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The unit cell of the title compound, [Ni(C16H10ClN6)2]·2CH3OH, consists of a neutral complex and two methanol mol­ecules. In the complex, the two tridentate 2-(3-(4-chloro­phen­yl)-1H-1,2,4-triazol-5-yl)-6-(1H-pyrazol-1-yl)pyridine ligands coordinate to the central NiII ion through the N atoms of the pyrazole, pyridine and triazole groups, forming a pseudo­octa­hedral coordination sphere. Neighbouring tapered mol­ecules are linked through weak C—H(pz)⋯π(ph) inter­actions into monoperiodic chains, which are further linked through weak C—H⋯N/C inter­actions into diperiodic layers. The inter­molecular contacts were qu­anti­fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H⋯H 32.8%, C⋯H/H⋯C 27.5%, N⋯H/H⋯N 15.1%, and Cl⋯H/H⋯Cl 14.0%. The average Ni—N bond distance is 2.095 Å. Energy framework analysis at the HF/3–21 G theory level was performed to qu­antify the inter­action energies in the crystal structure. [ABSTRACT FROM AUTHOR]

The reaction of cadmium iodide with 3-amino­pyrazole (3-apz) in ethano­lic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, catena-poly[[di­iodido­cadmium(II)]-bis­(μ-3-amino-1H-pyrazole)-κ²N²:N³;κ²N³:N²], [CdI2(C3H5N3)2]n or [CdI2(3-apz)2]n. Its asymmetric unit consists of a half of a Cd2+ cation, an iodide anion and a 3-apz mol­ecule. The Cd2+ cations are coordinated by two iodide anions and two 3-apz ligands, generating trans-CdN4I2 octa­hedra, which are linked into chains by pairs of the bridging ligands. In the crystal, the ligand molecules and iodide anions of neighboring chains are linked through inter­chain hydrogen bonds into a di-periodic network. The inter­molecular contacts were qu­anti­fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative quantitative contributions of the weak inter­molecular contacts. [ABSTRACT FROM AUTHOR]

The reaction of cadmium iodide with 3-amino­pyrazole (3-apz) in ethano­lic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, catena-poly[[di­iodido­cadmium(II)]-bis­(μ-3-amino-1H-pyrazole)-κ²N²:N³;κ²N³:N²], [CdI2(C3H5N3)2]n or [CdI2(3-apz)2]n. Its asymmetric unit consists of a half of a Cd2+ cation, an iodide anion and a 3-apz mol­ecule. The Cd2+ cations are coordinated by two iodide anions and two 3-apz ligands, generating trans-CdN4I2 octa­hedra, which are linked into chains by pairs of the bridging ligands. In the crystal, the ligand mol­ecules and iodide anions of neighboring chains are linked through inter­chain hydrogen bonds into a di-periodic network. The inter­molecular contacts were qu­anti­fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative qu­anti­tative contributions of the weak inter­molecular contacts. [ABSTRACT FROM AUTHOR]

Octahedrally coordinated spin crossover (SCO) FeII complexes represent an important class of switchable molecular materials. This study presents the synthesis and characterisation of a novel complex, [FeII(ppt-2Fph)2]0·2MeOH, where ppt-2Fph is a new asymmetric ionogenic tridentate planar ligand 2-(5-(2-fluorophenyl)-4H-1,2,4-triazol-3-yl)-6-(1H-pyrazol-1-yl)pyridine. The complex exhibits a hysteretic thermally induced SCO transition at 285 K on cooling and at 293 K on heating, as well as light induced excited spin state trapping (LIESST) at lower temperatures with a relaxation T(LIESST) temperature of 73 K. Single crystal analysis in both spin states shows that the compound undergoes an unusual partial (25%) reversible order–disorder of the asymmetrically substituted phenyl group coupled to the thermal SCO. The highly cooperative SCO transition, analysed by structural energy framework analysis at the B3LYP/6-31G(d,p) theory level, revealed the co-existence of stabilising and destabilising energy variations in the lattice. The observed antagonism of intermolecular interactions and synchronous rotational disorder, which contributes to the overall entropy change, is suggested to be at the origin of the cooperative SCO transition. [ABSTRACT FROM AUTHOR]

Chemical composition is leading among the numerous factors that determine the spin transition properties of coordination compounds. Classic dicyanometallic bridges {M(CN)2}− are commonly used to build Hofmann-like spin-crossover frameworks, but some extended bridges are also synthetically available. In this paper, we describe a successful synthesis of two very similar spin-crossover frameworks that differ in the cyanometallic bridges involved, namely [Fe(etpz)2{Ag(CN)2}2] (1) and {Fe(etpz)2[Ag2(CN)3][Ag(CN)2]} (2) (where etpz = 2-ethylpyrazine). Magnetic and Mössbauer studies demonstrated the occurrence of abrupt one-step high-spin (HS) ↔ low-spin (LS) transitions for both complexes. The spin transition temperatures are T1/2 ↓ = 233 K and T1/2 ↑ = 243 K for 1 and T1/2 ↓ = 188 K and T1/2 ↑ = 191 K for 2 with thermal hysteresis loops of 10 K for 1 and 3 K for 2. The bridging mononuclear [Ag(CN)2]− units and FeII cations assemble to form infinite 2D layers in the structure of 1. Interestingly, compound 2 forms 2D layers of FeII cations bridged by both binuclear [Ag2(CN)3]− and mononuclear [Ag(CN)2]− units. The structures of 1 and 2 comprise different types of intermolecular interactions including Ag⋯Ag and Ag⋯Netpz, which induce the creation of supramolecular 3D frameworks. The synergy between metallophilic interactions and the spin transition is also confirmed by the variation of Ag⋯Ag distances during spin crossover. The characterization of such analogues allowed us to analyze in detail the effect of the cyanometallic bridge on the structure of new frameworks and on the bistability in Hofmann-like complexes. [ABSTRACT FROM AUTHOR]

The synthetic availability of molecular water oxidation catalysts containing highvalent ions of 3d metals in the active site is a prerequisite to enabling photo- and electrochemical water splitting on a large scale. Herein, the synthesis and crystal structure of diammonium {μ-1,3,4,7,8,10,12,13,16,17,19,22-dodecaazatetracyclo[ 8.8.4.1³,17.18,12]tetracosane-5,6,14,15,20,21-hexaonato}ferrate(IV) acetic acid trisolvate, (NH4)2[FeIV(C12H12N12O6)]·3CH3COOH or (NH4)2[FeIV(L-6H)]·3CH3COOH is reported. The FeIV ion is encapsulated by the macropolycyclic ligand, which can be described as a dodeca-aza-quadricyclic cage with two capping triazacyclohexane fragments making three five- and six sixmembered alternating chelate rings with the central FeIV ion. The local coordination environment of FeIV is formed by six deprotonated hydrazide nitrogen atoms, which stabilize the unusual oxidation state. The FeIV ion lies on a twofold rotation axis (multiplicity 4, Wyckoff letter e) of the space group C2/c. Its coordination geometry is intermediate between a trigonal prism (distortion angle φ = 0°) and an antiprism (φ = 60°) with φ = 31.1°. The Fe--N bond lengths lie in the range 1.9376 (13)-1.9617 (13) Å, as expected for tetravalent iron. Structure analysis revealed that three acetic acid molecules additionally cocrystallize per one iron(IV) complex, and one of them is positionally disordered over four positions. In the crystal structure, the ammonium cations, complex dianions and acetic acid molecules are interconnected by an intricate system of hydrogen bonds, mainly via the oxamide oxygen atoms acting as acceptors. [ABSTRACT FROM AUTHOR]

The reaction of cadmium bromide tetra­hydrate with 3-amino­pyrazole (3-apz) in ethano­lic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, catena-poly[[di­bromido­cadmium(II)]-bis­(μ-3-amino-1H-pyrazole)-κ²N³:N²;κ²N²:N³], [CdBr2(C3H5N3)2]n or [CdBr2(3-apz)2]n. Its asymmetric unit consists of a half of a Cd2+ cation, a bromide anion and a 3-apz mol­ecule. The Cd2+ cations are coordinated by two bromide anions and two 3-apz ligands, generating trans-CdN4Br2 octa­hedra, which are linked into chains by pairs of the bridging ligands. In the crystal, the ligand mol­ecules and bromide anions of neighboring chains are linked through inter­chain hydrogen bonds into a two-dimensional network. The inter­molecular contacts were qu­anti­fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative qu­anti­tative contributions of the weak inter­molecular contacts. [ABSTRACT FROM AUTHOR]

The title compound, [FeLi2(C12H12N12O6)(H2O)4]⋅4H2O, consists of iron complex anions, lithium cations and water molecules. The complex anion shows a clathrochelate topology. The coordination geometry of the FeIV centre is intermediate between a trigonal prism and a trigonal antiprism. In the crystal, the complex anions are connected through two Li cations into dimers, which are connected by Li--O bonds, forming infinite chains along the b-axis direction. [ABSTRACT FROM AUTHOR]

The unit cell of the title compound, [Fe(C18H15N6O2)2]•2CH3OH•2CHCl3, consists of a charge-neutral complex molecule, two methanol and two chloroform molecules. In the complex, the two tridentate 2-(5-(3,4-dimethoxyphenyl)-1,2,4-triazol-3-yl)-6-(pyrazol-1-yl)pyridine ligands coordinate to the central FeII ion through the N atoms of the pyrazole, pyridine and triazole groups, forming a pseudo-octahedral coordination sphere. Neighbouring tapered molecules are linked through weak C--H(pz)• • •π(ph) interactions into one-dimensional chains, which are joined into two-dimensional layers through weak C--H• • •N/C/ O interactions. Furthermore, the layers stack in a three-dimensional network linked by weak interlayer C--H• • •π interactions of the methoxy and phenyl groups. The intermolecular contacts were quantified using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H• • •H 32.0%, H• • •C/C• • •H 26.3%, H• • •N/N• • •H 13.8%, and • • •O/O• • •H 7.5%. The average Fe--N bond distance is 2.185 Å, indicating the high-spin state of the FeII ion. Energy framework analysis at the HF/3-21 G theory level was performed to quantify the interaction energies in the crystal structure. [ABSTRACT FROM AUTHOR]

Lead halide hybrid perovskites incorporating chiral organic cations attract considerable attention due to their promising application in multifarious optoelectronic devices. However, the examples of chiral hybrid perovskites are still limited, which greatly impedes their further studies in various optoelectronic fields. Herein, we report on new low-dimensional lead-halide hybrid perovskites incorporating the enantiopure chiral α-amino acid L -proline. Two hybrid perovskites (L -proH)PbBr3·H2O (Pro-PbBr3) and (L -proH)4Pb3Br10·4H2O (Pro-Pb3Br10) have been synthesized by employing different ratios of organic and inorganic precursors. According to structural analysis, the inorganic sublattice of compound Pro-PbBr3 is built of one-dimensional (1D) [PbX3]∞n− lead halide chains, whereas the inorganic sublattice of compound Pro-Pb3Br10 is built upon a rare two-dimensional (2D) [Pb3Br10]∞4n− honeycomb-type inorganic framework. Hirshfeld surface analysis revealed an important role of various hydrogen bonding interactions in providing the binding between organic and inorganic parts of these hybrid perovskites. The optical band gap values of new hybrid perovskites as estimated using the Tauc plot approach are 4.19 eV (Pro-PbBr3) and 4.13 eV (Pro-Pb3Br10). Also, new compounds display low-temperature broadband photoluminescence which can be attributed to the self-trapped excitons. These results show the potential of α-proline for constructing novel and highly demanded chiral hybrid perovskites, which will hold great promise for further optoelectronic applications. [ABSTRACT FROM AUTHOR]

Using the direct synthesis method, by oxidative dissolution of copper powder in the presence of CuBr2 and C5H8N2 (3,5-dimethyl-1H-pyrazole), three different types of crystals were formed, isolated, and identified. Three new coordination compounds, trinuclear [Cu3(µ3-OH)( µ2-C5H7N2Br)( µ2-Br)3(C5H8N2)5Br]⋅CHCh (where C5H7N2Br - 4-bromo-3,5-dimethylpyrazole) (1) (orthorhombic, Pnma), binuclear [Cu2(µ2-C5H7N2Br)( µ2-Br)( C5H7N2)4Br2]⋅2CHCl3 (2) (monoclinic, C2/c) and mononuclear [CuBr2( C5H7N2)3] (3) (triclinic, PI), have been obtained. According to the single-crystal X-ray diffraction analysis, the complex 1 is a trinuclear six-membered cycle, where copper atoms are connected by three types of bridges: µ2-bromide ions, µ2-4-bromo-3,5-dimethylpyrazole molecule, and µ3-hydroxo group. The binuclear complex 2 is formed due to a connection between two copper atoms by a bidentate-bridging bromide ion and a bridged 4-brominated 3,5-dimethylpyrazole molecule. Coordination compound 3 is a mono-nuclear trigonal-bipyramidal copper(II) complex. During the reaction, some part of 3,5-dimethylpyrazole molecules was brominated in the 4th position of the pyrazole ring. The Hirshfeld surface analysis reveals that the inter- molecular H⋯H contacts have the highest contribution to the crystal packing of all compounds: 66.9 % for 1, 54.4 % for 2, and 66.5 % for 3. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, [FeII(C16H9Cl2N6)2]·2CH3OH, consists of half of a charge-neutral complex molecule and a discrete methanol molecule. The planar anionic tridentate ligand 2-[5-(3,5-dichlorophenyl)-4H-1,2,4-triazol-3-ato]-6-(1H-pyrazol-1-yl)pyridine coordinates to the FeII ion through the N atoms of the pyrazole, pyridine and triazole groups, forming a coordination sphere of the central ion that deviates moderately from an octahedral geometry. The average Fe--N bond distance is 1.953 A °, indicating the low-spin state of the FeII ion. The cone-like-shaped molecules, nested into each other, are linked through double weak C--H(pz)· · ·π(ph) interactions into mono-periodic columns, which are further linked through weak C--H· · ·N'/C' interactions into di-periodic layers. The layers interact through double weak C-H(ph)· · ·Cl bonds with neighbouring molecules. Energy framework analysis at the B3LYP/6-31 G(d,p) theory level reproduces the strong interaction within the layers and the weaker interlayer interactions. Intermolecular contacts were quantified using Hirshfeld surface analysis and two-dimensional fingerprint plots, the relative contributions of the contacts to the crystal packing being H· · ·H 26.1%, H· · ·C/C· · ·H 24.4%, H· · ·Cl/Cl· · ·H 18.9% and H· · ·N/N· · ·H 12.1%. [ABSTRACT FROM AUTHOR]

The unit cell of the title compound, [FeII(C17H12BrN6O)2].2MeOH, consists of a charge-neutral complex molecule and two independent molecules of methanol. In the complex molecule, the two tridentate ligand molecules 2-[5-(3-bromo-4-methoxyphenyl)-4H-1,2,4-triazol-3-yl]-6-(1H-pyrazol-1-yl)pyridine coordinate to the FeII ion through the N atoms of the pyrazole, pyridine and triazole groups, forming a pseudo-octahedral coordination sphere around the central ion. In the crystal, neighbouring asymmetric molecules are linked through weak C--H(pz)...π(ph) interactions into chains, which are then linked into layers by weak C-H···N/C interactions. Finally, the layers stack into a three-dimensional network linked by weak interlayer C--H...π interactions between the methoxy groups and the phenyl rings. The intermolecular contacts were quantified using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative contributions of the contacts to the crystal packing to be H...H 34.2%, H...C/C...H 25.2%, H...Br/Br...H 13.2%, H....N/N....H 12.2% and H·O/O...H 4.0%. The average Fe--N bond distance is 1.949 A °, indicating the lowspin state of the FeII ion. Energy framework analysis at the HF/3-21 G theory level was performed to quantify the interaction energies in the crystal structure. [ABSTRACT FROM AUTHOR]

9-Amino­acridinium chloride N,N-di­methyl­formamide monosolvate, C13H11N2+Cl−·C3H7NO, crystallizes in the monoclinic space group P21/c. The salt was crystallized from N,N-di­methyl­formamide. The asymmetric unit consists of two C13H11N2+Cl− formula units. The 9-amino­acridinium (9-AA) mol­ecules are protonated with the proton on the N atom of the central ring. This N atom is connected to an N,N-di­methyl­formamide mol­ecule 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 anti­parallel manner. The mol­ecules are linked via a network of multidirectional π–π inter­actions between the 9-AA rings, and the whole lattice is additionally stabilized by electrostatic inter­actions between ions. [ABSTRACT FROM AUTHOR]

Mn cage complexes are rare, and the ones successfully isolated in the solid state are not stable in water and organic solvents. Herein, we present the first report of mononuclear Mn clathrochelates, in which the encapsulated metal exists in the oxidation state +4. The complexes are extremely stable in the crystalline state and in solutions and show rich redox chemistry. [ABSTRACT FROM AUTHOR]

Chiral hybrid organic–inorganic perovskites (HOIPs) attract attention due to their potential for application in optoelectronic, spintronic and photovoltaic devices. However, to this day the range of available chiral HOIPs is still scarce. In this context, we synthesized and thoroughly characterized two pairs of enantiomeric HOIPs incorporating enantiopure α-alanine, the simplest chiral amino acid: (AlaH)PbX3 (Ala = R-alanine or S-alanine, X = Br or I). Single-crystal XRD measurements revealed an unusual 2D anionic motif, which consists of haloplumbate octahedra bonded together in an edge-sharing manner along the c axis and in a corner-sharing manner along the b axis. Four compounds undergo melting/crystallization at unusually low temperatures. New compounds also display photoluminescence in the visible range: 380–640 nm (X = Br) and 480–640 nm (X = I). Electronic spectroscopy reveals an optical response typical for semiconductive materials with optical band gaps of 3.12 eV (X = Br) and 2.48 eV (X = I). These results show that the incorporation of simple and easily accessible α-alanine (and other chiral amino acids) as a cationic part is an efficient way for obtaining highly demanding chiral HOIPs. [ABSTRACT FROM AUTHOR]

Hofmann-like cyanometallic complexes represent one of the biggest and well-known classes of FeII spin-crossover compounds. In this paper, we report on the first FeII Hofmann clathrate analogues with unsubstituted 1,2,3-triazole, which exhibit temperature induced spin transition. Two new coordination polymers with the general formula [FeII(1,2,3-triazole)2MII(CN)4] (M = Pt, Pd) undergo abrupt hysteretic spin crossover in the range of 190–225 K as revealed by magnetic susceptibility measurements. Two compounds are isostructural and are built of infinite cyanometallic layers which are supported by 1,2,3-triazole ligands. The thermal hysteresis loop is very stable at different scan rates from 0.5 to 10 K min−1. The compounds display strong thermochromic effect, changing their colour from pink in the low-spin state to white in the high-spin state. Our findings show that 1,2,3-triazole is suitable for elaboration of spin-crossover Hofmann clathrate analogues, and its use instead of more classical azines can advantageously expand this family of complexes. [ABSTRACT FROM AUTHOR]

Spin‐crossover complexes form one of the biggest families of switchable compounds. Here we show a new way to obtain spin‐crossover materials by direct synthesis from metallic iron. Four complexes of FeII with 4‐R‐1,2,4‐triazoles have been synthesized by a direct metal oxidation: [Fe(NH2trz)3]SO4, [Fe(NH2trz)3](BF4)2 and two polymorphs of [Fe(Htrz)2(trz)]BF4. Surprisingly high quality of PXRD pattern of [Fe(NH2trz)3]SO4 allowed to perform Rietveld refinement and obtain reliable crystal structure of the latter. All compounds have been studied by magnetic susceptibility measurements, optical reflectivity, differential scanning calorimetry and Raman spectroscopy. Importantly, spin‐crossover characteristics of the complexes obtained by this unusual method are preserved, thus revealing a new effective approach of "direct synthesis" towards switchable coordination compounds. [ABSTRACT FROM AUTHOR]

Two new 2D spin-crossover (SCO) analogues of Hofmann clathrates of composition [Fe(phth)2MII(CN)4] (where phth = phthalazine; MII = Pd, Pt) have been synthesized and their structures and switchable behaviour have been characterized. Single-crystal X-ray analysis reveals that the Pt and Pd derivatives contain FeII centres equatorially surrounded by four equivalent μ4-[MII(CN)4]2− groups. Two crystallographically equivalent phthalazine (phth) ligands occupy the axial positions of each FeII site, completing its octahedral coordination environment. The stabilization of these structures is realized via supramolecular C–H⋯M interactions and π–π stacking. Temperature-dependent magnetic susceptibility measurements showed that Pt (T1/2↓ = 211 K and T1/2↑ = 218 K) and Pd (T1/2↓ = 202 K and T1/2↑ = 207 K) derivatives display cooperative spin crossover with narrow thermal hysteresis loops. In addition, spin crossover in these complexes was characterized by optical measurements, differential scanning calorimetry, and IR and Raman spectroscopy. This research shows that the use of phthalazine leads to the production of new SCO systems with attractive transition characteristics and opens up new perspectives for the design of switchable complexes based on fused bicyclic azine ligands. [ABSTRACT FROM AUTHOR]

The unit cell of the title compound, [Zn(C17H18N3O4)2]·CH4O·C2H6O, contains two complex molecules related by an inversion centre, plus one methanol and one ethanol solvent molecule per complex molecule. In each complex, two deprotonated pyridine aroylhydrazone ligands {3,4,5-trimethoxy-N'-[1-(pyridin-2-yl)ethylidene]benzohydrazide} coordinate to the ZnII ion through the N atoms of the pyridine group and the ketamine, and, additionally, through the O atom of the enolate group. In the crystal, dimers are formed by π-π interactions between the planar ligand moieties, which are further connected by C···O and C···C interactions. The intermolecular interactions were investigated using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing that the most important contributions for the crystal packing are from H···H (44.8%), H···C/C···H (22.2%), H···O/O···H (18.7%) and C···C (3.9%) interactions. [ABSTRACT FROM AUTHOR]

In the molecule of the title anthracene derivative, C22H17NO2, the benzene ring is inclined to the mean plane of the anthracene ring system (r.m.s. deviation = 0.024 Å) by 75.21 (9)°. In the crystal, molecules are linked by pairs of O--H ⋯O hydrogen bonds, forming classical carboxylic acid inversion dimers with an R²2(8) ring motif. The dimers are linked by C--H ⋯π interactions, forming a supramolecular framework. [ABSTRACT FROM AUTHOR]