Copper(II) and Cadmium(II) Complexes Based on N,N‐Bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine Ligand: Syntheses,Structures, Magnetic,and Luminescent Properties

The reaction of the aryl‐oxide ligand H₂L [H₂L = N,N‐bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine] with CuSO₄ · 5H₂O, CuCl₂ · 2H₂O, CuBr₂, CdCl₂ · 2.5H₂O, and Cd(OAc)₂ · 2H₂O, respectively, under hydrothermal conditions gave the complexes [Cu(H₂L¹)₂] · SO₄ · 3CH₃OH ( 1 ), [Cu₂(H₂L²)₂Cl₄] ( 2 ), [Cu₂(H₂L²)₂Br₄] ( 3 ), [Cd₂(HL)₂Cl₂] ( 4 ), and [Cd₂(L)₂(CH₃COOH)₂] · H₂L ( 5 ), where H₂L¹ [H₂L¹ = 2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenol] and H₂L² [H₂L² = 2‐(2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenoxy)‐4, 6‐dimethylphenol] were derived from the solvothermal in situ metal/ligand reactions. These complexes were characterized by IR spectroscopy, elementary analysis, and X‐ray diffraction. A low‐temperature magnetic susceptibility measurement for the solid sample of 2 revealed antiferromagnetic interactions between two central copper(II) atoms. The emission property studies for complexes 4 and 5 indicated strong luminescence emission.     

Crystal Structures,Magnetic Properties and Catecholase‐Like Activities of μ‐Alkoxo‐μ‐Carboxylato Double Bridged Dinuclear and Tetranuclear Copper(II) Complexes

One μ‐alkoxo‐μ‐carboxylato bridged dinuclear copper(II) complex, [Cu₂(L¹)(μ‐C₆H₅CO₂)] ( 1 )(H₃L¹ = 1,3‐bis(salicylideneamino)‐2‐propanol)), and two μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear copper(II) complexes, [Cu₄(L¹)₂(μ‐C₈H₁₀O₄)(DMF)₂]·H₂O ( 2 ) and [Cu₄(L²)₂(μ‐C₅H₆O₄]·2H₂O·2CH₃CN ( 3 ) (H₃L² = 1,3‐bis(5‐bromo‐salicylideneamino)‐2‐propanol)) have been prepared and characterized. The single crystal X‐ray analysis shows that the structure of complex 1 is dimeric with two adjacent copper(II) atoms bridged by μ‐alkoxo‐μ‐carboxylato ligands where the Cu···Cu distances and Cu‐O(alkoxo)‐Cu angles are 3.5 11 Å and 132.8°, respectively. Complexes 2 and 3 consist of a μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear Cu(II) complex with mean Cu‐Cu distances and Cu‐O‐Cu angles of 3.092 Å and 104.2° for 2 and 3.486 Å and 129.9° for 3 , respectively. Magnetic measurements reveal that 1 is strong antiferromagnetically coupled with 2J =‐210 cm^?1 while 2 and 3 exhibit ferromagnetic coupling with 2J = 126 cm^?1 and 82 cm^?1 (averaged), respectively. The 2J values of 1–3 are correlated to dihedral angles and the Cu‐O‐Cu angles. Dependence of the pH at 25 °C on the reaction rate of oxidation of 3,5‐di‐tert‐butylcatechol (3,5‐DTBC) to the corresponding quinone (3,5‐DTBQ) catalyzed by 1–3 was studied. Complexes 1–3 exhibit catecholase‐like active at above pH 8 and 25 °C for oxidation of 3,5‐di‐tert‐butylcatechol.     

Tetra‐μ‐acetato‐κ2O:O′‐bis[(4‐phenylpyridine‐κN)copper(II)]

The title compound, [Cu₂(C₂H₃O₂)₄(C₁₁H₉N)₂] or [Cu₂(MeCO₂)₄(phpy)₂] (phpy is 4‐phenyl­pyridine), consists of centrosymmetric dimers in which the Cu^II atoms display a square‐pyramidal CuO₄N coordination, with four acetate O atoms in the basal plane [Cu—O 1.975 (3)–1.987 (3) Å] and the phpy N atom in the apical position [Cu—N 2.150 (3) Å]. The Cu atoms are 2.654 (1) Å apart and are bridged by four acetate groups. The discrete dimers are extended into a three‐dimensional supramolecular array through intermolecular π–π‐stacking interactions.     

Octahedral and Cyclic [Ag6] Cluster Cores Stabilized by {Ag3(Spz)3(N‐triphos)3} Motifs [HSpz = Pyrazine‐2‐thiolate,N‐triphos = Tris((diphenylphosphanyl)methyl)amine]: Ag···Ag Interactions

The complexes [Ag₁₂(Spz)₁₂(N‐triphos)₂][Ag₃(Spz)₃(N‐triphos)]₂ · (DMF)₆ ( 1 ) and [Ag₁₈(Spz)₁₂(N‐triphos)₄(CF₃CO₂)₆] ( 2 ) were synthesized and structurally characterized by X‐ray diffraction [HSpz = pyrazine‐2‐thiolate, N‐triphos = tris((diphenylphosphanyl)methyl)amine]. The central [Ag₆] ring with chair‐conformation in 1 and the ideally octahedral [Ag₆] cluster core in 2 are both stabilized by the tripodal building units of neutral [Ag₃(Spz)₃(N‐triphos)] compound. The Ag ··· Ag distances of the [Ag₆] moieties in 1 and 2 are 3.07 and 2.81 Å, respectively, exhibiting intermetallic interactions, which can enhance the stability of [Ag₆] conformations. In addition, the π ··· π interactions between parallel pyrazine rings could impose on the building and the Ag ··· Ag interactions of these Ag–S clusters.     

Synthesis,Structure, and Solution Study of a Mercury(II) Complex with the Ligand [1‐(2‐Methoxyphenyl)‐3‐(4‐chlorophenyl)]triazene

The title ligand, [1‐(2‐methoxyphenyl)‐3‐(4‐chlorophenyl)]triazene, H L ( 1 ), was prepared. In a reaction with Hg(NO₃)₂ it forms the complex [Hg(C₂₆H₂₂Cl₂N₆O₂)], [Hg L ₂] ( 2 ). Both compounds were characterized by means of X‐ray crystallography, CHN analysis, FT‐IR, ¹H NMR, and ¹³C NMR spectroscopy. In the structure of compound 1 , two independent fragments are present in the unit cell. They exhibit trans arrangement about the –N=N– double bond. The dihedral angles between two benzene rings in both fragments are 4.36 and 18.79 Å, respectively. Non‐classic C–H ··· N hydrogen bonding and C–H ··· π interactions form a layer structure along the crystallographic ab plane [110]. In compound 2 , the Hg^II atom is hexacoordinated by two tridentate [1‐(2‐methoxyphenyl)‐3‐(4‐chlorophenyl)]triazenide ligands through a N₂O₂ set. In addition, in the structure of 2 , monomeric complexes are connected to each other by C–H ··· π stacking interactions, resulting in a 2D architecture. These C–H ··· π edge‐to‐face interactions are present with H ··· π distances of 3.156 and 3.027 Å. The results of studies of the stoichiometry and formation of complex 2 in methanol solution were found to support its solid state stoichiometry.     

Synthesis and Crystal Structure of [Cu2(H2O)2(phen)2(OH)2][Cu2(phen)2(OH)2(CO3)2] · 10 H2O with phen = 1,10‐phenanthroline

The blue copper complex [Cu₂(H₂O)₂(phen)₂(OH)₂][Cu₂(phen)₂(OH)₂(CO₃)₂] · 10 H₂O, which was prepared by reaction of 1,10‐phenanthroline monohydrate, CuCl₂ · 2 H₂O and Na₂CO₃ in the presence of succinic acid in CH3OH/H₂O at pH = 13.0, crystallized in the triclinic space group P1 (no. 2) with cell dimensions: a = 9.515(1) Å, b = 12.039(1) Å, c = 12.412(2) Å, α = 70.16(1)°, β = 85.45(1)°, γ = 81.85(1)°, V = 1323.2(2) ų, Z = 1. The crystal structure consists of dinuclear [Cu₂(H₂O)₂(phen)₂(OH)₂]²⁺ complex cations, dinuclear [Cu₂(phen)₂(OH)₂(CO₃)₂]^2– complex anions and hydrogen bonded H₂O molecules. In both the centrosymmetric dinuclear cation and anion, the Cu atoms are coordinated by two N atoms of one phen ligand, three O atoms of two μ‐OH groups and respectively one H₂O molecule or one CO₃^2– anion to complete distorted [CuN₂O₃] square‐pyramids with the H₂O molecule or the CO₃^2– anion at the apical position (equatorial d(Cu–O) = 1.939–1.961 Å, d(Cu–N) = 2.026–2.051 Å and axial d(Cu–O) = 2.194, 2.252 Å). Two adjacent [CuN₂O₃] square pyramids are condensed via two μ‐OH groups. Through the interionic hydrogen bonds, the dinuclear cations and anions are linked into 1D chains with parallel phen ligands on both sides. Interdigitation of phen ligands of neighboring 1D chains generated 2D layers, between which the hydrogen bonded water molecules are sandwiched.     

New Suberato‐bridged Supramolecular Layers: Crystal Structure of [Cu2(phen)2(C8H12O4)2] · 3 H2O with phen = 1,10‐phenanthroline

The reaction of CuCl₂ · 2 H₂O, 1,10‐phenanthroline (phen), suberic acid and Na₂CO₃ in a CH₃CN–H₂O solution yielded blue needle‐like crystals of [Cu₂(phen)₂(C₈H₁₂O₄)₂] · 3 H₂O. The crystal structure (monoclinic, P2₁/n, a = 10.756(2) Å, b = 9.790(2) Å, c = 18.593(4) Å, β = 91.15(3)°, Z = 2, R = 0.043, wR² = 0.1238) consists of suberato‐bridged [Cu₂(phen)₂(C₈H₁₂O₄)_4/2] layers and hydrogen bonded H₂O molecules. The Cu atoms are coordinated by two N atoms from one bidentate chelating phen ligand and three carboxyl O atoms from different suberato ligands to form distorted [CuN₂O₃] square‐pyramids with one carboxyl O atom at the apical position (d(Cu–N) = 2.017(2), 2.043(3) Å, basal d(Cu–O) = 1.936(2), 1.951(2) Å and axial d(Cu–O) = 2.389(2) Å). Two [CuN₂O₃] square‐pyramids are condensed via a common O–O edge to a centrosymmetric [Cu₂N₄O₄] dimer with the Cu…Cu distance of 3.406(1) Å indicating no interaction between Cu atoms. The resultant [Cu₂N₄O₄] dimers are interlinked by the tridentate suberato ligands to form [Cu₂(phen)₂(C₈H₁₂O₄)_4/2] layers parallel to (101). These are assembled via π‐π stacking interactions into 3D network with H₂O molecules in the tunnels extending in the [010] direction.     

Synthesis,Structure and Photoluminescent Properties of Zn(II)/Cd(II)‐Complexes Containing 2,4,6‐Tris‐(benzimidazolyl‐2‐yl)pyridine Ligand

Hydrothermal reactions of tridentate rigid 2,4,6‐tris‐(benzimidazolyl‐2‐yl)pyridine (pytbzim) ligand and Zn(II)/Cd(II) salts generate binuclear complexes {[Cd₂Cl₂(pytbzim)₂(H₂O)₂]·2NO₃}_n ( 1 ) and two isomorphs {[M₂Cl₂(pytbzim)₂(H₂O)₂]Cl₂·2H₂O}_n [M=Cd ( 2 ), Zn ( 3 )]. All complexes include [M₂Cl₂(pytbzim)₂(H₂O)₂] dimers, which are further connected into a three‐dimensional supramolecular networks through ?‐? stacking interaction and hydrogen bonds. The solid state photoluminescent studies reveal good fluorescent properties of the pytbzim ligand and complexes 1 – 2 at room temperature.     

Structural and Coordinative Variability in Zinc(II), Cadmium(II), and Mercury(II) Complexes of 2‐Pyridineformamide 3‐Hexamethyleneiminylthiosemicarbazone

Sodium in dry methanol reduces 2‐cyanopyridine in the presence of 3‐hexamethyleneiminylthiosemicarbazide and produces 2‐pyridineformamide 3‐hexamethyleneiminylthiosemicarbazone, HAmhexim ( 1 ). Complexes with zinc(II ), cadmium(II ) and mercury(II ) have been prepared and characterized by spectroscopic techniques. In addition, the crystal structures of HAmhexim ( 1 ), [Zn(Amhexim)(OAc)]₂μ·μDMSO ( 2 ), [Cd(HAmhexim)Cl₂]μ·μDMSO ( 7 ), [Cd(Amhexim)₂] ( 8 ), [Cd(HAmhexim)Br₂]μ·μDMSO ( 9 ), [Cd(HAmhexim)I₂]μ·μEtOH ( 10 ), [Hg(HAmhexim)Cl₂]μ·μDMSO ( 11 ), [Hg(Amhexim)Br]₂ ( 13 ), [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O ( 14 ) and [Hg(Amhexim)I]₂ ( 15 ) have been determined. Coordination of the anionic and neutral thiosemicarbazone ligand occurs through the pyridine nitrogen atom, imine nitrogen atom, and thiolato or thione sulfur atom. In [Zn(Amhexim)(OAc)]₂ one of the bridging acetato ligands has monodentate coordination and the other bridges in a bidentate manner. [Cd(Amhexim)₂] is a 6‐coordinate species while the other cadmium complexes are 5‐coordinate. In [Hg(Amhexim)Br]₂ and [Hg(Amhexim)I]₂ the thiolato sulfur atoms act as bridges between the Hg atoms to form dimeric compounds and [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O is a trinuclear complex with three different centers — two metallic centers have a 5‐coordination and the another one has 4‐coordination. In addition, [Hg(HAmhexim)Cl₂]μ·μDMSO and [Hg₃(HAmhexim)(Amhexim)Br₅]μ·μH₂O shown a supramolecular one‐dimensional hydrogen‐bonded self‐assembling.     

Hydroxo‐bridged Tetranuclear CuII Complexes: {[Cu(bpy)(OH)]4Cl2}Cl2 · 6 H2O and {[Cu(phen)(OH)]4(H2O)2}]Cl4 · 4 H2O

The blue tetranuclear Cu^II complexes {[Cu(bpy)(OH)]₄Cl₂}Cl₂ · 6 H₂O ( 1 ) and {[Cu(phen)(OH)]₄(H₂O)₂}Cl₄ · 4 H₂O ( 2 ) were synthesized and characterized by single crystal X‐ray diffraction. ( 1 ): P 1 (no. 2), a = 9.240(1) Å, b = 10.366(2) Å, c = 12.973(2) Å, α = 85.76(1)°, β = 75.94(1)°, γ = 72.94(1)°, V = 1152.2(4) ų, Z = 1; ( 2 ): P 1 (no. 2), a = 9.770(3) Å, b = 10.118(3) Å, c = 14.258(4) Å, α = 83.72(2)°, β = 70.31(1)°, γ = 70.63(1)°, V = 1252.0(9) ų, Z = 1. The building units are centrosymmetric tetranuclear {[Cu(bpy)(OH)]₄Cl₂}²⁺ and {[Cu(phen)(OH)]₄(H₂O)₂}⁴⁺ complex cations formed by condensation of four elongated square pyramids CuN₂(OH)₂L^ap with the apical ligands L^ap = Cl, H₂O, OH. The resulting [Cu₄(μ₂‐OH)₂(μ₃‐OH)₂] core has the shape of a zigzag band of three Cu₂(OH)₂ squares. The cations exhibit intramolecular and intermolecular π‐π stacking interactions and the latter form 2D layers with the non‐bonded Cl^– anions and H₂O molecules in between (bond lengths: Cu–N = 1.995–2.038 Å; Cu–O = 1.927–1.982 Å; Cu–Cl^ap = 2.563; Cu–O^ap(OH) = 2.334–2.369 Å; Cu–O^ap(H₂O) = 2.256 Å). The Cu…Cu distances of about 2.93 Å do not indicate direct interactions, but the strongly reduced magnetic moment of about 2.74 B.M. corresponds with only two unpaired electrons per formula unit of 1 (1.37 B.M./Cu) and obviously results from intramolecular spin couplings (χ_m(T‐θ) = 0.933 cm³ · mol^–1 · K with θ = –0.7 K).     

Tetra­aqua(5‐fluoro­uracil‐1‐acetato‐O)copper(II) tetra­hydrate

In the title complex, [Cu(C₆H₄FN₂O₄)₂(H₂O)₄]·4H₂O, the Cu atom is located in the centre of a distorted octahedral geometry. The coordination atoms are six O atoms provided by two carboxyl­ate groups [coordinated in a monodentate mode, with Cu—O = 1.9551 (10) Å] and four water mol­ecules [Cu—O = 1.9241 (13) and 2.5771 (14) Å]. In addition, one intramolecular hydrogen bond and ten intermolecular hydrogen bonds make up a three‐dimensional network.     

Syntheses and Structures of Two Selenite Chloride Hydrates: Co(HSeO3)Cl · 3 H2O and Cu(HSeO3)Cl · 2 H2O

The first selenite chloride hydrates, Co(HSeO₃)Cl · 3 H₂O and Cu(HSeO₃)Cl · 2 H₂O, have been prepared from solution and characterised by single‐crystal X‐ray diffraction. The cobalt phase adopts an unusual “one‐dimensional” structure built up from vertex‐sharing pyramidal [HSeO₃]^2–, and octahedral [CoO₂(H₂O)₄]^2– and [CoO₂(H₂O)₂Cl₂]^4– units. Inter‐chain bonding is by way of hydrogen bonds or van der Waals' interactions. The atomic arrangement of the copper phase involves [HSeO₃]^2– pyramids and Jahn‐Teller distorted [CuCl₂(H₂O)₄] and [CuO₄Cl₂]^8– octahedra, sharing vertices by way of Cu–O–Se and Cu–Cl–Cu bonds. Crystal data: Co(HSeO₃)Cl · 3 H₂O, M_r = 276.40, triclinic, space group P 1 (No. 2), a = 7.1657(5) Å, b = 7.3714(5) Å, c = 7.7064(5) Å, α = 64.934(1)°, β = 68.894(1)°, γ = 71.795(1)°, V = 337.78(7) ų, Z = 2, R(F) = 0.036, wR(F) = 0.049. Cu(HSeO₃)Cl · 2 H₂O, M_r = 263.00, orthorhombic, space group Pnma (No. 62), a = 9.1488(3) Å, b = 17.8351(7) Å, c = 7.2293(3) Å, V = 1179.6(2) ų, Z = 8, R(F) = 0.021, wR(F) = 0.024.     

Bis(μ‐di‐2‐pyridyl­aminato 1‐oxide)­bis­[(tri­fluoro­acetato)copper(II)] aceto­nitrile disolvate

The crystal structure of the title compound, [Cu₂(C₂F₃O₂)₂(C₁₀H₈N₃O)₂]·2CH₃CN, contains discrete [Cu₂(CF₃COO)₂(O‐dpa)₂] mol­ecules (O‐dpaH is di‐2‐pyridyl­amine 1‐oxide) which have imposed crystallographic twofold symmetry and an aceto­nitrile mol­ecule of solvation. The O‐dpa⁻ ligand is both bidentate and bridging, linking two Cu atoms with a separation of 3.4270 (11) Å. Each Cu atom is surrounded by four coordinated atoms that are almost coplanar, with dimensions Cu—N = 1.940 (2) and 1.984 (3) Å, and Cu—O = 1.912 (2) and 1.945 (2) Å.     

Two Novel CuII Phenanthroline Adipato Complexes with π‐π Stacking Interactions: [Cu(phen)2(C6H8O4)] · 4.5 H2O and [(Cu2(phen)2Cl2)(C6H8O4)] · 4 H2O

The blue copper complex compounds [Cu(phen)₂(C₆H₈O₄)] · 4.5 H₂O ( 1 ) and [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)] · 4 H₂O ( 2 ) were synthesized from CuCl₂, 1,10‐phenanthroline (phen) and adipic acid in CH₃OH/H₂O solutions. [Cu(phen)₂‐ (C₆H₈O₄)] complexes and hydrogen bonded H₂O molecules form the crystal structure of ( 1 ) (P1 (no. 2), a = 10.086(2) Å, b = 11.470(2) Å, c = 16.523(3) Å, α = 99.80(1)°, β = 115.13(1)°, γ = 115.13(1)°, V = 1617.5(5) ų, Z = 2). The Cu atoms are square‐pyramidally coordinated by four N atoms of the phen ligands and one O atom of the adipate anion (d(Cu–O) = 1.989 Å, d(Cu–N) = 2.032–2.040 Å, axial d(Cu–N) = 2.235 Å). π‐π stacking interactions between phen ligands are responsible for the formation of supramolecular assemblies of [Cu(phen)₂(C₆H₈O₄)] complex molecules into 1 D chains along [111]. The crystal structure of ( 2 ) shows polymeric [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)_2/2] chains (P1 (no. 2), a = 7.013(1) Å, b = 10.376(1) Å, c = 11.372(3) Å, α = 73.64(1)°, β = 78.15(2)°, γ = 81.44(1)°, V = 773.5(2) ų, Z = 1). The Cu atoms are fivefold coordinated by two Cl atoms, two N atoms of phen ligands and one O atom of the adipate anion, forming [CuCl₂N₂O] square pyramids with an axial Cl atom (d(Cu–O) = 1.958 Å, d(Cu–N) = 2.017–2.033 Å, d(Cu–Cl) = 2.281 Å; axial d(Cu–Cl) = 2.724 Å). Two square pyramids are condensed via the common Cl–Cl edge to centrosymmetric [Cu₂Cl₂N₄O₂] dimers, which are connected via the adipate anions to form the [(Cu₂(phen)₂Cl₂)(C₆H₈O₄)_2/2] chains. The supramolecular 3 D network results from π‐π stacking interactions between the chains. H₂O molecules are located in tunnels.     

An Azelaato‐bridged Dinuclear Copper(II) Complex, [Cu2(phen)2(C9H14O4)2] · 6 H2O (phen = 1,10‐phenanthroline)

The title compound [Cu₂(phen)₂(C₉H₁₄O₄)₂] · 6 H₂O was prepared by the reaction of CuCl₂ · 2 H₂O, 1,10‐phenanthroline (phen), azelaic acid and Na₂CO₃ in a CH₃OH/H₂O solution. The crystal structure (monoclinic, C2/c (no. 15), a = 22.346(3), b = 11.862(1), c = 17.989(3) Å, β = 91.71(1)°, Z = 4, R = 0.0473, wR² = 0.1344 for 4279 observed reflections) consists of centrosymmetric dinuclear [Cu₂(phen)₂(C₉H₁₄O₄)₂] complexes and hydrogen bonded H₂O molecules. The Cu atom is square‐planar coordinated by the two N atoms of the chelating phen ligand and two O atoms of different bidentate bridging azelaate groups with d(Cu–N) = 2.053, 2.122(2) Å and d(Cu–O) = 1.948(2), 2.031(2) Å. Two azelaate anions bridge two common Cu atoms via the terminal O atoms (d(C–O) = 1.29(2) Å; d(C–C) = 1.550(4)–1.583(4) Å). Phen ligands of adjacent complexes cover each other at distances of about 3.62 Å, indicating π‐π stacking interaction, by which the complexes are linked to 1 D bands.     

A New Preparative Route of the “Stepped‐Cubane” Tetranuclear Copper(II) Compound, [Cu4(μ2‐OH)2(μ3‐OH)2Cl2(bipy)4]Cl2 · 6H2O

The compound [Cu₄(μ₂‐OH)₂(μ₃‐OH)₂Cl₂(bipy)₄]Cl₂ · 6H₂O ( 1 ) was obtained by recrystallization of [Cu(HB)₂(2, 2′‐bipy)] · H₂O (H₂B = diphenylglycolic acid) from EtOH/CH₂Cl₂ and their structure has been determined by single‐crystal X‐ray analysis. The cationic complex may be described as based on a Cu₄(OH)₄ core with a “stepped cubane” structure. The coordination polyhedron around each copper is a distorted square pyramid. The tetranuclear units are linked in the crystal by C‐H…Cl hydrogen bonds and by π‐π interactions between bipyridine rings. IR data are also presented.     

Hexaaquacobalt(II) and hexaaquanickel(II) bis(μ‐pyridine‐2,6‐dicarboxylato)bis[(pyridine‐2,6‐dicarboxylato)bismuthate(III)] dihydrate

The title complexes, hexaaquacobalt(II) bis(μ‐pyridine‐2,6‐dicarboxylato)bis[(pyridine‐2,6‐dicarboxylato)bismuthate(III)] dihydrate, [Co(H₂O)₆][Bi₂(C₇H₄NO₄)₄]·2H₂O, (I), and hexaaquanickel(II) bis(μ‐pyridine‐2,6‐dicarboxylato)bis[(pyridine‐2,6‐dicarboxylato)bismuthate(III)] dihydrate, [Ni(H₂O)₆][Bi₂(C₇H₄NO₄)₄]·2H₂O, (II), are isomorphous and crystallize in the triclinic space group P. The transition metal ions are located on the inversion centre and adopt slightly distorted MO₆ (M = Co or Ni) octahedral geometries. Two [Bi(pydc)₂]⁻ units (pydc is pyridine‐2,6‐dicarboxylate) are linked via bridging carboxylate groups into centrosymmetric [Bi₂(pydc)₄]²⁻ dianions. The crystal packing reveals that the [M(H₂O)₆]²⁺ cations, [Bi₂(pydc)₄]²⁻ anions and solvent water molecules form multiple hydrogen bonds to generate a supramolecular three‐dimensional network. The formation of secondary Bi...O bonds between adjacent [Bi₂(pydc)₄]²⁻ dimers provides an additional supramolecular synthon that directs and facilitates the crystal packing of both (I) and (II).     

Pb(II) and Mn(II) Coordination Compounds Involving 5,5′‐(1,4‐Phenylene)bis(1H‐tetrazole):Synthesis,Characterization, and Effect on Thermal Decomposition of Ammonium Perchlorate

Two coordination compounds [Pb₄(BDT)₃(OH)₂(H₂O)₄]·H₂O ( 1 ) and [Mn(H₂O)₆]·(HBDT)₂·2H₂O ( 2 ) [H₂BDT?5,5′‐(1,4‐phenylene)bis(1H‐tetrazole)] had been hydrothermally synthesized. 1 and 2 had been characterized by single‐crystal X‐ray diffraction, IR, elemental and thermal analyses. Structural analysis reveals that 1 exhibits 2D layer structure extended through BDT with two different coordination modes rings in transverse and vertical. 2 consists of [Mn(H₂O)₆]²⁺, free HBDT and water. In addition, 1 and 2 were explored as luminescent materials and additives to promote the thermal decomposition of ammonium perchlorate by differential scanning calorimetry.     

Bis­[tris(3‐cyclo­hexyl­pyrazol‐1‐yl)­hydridoborato]copper(II) di­chloro­methane disolvate

The title compound, [Cu(C₂₇H₄₀BN₆)₂]·2CH₂Cl₂, contains a four‐coordinate Cu^II ion lying on a crystallographic inversion centre, giving rise to a near‐regular square‐planar stereochemistry. There is an axial contact of 2.71 Å between the Cu ion and ligand B—H group, although this is unlikely to correspond to a significant `agostic' interaction.     

Crystal Structures and Luminescent Properties of Two Zinc(II) Coordination Compounds with a β‐Diketonate Derivative Ligand

The β‐diketonate derivative ligand [H₂L = 6‐(3‐hydroxy‐1‐oxo‐3‐pyrryl‐2‐propen‐1‐yl)‐2‐pyridinecarboxylic acid] and its zinc(II) coordination complexes, [Zn(H₂L)Cl₂] · (EtOH)(H₂O) ( 1 ) and [Zn₄(L)₄(H₂O)₂] · 5H₂O ( 2 ), were prepared and characterized by elemental analysis, IR and NMR spectroscopy, and single‐crystal X‐ray diffraction. Complex 1 is a mononuclear structure. Complex 2 is a [2 × 2] grid tetranuclear structure. The luminescent properties of the free ligand H₂L and complexes 1 and 2 in methanol solution were studied.