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• A novel nickel(II) complex was synthesized via a template reaction. • The central Ni atom exhibits square planar coordination. • Calculated (DFT) geometry aligns well with experimental (X-ray diffraction) values. • The compound is an excellent candidate for nonlinear optical material. • Molecular docking suggests that the complex has anti-Alzheimer's potential. The title compound, [Ni(C 11 H 14 N 10 O 3)]·2H 2 O, was synthesized through a template reaction involving 1-methyl-1H-1,2,4-triazole-5-carbohydrazide and formaldehyde in the presence of Ni(II) chloride. The ligand is formed through the template binding of two hydrazide-containing fragments with three formaldehyde molecules. Coordinating in a tetradentate manner, the ligand forms three fused chelate rings, and the central Ni atom exhibits square planar coordination. In the crystals, complex molecules interconnect via hydrogen bonds with water molecules, forming chains in the [11ī] crystallographic direction. DFT analysis indicates that the complex molecule demonstrates a noteworthy electron-donating ability and exhibits non-linear optical (NLO) activity. Molecular docking suggests that the title compound has the potential to function as an anti-Alzheimer's agent. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Synthesis of the [Fe(hptrz)3](OTs)2 spin crossover nanoparticle samples was performed. Transmission electronic microscopy was used to determine the size and size distribution of the nanoparticle samples for which a size range of 35–70nm was found – depending on the composition and the stoichiometry of the reverse micelle hexane-tergitol-water system. The factors susceptible to influence the aggregation degree of the nanoparticles, i.e., the starting experimental conditions, the experiment time and the effect of sonication were also studied. In comparison with the bulk powder sample, these nano-materials still exhibit spin crossover near room temperature with a hysteresis loop. The size-properties relationship concerning the present compound and analogue complexes within this family is also discussed. [Copyright &y& Elsevier]

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]

Abstract: The title compound, trans-[PtCl2(NCNMe2)(Me2SO)], is the first example of the structurally characterized PtII species having the nitrile and the sulfoxide ligands in the trans-position to each other. The most significant feature of this structure is the non-linear arrangement of the Ptph name="sbnd" />C1 fragment providing the rare case of the bent form of the dialkylcyanamide ligand. [Copyright &y& Elsevier]

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]

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]

The title compound, C14H12BrNO2, was synthesized by the condensation reaction of 2,3-di­hydroxy­benzaldehyde and 2-bromo-3-methyl­aniline. It crystallizes in the centrosymmetric triclinic space group P. The configuration about the C=N bond is E. The dihedral angle between the planes of the 5-(2-bromo-3-methyl­phenyl ring and the catechol ring is 2.80 (17)°. In the crystal, O—H···O hydrogen-bond inter­actions consolidate the crystal packing. [ABSTRACT FROM AUTHOR]

In the title com­plex, [Cu(C18H12F6N2O4)]·0.5C6H6O2, the CuII ion has a square-planar coordination geometry, being ligated by two N and two O atoms of the tetra­dentate open-chain Schiff base ligand 6,6′-{(1E,1′E)-[ethane-1,2-diylbis(aza­nylyl­idene)]bis­(methanylyl­idene)}bis­[2-(tri­fluoro­meth­oxy)phenol]. The crystal packing is stabilized by intra­molecular O—H∙∙∙O and inter­molecular C—H∙∙∙F, C—H∙∙∙O and C—H∙∙∙π hydrogen bonds. In addition, weak π–π inter­actions form a three-dimensional structure. Hirshfeld surface analysis and two-dimensional fingerprint plots were performed and created to analyze the inter­molecular inter­actions present in the crystal, indicating that the most important contributions for the crystal packing are from F∙∙∙H/H∙∙∙F (25.7%), H∙∙∙H (23.5%) and C∙∙∙H/H∙∙∙C (12.6%) inter­actions. [ABSTRACT FROM AUTHOR]

In the title compound, bis­(2-meth­oxy­ethyl xanthato-κS)(N,N,N′,N′-tetra­methyl­-ethylenedi­amine-κ²N,N′)zinc(II) acetone hemisolvate, [Zn(C4H7O2S2)2(C6H16N2)]·0.5C3H6O, the ZnII ion is coordinated by two N atoms of the N,N,N′,N′-tetra­methyl­ethylenedi­amine ligand and two S atoms from two 2-meth­oxy­ethyl xanthate ligands. The amine ligand is disordered over two orientations and was modelled with refined occupancies of 0.538 (6) and 0.462 (6). The mol­ecular structure features two C—H∙∙∙O and two C—H∙∙∙S intra­molecular inter­actions. In the crystal, mol­ecules are linked by weak C—H∙∙∙O and C—H∙∙∙S hydrogen bonds, forming a three-dimensional supra­molecular architecture. The mol­ecular structure was optimized using density functional theory (DFT) at the B3LYP/6–311 G(d,p) level. The smallest HOMO–LUMO energy gap (3.19 eV) indicates the suitability of this crystal for optoelectronic applications. The mol­ecular electrostatic potential (MEP) further identifies the positive, negative and neutral electrostatic potential regions of the mol­ecules. Half a mol­ecule of disordered acetone was removed with the solvent-mask procedure in OLEX2. [ABSTRACT FROM AUTHOR]

The first example of a Cu(ii) 12-MC-4 hydroxamic metallacrown containing an ethylphosphonate group as an additional donor function in the β-position with respect to the hydroxamic group is described. The solution equilibrium of ethylphosphonoacetohydroxamic acid (PAHEt) with Cu(ii) was investigated in aqueous solution by a combination of potentiometry, mass spectrometry, UV-Vis and EPR spectroscopies, and isothermal titration calorimetry. A model containing mononuclear [CuL], [CuL2]2− and [CuL2H−1]3− and pentanuclear [Cu5(LH−1)4]2− species is proposed. The predominance of the [Cu5(LH−1)4]2− species in solution over the pH range 4–9 was confirmed by the signals present in the ESI-MS spectra, as well as the absence of the EPR signal. In addition, the results of isothermal titration calorimetry indicated the stoichiometry of the complex form at pH 5.5 as 1.25. Even if forming a less stable MC complex, PAHEt offers the formation of 12-MC-4 in a broad pH range, which distinguishes it especially from α-aminohydroxamic acids. The compound corresponding to the pentameric metallacrown complex was isolated in the solid state as {Na4(H2O)6(Ac)[Cu5(PAHEt-3H)4(Ac)]}2·3H2O (1), whose crystal structure was determined by X-ray analysis. The centrosymmetric decanuclear complex anion of (1) consists of two pentanuclear 12-MC-4 fragments formed by five Cu(ii) ions and four triply deprotonated residues of the phosphonoacetohydroxamate ligand, and is associated with eight sodium cations, two acetate anions and twelve water molecules taking part in sodium cation coordination, as well as solvate water molecules. The stability of MCs under conditions of competitive complex formation, as well as their reactivity with respect to a strong chelating agent, 2,2′-dipyridyl (dipy), was examined, and as a result a 1D coordination polymer featuring mixed-ligand mononuclear units {[Cu(dipy)(PAHEt-2H)]}n·1.86nH2O (2) was formed. In addition the chelating capacity of this ligand toward Ni(ii) and Zn(ii) ions was studied in solution. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, C15H12N2O2, contains two crystallographically independent mol­ecules in which the dihedral angles between the benzene rings in each are 13.26 (5) and 7.87 (5)°. An intra­molecular O—H···N hydrogen bonds results in the formation of an S(6) ring motif. In the crystal, mol­ecules are linked by weak C—H···O and C—H···N hydrogen bonds, forming layers parallel to (011). In addition, π–π stacking inter­actions with centroid–centroid distances in the range 3.693 (2)–3.931 (2) Å complete the three-dimensional network. [ABSTRACT FROM AUTHOR]

The title compound, C9H11NO2, was obtained as unexpected product from the reaction of (4-{2-benz­yloxy-5-[(E)-(3-chloro-4-methyl­phen­yl)diazen­yl]benzyl­idene}-2-phenyl­oxazol-5(4H)-one) with 2-meth­oxy­aniline in the presence of acetic acid as solvent. The amide group is not coplanar with the benzene ring, as shown by the C—N—C—O and C—N—C—C torsion angles of −2.5 (3) and 176.54 (19)°, respectively. Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the most important contributions to the crystal packing are from H⋯H (53.9%), C⋯H/H⋯C (21.4%), O⋯H/H⋯O (21.4%) and N⋯H/H⋯N (1.7%) inter­actions. [ABSTRACT FROM AUTHOR]

In the title compounds, 9-bromo-2,5-dimethyl-11,12-di­hydro-5H-5,11-methano­benzo[g][1,2,4]triazolo[1,5-c][1,3,5]oxa­diazo­cine, C13H13BrN4O (I), and 7-meth­oxy-5-methyl-2-(pyridin-4-yl)-11,12-di­hydro-5H-5,11-methano­benzo[g][1,2,4]tri­azolo[1,5-c][1,3,5]oxa­diazo­cine, C18H17N5O2 (II), the triazole ring is inclined to the benzene ring by 85.15 (9) and 76.98 (5)° in compounds I and II, respectively. In II, the pyridine ring is almost coplanar with the triazole ring, having a dihedral angle of 4.19 (8)°. In the crystal of I, pairs of N—HN hydrogen bonds link the mol­ecules to form inversion dimers with an R2²(8) ring motif. The dimers are linked by C—H...π and C—Br...π inter­actions forming layers parallel to the bc plane. In the crystal of II, mol­ecules are linked by N—H...N and C—H...O hydrogen bonds forming chains propagating along the b-axis direction. The inter­molecular inter­actions were investigated using Hirshfeld surface analysis and two-dimensional fingerprint plots, and the mol­ecular electrostatic potential surface was also analysed. The Hirshfeld surface analysis of I suggests that the most significant contributions to the crystal packing are H...H (42.4%) and O...H/H...O (17.9%) contacts. For compound II, the H...H (48.5%), C...H/H...C (19.6%) and N...H/H...N (16.9%) inter­actions are the most important contributions. [ABSTRACT FROM AUTHOR]

A water-stable FeIV clathrochelate complex catalyses fast and homogeneous photochemical oxidation of water to dioxygen with a turnover frequency of 2.27 s−1 and a maximum turnover number of 365. An FeV intermediate generated under catalytic conditions is trapped and characterised using EPR and Mössbauer spectroscopy. [ABSTRACT FROM AUTHOR]

A new iron(ii)-based spin-crossover compound with thermal hysteresis operating under ambient conditions is reported. This complex exhibits a high reproducibility of the spin transition in many successive thermal cycles, stability of both spin states at room temperature and an attractive operational temperature range. [ABSTRACT FROM AUTHOR]

The title compound, C14H12ClNO3, is a Schiff base that exists in the keto–enamine tautomeric form and adopts a Z configuration. In the crystal, the dihedral angle between the planes of the benzene rings is 5.34 (15)°. The roughly planar geometry of the mol­ecule is stabilized by a strong intra­molecular N—HO hydrogen bond. In the crystal, pairs of centrosymmetrically related mol­ecules are linked by O—H···O hydrogen bonds, forming R2²(10) rings. Besides this, the mol­ecules form stacks along the [001] direction with C—H···π and C—H···Cl contacts between the stacks. The inter­molecular inter­actions in the crystal were analysed using Hirshfeld surfaces. The most significant contribution to the crystal packing is from H···H contacts (30.8%). [ABSTRACT FROM AUTHOR]

In the title complex, (6,6′-{(1E,1′E)-[ethane-1,2-diylbis(aza­nylyl­idene)]bis(methanylyl­idene)}bis­[2-(tri­fluoro­meth­oxy)phenol]-κ4O,N,N′,O′)nickel(II), [Ni(C18H12F6N2O4)], the nickel(II) ion has a square-planar coordination sphere, being ligated by two N and two O atoms of the Schiff base ligand 6,6′-{(1E,1′E)-[ethane-1,2-diylbis(aza­nylyl­idene)]bis­(methanylyl­idene)}bis­[2-(tri­fluoro­meth­oxy)phenol] (L). Inversion-related mol­ecules are linked by a short Ni···Ni inter­action of 3.2945 (6) Å forming a dimer. In the crystal, the dimers stack up the a axis, with a closest Ni···Ni separation of ca 3.791 Å. There are no other significant inter­molecular inter­actions present. However, the Hirshfeld surface analysis and the two-dimensional fingerprint plots indicate that the packing is dominated by H···F/F···H, H···H, O···H/H···O and C···H/H···C contacts. [ABSTRACT FROM AUTHOR]

Five new mononuclear complexes formed by the polynucleating ligand 2-[1-(3,5-dimethyl)pyrazolyl]-2-hydroxyimino-N′-[1-(2-pyridyl)ethylidene]acetohydrazide (H L ): [Ni( L )(H L )]ClO 4 ·2CH 3 OH ( 1 ), [Ni( L ) 2 ]·CH 3 OH ( 2 ), [Zn( L )(H L )]ClO 4 ·2CH 3 OH ( 3 ), [Zn( L ) 2 ]·CH 3 OH ( 4 ) and [Cu( L ) 2 ]·CH 3 OH ( 5 ) were synthesized and characterized by elemental analysis, mass-spectrometry, IR-spectroscopy and X-ray analysis. The complexes reveal distorted octahedral N 4 O 2 coordination arrangement formed by both protonated and deprotonated ( 1 , 3 ) or two deprotonated ligand molecules ( 2 , 4 , 5 ). The presence of non-coordinated oxime and pyrazole groups resulted in the formation of extensive systems of hydrogen bonds in the crystal packing of 1 – 5 . Potentiometric titrations, ESI-MS and spectrophotometric studies of complex formation in MeOH/H 2 O solutions indicated the presence of mono- and polynuclear complexes with Cu(II), Ni(II) and Zn(II) ions. The solution studies carried out for an excess of Cu(II) over H L ligand (2:1 and 3:2 M ratio) indicated also the formation of polynuclear Cu 3 L 2 H x species, with an involvement of additional nitrogen donors in copper coordination. In binuclear complex [Cu 2 (L) 2 (DMF) 2 ](ClO 4 ) 2 ·DMF( 6 ) obtained in solid state, the Cu(II) coordination, analogous to the one in 1 – 5 , was supported by pyrazole N atom. [ABSTRACT FROM AUTHOR]

1,2,4-triazoles attract attention as actively used medications and ligands for constructing coordination architectures. In this paper we describe four optically active 4-substituted 1,2,4-triazoles that have been prepared by Bayer's synthesis from the corresponding aliphatic chiral amines. This approach tends to be universal towards different triazoles and permits to conserve a homochirality of substrates. Novel asymmetric molecules have been characterized by spectroscopic techniques and their structures have been retrieved from the single crystal X-ray analysis. Chiro-optical studies of these heterocycles have been made by means of circular dichroism spectroscopy. [ABSTRACT FROM AUTHOR]

Spin transitions are a spectacular example of molecular switching that can provoke extreme electronic and structural reorganizations in coordination compounds. A new 3D cyanoheterometallic framework, [Fe(pz){Au(CN)2}2], has been synthesized in which a highly cooperative spin crossover has been observed at 367 and 349 K in heating and cooling modes, respectively. Mössbauer spectroscopy revealed a complete transition between the diamagnetic and paramagnetic states of the iron centres. The low-spin-to-high-spin transition induced a drastic structural distortion involving a large one-directional expansion (ca. 10.6 %) and contraction (ca. 9.6 %) of the lattice. Negative thermal expansion along the c axis was detected below and above the transition temperature. [ABSTRACT FROM AUTHOR]

Discovery of spin-crossover (SCO) behavior in the family of FeII-based Hofmann clathrates has led to a "new rush" in the field of bistable molecular materials. To date this class of SCO complexes is represented by several dozens of individual compounds, and areas of their potential application steadily increase. Starting from Fe2+, square planar tetracyanometalates MII(CN)42- (MII = Ni, Pd, Pt) and 2-substituted pyrazines Xpz (X = Cl, Me, I) as coligands we obtained a series of nine new Hofmann clathrate-like coordination frameworks. X-ray diffraction reveals that in these complexes FeII ion has a pseudo-octahedral coordination environment supported by four µ4-tetracyanometallates forming its equatorial coordination environment. Depending on the nature of X and M, axial positions are occupied by two 2X-pyrazines (X = Cl and MII = Ni (1), Pd (2), Pt (3); X = Me and MII = Ni (4), Pd (5)) or one 2X-pyrazine and one water molecule (X = I and MII = Ni (7), Pd (8), Pt (9)), or, alternatively, two distinct FeII positions with either two pyrazines or two water molecules (X = Me and MII = Pt (6)) are observed. Temperature behavior of magnetic susceptibility indicates that all compounds bearing FeN6 units (1-6) display cooperative spin transition, while FeII ions in N5O or N4O2 surrounding are high spin (HS). Structural changes in the nearest FeII environment upon low-spin (LS) to HS transition, which include ca. 10% Fe-N distance increase, lead to the cell expansion. Mössbauer spectroscopy is used to characterize the spin state of all HS, LS, and intermediate phases of1-9 (see abstract figure). Effects of a pyrazine substituent and MII nature on the hyperfine parameters in both spin states are established. [ABSTRACT FROM AUTHOR]

The diversity of spin crossover (SCO) complexes that, on the one hand, display variable temperature, abruptness and hysteresis of the spin transition, and on the other hand, are spin-sensitive to the various guest molecules, makes these materials unique for the detection of different organic and inorganic compounds. We have developed a homochiral SCO coordination polymer with a spin transition sensitive to the inclusion of the guest 2-butanol, and these solvates with ( R)- and ( S)-alcohols demonstrate different SCO behaviours depending on the chirality of the organic analyte. A stereoselective response to the guest inclusion is detected as a shift in the temperature of the transition both from dia- to para- and from para- to diamagnetic states in heating and cooling modes respectively. Furthermore, the Mössbauer spectroscopy directly visualizes how the metallic centres in a chiral coordination framework differently sense the interaction with guests of different chiralities. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis of the Zn(II) complex with H 2 L = 2-hydroxyiminopropanoic acid. The final structure incorporated two linear dimeric anions with two Zn 2+ atoms, which are linked by a carbonate anion into a tetranuclear unit. In each dinuclear unit, the two Zn(II) ions are coordinated by three molecules of the doubly deprotonated ligand in two different coordination modes. This result is confirmed both by X-ray crystallography and by ESI-MS investigations of the crystals dissolved in water. Equilibrium studies of the zinc(II) complexes formed by H 2 L in aqueous solution based on independent pH-metric titrations and zinc ion-selective electrode (ISE) titrations indicate that the mononuclear ZnLH complex appears to be the dominating equilibrium species at pH 4–6 at various ligand-to-metal ratios. Under excess of the ligand at pH 6–8, the ZnL 2 H species, further stabilized by a hydrogen bond between the deprotonated and protonated oxime groups, becomes the predominating species besides the ZnL complex. [ABSTRACT FROM AUTHOR]

Abstract: By using a synthetic approach alternative to the ones described up to now two tri- and tetranuclear mixed valence Co(II,III) complexes have been obtained ([Li(H2O)4]2[Co(CoL3)2(Li(H2O)3)2] and K[Co(CoL3)2Co(H2O)5]·H2O, respectively) in which the cobalt ions are linked by (N–O) oxime bridges. For both these compounds, a hydrazide derivative (2-hydroxyiminopropanehydrazide, HPH) has been used as starting ligand and then it underwent hydrolytical decomposition to 2-hydroxyiminopropanoic acid, H2L, ion upon coordination with cobalt. Cobalt(II) complexes formed by 2-hydroxyiminopropanoic acid in aqueous solution have been studied using independent pH-metric titrations as well as a combination of fibre-optics UV–Vis spectroscopy and pH glass-electrode potentiometry. The mononuclear CoL2H complex appeared to be the dominating equilibrium species within pH 6–9, most probably due to a hydrogen bond between the deprotonated and protonated oxime groups stabilizing planar cis-coordination. [Copyright &y& Elsevier]

Abstract: 5-Acetyl-substituted pyrazole-3-carboxylic acid (H2 L) forms [2×2] grid-like tetranuclear Cu(II) complexes with four five-coordinated copper(II) ions bridged by pyrazolate groups. Despite a significant dissociation of [Cu4 L 4(H2O)4]·4H2O (1) in aqueous solution1, it was possible to substitute the coordinated water molecules by pyridine ligands or azide anions. The resulting tetranuclear complexes [Cu4 L 4Py4]·2H2O (2) and Na4[Cu4 L 4(N3)4]·7MeOH (3) were isolated and studied by X-ray diffraction analysis. In 2 and 3 the azide anions or pyridine molecules complete the distorted square-pyramidal coordination of each copper(II) center. Magnetic susceptibilities of the obtained compounds have been measured by SQUID techniques. Simulation of the data using a Heisenberg spin Hamiltonian approach showed that the bridges between the metals mediate weak intramolecular antiferromagnetic coupling (J in the range −13.3 to −17.1cm−1) and lead to a singlet ground state in all cases. [Copyright &y& Elsevier]

Abstract: Two [2×2] grid-like complexes, [Cu4(L1 )4]·2МеОН·2Н2О·dmf (1) and [Cu4(L2 )4]·2NaClO4·2МеОН (2) based on new substituted pyrazole ligands 5-(1-((2-aminoethyl)imino)ethyl)-4-methyl-1H-pyrazole-3-carboxylic (H2 L1 ) acid and 5-(1-((3-aminopropyl)imino)ethyl)-4-methyl-1H-pyrazole-3-carboxylic acid (H2 L2 ) have been synthesized and characterized spectroscopically and crystallographically. It was found that the ligand H2 L2 condenses with 3-acetyl-4-methyl-pyrazole-5 carbonic acid (H2 L) to produce a new dinuclear Cu(II) complex upon reaction with Cu(ClO4)2·6H2O and CuAc2·2H2O. In the grid complexes the four Cu(II) atoms are in square-pyramidal environment formed by two pyrazole, imine and amine N atoms, and the carboxylate O atom and occupy the corners of a [2×2] grid with the Cu⋯Cu separations, varying from 3.998(1) to 4.2049(9) and 4.794(1) to 5.091(1)Å for the adjacent and diagonal atoms, respectively. In the dinuclear complex 3 the metal ions are found in square planar environment with their coordination planes lying roughly within the plane of the pyrazolate heterocycle. The separation between Cu(II) centers is 3.921(1)Å. Magnetic susceptibility measurements of 3 revealed the presence of strong antiferromagnetic interaction, with a J value of −207.5cm−1. This is larger than the J values found for the 1 and 2 grid complexes, which are −20.2 and −18.3cm−1, respectively. [Copyright &y& Elsevier]

Abstract: Cobalt(III) complexes with new oxime-containing Schiff base ligands: 2-hydroxyimino-N′-[1-(2-pyridyl)ethylidene]propanohydrazone (Hpop) and 2-hydroxyimino-N′-[(pyridine-2-yl)methylidene]propanohydrazone (Hpoa) have been investigated. The crystal and the molecular structure of 2[Co(pop)2]Br·3CH3OH·0.5H2O (1) has been determined using single-crystal X-ray diffraction methods. Electrospray ionization mass spectrometry confirmed the presence of polynuclear complexes with Co(II). The potentiometric and spectrophotometric results in 10/90 (v/v) DMSO/water solution reveal that both of the oxime-containing Schiff base ligands show a very high efficacy in the coordination of Co(II) ions. As it has been indicated, the difference between the two ligands in their complexing ability may be attributed to the presence of the methyl group in Hpop and by the steric interaction during chelate formation. The experiments in solution were carried out under an inert atmosphere since in both cases the complexes are capable of dioxygen uptake, followed by irreversible oxidation to Co(III) complexes. [Copyright &y& Elsevier]

The title compound, [Cu(ClO4)2(C6H6N2O2)2], contains neutral molecules of a centrosymmetric mononuclear copper(II) complex, in which the zwitterionic hydroxamic acid ligand is O, O′-chelated to the CuII atom. The CuII atom lies on an inversion centre and has a distorted tetragonal-bipyramidal environment, being coordinated by four O atoms of the two N-hydroxynicotinamide molecules forming the equatorial plane, and by two O atoms of the perchlorate anions occupying the axial positions. [ABSTRACT FROM AUTHOR]

The crystal structure of the title salt, C6H7N2O2+·Cl−, consists of N-hydroxy­isonicotinamidium cations and Cl− anions linked through N—H⋯Cl, O—H⋯Cl and N—H⋯O hydrogen bonds into layers arranged parallel to the (010) plane. [ABSTRACT FROM AUTHOR]

The centrosymmetric neutral mononuclear title complex, [Ni(C5H5N2O3)2(C2H8N2)2]·6H2O, has the Ni centre in a distorted octa­hedral environment, defined by six N atoms belonging to two chelating ethyl­enediamine mol­ecules and two cyano N atoms derived from cyanoxime ligands. The O atom of the deprotonated oxime group forms hydrogen bonds with two solvent water mol­ecules. [ABSTRACT FROM AUTHOR]

Abstract: The anionic [CuIII(LH−4)]− complex (L=8,17-dioxa-1,2,5,6,10,11,14,15-octaaza-tricyclo[13.3.1] eicosane-3,4,12,13-tetrone) is one of the rare copper(III) compounds, which exhibits high stability in basic aqueous solution. This copper(III) compound catalyses the reduction of molecular oxygen by l-ascorbic acid at pH 7.97, in Tris–HCl buffer solution at the ionic strength of 0.1M (NaCl). Stoichiometry of the reaction (2:1.07 for l-ascorbic acid:dioxygen) indicates formation of water and dehydroascorbic acid as primary products. Based on detailed kinetic measurements, the rate equation–d[AscH−]/dt = k obs [AscH−]0.5[CuIII(LH−4)][O2]0.5 was obtained. The proposed mechanism includes a fast redox pre-equilibrium between the copper(III) centre and its reduced, copper(II) form, induced by the presence of l-ascorbate. The equilibrium constant K 1′ at pH 8 (8.78±3.11×10−3) and k values for the forward and backward reactions (1.18±0.68×106 and 1.46±0.82×108 M−2 s−1, respectively) were determined by stopped-flow technique, following the decrease in absorbance of the copper(III) form at 550nm. In the presence of molecular oxygen, re-oxidation of the copper(II) form of the catalyst takes place, based on cyclic voltammetry (CV) measurements. The decrease of the Cu(II)→Cu(III) oxidation and the subsequent increase of the Cu(III)→Cu(II) reduction current peaks in the CV spectrum, when argon is exchanged to dioxygen atmosphere, indicate a relatively fast oxidation rate for [CuII(LH−4)]2−. The determined ΔS ‡ (−41±2Jmol−1 K−1) for the catalytic reaction indicate an associative mechanism for the formation of the catalytically active copper–oxygen species that will react with the l-ascorbate to yield dehydroascorbate as product. [Copyright &y& Elsevier]

Abstract: The synthesis, crystal structure and magnetic properties of manganese(III) binuclear complexes [MnIII 2(L–3Н)2(CH3ОH)4]·2CH3ОH (1) and [MnIII 2(L–3Н)2(Py)4]·2Py (2) (L =3-[(1E)-N-hydroxyethanimidoyl]-4-methyl-1H-pyrazole-5-carboxylic acid) are reported. The ligand contains two distinct donor compartments formed by the pyrazolate-N and the oxime or the carboxylic groups. The complexes were characterized by X-ray single crystal diffraction, revealing that both 1 and 2 consist of dinuclear units in which the two metal ions are linked by double pyrazolate bridges with a planar {Mn2N4} core. Cryomagnetic measurements show antiferromagnetic interaction with g =1.99, J =−3.6cm−1, Θ =−2.02K for 1 and g =2.00, J =−3.7cm−1, Θ =1.43K for 2. [ABSTRACT FROM AUTHOR]

Abstract: Cobalt(III) complexes with new open chain oxime ligands: N,N′-bis(2-hydroxyiminopropionyl)-1,2-aminoethane (H2pen) and N,N′-bis(2-hydroxyiminopropionyl)-1,3-diaminopropane (H2pap) have been investigated. Single crystals of Co(papH−1)(Im2)·CH3OH (1) and Co(papH−1)(MEA)2·1.5H2O (2) (where Im=imidazole, MEA=monoethanolamine) suitable for X-ray crystallography were grown by slow evaporation of methanol/water solutions at room temperature. The molecular structures have been determined using single-crystal X-ray diffraction methods. The potentiometric and spectrophotometric results in aqueous solution reveal that both of the open chain ligands show a very high efficacy in the coordination of Co(II) ions. As it has been indicated, differences between the two oxime ligands in complexing ability may be attributed to the longer –CH2– chain in H2pap and by that a better fit of the relatively large Co(II) ion to the accessible binding site. One of the complex species confirmed under inert atmosphere, namely of type Co(LH−1)− (where L = pap or pen), has been shown as the “active” form, capable of dioxygen uptake followed by irreversible oxidation to Co(III). [ABSTRACT FROM AUTHOR]

A series of dizinc(II) complexes based on the pyrazolate ligands 3-[(1E)-N-hydroxyethanimidoyl]-4-methyl-1H-pyrazole-5-carboxylic acid (H3L1), (1E,1′E)-1,1′-(4-methyl-1H-pyrazole-3,5-diyl)diethanone dihydrazone (HL2), (E,E)-(4-methyl-1H-pyrazole-3,5-diyl)bis(methylmethanone) dioxime (H3L3), (E,E)-(4-phenyl-1H-pyrazole-3,5-diyl)bis(phenylmethanone) dioxime (H3L4), and 1H-pyrazole-3,5-dicarboxylic acid (H3L5) have been synthesized and investigated as functional models of phosphoesterases, focusing on correlations between the hydrolytic activity and molecular parameters of the bimetallic core. Speciation of the various dizinc complexes in solution has been determined potentiometrically, and the structures in the solid state have been established by X-ray crystallography. The hydrolysis of two phosphoesters, an RNA model 2-hydroxypropyl-p-nitrophenyl phosphate (HPNP) and the pesticide paraoxon-ethyl (POE), promoted by the dinuclear phosphoesterase model complexes has been investigated in DMSO/buffered water (1:1) at 50 °C as a function of complex concentration, substrate concentration, and pH. Drastic differences in the hydrolytic activities of [Zn2(HL1)2]0, [Zn2(L2)2]2+, [Zn2(H2L3)2]2+, and [Zn2(HL5)2]2− are observed and can be attributed to molecular peculiarities. Pyrazolate-bridged dinuclear zinc(II) complexes seem to provide a sufficient number of coordination sites for both activating the substrate and generating the nucleophile, where the phosphate esters are preferentially bound in a bidentate bridging fashion (in the case of HPNP) and in a monodentate fashion (in the case of POE). Bicompartmental pyrazolate-based ligands with chelating arms appended at the 3- and 5-positions of the heterocycle exhibit a unique capacity for forming dinuclear complexes, which further are able to hydrolyze the phosphoester bond. The prerequisite for hydrolytic activity is the specific distance between metal ions, governed by the nature of chelating substituents, and the ability of such a system to create a nucleophilic group. The presented dinuclear zinc complexes, with a metal−metal separation in the range of 3.750−4.114 Å, act as efficient catalysts of phosphoester bonds under mild conditions. [ABSTRACT FROM AUTHOR]

The formation of both binary and ternary 12-metallacrown-4 complexes of a-aminohydroxamic acids with Cu(II) has been investigated by means of electrospray mass spectrometry, potentiometry and UV-Vis spectroscopy. The formation of a ternary complex composed of phenylalanine and glycine hydroxamic acids was found to be particularly favorable. Among metal used to obtain metallacrowns only Cu(II) was found to be appropriate. [ABSTRACT FROM AUTHOR]

Complex formation properties of a novel water soluble thiazolyloxime 2-(4-methylthiazol-2-yl)-2-(hydroxyimino)acetic acid (H3L1) with Cu2+ and Ni2+ were investigated in solution by potentiometrical and spectral (UV–Vis, EPR, NMR) methods. All Cu2+ and most of Ni2+ complex species detected in solution were found to have square-planar MN4 core with oxime and heterocyclic nitrogen atoms which was rationalized in terms of destabilizing effect of repulsive interaction between oxygen atom of carboxylic group and nitrogen atom of thiazole ring in N,O-coordinated ligand conformation. It has been found that stability of metal complexes in a series of oxime ligands is dependent upon basicity of nitrogen atom of oxime group. The thiazolyloxime forms less stable complexes with Cu2+ but stronger ones with Ni2+ ions when compared to parent 2-(hydroxyimino)propanoic acid. The lower stability obtained for Cu2+ complexes was elucidated in terms of negative inductive effect of the thiazole and nitrile substituents as well as an effect of intramolecular attractive interaction between thiazolyl sulfur and oxime oxygen atoms in thiazolyloxime. In the case of Ni2+ the complexes formed are square-planar and it is why thiazolyl ligand is more effective in metal ion binding than simple 2-(hydroxyimino)propanoic acid forming only octahedral species. The solid state structure of the Co3+ complex K3[Co(HL1)3]·5.5H2O (1) was studied by X-ray analysis. The thiazolyloxime ligand is coordinated to Co3+ via oxime nitrogen and carboxylate oxygen atoms forming five-membered chelate rings. [Copyright &y& Elsevier]

[Display omitted] • Nucleation and growth phenomena are associated with the thermally-induced SCO. • Significant kinetic effects on the hysteresis behaviour are observed. • Ultra-slow switching rates and phase-boundary propagation velocities are observed. • Unique SCO properties are associated with numerous microstructural defects. Nucleation and growth phenomena associated with the thermally-induced spin transition was studied using optical microscopy in single crystals of a cyanoheterometallic coordination polymer [Fe(1,6-naphthyridine) 2 (Ag(CN) 2) 2 ]. Despite the fact that the spin-crossover phenomenon occurs near room temperature (ca. 290–300 K), the experimental results show the existence of significant kinetic effects on the hysteretic behaviour of the spin transition in this compound. Ultra-slow switching rates and phase-boundary propagation velocities were observed (down to 3 nm s−1), several orders of magnitude lower than customary. Our observations indicate that these peculiar spin-crossover properties (slow switching kinetics, scan-rate-dependent transition temperatures) are presumably related to the presence of numerous microstructural defects in the crystals, which is an intrinsic characteristic of this compound. [ABSTRACT FROM AUTHOR]

The title compound, [Cu2(C2O4)Cl2(C7H9N3)2], contains neutral mol­ecules of a centrosymmetric dinuclear oxalate-bridged copper(II) complex, in which the oxalate ligand is coordinated in a bis-bidentate bridging mode to the Cu atoms. Each Cu atom has a distorted square-pyramidal environment, being coordinated by two N atoms of the [1-(pyridin-2-yl)­ethyl­idene]hydrazine ligand, two O atoms of the doubly deprotonated oxalate anion and one Cl− anion. [ABSTRACT FROM AUTHOR]

The reaction of cadmium iodide with 3-amino-pyrazole (3-apz) in ethano-lic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, catena -poly[[di-iodido-cadmium(II)]-bis-(μ-3-amino-1 H -pyrazole)-κ 2 N 2 : N 3 ;κ 2 N 3 : N 2 ], [CdI 2 (C 3 H 5 N 3 ) 2 ] n or [CdI 2 (3-apz) 2 ] n . Its asymmetric unit consists of a half of a Cd 2+ cation, an iodide anion and a 3-apz mol-ecule. The Cd 2+ cations are coordinated by two iodide anions and two 3-apz ligands, generating trans -CdN 4 I 2 octa-hedra, which are linked into chains by pairs of the bridging ligands. In the crystal, the ligand mol-ecules and iodide anions of neighboring chains are linked through inter-chain hydrogen bonds into a di-periodic network. The inter-molecular contacts were qu-anti-fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative qu-anti-tative contributions of the weak inter-molecular contacts., (© Kuzevanova et al. 2024.)

Octahedrally coordinated spin crossover (SCO) Fe II complexes represent an important class of switchable molecular materials. This study presents the synthesis and characterisation of a novel complex, [Fe II (ppt-2Fph) 2 ] 0 ·2MeOH, where ppt-2Fph is a new asymmetric ionogenic tridentate planar ligand 2-(5-(2-fluorophenyl)-4 H -1,2,4-triazol-3-yl)-6-(1 H -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.

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 [Ag 2 (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 T 1/2 ↓ = 233 K and T 1/2 ↑ = 243 K for 1 and T 1/2 ↓ = 188 K and T 1/2 ↑ = 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 Fe II cations assemble to form infinite 2D layers in the structure of 1. Interestingly, compound 2 forms 2D layers of Fe II cations bridged by both binuclear [Ag 2 (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⋯N etpz , 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.

The synthetic availability of mol-ecular water oxidation catalysts containing high-valent ions of 3 d 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 di-ammonium {μ-1,3,4,7,8,10,12,13,16,17,19,22-dodeca-aza-tetra-cyclo-[8.8.4.1 3,17 .1 8,12 ]tetra-cosane-5,6,14,15,20,21-hexa-onato}ferrate(IV) acetic acid tris-olvate, (NH 4 ) 2 [Fe IV (C 12 H 12 N 12 O 6 )]·3CH 3 COOH or (NH 4 ) 2 [Fe IV ( L -6H)]·3CH 3 COOH is reported. The Fe IV ion is encapsulated by the macropolycyclic ligand, which can be described as a dodeca-aza-quadricyclic cage with two capping tri-aza-cyclo-hexane fragments making three five- and six six-membered alternating chelate rings with the central Fe IV ion. The local coord-ination environment of Fe IV is formed by six deprotonated hydrazide nitro-gen atoms, which stabilize the unusual oxidation state. The Fe IV ion lies on a twofold rotation axis (multiplicity 4, Wyckoff letter e ) of the space group C 2/ c . Its coordination geometry is inter-mediate between a trigonal prism (distortion angle φ = 0°) and an anti-prism (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 tetra-valent iron. Structure analysis revealed that three acetic acid mol-ecules additionally co-crystallize 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 mol-ecules are inter-connected by an intricate system of hydrogen bonds, mainly via the oxamide oxygen atoms acting as acceptors., (© Plutenko et al. 2024.)

The reaction of cadmium bromide tetra-hydrate with 3-amino-pyrazole (3-apz) in ethano-lic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, catena -poly[[di-bromido-cadmium(II)]-bis-(μ-3-amino-1 H -pyrazole)-κ 2 N 3 : N 2 ;κ 2 N 2 : N 3 ], [CdBr 2 (C 3 H 5 N 3 ) 2 ] n or [CdBr 2 (3-apz) 2 ] n . Its asymmetric unit consists of a half of a Cd 2+ cation, a bromide anion and a 3-apz mol-ecule. The Cd 2+ cations are coordinated by two bromide anions and two 3-apz ligands, generating trans -CdN 4 Br 2 octa-hedra, which are linked into chains by pairs of the bridging ligands. In the crystal, the ligand mol-ecules and bromide anions of neighboring chains are linked through inter-chain hydrogen bonds into a two-dimensional network. The inter-molecular contacts were qu-anti-fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative qu-anti-tative contributions of the weak inter-molecular contacts., (© Kuzevanova et al. 2023.)

The title compound, [FeLi 2 (C 12 H 12 N 12 O 6 )(H 2 O) 4 ]·4H 2 O, consists of iron complex anions, lithium cations and water mol-ecules. The complex anion shows a clathrochelate topology. The coordination geometry of the Fe IV centre is inter-mediate between a trigonal prism and a trigonal anti-prism. 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., (© Plutenko et al. 2023.)

The unit cell of the title compound, [Fe(C 18 H 15 N 6 O 2 ) 2 ]·2CH 3 OH·2CHCl 3 , consists of a charge-neutral complex mol-ecule, two methanol and two chloro-form mol-ecules. In the complex, the two tridentate 2-(5-(3,4-di-meth-oxy-phen-yl)-1,2,4-triazol-3-yl)-6-(pyrazol-1-yl)pyridine ligands coordinate to the central Fe II ion through the N atoms of the pyrazole, pyridine and triazole groups, forming a pseudo-octa-hedral coordination sphere. Neighbouring tapered mol-ecules are linked through weak C-H(pz)⋯π(ph) inter-actions into one-dimensional chains, which are joined into two-dimensional layers through weak C-H⋯N/C/O inter-actions. Furthermore, the layers stack in a three-dimensional network linked by weak inter-layer C-H⋯π inter-actions of the meth-oxy and phenyl groups. The inter-molecular contacts were qu-anti-fied 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 H⋯O/O⋯H 7.5%. The average Fe-N bond distance is 2.185 Å, indicating the high-spin state of the Fe II ion. Energy framework analysis at the HF/3-21 G theory level was performed to qu-antify the inter-action energies in the crystal structure., (© Znovjyak et al. 2023.)

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)PbBr 3 ·H 2 O ( Pro-PbBr 3 ) and (L-proH) 4 Pb 3 Br 10 O ( 2 O ( Pro-Pb 3 Br 10 ) have been synthesized by employing different ratios of organic and inorganic precursors. According to structural analysis, the inorganic sublattice of compound Pro-PbBr 3 is built of one-dimensional (1D) [PbX 3 ] ∞ n - lead halide chains, whereas the inorganic sublattice of compound Pro-Pb 3 Br 10 is built upon a rare two-dimensional (2D) [Pb 3 Br 10 ] ∞ 4 n - 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-PbBr 3 ) and 4.13 eV ( Pro-Pb 3 Br 10 ). 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.