Synthesis, structures, and antimicrobial activity of nickel(II) and Zinc(II) complexes with 5-methoxy-2-[(3-methylaminopropylimino)methyl]phenol

The Schiff base 5-methoxy-2-[(3-methylaminopropylimino)methyl]phenol (MMP) derived from 4-methoxysalicylaldehyde and N-methylpropane-1,3-diamine and its nickel(II) and zinc(II) complexes [Ni(MMP)₂(NCS)₂] (I) and [ZnCl₂(MMP)] (II), have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination. The crystal of I is monoclinic: space group P2₁/c, a = 9.0488(8), b = 12.7768(12), c = 12.9232(11) Å, β = 101.927(5)°, V = 1461.9(2) ų, Z = 2. The crystal of II is orthorhombic: space group Pbca, a = 11.6991(7), b = 13.2839(8), c = 20.4451(12) Å, V = 3177.4(3) ų, Z = 8. The Schiff base coordinates to the metal atoms through the phenolate O and imine N atoms. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.     

Synthesis and crystal structures of two zinc(II) complexes derived from 4-bromo-2-(cyclopentyliminomethyl)phenol with different solvents

Two new mononuclear zinc(II) complexes, [ZnL₂] (I) and [ZnL₂] · 2MeOH (II) (HL = 4-bromo-2-(cyclopentyliminomethyl)phenol), were synthesized by the reaction of the Schiff base HL with zinc acetate in ethanol and methanol solutions, respectively. Both complexes were characterized by elemental analyses and single-crystal X-ray diffraction. The crystal of I is orthorhombic: space group Pbca, a = 14.711(3), b = 13.223(3), c = 24.870(5) Å, V = 4837.8(18) ų, Z = 8. The crystal of II is monoclinic: space group C2/c, a = 20.581(5), b = 10.660(3), c = 15.428(4) Å, β = 119.919(3)°, V = 2933.7(13) ų, Z = 4. The Zn atom in each complex is four-coordinated by two imine N and two phenolic O atoms, forming a tetrahedral geometry. Complex II possesses crystallographic two-fold rotation axis symmetry.     

Hydrothermal synthesis, crystal structure, and photoluminescence of Pb(II) and Mn(II) coordination polymers based on imidazo[4,5-f][1,10]phenanthroline

Two new coordination polymers, [Pb(IDPT)₂(NO₃)₂] (I) and [Mn(IDPT)(SO₄)(H₂O)₂] (II) (IDPT = imidazo[4,5-f][1,10]phenanthroline), were synthesized by hydrothermal method and characterized by elemental analysis and single-crystal X-ray diffraction technique. The results reveal that the complex I belongs to monoclinic crystal system, space group C2/c and complex II belongs to monoclinic crystal system, P2₁/c space group. The cell parameters are: a = 19.1970(13), b = 7.3875(5), c = 17.3825(12) Å, β = 100.47(10)°, V = 2424.0(3) ų, Z = 4, F(000) = 1488 for I; a = 10.9135(6), b = 7.0230(4), c = 19.7034(10) Å, β = 99.32(10)°, V = 1490.25(14) ų, Z = 4, F(000) = 828 for II. In the structure of complex I, the metal center Pb(II) is six-coordinated, displays an octahedral geometry. Each molecule is further connected with neighboring one via π-π interactions into 1D chain. In complex II, Mn(II) is six-coordinated to form a distorted octahedral geometry. Compound II displays 1D supramolecular chain formed through hydrogen bonds. Additionally, the fluorescent properties for the complexes were investigated. Complexes I and II exhibit strong photoluminescence with emission maximum at 583 and 529 nm at room temperature.     

Synthesis and crystal structures of the zinc(II) complexes with a tridentate Schiff base (1-pyridin-2-ylethylidene)pyridin-2-ylmethylamine

Two new isostructural zinc(II) complexes, [ZnCl₂(L)] (I) and [ZnBr₂(L)] (II), derived from the Schiff base ligand (1-pyridin-2-ylethylidene)pyridin-2-ylmethylamine (L), have been prepared and characterized by physicochemical methods and single-crystal X-ray crystallography. The crystal of I is monoclinic: space group P2₁/c, a = 11.699(3) Å, b = 8.460(2) Å, c = 14.766(3) Å, β = 99.686(3)°, V = 1440.6(6) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/n, a = 8.166(2) Å, b = 15.153(3) Å, c = 11.966(2) Å, β = 96.964(2)°, V = 1469.7(5) ų, Z = 4. The geometry of the pentacoordinated zinc atoms in both complexes is best described as a square pyramid.     

Synthesis, crystal structures, and biological activity of zinc(II) complexes derived from 4-bromo-2-[(3-diethylaminopropylimino)methyl]phenol

Two new Schiff base zinc(II) complexes, [ZnBr₂L] (I) and [ZnCl₂L] (II), where L is 4-bromo-2-[(3-diethylaminopropylimino)methyl]phenol, were synthesized and characterized by physico-chemical methods and single crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/n a = 7.250 (2), b = 16.136 (3), c = 15.802 (3) Å, β = 90.027 (3)°, V = 1848.6 (7) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/n, a = 7.177 (3), b = 15.970 (4), c = 15.689 (3), β = 91.674 (3)°, V = 1797.5 (9) ų, Z = 4. The Zn atom in each complex is four-coordinated by one phenolate O and one imine N atoms of the Schiff base ligand and two halide atoms, forming a tetrahedral coordination. The urease inhibitory activities of the complexes were evaluated.     

Syntheses, crystal structures, and fluorescence properties of Zinc(II) complexes with multi-dentate Schiff bases

Two new structurally similar mononuclear Schiff base zinc(II) complexes, [ZnBr(ClMP)] (I) and [ZnCl(NMP)] (II) (ClMP = 4-chloro-2-[(3-morpholin-4-ylpropylimino)methyl]phenolate; NMP = 4-nitro-2-[(3-morpholin-4-ylpropylimino)methyl]phenolate), and two new dinuclear Schiff base zinc(II) complexes, [Zn₂(EMP)₂I₂] (III), and [Zn₂(MPA)(CH₃OH)₂(N₃)₂] (IV) (EMP = 5-diethylamino-2-[(2-dimethylaminoethylimino)methyl]phenolate; MPA = N,N′-bis(3-methoxysalicylidene)propane-1,3-diamine), have been prepared and characterized mainly by single-cyrstal X-ray diffraction. Complex I crystallizes in the monoclinic space group P2₁/n with unit cell dimensions: a = 15.116(3), b = 9.465(1), c = 23.714(4) Å, β = 104.358(2)°, V = 3286.9(8) ų, Z = 8, R ₁ = 0.0439, and wR ₂ = 0.0736. Complex II crystallizes in the monoclinic space group P2₁/c with unit cell dimensions: a = 7.253(2), b = 16.652(4), c = 13.568(3) Å, β = 96.600(2)°, V = 1627.8(6) ų, Z = 4, R ₁ = 0.0417, and wR ₂ = 0.0809. Complex III crystallizes in the monoclinic space group C2/c with unit cell dimensions: a = 27.962(2), b = 8.246(2), c = 31.605(3) Å, β = 90.343(2)°, V = 7287.4(15) ų, Z = 8, R ₁ = 0.0721, and wR ₂ = 0.1709. Complex IV crystallizes in the monoclinic space group C2/c with unit cell dimensions: a = 20.483(3), b = 11.344(2), c = 14.909(3) Å, β = 131.650(1)°, V = 2588.6(7) ų, Z = 4, R ₁ = 0.0343, and wR ₂ = 0.0792. Each Zn atom in I and II are four-coordinated in a tetrahedral geometry by the NNO donor set of the Schiff base ligand and one halide atom. The Zn atoms in III are in square pyramidal coordination, and those in IV are in octahedral and tetrahedral coordination. Thermal stability and fluorescence properties of the complexes I and II have also been determined.     

Synthesis,crystal structures,and biological property of dinuclear oxovanadium(V) complexes derived from tridentate Schiff bases

A pair of structurally similar dinuclear oxovanadium(V) complexes, [VO₂L¹]₂ (I) and [VO₂L²]₂ (II), where L¹ and L² are the mono-anionic form of 2-[(2-isopropylaminoethylimino)methyl]-4-methylphenol (HL¹) and 4-fluoro-2-[(2-isopropylaminoethylimino)methyl]phenol (HL²), respectively, have been synthesized and characterized by elemental analysis, FT-IR spectra, and single crystal X-ray determination. The crystal of I is monoclinic: space group P2₁/c, a = 12.528(1), b = 12.266(1), c = 9.432(1) Å, β = 104.814(3)°, V = 1401.2(3) ų, Z = 2. The crystal of I is monoclinic: space group P2₁/n, a = 12.3128(5), b = 6.5124(3), c = 17.1272(7) Å, β = 105.863(1)°, V = 1321.1(1) ų, Z = 2. The V…V distances are 3.210(1) Å in I and 3.219(1) Å in II. The V atoms in the complexes are in octahedral coordination. Biological assay indicates that complex II, bearing fluoro-substitute groups, has stronger antimicrobial activity against most bacteria than complex I which bearing methyl-substitute groups.     

Synthesis and crystal structures of two azido-bridged copper(II) complexes with schiff bases

Two new end-on azido-bridged dinuclear copper(II) complexes with the formula [Cu(μ_1,1-N₃)₂(IEP)₂] (I) and [Cu(μ_1,1-N₃)₂(EMP)₂] (II), where IEP and EMP are the deprotonated forms of 2-[1-(2-isopropylaminoethylimino)ethyl]phenol and 2-ethoxy-6-[(2-methylaminoeth-ylimino)methyl]phenol, respectively, were synthesized. Both complexes were characterized by elemental analyses and IR spectra. The crystal structures were determined by the X-ray diffraction. The crystal of I is monoclinic: space group P2₁/c, a = 9.662(2), b = 15.282(3), c = 10.639(2) Å, β = 115.418(10)°, V = 1418.9(5) ų, Z = 2. The crystal of II is monoclinic: space group P2₁/n, a = 12.588(2), b = 7.705(1), c = 14.481(2), β = 91.736(5)°, V = 1403.9(2) ų, Z = 2. The two Cu atoms in each complex are bridged by two end-on azide groups. Each Cu atom is in a square pyramidal coordination. The Cu…Cu distances are 3.230(2) Å in I and 3.150(2) Å in II.     

Synthesis and crystal structures of cobalt(III) and zinc(II) complexes derived from 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol with urease inhibitory activity

A new mononuclear cobalt(III) complex, [CoL₂(N₃)]₂ · CH₃OH (I), and a new mononuclear zinc(II) complex, [ZnLCl(CH₃OH)] (II) (HL = 4-chloro-2-[(2-morpholin-4-ylethylimino)methyl]phenol), were prepared and structurally characterized by elemental analyses, infrared spectroscopy, and single- crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/c, a = 18.742(2) Å, b = 15.197(2) Å, c = 25.646(2) Å, β = 125.996(3)°, V = 5909.8(11) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/c, a = 7.257(1) Å, b = 24.707(2) Å, c = 9.637(1) Å, β = 101.557(2)°, V = 1692.9(3) ų, Z = 4. The Co atom in I is in an octahedral coordination, and the Zn atom in II is in a trigonal-bipyramidal coordination. The urease inhibitory test shows that complex I has strong urease inhibitory activity, while complex II has no activity.     

Synthesis,characterization, and crystal structures of two Schiff base zinc(II) complexes with urease inhibitory activities

Two Schiff base zinc(II) complexes, [ZnBr₂L¹] · 2CH₃OH (I) (I) and [ZnBr₂L²] (II), where L¹ is 4-chloro-2-[(2-piperazin-1-ylethylimino)methyl]phenol and L² is 4-chloro-2-[(3-diethylaminopropylimino)methyl]phenol were synthesized and structurally characterized. The crystal of I is monoclinic: space group P2₁/c, a = 9.831(3), b = 18.680(6), c = 11.879(4) Å, β = 94.660(6)°, V = 2174.3(11) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/n, a = 7.2310(14), b = 16.037(3), c = 15.856(3), β = 90.01(3)°, V = 1838.7(6) ų, Z = 4. The Zn atom in each complex is four-coordinated by one phenolate O and one imine N atoms of the Schiff base ligand and two bromide atoms, forming a tetrahedral coordination. The urease inhibitory activities of the complexes were evaluated.     

Synthesis,crystal structures,and antimicrobial activity of copper(II) and zinc(II) complexes derived from 2-bromo-4-chloro-6-[(2-morpholin-4-ylethylimino)methyl]phenol

An end-to-end azido-bridged dinuclear copper(II) complex [Cu₂L₂(μ_1,3-N₃)](NO₃) (I) and a mononuclear zinc(II) complex [ZnCl₂(HL)] ? CH₃OH (II), where L is 2-brom-4-chloro-6-[(2-morpholin- 4-ylethylimino)methyl]phenolate, have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination (CIF files CCDC nos. 1415217 (I), 1415218 for (II)). The crystal of I is monoclinic: space group C2/c, a = 28.684(2), b = 7.1787(5), c = 18.292(1) Å, β = 117.887(3)°, V = 3329.1(4) ų, Z = 4. The crystal of II is monoclinic: space group P2₁/c, a = 10.8207(9), b = 12.3398(7), c = 14.9477(7) Å, β = 93.473(3)°, V = 1992.2(2) ų, Z = 4. The Schiff base ligand in I coordinates to the Cu atom through the phenolate O, imine N, and morpholine N atoms, while the Schiff base ligand in II coordinates to the Zn atom through the phenolate O and imine N atoms, with the morpholine N atom protonated. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans was studied.     

Synthesis, structures, and antimicrobial activity of nickel(II) and zinc(II) complexes with Schiff bases derived from 3-bromosalicylaldehyde

The Schiff bases 2-bromo-6-[(3-cyclohexylaminopropylimino)methyl]phenol (HCMP) and 2-bromo-6-[(3-dimethylaminopropylimino)methyl]phenol (HDMP) derived from 3-bromosalicylaldehyde with N-cyclohexylpropane-1,3-diamine and N,N-dimethylpropane-1,3-diamine, respectively, and their nickel(II) and zinc(II) complexes [Ni(CMP)₂] (I) and [ZnCl₂(HDMP)] (II) have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination. The crystal of I is monoclinic: space group P2₁/c, a = 12.0304(6), b = 13.1594(6), c = 10.2445(5) Å, β = 101.019(1)°, V = 1591.9(1) ų, Z = 2. The crystal of II is monoclinic: space group C2/c, a = 22.286(5), b = 12.210(3), c = 14.513(3) Å, β = 124.118(3)°, V = 3269.5(13) ų, Z = 8. The Schiff base HCMP coordinates to the Ni atom through the phenolate O, imine N, and amine N atoms, while the Schiff base HDMP coordinates to the Zn atom through the phenolate O and imine N atoms. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.     

Synthesis,characterization, crystal structures,and antimicrobial activity of cobalt(II) and iron(III) complexes derived from N'-(2-hydroxybenzylidene)-3-methylbenzohydrazide

A new cobalt(II,III) complex, [Co^IIIL₂]₂[Co ₂ ^II (HL)₂(OH₂)₂(CH₃OH)₂] ? 2H₂O (I) and a new iron(III) complex, [Fe^III(HL)₂](NO₃) (II), where L^2– and HL^– are the dianionic and monoanionic form of N'-(2-hydroxybenzylidene)-3-methylbenzohydrazide, respectively, have been prepared and characterized by elemental analyses, infrared and UV-Vis spectroscopy and single-cyrstal X-ray diffraction (CIF files CCDC nos. 1417971 (I), 1417979 (II)). Complex I crystallizes in the monoclinic space group P2₁/n with unit cell dimensions a = 16.1665(9), b = 14.5692(8), c = 19.086(1) Å, β = 96.347(1)°, V = 4467.9(4) ų, Z = 2, R ₁ = 0.0521, and wR ₂ = 0.1411. Complex II crystallizes in the orthorhombic space group Pbcn with unit cell dimensions a = 12.475(1), b = 12.202(1), c = 18.859(2) Å, V = 2870.8(4) ų, Z = 4, R ₁ = 0.0796, and wR ₂ = 0.1981. The metal atoms in the complexes are in octahedral coordination. Crystals of the complexes are stabilized by hydrogen bonds. The efficiency of the aroylhydrazone and the two complexes was evaluated against B. subtilis, S. aureus, E. coli, P. fluorescence, C. albicans and A. niger, with the complexes demonstrating enhanced activity relatively to the free ligand.     

Heteroligand zinc(II) and copper(II) complexes with naphthylacetic acid and monoethanolamine: Syntheses and crystal structures

New heteroligand Cu(II) and Zn(II) complexes with the α-naphthylacetic acid anion (NAA) and monoethanolamine (MEA), [M(NAA)₂(MEA)₂] (M = Cu²⁺, (I), Zn²⁺ (II)), are synthesized. The crystal structures of the obtained complexes are determined by X-ray diffraction analysis (CIF files CCDC 984097 (I) and 930946 (II)). The crystals are monoclinic, for I: a = 18.8140(9) Å, b = 4.82500(14) Å, c = 16.0360(7) Å, β = 115.135(6)°, V = 1317.87(11) ų, space group P2₁/c, Z = 2; for II: a = 32.9760(14) Å, b = 5.0911(3) Å, c = 15.7994(10) Å, β = 94.418(5)°, V = 2644.6(3) ų, space group C2/c, Z = 4. In the structure of complex I, the Cu²⁺ ion arranged in the symmetry center is coordinated at the vertices of the distorted octahedron by the oxygen atoms of two NAA molecules (Cu-O(2) 2.019(4) Å) and two MEA molecules. The latter is the bidentate-chelating ligand and coordinates the metal through the O and N atoms to form the five-membered metallocycle (Cu-O(3) 2.457(5), Cu-N(1) 1.986(5) Å). In complex II, the Zn atom (on axis 2) is coordinated at the vertices of the distorted tetrahedron by the oxygen atoms of two NAA molecules (Zn-O(2) 1.976(4) Å) and the nitrogen atoms of two MEA molecules (Zn-N 2.034(6) Å). The character of the interaction of coordinated NAA and MEA ligands and methods for packing complexes I and II are considered on the basis of the structural data.     

Synthesis and crystal structure of zinc(II) and manganese(II) complexes of 2-(diphenylacetyl)indandione-1,3

Zinc(II) and manganese(II) complexes of 2-(diphenylacetyl)indandione-1,3 (HL) were synthesized. Crystals of [M(DMSO)₂L₂] · CHCl₃, where M= Zn^(II) (I) and Mn^(II) (II), obtained from chloroform plus dimethyl sulfoxide (DMSO) mixture were found to be isostructural based on the similarity of their unit cell parameters and unit cell volumes. The crystals are triclinic, Z = 2, space group P \(\bar 1\); a = 10.422(1) Å, b = 11.929(1) Å, c = 20.429(1) Å, α = 73.616(1)°, β = 85.095(1)°, γ = 77.586(1)° for complex I; a = 10.436(1) Å, b = 12.297(1) Å, c = 19.924(2) Å, α = 78.138(2)°, β = 87.625(2)°, γ = 82.048(2)° for complex II. X-ray structural analysis of complex I was carried out. For complex II, the structure was not refined because all of its atoms are each disordered over three to five positions. The two DMSO molecules in complex I coordinate the central metal atoms in the monodentate mode via their donor oxygen atoms to occupy an axial position and an equatorial position in an octahedral polyhedron. The other four positions are occupied by the four oxygen atoms of the two deprotonated ligands L^? coordinated in the bidentate-cyclic mode. The outer sphere of complex I contains the solvating chloroform molecule.     

Coordination molecular compounds of cadmium(II) iodide with dimethylpyridines

The reactions of CdI₂ with dimethylpyridines (Me₂Py is C₇H₉N) afford complexes CdI₂(2,3-Me₂Py)₂] (I), [CdI₂(2,6-Me₂Py) (II), and CdI₂(3,5-Me₂Py)₂ (III). The structures of compounds I and II are determined. The crystals of complex I are orthorhombic, space group Pbca, a = 7.930(1) Å, b = 15.537(1) Å, c = 29.943(1) Å, V = 3689.1(5) ų, ρ_calcd = 2.090 g/cm³, Z = 8. The crystals of complex II are monoclinic, space group C2/c, a = 14.784(1), b = 11.991(1), c = 17.711(1) Å, β = 90.39(1)°, V = 1081.1(2) ų, ρ_calcd = 2.908 g/cm³, Z = 4. The structure of compound I is built of discrete neutral complexes [CdI₂(2,3-Me₂Py)₂]. The Cd polyhedron is a distorted tetrahedron (Cd-I 2.289–2.295, Cd-N 2.708–2.734 Å, angles N(I)CdN(I) 103.1°-114.8°). Polymer chains [CdI₂(2,6-Me₂Py)]_∞ extended along the direction [100] are observed due to the bridging iodine atoms in structure II. The Cd polyhedron is a trigonal bipyramid containing iodine atoms at the axial vertices (Cd-I_aks 3.040 Å) and two iodine atoms and the nitrogen atom of the Me₂Py ligand in the equatorial plane Me₂Py (Cd-I_eq 2.840 Å, Cd-N 2.309 Å). The compounds in the solid state are photoluminescent.     

Crystal structures of copper(II) and zinc(II) complexes derived from 3-(2-pyridyl)pyrazole

Two dinuclear complexes [Zn(μ-L)(NO₃)(H₂O)]₂ (1) and [Cu₂(μ-L)₂(HL)₂](NO₃)₂(C₁₂H₈Br₂)_0.5·H₂O (2), (HL = 3-(2-pyridyl)pyrazole, C₁₂H₈Br₂ = 4,4′-dibromobiphenyl) are synthesized under hydrothermal conditions and characterized by elemental analysis and X-ray single crystal diffraction. Crystal data for 1: triclinic, \(P\bar 1\), a = 8.8478(7) Å, b = 15.0550(11) Å, c = 16.4310(12) Å, α = 107.588(4)°, β = 112.498(3)°, γ = 115.595(3)°, V = 2099.8(9) ų, Z = 2; for 2: triclinic, \(P\bar 1\), a = 7.2870(15) Å, b = 8.6840(17) Å, c = 9.3290(19) Å, α = 107.588(4)°, β = 112.498(3)°, γ = 115.595(3)°, V = 528.77(18) ų, Z = 1. Complex 1 and 2 are both dinuclear structures which are further packed into a 1D supramolecular chain and a 3D supramolecular framework via weak C–H…O hydrogen bond interactions respectively.     

Crystal structure of two hydrate phases of ciprofloxacindi-um tetrachloridocobaltate(II)

New (C₁₇H₂₀FN₃O₃)₂[CoCl₄]₂·3H₂O (I) and C₁₇H₂₀FN₃O₃[CoCl₄]·H₂O (II) compounds, where C₁₇H₁₈FN₃O₃ is ciprofloxacin (CfH), are synthesized and their crystal structures are determined. Crystallographic data for I: a = 18.441(5) Å, b = 9.030(3) Å, c = 27.551(8) Å, V = 4588(4) ų, space group Pca2₁, Z = 4; for II: a = 9.305(3) Å, b = 9.885(3) Å, c = 12.999(4) Å, α = 82.782(4)°, β = 72.954(4)°, γ = 89.736(4)°, V = 1133(1) ų, P-1 space group, Z = 2. Both structures contain CfH ₃ ²⁺ ion pairs bonded by the π-π interaction. Additionally, in the crystal of I there is a stacking interaction between the π clouds of aromatic rings and hydrogen atoms of the cyclopropyl group linking the pairs of molecules with each other. The structure of the centrosymmetric crystal of triclinic phase II is also formed from CfH ₃ ²⁺ ion pairs bonded by the π-π interaction, which, in this case, are not independent because they are related by the symmetry center. Hydrogen bonds form a branched three-dimensional network linking the CfH ₃ ²⁺ and CoCl ₄ ^2? ions and water molecules.     

Crystal and molecular structures of bis(2,2,6,6-tetramethyl-3-methylaminoheptan-5-onate) copper(II) and nickel(II)

Two bis-chelates M(tmih)₂ (M = Cu(II), Ni(II), tmih = (CH₃)₃C(NCH₃)CHCOC(CH₃)₃)^? are synthesized and their crystal structures are determined using XRD (Bruker APEX-II diffractometer with a CCD detector, λMoK _α, λCuK _α, graphite monochromator, T = 240(2) K and 296(2) K): Cu(tmih)₂ (I) (space group P2₁/c, a = 12.9670(8) Å, b = 18.4921(9) Å, c = 11.0422(6) Å, β = 93.408(4)°, V = 2643.1(3) ų, Z = 4) and Ni(tmih)₂ (II) (space group P2₁/c, a = 12.810(2) Å, b = 18.529(2) Å, c = 11.243(2) Å, β = 91.959(7)°, V = 2667.1(6) ų, Z = 4). The complexes are isostructural; the coordination polyhedron of metal atoms is a flattened tetrahedron formed from two O atoms (Cu-O of 1.901(2) Å, 1.892(2) Å, Ni-O of 1.845(2) Å, 1.833(2) Å) and two N atoms (Cu-N of 1.976(3) Å, 1.972(3) Å, Ni-N of 1.911(2) Å, 1.920(2) Å) of the ligand; the chelate OMN angles (M = Cu(II), Ni(II)) are in the 87.4–93.1° range; the OMO and NMN angles are 162.2° and 167.2° in I, 171.1° and 173.2° in II. The complexes have the molecular structures formed from isolated molecules bonded by van der Waals interactions. Using a quantum chemical hybrid M06 method, the structures of copper(II) chelates with the H, CH₃, CH₂CH₃, CH(CH₃)₂, and C(CH₃)₃ substituents at the nitrogen atom are calculated. Found that with a bulky substituent at the nitrogen atom, the formation of chelates is hindered due to the intraligand repulsion between the atoms of this substituent and the tert-butyl group.     

Synthesis, characterization, solvatochromic behavior and crystal structures of complexes [CoIII(salophen)(thioacetamide)2]ClO4 and [CoIII(salophen)(thiobenzamide)2]ClO4

Two new cobalt(III) complexes of the Schiff base N,N′-disalicylidene-1,2-phenylendiimine dianion (salophen), trans- [Co^III(salophen)(ta)₂]ClO₄, (ta = thioacetamide) (1) and trans-[Co^III(salophen)(tb)₂]ClO₄, (tb = thiobenzamide) (2) were synthesized and characterized using single-crystal X-ray diffraction and spectroscopic techniques. Both complexes show solvatochromism in a variety of solvents. Complex (1) crystallized from CHCl₃ as a solvate of orthorhombic symmetry, space group Pca2₁ with a = 17.3480(10) Å, b = 18.7522(10) Å, c = 18.8128(11) Å, α = β = γ = 90°, and Z = 8. The cobalt(III) center lies in a distorted octahedral environment. The crystal structure of (1) consists of two independent [Co^III(salophen)(ta)₂]⁺ cations and ClO₄ ^- anions held together essentially via hydrogen bonds and π-π stacking interactions. Complex (2), forming also a CHCl₃ solvate, crystallized in the monoclinic space group P2₁/n with a = 14.710(3) Å, b = 13.506(3) Å, c = 18.595(4) Å, β = 100.295(4)°, and Z = 4. The geometry around cobalt(III) center is a distorted octahedron. The crystal structure of (2) contains a [Co^III(salophen)(tb)₂]⁺ complex with a remarkably twisted salophen ligand. Both complexes, (1) and (2), contain approximately one disordered CHCl₃ molecule per Co in the solid state.