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The organic–inorganic lead halide hybrids comprising semiconducting perovskite components and organic modules have proven to be promising candidates for optoelectronic applications. The modulation of the inorganic components as optical centres by diverse organic cationic templates is under intense investigation. Herein, we successfully prepared new one-dimensional lead halide hybrid perovskites [L1]2n[Pb2Cl6]n∞·nH2O (1) and [PbBr2(L2)]n∞·0.5nH2O (2), and the dimeric complex [PbBr2(L3)]2 (3) in water media. In 1, 2-(2-hydroxyethyl)-2H-imidazo[1,5-a]pyridinium cation [L1]+ resulted from the oxidative condensation–cyclization between formaldehyde, ethanolamine and 2-pyridinecarbaldehyde (2-PCA); the polydentate Schiff base ligands L2 and L3 formed in the in situ condensation of 2-PCA and ethanolamine or ethylenediamine, respectively. The lead chloride hybrid 1 contains the previously unreported type of a [Pb2Cl6]∞ double chain constructed from three-edge- and five-edge-sharing PbCl6 octahedra, and cations forming π-bonded stacks aligned along the inorganic wires. In the crystal of 2, pairs of the double-side organically decorated [PbBr2(L2)]∞ chains built of corner-sharing PbBr3N2O octahedra arrange hydrophilic channels to host water molecules. In the solid state, the identically stacked dimers of 3 form columns parallel to the ab plane with the Pb2Br4 moieties in the column being strictly coplanar. Hirshfeld surface analysis was used to rationalize the packing patterns through hydrogen bonds of O−H···O/Cl and C−H···O/Cl types with the involvement of OH groups of [L1]+, L2 and water molecules in 1 and 2, as well as C–H∙∙∙Br hydrogen bonding in 2 and 3. The QTAIM analysis of non-covalent interactions in 1–3 was performed. According to the analysis of the solid-state UV–visible reflectance spectra by a Tauc plot, the optical band gap values of 1, 2 and 3 as direct gap semiconductors were estimated to be 3.36, 3.13 and 2.96 eV, respectively. [ABSTRACT FROM AUTHOR]

The hybrid salt bis(2-methylimidazo[1,5-a]pyridin-2-ium) hexachloridostannate( IV), (C8H9N2)2[SnCl6], crystallizes in the monoclinic space group P21/n with the asymmetric unit containing an Sn0.5Cl3 fragment (Sn site symmetry 1) and one organic cation. The five- and six-membered rings in the cation are nearly coplanar; bond lengths in the pyridinium ring of the fused core are as expected; the C--N/C bond distances in the imidazolium entity fall in the range 1.337 (5)-1.401 (5) Å. The octahedral SnCl62- dianion is almost undistorted with the Sn--Cl distances varying from 2.4255 (9) to 2.4881 (8) Å and the cis Cl--Sn--Cl angles approaching 90°. In the crystal, π-stacked chains of cations and loosely packed SnCl62- dianions form separate sheets alternating parallel to (101). Most of the numerous C--H• • •Cl--Sn contacts between the organic and inorganic counterparts with the H• • •Cl distances above the van der Waals contact limit of 2.85 Å are considered a result of crystal packing. [ABSTRACT FROM AUTHOR]

Quaternary phosphonium salts are popular candidates used in many chemical transformations and synthetic chemistry, notably in catalysis. We have examined the single crystals of two bulky phosphonium compounds, tetra([1,1′-biphenyl]-4-yl) phosphonium dicyanamide (C48H36P+·N(CN)2−, compound 1), and tetra([1,1′-biphenyl]-4-yl) phosphonium bromide hydrate (C48H36P+·Br−, CH3CN, H2O, compound 2), and herein report the structural properties for the compounds with an emphasis on the influence of the ion-ion interaction towards self-assembly; the overall self-assembly for both structures is very similar, with subtle differences in the cell parameters. The symmetrical tetra ([1,1′-biphenyl]-4-yl) phosphonium cations in both compounds self-assembled to form robust stacked columns in the solid-state, with voids occupied by anions or solvent molecules. Quantitative examination of intermolecular interactions using Hirshfeld surface analysis found that classical and non-classical hydrogen bonding appears to be the dominant contributor in stabilizing the self-assembly in both cases. The present work can not only benefit in understanding the mutual interaction between the sterically encumbered tetra ([1,1′-biphenyl]-4-yl) phosphonium cations and between counterions, but also provide insights for the self-assembled arrays in the solid-state. [ABSTRACT FROM AUTHOR]

The title compound, [Fe(C3H7NO)6][Cd2Cl7], crystallizes in the trigonal space group R3̅ and is assembled from discrete [Fe(DMF)6] 3+ cations (DMF = N,Ndimethylformamide) and [Cd2Cl7] 3- anions. In the cation, the iron(III) atom, located on a special position of 3̅ site symmetry, is coordinated by six oxygen atoms from DMF ligands with all Fe—O distances being equal [2.0072 (16) A˚ ]. A slight distortion of the octahedral environment of the metal comes from the cis O—Fe—O angles deviating from the ideal value of 90 [86.85 (7) and 93.16 (7)] whilst all the trans angles are strictly 180. The central Cl atom of the [Cd2Cl7] 3- anion is also located on a special position of 3̅ site symmetry and bridges two corner sharing, tetrahedrally coordinated CdII atoms. The two Cd atoms and the central Cl atom are colinear. The two sets of terminal chloride ligands on either side of the dumbbell-like anion are rotated relative to each other by 30. In the crystal, the cations and anions, stacked one above the other along the c-axis direction, are held in place principally by electrostatic interactions. There are also C—H...Cl and C—H...O interactions, but these are rather weak. Of the six crystal structures reported to date for ionic salts of [Fe(DMF)6] n+ cations (n = 2, 3), five contain FeII ions. The title compound is the second example of a stable compound containing the [Fe(DMF)6] 3+ cation. The existence of both [Fe(DMF)6] 2+ and [Fe(DMF)6] 3+ cations shows that the DMF ligand coordination sphere can accommodate changes in the charge and spin states of the metal centre. [ABSTRACT FROM AUTHOR]

The monocation product of the oxidative condensation-cyclization between two molecules of pyridine-2-carbaldehyde and one molecule of CH3NH2·HCl in methanol, 2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridinium, was isolated in the presence of metal ions as bis[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] tetraiodocadmate, (C13H12N3)2[CdI4], (I), and the mixed chloride/nitrate salt, bis[2-methyl-3-(pyridin-2-yl)imidazo[1,5-a]pyridin-2-ium] 1.5-chloride 0.5-nitrate trihydrate, 2C13H12N3+·1.5Cl-·0.5NO3-·3H2O, (II). Hybrid salt (I) crystallizes in the space group P21/n with two [L]2[CdI4] molecules in the asymmetric unit related by pseudosymmetry. In the crystal of (I), layers of organic cations and of tetrahalometallate anions are stacked parallel to the ab plane. Antiparallel L+ cations disposed in a herring-bone pattern form π-bonded chains through aromatic stacking. In the inorganic layer, adjacent tetrahedral CdI4 units have no connectivity but demonstrate close packing of iodide anions. In the crystal lattice of (II), the cations are arranged in stacks propagating along the a axis; the one-dimensional hydrogen-bonded polymer built of chloride ions and water molecules runs parallel to a column of stacked cations. [ABSTRACT FROM AUTHOR]

The crystal structures of the α-alums rubidium chromium bis(­sulfate) dodecahydrate, RbCr(SO4)2·12H2O, and caesium chromium bis[tetraoxoselenate(VI)] dodecahydrate, CsCr(SeO4)2·12H2O, have been determined by X-ray diffraction at 293 and 12 K. The metal atoms lie on sites and the anions lie on threefold rotation axes. The accurate and extensive data sets lead to much more precise determinations than are available from earlier work, particularly at 12 K. The changes in the atomic displacement parameters between 293 and 12 K correspond to the respective predominances of intermolecular and intramolecular vibrational effects. [ABSTRACT FROM AUTHOR]

The crystal structure of the title compound, [ReCl4(C8H10N2)2], has been determined by X-ray diffraction at 11 K and by neutron diffraction at 20 K. The accurate and extensive data sets lead to more precise determinations than are available from earlier work. The agreement in atomic positional and displacement parameters at these very low temperatures is good. The results will facilitate re-examination of the magnetic structure of the complex. The Re atom lies on a special position and the molecule has twofold crystallographic symmetry. [ABSTRACT FROM AUTHOR]

Precise X-ray determinations of the crystal structure of the 1:2 complex of N-ethyl- N-methyl­morpholinium and 7,7,8,8-tetra­cyano- p-quinodi­methanide, abbreviated as MEM-TCNQ or MEM(TCNQ)2 (C7H16NO+·2C12H4N40.5−), have been performed at 293 and at 10 K. Evidence for the expected spin-Peierls transition at 19 K is not found, and this may follow from radiation damage to the crystal or from insufficient equipment sensitivity. [ABSTRACT FROM AUTHOR]

The crystal structure of Na2Fe(CN)5(NO)·2D2O, disodium penta­cyano­nitro­syl­ferrate(III) bis­(dideuterium oxide), has been determined by X-ray diffraction at 11 and 293 K, and by neutron diffraction at 15 K. The accurate and extensive data sets lead to more precise determinations than are available from earlier work. The agreement in atomic positional and displacement parameters between the determinations at low temperature is very good. [ABSTRACT FROM AUTHOR]

The crystal structure of dicaesium potassium hexacyanomanganese(III) has been determined by X-ray diffraction at 293, 85 and 10 K. The Mn and K atoms lie on inversion centres and the Cs atom is in a general position. The accurate and extensive data sets collected should be suitable for charge-density analysis studies. [ABSTRACT FROM AUTHOR]

The crystal structure of trisodium hexanitro­cobaltate(III) has been determined by X-ray diffraction at 293 and 10 K. It contains the slightly distorted octahedral Co(NO2)63− anion. [ABSTRACT FROM AUTHOR]

The title compound, (NH4)ZnPO4-HEX, is built up from a three-dimensional network of ZnO4 and PO4 tetrahedra [ dav(Zn-O) = 1.9400 (7) Å and dav(P-O) = 1.5396 (7) Å], fused together via Zn-O-P links [θav = 133.47 (4)°]. An undisordered linear Zn-O-P bond occurs (all three atoms lie on a threefold axis). Extra-framework NH4+ cations, which interact with the [ZnPO4]− framework by hydrogen bonds, complete the crystal structure. [ABSTRACT FROM AUTHOR]

The crystal structure of tricaesium cobalt pentachloride has been determined by X-ray diffraction at 10 K. The Co atom is at a site with symmetry, one Cs atom is at a site with 42 symmetry, the other has mm site symmetry, one Cl ligand has 4/ m symmetry and the other has m symmetry. The accurate and extensive data set collected should be suitable for charge-density analysis studies. In the CoCl42− ion, as the temperature is lowered, the Co-Cl bond length increases a little and the small distortion of the tetrahedron (site symmetry 2 m) is slightly reduced. [ABSTRACT FROM AUTHOR]

The crystal structure of tripotassium sodium hexa­chloro­ferrate(II) has been determined by X-ray diffraction at 293, 84 and 9.5 K. The accurate and extensive data sets collected should be suitable for charge-density analysis studies. [ABSTRACT FROM AUTHOR]

The hybrid salt bis-(2-methyl-imidazo[1,5- a ]pyridin-2-ium) hexa-chlorido-stannate(IV), (C 8 H 9 N 2 ) 2 [SnCl 6 ], crystallizes in the monoclinic space group P 2 1 / n with the asymmetric unit containing an Sn 0.5 Cl 3 fragment (Sn site symmetry ) and one organic cation. The five- and six-membered rings in the cation are nearly coplanar; bond lengths in the pyridinium ring of the fused core are as expected; the C-N/C bond distances in the imidazolium entity fall in the range 1.337 (5)-1.401 (5) Å. The octa-hedral SnCl 6 2- dianion is almost undistorted with the Sn-Cl distances varying from 2.4255 (9) to 2.4881 (8) Å and the cis Cl-Sn-Cl angles approaching 90°. In the crystal, π-stacked chains of cations and loosely packed SnCl 6 2- dianions form separate sheets alternating parallel to (101). Most of the numerous C-H⋯Cl-Sn contacts between the organic and inorganic counterparts with the H⋯Cl distances above the van der Waals contact limit of 2.85 Å are considered a result of crystal packing., (© Vassilyeva et al. 2023.)

The title compound, [Fe(C 3 H 7 NO) 6 ][Cd 2 Cl 7 ], crystallizes in the trigonal space group R and is assembled from discrete [Fe(DMF) 6 ] 3+ cations (DMF = N , N -di-methyl-formamide) and [Cd 2 Cl 7 ] 3- anions. In the cation, the iron(III) atom, located on a special position of site symmetry, is coordinated by six oxygen atoms from DMF ligands with all Fe-O distances being equal [2.0072 (16) Å]. A slight distortion of the octa-hedral environment of the metal comes from the cis O-Fe-O angles deviating from the ideal value of 90° [86.85 (7) and 93.16 (7)°] whilst all the trans angles are strictly 180°. The central Cl atom of the [Cd 2 Cl 7 ] 3- anion is also located on a special position of site symmetry and bridges two corner sharing, tetra-hedrally coordinated Cd II atoms. The two Cd atoms and the central Cl atom are colinear. The two sets of terminal chloride ligands on either side of the dumbbell-like anion are rotated relative to each other by 30°. In the crystal, the cations and anions, stacked one above the other along the c -axis direction, are held in place principally by electrostatic inter-actions. There are also C-H⋯Cl and C-H⋯O inter-actions, but these are rather weak. Of the six crystal structures reported to date for ionic salts of [Fe(DMF) 6 ] n + cations ( n = 2, 3), five contain Fe II ions. The title compound is the second example of a stable compound containing the [Fe(DMF) 6 ] 3+ cation. The existence of both [Fe(DMF) 6 ] 2+ and [Fe(DMF) 6 ] 3+ cations shows that the DMF ligand coordination sphere can accommodate changes in the charge and spin states of the metal centre., (© Vassilyeva et al. 2021.)

The monocation product of the oxidative condensation-cyclization between two mol-ecules of pyridine-2-carbaldehyde and one mol-ecule of CH 3 NH 2 ·HCl in methanol, 2-methyl-3-(pyridin-2-yl)imidazo[1,5- a ]pyridinium, was isolated in the presence of metal ions as bis-[2-methyl-3-(pyridin-2-yl)imidazo[1,5- a ]pyridin-2-ium] tetra-iodo-cadmate, (C 13 H 12 N 3 ) 2 [CdI 4 ], (I), and the mixed chloride/nitrate salt, bis-[2-methyl-3-(pyridin-2-yl)imidazo[1,5- a ]pyridin-2-ium] 1.5-chlor-ide 0.5-nitrate trihydrate, 2C 13 H 12 N 3 + ·1.5Cl - ·0.5NO 3 - ·3H 2 O, (II). Hybrid salt (I) crystallizes in the space group P 2 1 / n with two [ L ] 2 [CdI 4 ] mol-ecules in the asymmetric unit related by pseudosymmetry. In the crystal of (I), layers of organic cations and of tetra-halometallate anions are stacked parallel to the ab plane. Anti-parallel L + cations disposed in a herring-bone pattern form π-bonded chains through aromatic stacking. In the inorganic layer, adjacent tetra-hedral CdI 4 units have no connectivity but demonstrate close packing of iodide anions. In the crystal lattice of (II), the cations are arranged in stacks propagating along the a axis; the one-dimensional hydrogen-bonded polymer built of chloride ions and water mol-ecules runs parallel to a column of stacked cations.