Search

This study presents the synthesis, characterization and Hirshfeld surface analysis of a small organic ammonium salt, C 2 H 7 BrN + ·Br - . Small cations like the one in the title compound are considered promising components of hybrid perovskites, crucial for optoelectronic and photovoltaic applications. While the incorporation of this organic cation into various hybrid perovskite structures has been explored, its halide salt counterpart remains largely uninvestigated. The obtained structural results are valuable for the synthesis and phase analysis of hybrid perovskites. The title compound crystallizes in the solvent-free form in the centrosymmetric monoclinic space group P 2 1 / c , featuring one organic cation and one bromide anion in its asymmetric unit, with a torsion angle of -64.8 (2)° between the ammonium group and the bromine substituent, positioned in a gauche conformation. The crystal packing is predominantly governed by Br⋯H inter-actions, which constitute 62.6% of the overall close atom contacts., (© Semenikhin et al. 2024.)

In the crystal structure of the title compound, [Cu(NO 3 ) 2 (C 3 H 5 N 3 ) 4 ], the Cu II atom is situated on an inversion center (Wyckoff position 2 c of space group P 2 1 / n ) and shows an octa-hedral [N 4 O 2 ] coordination environment. The axial positions are occupied by O atoms of nitrate anions, while the equatorial positions are taken up by the N atoms of four 3-amino-pyrazole ligands. As a result of the tautomerism of the latter, two coordinate with the N 1 -atom of 3-amino-pyrazole while the other two with the N 2 -atom. The presence of pyrrole-like N-H groups and amine substituents as donor groups leads to numerous intra- and inter-molecular hydrogen-bonding inter-actions, which were qu-anti-fied by Hirshfeld surface analysis., (© Kucheriv et al. 2023.)

The crystal structure of the title salt, bis-(3-carb-oxy-1-methyl-pyridinium) octa-bromide, 2C 7 H 8 NO 2 + ·Br 8 2- , consists of 3-carb-oxy-1-methyl-pyridinium ( N -methyl-nicotinic acid) cations, which are stacked between relatively rare [Br 8 ] 2- anions. The polybromide [Br 8 ] 2- anions connected with a Br 3 mol-ecule in a - anions connected with a Br 2 mol-ecule in a Z anions through π⋯Br inter-actions that induce the creation of a supra-molecular tri-periodic network. In addition, the presence of weak C-H⋯Br contacts leads to the creation of layers, which align parallel to (11).8 ] 2- anions through π⋯Br inter-actions that induce the creation of a supra-molecular tri-periodic network. In addition, the presence of weak C-H⋯Br contacts leads to the creation of layers, which align parallel to (11)., (© Sirenko et al. 2023.)

In the title compound [Fe 2 (C 2 O 4 )(C 8 H 8 N 4 ) 4 ](CH 3 C 6 H 4 SO 3 ) 2 ·2.75H 2 O, the two Fe II ions have a highly distorted octa-hedral FeN 4 O 2 environment formed by two bidentate triazole-based chelating ligands and a bis-bidentate oxalate bridging anion that connects the metal ions. Stabilization within the crystal structure is provided via a system of O-H⋯O and N-H⋯O hydrogen bonding, which determines the formation of a two-dimensional architecture along the a- axis direction., (© Petrenko et al. 2022.)

In the title polymeric coordination compound, {[FePt(CN) 4 (H 2 O) 2 ]·1.33CH 3 OH} n , the Fe II cation (site symmetry 4/ mm.m ) is coordinated by the N atoms of four cyanide anions (CN - ) and the O atoms of two water mol-ecules, forming a nearly regular [FeN 4 O 2 ] octa-hedron. According the Fe-N and Fe-O bond lengths, the Fe II atom is in the high-spin state. The cyanide anions act in a bridging manner to connect the Fe II and Pt II atoms. The [Pt(CN) 4 ] 2- moieties (Pt with site symmetry 4/ mm.m ) have a perfect square-planar shape. The latter anion is located perpendicular to the FeN 4 plane, thus ensuring the creation of a three-dimensional framework. The crystal structure features methanol solvent mol-ecules of which 4/3 were located per Fe II cation. These solvent mol-ecules are located in hexa-gonal pores; they inter-act with coordinating water mol-ecules through weak hydrogen bonds. Other guest mol-ecules could not be modelled in a satisfactory way and their contribution to the scattering was removed by a mask procedure., (© Hiiuk et al. 2022.)

9-Amino-acridinium chloride N , N -di-methyl-formamide monosolvate, C 13 H 11 N 2 + Cl - ·C 3 H 7 NO, crystallizes in the monoclinic space group P 2 1 / c. The salt was crystallized from N , N -di-methyl-formamide. The asymmetric unit consists of two C 13 H 11 N 2 + Cl - -di-methyl-formamide mol-ecule by a hydrogen bond. The H atoms of the amino groups create short contacts with two chloride ions. The 9-AA cations in adjacent layers are oriented in an anti-parallel manner. The mol-ecules are linked N a network of multidirectional π-π inter-actions between the 9-AA rings, and the whole lattice is additionally stabilized by electrostatic inter-actions between ions.N -di-methyl-formamide mol-ecule by a hydrogen bond. The H atoms of the amino groups create short contacts with two chloride ions. The 9-AA cations in adjacent layers are oriented in an anti-parallel manner. The mol-ecules are linked via a network of multidirectional π-π inter-actions between the 9-AA rings, and the whole lattice is additionally stabilized by electrostatic inter-actions between ions., (© Fritsky et al. 2021.)

In the title compound [Fe(bpe)(Hbpe)Au(CN) 2 ][Au(CN) 2 ] 2 ·bpe·2H 2 O} n [where bpe = 1,2-bis-(pyridin-4-yl)ethene, C 12 H 10 N 2 ], the Fe II ion is coordinated in a distorted octa-hedral [FeN 4 O 2 ] environment by two di-cyano-aurate anions, two water mol-ecules and two partially protonated 1,2-di(4-pyrid-yl)ethyl-ene mol-ecules. Di-cyano-aurate anions bridge the Fe II cations, forming infinite chains, which propagate along the a- axis direction. The chains are connected via aurophilic inter-actions with two non-coordinated di-cyano-aurate anions for each Fe II ion. The polymeric chains inter-act with each other via π-π stacking between the guest bpe mol-ecules and multiple hydrogen bonds., (© Partsevska et al. 2020.)

In the asymmetric unit of the title coordination compound, {[Cu(CN)(C 4 H 3 OC 2 H 5 N 2 )][Cu(CN)]} n , there are two Cu atoms with different coordination environments. One Cu I ion is coordinated in a triangular coordination geometry by the N atom of the 2-eth-oxy-pyrazine mol-ecule and by two bridging cyanide ligands, equally disordered over two sites exchanging C and N atoms, thus forming polymeric chains parallel to the c axis. The other Cu atom is connected to two bridging cyanide groups disordered over two sites with an occupancy of 0.5 for each C and N atom, and forming an almost linear polymeric chain parallel to the b axis. In the crystal, the two types of chain, which are orthogonal to each other, are connected by cuprophilic Cu⋯Cu inter-actions [2.7958 (13) Å], forming two-dimensional metal-organic coordination layers parallel to the bc plane. The coordination framework is further stabilized by weak long-range (electrostatic type) C-H⋯π inter-actions between cyano groups and 2-eth-oxy-pyrazine rings., (© Partsevska et al. 2019.)

In the title polymeric complex, {[FePt(CN) 4 (H 2 O) 2 ]·2C 3 H 6 O} n , the Fe II cation has an octa-hedral [FeN 4 O 2 ] geometry being coordinated by two water mol-ecules and four cyanide anions. The Pt cation is located on an inversion centre and has a square-planar coordination environment formed by four cyanide groups. The tetra-cyano-platinate anions bridge the Fe II cations to form infinite two-dimensional layers that propagate in the bc plane. Two guest mol-ecules of acetone per Fe II are located between the layers. These guest acetone mol-ecules inter-act with the coordinated water mol-ecules by O-H⋯O hydrogen bonds., (© Kuzevanova et al. 2019.)

In the title metal-organic framework, [Fe(C 6 H 8 N 2 ) 2 {Cu(CN) 2 } 2 ] n , the low-spin Fe II ion lies at an inversion centre and displays an elongated octa-hedral [FeN 6 ] coordination environment. The axial positions are occupied by two symmetry-related bridging 2-ethyl-pyrazine ligands, while the equatorial positions are occupied by four N atoms of two pairs of symmetry-related cyanide groups. The Cu I centre is coordinated by three cyanide carbon atoms and one N atom of a bridging 2-ethyl-pyrazine mol-ecule, which form a tetra-hedral coordination environment. Two neighbouring Cu atoms have a short Cu⋯Cu contact [2.4662 (7) Å] and their coordination tetra-hedra are connected through a common edge between two C atoms of cyanide groups. Each Cu 2 (CN) 2 unit, formed by two neighbouring Cu atoms bridged by two carbons from a pair of μ-CN groups, is connected to six Fe II centres via two bridging 2-ethyl-pyrazine mol-ecules and four cyanide groups, resulting in the formation of a polymeric three-dimensional metal-organic coordination framework.

In the title polymeric complex, {[Fe(CN) 2 (C 10 H 8 N 2 ) 2 (H 2 O) 2 ][Au(CN) 2 ]} n , the Fe II ion, which is located on a twofold rotation axis, has a slightly distorted FeN 4 O 2 octa-hedral geometry. It is coordinated by two phenyl-pyrazine mol-ecules, two water mol-ecules and two di-cyano-aurate anions, the Au atom also being located on a second twofold rotation axis. In the crystal, the coordinated di-cyano-aurate anions bridge the Fe II ions to form polymeric chains propagating along the b -axis direction. In the crystal, the chains are linked by O water -H⋯N di-cyano-aurate anions hydrogen bonds and aurophillic inter-actions [Au⋯Au = 3.5661 (3) Å], forming layers parallel to the bc plane. The layers are linked by offset π-π stacking inter-actions [inter-centroid distance = 3.643 (3) Å], forming a supra-molecular metal-organic framework.

In the title metal-organic framework, [Fe(C 4 H 3 BrN 2 ) 2 {Cu(CN) 2 } 2 ] n , the Fe II cation is located on an inversion center and has a slightly elongated octa-hedral coordination environment [FeN 6 ], ligated by two pyrazine N atoms of symmetry-related bridging 2-bromo-pyrazine mol-ecules in the axial positions and by four N atoms of pairs of symmetry-related cyanido groups in the equatorial positions. The Cu I center has a fourfold coordination environment [CuC 3 N], with an almost perfect trigonal-pyramidal geometry, formed by three cyanido C atoms and an N atom of a bridging 2-bromo-pyrazine mol-ecule. Copper(I) centers related by a twofold rotation axis are bridged by two carbon atoms from a pair of μ-CN groups, resulting in Cu 2 (CN) 2 units. Each Cu 2 (CN) 2 unit is linked to six Fe II cations via a pair of linear CN units, the pair of μ-CN groups and two bridging 2-bromo-pyrazine ligands, resulting in the formation of a metal-organic framework, which is additionally stabilized by the short Cu⋯Cu contacts of 2.4450 (7) Å.

In the title polymeric complex, {[Fe(C 12 H 10 N 2 ) 2 (H 2 O) 4 ](CH 3 C 6 H 4 SO 3 ) 2 ·2CH 3 OH} n , the Fe II cation, located on an inversion centre, is coordinated by four water mol-ecules in the equatorial positions and two 1,2-bis-(pyridin-4-yl)ethene mol-ecules in the axial positions. This results in a distorted octa-hedral geometry for the [N 2 O 4 ] coordination polyhedron. The 1,2-bis-(pyridin-4-yl)ethene mol-ecules bridge the Fe II cations, forming polymeric chains running along the a- axis direction. Stabilization of the crystal structure is provided by O-H⋯O hydrogen bonds; these are formed by coordinated water mol-ecules as donors towards the O atoms of the methanol mol-ecules and tosyl-ate anions as acceptors of protons, leading to the formation of a three-dimensional supra-molecular network. Weak C-H⋯O hydrogen bonds are also observed in the crystal.

In the title polymeric complex, [Au 2 Fe(CN) 4 (C 4 H 3 IN 2 ) 2 (C 2 H 6 O)] n , the Fe II cation is coordinated by two iodo-pyrazine mol-ecules, one ethanol mol-ecule and three di-cyano-aurate anions in a distorted N 5 O octa-hedral geometry. In the crystal, the di-cyano-aurate anions bridge the Fe II cations to form polymeric chains propagating along the b- axis direction. Stabilization of the crystal structure is provided by O-H⋯N hydrogen bonds and π-π stacking between parallel iodo-pyrazine rings of neighbouring chains, the centroid-centroid distances being 3.654 (10) and 3.658 (9) Å.

The title salt, [Fe(II)(C4H3ClN2)2(H2O)4](C7H7O3S)2, contains a complex cation with point group symmetry 2/m. The high-spin Fe(II) cation is hexa-coordinated by four symmetry-related water and two N-bound 2-chloro-pyrazine mol-ecules in a trans arrangement, forming a distorted FeN2O4 octa-hedron. The three-dimensional supra-molecular structure is supported by inter-molecular O-H⋯O hydrogen bonds between the complex cations and tosyl-ate anions, and additional π-π inter-actions between benzene and pyrazine rings. The methyl H atoms of the tosyl-ate anion are equally disordered over two positions.

In the crystal of the title compound, [Fe(NCS)3(H2O)3]·3C6H8N2, the Fe(III) cation is located on a threefold rotation axis and is coordinated by three N atoms of the thiocyanate anions and three water mol-ecules in a fac arrangement, forming a slightly distorted N3O3 octa-hedron. Stabilization within the crystal structure is provided by O-H⋯N hydrogen bonds; the H atoms from coordinating water mol-ecules act as donors to the N atoms of guest 2,3-di-methyl-pyrazine mol-ecules, leading to a three-dimensional supra-molecular framework.