An alternative approach to hard-X-ray photoelectron spectroscopy (HAXPES) has been established. The instrumental key feature is an increase of the dimensionality of the recording scheme from 2D to 3D. A high-energy momentum microscope detects electrons with initial kinetic energies up to 8 keV with a k-resolution of 0.025 Å−1, equivalent to an angular resolution of 0.034°. A special objective lens with k-space acceptance up to 25 Å−1 allows for simultaneous full-field imaging of many Brillouin zones. Combined with time-of-flight (ToF) parallel energy recording this yields maximum parallelization. Thanks to the high brilliance (1013 hν s−1 in a spot of <20 µm diameter) of beamline P22 at PETRA III (Hamburg, Germany), the microscope set a benchmark in HAXPES recording speed, i.e. several million counts per second for core-level signals and one million for d-bands of transition metals. The concept of tomographic k-space mapping established using soft X-rays works equally well in the hard X-ray range. Sharp valence band k-patterns of Re, collected at an excitation energy of 6 keV, correspond to direct transitions to the 28th repeated Brillouin zone. Measured total energy resolutions (photon bandwidth plus ToF-resolution) are 62 meV and 180 meV FWHM at 5.977 keV for monochromator crystals Si(333) and Si(311) and 450 meV at 4.0 keV for Si(111). Hard X-ray photoelectron diffraction (hXPD) patterns with rich fine structure are recorded within minutes. The short photoelectron wavelength (10% of the interatomic distance) `amplifies' phase differences, making full-field hXPD a sensitive structural tool.

The design and performance of the high-resolution wavelength-dispersive multi-crystal von Hamos-type spectrometer at PETRA III beamline P64 are described. Extended analyzer crystal collection available at the beamline allows coverage of a broad energy range from 5 keV to 20 keV with an energy resolution of 0.35–1 eV. Particular attention was paid to enabling two-color measurements by a combination of two types of analyzer crystals and two two-dimensional detectors. The performance of the spectrometer is demonstrated by elastic-line and emission-line measurements on various compounds.

A new Rococo 2 X-ray fluorescence detector was implemented into the cryogenic sample environment at the Hard X-ray Micro/Nano-Probe beamline P06 at PETRA III, DESY, Hamburg, Germany. A four sensor-field cloverleaf design is optimized for the investigation of planar samples and operates in a backscattering geometry resulting in a large solid angle of up to 1.1 steradian. The detector, coupled with the Xspress 3 pulse processor, enables measurements at high count rates of up to 106 counts per second per sensor. The measured energy resolution of ∼129 eV (Mn Kα at 10000 counts s−1) is only minimally impaired at the highest count rates. The resulting high detection sensitivity allows for an accurate determination of trace element distributions such as in thin frozen hydrated biological specimens. First proof-of-principle measurements using continuous-movement 2D scans of frozen hydrated HeLa cells as a model system are reported to demonstrate the potential of the new detection system.

Following the recent demonstration of grazing-incidence X-ray fluorescence (GIXRF)-based characterization of the 3D atomic distribution of different elements and dimensional parameters of periodic nanoscale structures, this work presents a new computational scheme for the simulation of the angular-dependent fluorescence intensities from such periodic 2D and 3D nanoscale structures. The computational scheme is based on the dynamical diffraction theory in many-beam approximation, which allows a semi-analytical solution to the Sherman equation to be derived in a linear-algebraic form. The computational scheme has been used to analyze recently published GIXRF data measured on 2D Si3N4 lamellar gratings, as well as on periodically structured 3D Cr nanopillars. Both the dimensional and structural parameters of these nanostructures have been reconstructed by fitting numerical simulations to the experimental GIXRF data. Obtained results show good agreement with nominal parameters used in the manufacturing of the structures, as well as with reconstructed parameters based on the previously published finite-element-method simulations, in the case of the Si3N4 grating.

A new diamond-anvil cell apparatus for in situ synchrotron X-ray diffraction measurements of liquids and glasses, at pressures from ambient to 5 GPa and temperatures from ambient to 1300 K, is reported. This portable setup enables in situ monitoring of the melting of complex compounds and the determination of the structure and properties of melts under moderately high pressure and high temperature conditions relevant to industrial processes and magmatic processes in the Earth's crust and shallow mantle. The device was constructed according to a modified Bassett-type hydro­thermal diamond-anvil cell design with a large angular opening (θ = 95°). This paper reports the successful application of this device to record in situ synchrotron X-ray diffraction of liquid Ga and synthetic PbSiO3 glass to 1100 K and 3 GPa.

This review discusses the state of the field of single-crystal diffuse scattering (SCDS), including detectors, data collection and the modelling techniques. High quality, three-dimensional volumes of SCDS data can now be collected at synchrotron light sources, allowing increasingly detailed and quantitative analyses to be undertaken.

A neutron crystallographic study of perdeuterated transthyretin reveals important aspects of the structure relating to its stability and its propensity to form fibrils, as well as evidence of a single water molecule that affects the symmetry of the two binding pockets.

A modulation wave approach is used to interpret the coupled longer range as well as truly short range order hidden in the highly structured diffuse intensity distributions of three representative such systems. The longer range as well as the truly short range order simultaneously encoded in such highly structured diffuse intensity distributions is highlighted.

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The reaction of ligand 5,7-di­hydro-1H,3H-dithieno[3,4-b:3',4'-e]pyrazine (L) with CuI lead to the formation of a three-dimensional coordination polymer, incorporating the well known [CuxIx]n staircase motif (x = 4). These polymer [Cu4I4]n chains are linked via the N and S atoms of the ligand to form the three-dimensional coordination polymer poly[(μ4-5,7-di­hydro-1H,3H-dithieno[3,4-b:3',4'-e]pyrazine-κ4N:N':S:S')tetra-μ3-iodido-tetra­copper], [Cu4I4(C8H8N2S2)]n (I). The asymmetric unit is composed of half a ligand mol­ecule, with the pyrazine ring located about a center of symmetry, and two independent copper(I) atoms and two independent I− ions forming the staircase motif via centers of inversion symmetry. The framework is consolidated by C—H⋯I hydrogen bonds.

The reaction of ligand 3,4,8,10,11,13-hexa­hydro-1H,6H-bis­([1,4]di­thio­cino)[6,7-b:6',7'-e]pyrazine (L) with CuI led to the formation of a two-dimensional coordination polymer, incorporating a [Cu2I2] motif. These units are linked via the four S atoms of the ligand to form the title two-dimensional coordination poly­mer, poly[[μ4-3,4,8,10,11,13-hexa­hydro-1H,6H-bis­([1,4]di­thio­cino)[6,7-b:6',7'-e]pyrazine]di-μ-iodido-dicopper(I)], [Cu2I2(C12H16N2S4)]n, (I). The asymmetric unit is composed of a ligand mol­ecule, two copper(I) atoms and two I− ions. Both copper(I) atoms are fourfold S2I2 coordinate with almost regular trigonal-pyramidal environments. In the crystal, the layers, lying parallel to (102), are linked by C—H⋯I hydrogen bonds, forming a supra­molecular framework.

The synthesis and structural characterization of the mol­ecular compound (μ3-benzene-1,2-di­thiol­ato)hexa­carbonyl­bis­(μ3-1,1,1,4,4,4-hexafluorobut-2-ene-2,3-dithiolato)tricobaltmolybdenum, [Co3Mo(C4F6S2)2(C6H4S2)(CO)6] or Mo(tfd)2(bdt)(Co(CO)2)3 (tfd is 1,1,1,4,4,4-hexafluorobut-2-ene-2,3-dithiolate and bdt is benzene-1,2-di­thiol­ate), are reported. The structure of the mol­ecule contains the molybdenum tris­(di­thiol­ene) complex Mo(tfd)2(bdt) coordinated as a multidentate ligand to three cobalt dicarbonyl units. Each of the three cobalt centers is relatively close to molybdenum, with Co⋯Mo distances of 2.7224 (7), 2.8058 (7), and 2.6320 (6) Å. Additionally, each of the cobalt centers is bound via main-group donor atoms, but each one in a different way: the first cobalt atom is coordinated by two sulfur atoms from different di­thiol­enes (bdt and tfd). The second cobalt atom is coordinated by one sulfur from one tfd and two olefinic carbons from another tfd. The third cobalt is coordinated by one sulfur from bdt and two sulfurs from tfd. This is, to the best of our knowledge, the first structurally characterized example of a molybdenum (tris­)di­thiol­ene complex that coordinates to cobalt. The F atoms of two of the –CF3 groups were refined as disordered over two sets of sites with ratios of refined occupancies of 0.703 (7):0.297 (7) and 0.72 (2):0.28 (2).

Bidentate and tridentate coordination of a 2,4-di-tert-butyl-substituted bridging amine bis­(phenolate) ligand to a palladium(II) center are observed within the same crystal structure, namely di­chlorido­({6,6'-[(ethane-1,2-diylbis(methyl­aza­nedi­yl)]bis­(methyl­ene)}bis­(2,4-di-tert-butyl­phenol))palladium(II) chlorido­(2,4-di-tert-butyl-6-{[(2-{[(3,5-di-tert-butyl-2-hy­droxy­phen­yl)meth­yl](meth­yl)amino}­eth­yl)(meth­yl)amino]­meth­yl}phenolato)palladium(II) methanol 1.685-solvate 0.315-hydrate, [PdCl2(C34H56N2O2)][PdCl(C34H55N2O2)]·1.685CH3OH·0.315H2O. Both complexes exhibit a square-planar geometry, with unbound phenol moieties participating in inter­molecular hydrogen bonding with co-crystallized water and methanol. The presence of both κ2 and κ3 coordination modes arising from the same solution suggest a dynamic process in which phenol donors may coordinate or dissociate from the metal center, and offers insight into catalyst speciation throughout Pd-mediated processes. The unit cell contains di­chlorido­({6,6'-[(ethane-1,2-diylbis(methyl­aza­nedi­yl)]bis­(methyl­ene)}bis­(2,4-di-tert-butyl­phenol))palladium(II), {(L2)PdCl2}, and chlorido­(2,4-di-tert-butyl-6-{[(2-{[(3,5-di-tert-butyl-2-hy­droxy­phen­yl)meth­yl](methyl)amino}eth­yl)(meth­yl)amino]­meth­yl}phenolato)palladium(II), {(L2X)PdCl}, mol­ecules as well as fractional water and methanol solvent mol­ecules.

Four manganese(II) bromide coordination complexes have been prepared with four pyridine N-oxides, viz. pyridine N-oxide (PNO), 2-methyl­pyridine N-oxide (2MePNO), 3-methyl­pyridine N-oxide (3MePNO), and 4-methyl­pyridine N-oxide (4MePNO). The compounds are bis­(μ-pyridine N-oxide)bis­[aqua­dibromido­(pyridine N-oxide)manganese(II)], [Mn2Br4(C5H5NO)4(H2O)2] (I), bis­(μ-2-methyl­pyridine N-oxide)bis­[di­aqua­dibromido­manganese(II)]–2-methyl­pyridine N-oxide (1/2), [Mn2Br4(C6H7NO)2(H2O)4]·2C6H7NO (II), bis­(μ-3-methyl­pyridine N-oxide)bis­[aqua­dibromido­(3-methyl­pyridine N-oxide)manganese(II)], [Mn2Br4(C6H7NO)4(H2O)2] (III), and bis­(μ-4-methyl­pyridine N-oxide)bis­[di­bromido­methanol(4-methyl­pyridine N-oxide)manganese(II)], [Mn2Br4(C6H7NO)4(CH3OH)2] (IV). All the compounds have one unique MnII atom and form a dimeric complex that contains two MnII atoms related by a crystallographic inversion center. Pseudo-octa­hedral six-coordinate manganese(II) centers are found in all four compounds. All four compounds form dimers of Mn atoms bridged by the oxygen atom of the PNO ligand. Compounds I, II and III exhibit a bound water of solvation, whereas compound IV contains a bound methanol mol­ecule of solvation. Compounds I, III and IV exhibit the same arrangement of mol­ecules around each manganese atom, ligated by two bromide ions, oxygen atoms of two PNO ligands and one solvent mol­ecule, whereas in compound II each manganese atom is ligated by two bromide ions, one O atom of a PNO ligand and two water mol­ecules with a second PNO mol­ecule inter­acting with the complex via hydrogen bonding through the bound water mol­ecules. All of the compounds form extended hydrogen-bonding networks, and compounds I, II, and IV exhibit offset π-stacking between PNO ligands of neighboring dimers.

The crystal structures of the disordered hemi-DMSO solvate of (E)-2-oxo-N'-(3,4,5-tri­meth­oxy­benzyl­idene)-2H-chromene-3-carbohydrazide, C20H18N2O6·0.5C2H6OS, and (E)-N'-benzyl­idene-2-oxo-2H-chromene-3-carbohydrazide, C17H12N2O3 (4: R = C6H5), are discussed. The non-hydrogen atoms in compound [4: R = (3,4,5-MeO)3C6H2)] exhibit a distinct curvature, while those in compound, (4: R = C6H5), are essential coplanar. In (4: R = C6H5), C—H⋯O and π–π intra­molecular inter­actions combine to form a three-dimensional array. A three-dimensional array is also found for the hemi-DMSO solvate of [4: R = (3,4,5-MeO)3C6H2], in which the mol­ecules of coumarin are linked by C—H⋯O and C—H⋯π inter­actions, and form tubes into which the DMSO mol­ecules are cocooned. Hirshfeld surface analyses of both compounds are reported, as are the lattice energy and inter­molecular inter­action energy calculations of compound (4: R = C6H5).

A one-dimensional ladder-type coordination polymer, poly[[(μ2-hydroxido)(μ2-1H-pyrazole-3,5-di­carboxyl­ato)gallium(III)] monohydrate], [Ga(C5H2N2O4)(OH)(H2O)]n or [Ga(HPDC)(OH)(H2O)]n, I, isotypic with a V3+ coordination polymer previously reported by Chen et al. [J. Coord. Chem. (2008). 61, 3556–3567] was prepared from Ga3+ and pyrazole-3,5-di­carb­oxy­lic acid monohydrate (H3PDC·H2O). Compound I was isolated using three distinct experimental methods: hydro­thermal (HT), microwave-assisted (MWAS) and one-pot (OP) and the crystallite size should be fine-tuned according to the method employed. The coordination polymeric structure is based on a dimeric Ga3+ moiety comprising two μ2-bridging hydroxide groups, which are inter­connected by HPDC2− anionic organic linkers. The close packing of individual polymers is strongly directed by the supra­molecular inter­actions, namely several O—H⋯O and N—H⋯O hydrogen-bonding inter­actions.

The title hydrated mol­ecular salt (systematic name: tetra-n-butyl­ammonium 2,6-dioxo-1,2,3,6-tetra­hydro­pyrimidine-4-carboxyl­ate monohydrate), C16H36N+·C5H3N2O4−·H2O, crystallizes with N—H⋯O and O—H⋯O hydrogen-bonded double-stranded anti­parallel ribbons consisting of the hydro­philic orotate monoanions and water mol­ecules, separated by the bulky hydro­phobic cations. The hydro­phobic and hydro­philic regions of the structure are joined by weaker non-classical C—H⋯O hydrogen bonds. An accurate structure analysis conducted at T = 100 K is compared to a lower-resolution less accurate determination using data measured at T = 295 K. The results of both analyses are evaluated using a knowledge-based approach, and it is found that the less accurate room-temperature structure analysis provides geometric data that are similar to those derived from the accurate low-temperature analysis, with both sets of results consistent with previously analyzed structures. A minor disorder of one methyl group in the cation at low temperature was found to be slightly more complex at room temperature; while still involving a minor fraction of the structure, the disorder at room temperature was found to require a non-routine treatment, which is described in detail.

A zinc metal–organic framework, namely poly[bis­(N,N-di­ethyl­formamide)(μ4-naphthalene-2,6-di­carboxyl­ato)(μ2-naphthalene-2,6-di­carboxyl­ato)dizinc(II)], [Zn(C12H6O4)(C15H11NO)]n, built from windmill-type secondary building units and forming zigzag shaped two-dimensional stacked layers, has been solvothermally synthesized from naphthalene-2,6-di­carb­oxy­lic acid and zinc(II) acetate as the metal source in N,N-di­ethyl­formamide containing small amounts of formic acid.

A reaction of copper(II) carbonate and potassium 4-sulfo­benzoic acid in water acidified with hydro­chloric acid yielded two crystalline products. Tetra­aqua­bis­(4-carb­oxy­benzene­sulfonato)­copper(II) dihydrate, [Cu(O3SC6H4CO2H)2(H2O)4]·2H2O, (I), crystallizes in the triclinic space group Poverline{1} with the Cu2+ ions located on centers of inversion. Each copper ion is coordinated to four water mol­ecules in a square plane with two sulfonate O atoms in the apical positions of a Jahn–Teller-distorted octa­hedron. The carboxyl­ate group is protonated and not involved in coordination to the metal ions. The complexes pack so as to create a layered structure with alternating inorganic and organic domains. The packing is reinforced by several O—H⋯O hydrogen bonds involving coordinated and non-coordinated water mol­ecules, the carb­oxy­lic acid group and the sulfonate group. Hexa­aqua­copper(II) 4-carb­oxy­benzene­sulfonate, [Cu(H2O)6](O3SC6H4CO2H)2, (II), also crystallizes in the triclinic space group Poverline{1} with Jahn–Teller-distorted octa­hedral copper(II) aqua complexes on the centers of inversion. As in (I), the carboxyl­ate group on the anion is protonated and the structure consists of alternating layers of inorganic cations and organic anions linked by O—H⋯O hydrogen bonds. A reaction of silver nitrate and potassium 4-sulfo­benzoic acid in water also resulted in two distinct products that have been structurally characterized. An anhydrous silver potassium 4-carb­oxy­benzene­sulfonate salt, [Ag0.69K0.31](O3SC6H4CO2H), (III), crystallizes in the monoclinic space group C2/c. There are two independent metal sites, one fully occupied by silver ions and the other showing a 62% K+/38% Ag+ (fixed) ratio, refined in two slightly different positions. The coordination environments of the metal ions are composed primarily of sulfonate O atoms, with some participation by the non-protonated carboxyl­ate O atoms in the disordered site. As in the copper compounds, the cations and anions cleanly segregate into alternating layers. A hydrated mixed silver potassium 4-carb­oxy­benzene­sulfonate salt dihydrate, [Ag0.20K0.80](O3SC6H4CO2H)·2H2O, (IV), crystallizes in the monoclinic space group P21/c with the Ag+ and K+ ions sharing one unique metal site coordinated by two water mol­ecules and six sulfonate O atoms. The packing in (IV) follows the dominant motif of alternating inorganic and organic layers. The protonated carboxyl­ate groups do not inter­act with the cations directly, but do participate in hydrogen bonds with the coordinated water mol­ecules. (IV) is isostructural with pure potassium 4-sulfo­benzoic acid dihydrate.

The crystal structure of the title compound, [Ni3(C8H4O4)3(C3H7NO)4], is a two-dimensional coordination network formed by trinuclear linear Ni3(tp)3(DMF)4 units (tp = terephthalate = benzene-1,4-di­carboxyl­ate and DMF = di­methyl­formamide) displaying a characteristic coordination mode of acetate groups in polynuclear metal–organic compounds. Individual trinuclear units are connected through tp anions in a triangular network that forms layers. One of the DMF ligands points outwards and provides inter­actions with equivalent planes above and below, leaving the second ligand in a structural void much larger than the DMF mol­ecule, which shows positional disorder. Parallel planes are connected mainly through weak C—H⋯O, H⋯H and H⋯C inter­actions between DMF mol­ecules, as shown by Hirshfeld surface analysis.

In the paper by Gomes et al. [Acta Cryst. (2019), E75, 1403–1410], there was an error and omission in the author and affiliation list.

The title compound, C9H7.5NO·C7H3.5ClNO4, was analysed as a disordered structure over two states, viz. co-crystal and salt, accompanied by a keto–enol tautomerization in the base mol­ecule. The co-crystal is 4-chloro-2-nitro­benzoic acid–quinolin-4(1H)-one (1/1), C7H4ClNO4·C9H7NO, and the salt is 4-hy­droxy­quinolinium 4-chloro-2-nitro­benzoate, C9H8NO+·C7H3ClNO4−. In the compound, the acid and base mol­ecules are held together by a short hydrogen bond [O⋯O = 2.4393 (15) Å], in which the H atom is disordered over two positions with equal occupancies. In the crystal, the hydrogen-bonded acid–base units are linked by N—H⋯O and C—H⋯O hydrogen bonds, forming a tape structure along the a-axis direction. The tapes are stacked into a layer parallel to the ab plane via π–π inter­actions [centroid–centroid distances = 3.5504 (8)–3.9010 (11) Å]. The layers are further linked by another C—H⋯O hydrogen bond, forming a three-dimensional network. Hirshfeld surfaces for the title compound mapped over shape-index and dnorm were generated to visualize the inter­molecular inter­actions.

The polymeric title compound, [Cu2(C2H3N)2(C3H6S2)2](PF6)2, represents an example of a one-dimensional coordination polymer resulting from the reaction of [Cu(MeCN)4][PF6] with 1,3-di­thiol­ane. The cationic one-dimensional ribbon consists of two copper(I) centers each ligated by one aceto­nitrile mol­ecule and inter­connected through two bridging 1,3-di­thiol­ane ligands. One S-donor site of each ligand is κ1-bound to Cu, whereas the second S atom acts as a four-electron donor, bridging two Cu atoms in a κ4-bonding mode. The positive charge of each copper cation is compensated for by a hexa­fluorido­phosphate counter-ion. In the crystal, the polymer chains are linked by a series of C—H⋯F hydrogen bonds, forming a supra­molecular framework. The crystal studied was refined as a two-component twin.

Two new chalcones containing both pyrazole and thio­phene substituents have been prepared and structurally characterized. 3-(3-Methyl-5-phen­oxy-1-phenyl-1H-pyrazol-4-yl)-1-(thio­phen-2-yl)prop-2-en-1-one, C23H18N2O2S (I), and 3-[3-methyl-5-(2-methyl­phen­oxy)-1-phenyl-1H-pyrazol-4-yl]-1-(thio­phen-2-yl)prop-2-en-1-one, C24H20N2O2S (II), are isomorphous as well as isostructural, and in each the thio­phene substituent is disordered over two sets of atomic sites having occupancies 0.844 (3) and 0.156 (3) in (I), and 0.883 (2) and 0.117 (2) in (II). In each structure, the mol­ecules are linked into sheets by a combination of C—H⋯N and C—H⋯O hydrogen bonds. Comparisons are made with some related compounds.

In the title compound, di­aqua­bis­(ethyl­enedi­amine-κ2N,N')copper(II) bis­(2-nitro­benzoate), [Cu(C2H8N2)2(H2O)2](C7H4NO4)2, two di­aqua­bis­(ethyl­enedi­amine)­copper(II) cations and four nitro­benzoate anions are present in the asymmetric unit. All four anions are `whole-mol­ecule' disordered over two sets of sites. The major components have refined occupancies of 0.572 (13), 0.591 (9), 0.601 (9) and 0.794 (10). The CuII ions exhibit slightly distorted octa­hedral geometries. In the crystal, cations and anions are connected to each other via N—H⋯O and O—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (200). The inter­molecular contacts in the crystal were further analysed using Hirshfeld surface analysis, which indicates that the most significant contacts are O⋯H/H⋯O (42.9%), followed by H⋯H (35.7%), C⋯H/H⋯C (14.2%), C⋯C (2.9%), C⋯O/O⋯C (2.2%), N⋯H/H⋯N (0.9%) and N⋯O/O⋯N (0.3%).

A copper(II) dimer with the deprotonated anion of 2-bromo­nicotinic acid (2-BrnicH), namely, tetrakis(μ-2-bromonicotinato-κ2O:O')bis[aquacopper(­II)](Cu—Cu), [Cu2(H2O)2(C6H3BrNO2)4] or [Cu2(H2O)2(2-Brnic)4], (1), was prepared by the reaction of copper(II) chloride dihydrate and 2-bromo­nicotinic acid in water. The copper(II) ion in 1 has a distorted square-pyramidal coordination environment, achieved by four carboxyl­ate O atoms in the basal plane and the water mol­ecule in the apical position. The pair of symmetry-related copper(II) ions are connected into a centrosymmetric paddle-wheel dinuclear cluster [Cu⋯Cu = 2.6470 (11) Å] via four O,O'-bridging 2-bromo­nicotinate ligands in the syn-syn coordination mode. In the extended structure of 1, the cluster mol­ecules are assembled into an infinite two-dimensional hydrogen-bonded network lying parallel to the (001) plane via strong O—H⋯O and O—H⋯N hydrogen bonds, leading to the formation of various hydrogen-bond ring motifs: dimeric R22(8) and R22(16) loops and a tetra­meric R44(16) loop. The Hirshfeld surface analysis was also performed in order to better illustrate the nature and abundance of the inter­molecular contacts in the structure of 1.