Synthesis,crystal structure and properties of di-μ2-alkoxo bridged binuclear manganese(III) Schiff base complexes

Transition Metal Chemistry - Preparation and isolation of the dimeric manganese(III) complex, [Mn2(Salpa)2(H2O)2Cl2] · 2DMF, (1), was accomplished by air oxidation of a solution containing...     

Self-assembly in transition metal complexes: structural characterization of a copper histamine nitrate [Cu(II)(him)2(NO3)2]

A new monomeric copper (II) complex with histamine (him), [Cu(II)(him)₂(No₃)₂], has been prepared by the reaction of Cu(NO₃)₂ with histaminium dichloride and its structure was determined by x-ray crystallography. The complex crystallizes in the triclinic system, space group with a = 5.7238(4), b = 8.7094(7), c = 9.2481(11) Å, = 69.693(8), = 73.242(7), = 71.050(7)°, V = 400.84(6) ų, and Z = 1. The structure consists of discrete [Cu(II)(him)₂(NO₃)₂] molecules in which the metal atom is centrosymmetrically coordinated by two histamine ligands forming an equatorial plane with Cu–N(imidazole ring) being 2.032(2) and Cu–N(NH₂ group) being 2.023(2) Å. Two O atoms from nitrate anions coordinate on the elongated axial positions with Cu–O being 2.549(2) Å. In the crystal structure, the molecules are organized by hydrogen bonds forming a two-dimensional network.     

Synthesis,crystal structure and properties of a novel di-μ2-aqua bridged binuclear manganese(III) Schiff base complex [Mn(vanen)(H2O)2]2(ClO4)2 · 2H2O

The preparation and isolation of the binuclear manganese(III) complex, [Mn(vanen)(H₂O)₂]₂(ClO₄)₂ · 2H₂O was accomplished by air oxidation of a solution containing H₂vanen^**, Et₃N, and Mn(ClO₄)₂ · 6H₂O in absolute EtOH. The crystal structure of complex was determined by X-ray crystallography, and consists of two molecules bridged by two water molecules through hydrogen bonding. The manganese atom is six-coordinate and presents a distorted octahedral coordination sphere, which consists of the two imine N atoms and two phenolic O atoms of vanen^2– ligand in the equatorial plane, with Mn–N bond distances of 1.975 and 1.987 Å, and Mn–O distances of 1.867 and 1.876 Å, respectively. The non-bonding interatomic MnMn distance is 4.79 Å. In the axial direction, the elongated Mn–O(H₂O) bond distances of 2.255 and 2.381 Å, respectively, are due to Jahn–Teller distortion at the d⁴ metal center. The presence of lattice and coordinate water molecules were also confirmed by the t.g. study and the i.r. spectra. Upon irradiation using visible light in water in the presence of p-benzoquinone, the complex demonstrates its ability to split water.     

Crystal structure of [Cu2(II)(dmpa)2(p-Cl-C6H5COO)2] (Hdmpa = N,N-dimethyl-3-amino-1-propanol)

The copper complex, [Cu₂(II)(dmpa)₂(p-Cl-C₆H₅COO)₂], has been prepared and its structure determined using X-ray crystallography. The dimer is a di-₂-alkoxo complex which is a five-coordinate copper dimer with unsupported alkoxo bridges. The complex crystallizes in the triclinic space group P-1 with a = 11.384(2), b = 14.636(5), c = 9.609(2) Å, = 100.07(2), = 104.33(3), = 72.79(2)°, V = 1471.8(7) ų, and Z = 2. The structure is comprised of discrete binuclear clusters in which the metal atoms are bridged by two alkoxo oxygens of the dmpa^– ligands. The Cu-O and Cu-N distances are in good agreement with those found for other copper(II) aminoalcoholato complexes. The Cu···Cu distance is 2.9765(6) Å. In the crystal, every two dimeric coordination molecules are combined together by the recognition through intermolecular hydrogen-bonding interactions between the apical water molecule and the non-coordinated O atom from the p-chlorobenzoato ligand, forminga tetramer.     

Synthesis,crystal structure and properties of a manganese(III) Schiff-base complex: [{Mn(vanen)(Him)(H2O)}{Mn(vanen)(Him)2}](ClO4)2 · 4H2O(H2vanen = N,N′-bis(methoxysalicylidene)-1,2-diaminoethane)

A novel manganese(III) complex, [{Mn(vanen)(Him)(H₂O)}(Mn(vanen)(Him)}](ClO₄)₂ · 4H2O [H₂vanen = N,N-bis(methoxysalicylidene)-1,2-diaminoethane], has been synthesized and characterized by elemental analysis, i.r. spectroscopy, t.g.a. and by an X-ray single crystal study. The complex consists of two sets of cations: [Mn(vanen)(Him)(H₂O)]⁺ (A) and [Mn(vanen)(Him)₂]⁺ (B), each of which has six-coordinate geometry, significantly elongated due to the Jahn-Teller distortion at the d⁴ manganese(III) center. The presence of lattice and coordinate water molecules are also confirmed by the t.g. study and the i.r. spectra.     

Crystal structure of [Co(bipy)(maleato) (H2O)3]·H2O (bipy = 2,2′-bipyridine)

Preparation of the mononuclear cobalt(II) complex, [Co(bipy)(maleato) (H₂O)₃]·H₂O (1) where bipy = 2,2-bipyridine, were accomplished by reaction of an aqueous solution containing sodium maleate and an ethanolic solution of Co(NO₃)₂·6H₂O and bipy. The crystal structure of complex (1) was determined by X-ray crystallography. The complex crystallizes in the monoclinic space group P2₁/n with a = 9.477(3), b = 7.660(2), c =23.526 (3) Å, = 97.64(2)°, V = 1692.6(6) ų, and Z = 4. The structure consists of discrete mononuclear cobalt molecules. The cobalt atom is six-coordinate and presents a slightly distorted octahedral geometry, which consists of the two imine N atoms of bipy, a terminal carboxylate O atom from maleato ligand, and a water O atom in the basal plane with Co—N bond distances of 2.116(2) and 2.124(3) Å and Co—O distances of 2.075(2) and 2.088(2) Å, respectively. The relatively shorter Co—O distances are due to the trans effect of the bipy ligand. The octahedral coordination is completed the other two water molecules. The coordinate and the lattice water molecules were identified by TG study.     

Crystal structure of [Mn(II)(phen)(ClCH2COO)2]n (phen = 1,10−phenanthroline)

A new polymeric manganese(II) complex, [Mn(II)(phen)(ClCH₂COO)₂]_n, was obtained from the reaction of Mn(ClCH₂COO)₂ with phen and its structure was determined by x-ray crystallography. The complex crystallizes in the monoclinic system, space group C2/c with a = 19.706(4), b = 11.381(3), c = 7.482(3) Å, = 94.01(3)°, V = 1674.0(8) ų, and Z = 4. The structure consists of an infinite chain. The manganese atom is located on a twofold axis and presents a distorted octahedral coordination sphere, which consists of the two N atoms of a phen ligand (Mn—N = 2.304(2) Å) and four carboxylato ligands. The Mn···Mn distance within the chain is 4.53 Å, and the carboxylato bridges present a syn-anti conformation.     

Crystal structure of [Mn2(III)(salpa)2Cl2(H2O)2] (H2salpa = 1-(salicylaldeneamino)-3-hydroxypropane)

The manganese complex, (Mn₂(III)(salpa)₂Cl₂(H₂O)₂], has been prepared and its structure determined using x-ray crystallography. The dimer is a di-₂-alkoxo complex which is a six-coordinate manganese dimer with unsupported alkoxide bridges and a rare example of a chloride- and water-containing manganese dimer. The complex crystallizes in the monoclinic space group P2₁/c with a = 9.315(5), b = 11.130(4), c = 11.637(5) Å, = 104.33(3)°, V = 1169.0(9) ų, and Z = 2. The structure comprises discrete binuclear clusters in which the metal atoms are bridged by two alkoxo oxygens of the salpa^2– ligands. The Mn—O and Mn—N distances are in good agreement with those found for other manganese(III) Schiff base complexes. The Mn—Cl and Mn—O3 distances are 2.585(2) and 2.371(2) Å, respectively, and the Mn ··· Mn distance is 3.001(1) Å. In the crystal, there are two types of hydrogen bonding between the H₂O molecule and the Cl atom with Cl ··· H(H₂O) distance of 2.33(6) (intramolecule: –1 + x, y, –1 + z) and 2.68(6) Å (intermolecule: –1 + x, 0.5–y, –0.5 + z).     

Schiff碱与锰(Ⅲ)的单核和双核配合物的合成与结构

本文报道合成了以水杨醛及邻香草醛缩丙醇胺Schiff碱与锰(Ⅲ)的六个新型配合物,其中［Mn₂(salpa)₂(PhCOO)₂］·2CH₂Cl₂,［Mn₂(vanpa)₂(PhCOO)₂］·2CHCl₃,［Mn₂(vanpa)₂(ClCH₂COO