39.4%) contacts.