Joy Chakraborty

Syntheses, characterisation, magnetism and photoluminescence of a homodinuclear Ln(III)-Schiff base family

A novel family of homodinuclear complexes of the general formula [Ln(2)L(2)(X)(2)] (where Ln = Nd(3+), Pr(3+), Sm(3+) and Tb(3+) for 1, 2, 3 and 4, respectively and X, the coordinated NO(3)(-) or Cl(-) anion) has been synthesised from the corresponding lanthanide(III) salts with the pentadentate dianionic Schiff base ligand, H(2)L [N(1),N(3)-bis(salicylideneimino)diethylenetriamine], that exhibits a N(3)O(2) donor set. Single crystal X-ray diffraction studies evidenced the isostructurality of this family of centrosymmetric neutral dinuclear entities where the Ln(III) metal centres are coupled together by two phenolato oxygen atoms belonging to two units of ligand (H(2)L). Interestingly, the two other phenolato groups of H(2)L are mono-coordinated to the metal ions. Temperature dependence (2-300K) magnetic susceptibility studies suggest the presence of an antiferromagnetic interaction operating via double phenolato bridges. Photoluminescence activities of the complexes have been studied and compared with their precursor ligand. All the complexes have been characterised with microanalytical and several spectroscopic techniques.

Two New Quadridentate Schiff Base Complexes of Nickel(II) and Cobalt(III): Synthesis, Structure and Spectral Characterisation

Two novel quadridentate Schiff base complexes, [NiIILH](ClO4)2・H2O (1) and [CoIIIL]- (ClO4)2・H2O (2) [LH, a Schiff base ligand: Ph(OH)C(Me)=NCH2CH2N(CH2CH2NH2)2] have been synthesised and characterised by elemental analyses, spectroscopic and electrochemical studies. The structures of both have been unequivocally established from single crystal X-ray diffraction studies. 1 and 2 crystallise in the monoclinic space group P21/n having cell parameters a = 8.536(1), b = 13.832(4), c = 18.194(2) Å , β = 100.00(10)°, Z = 4 for 1, and a = 10.819(5), b = 14.301(2), c=14.224(1) Å , β =97.04(2)°, Z =4 for 2. The complexes expose a square planar geometry around the metal centers chelated with three different types of nitrogen donor centers of the ligand.

A 'Butterfly'-Shaped Water Tetramer in a Cu4 Complex Supported by a Hydrazone Ligand: Synthesis, Crystal Structure, Magnetic Properties, and Quantum Chemical Study

A potentially tetradentate NOOO donor hydrazone ligand, LH2 (condensation product of benzhydrazide with O-vanillin) generates a tetranuclear CuII complex [Cu4(L)4]·4H2O (1), whose void spaces are occupied by water tetramers presenting a ‘butterfly’ conformation with the highest dihedral angle reported to date, as revealed by its X-ray crystal structure. 1 has also been characterized using various spectroscopic techniques, including IR, UV-vis, and elemental analysis. Variable temperature magnetic susceptibility measurements reveal the presence of moderate antiferromagnetic intra-tetramer coupling between the four CuII centres connected through simple oxo groups of the hydrazone ligand with two different coupling constants (J1 = –61.7(3) cm–1 and J2 = –92(1) cm–1) corresponding to the two different CuII tetramers identified in the X-ray structure. We also report a quantum chemical study (MP2(full)/6–311+G(3df,2p)//B3LYP/6–311+G(3df,2p)) to calculate the stability of the water tetramers.

Synthesis, Structure and Fluorescence Properties of a Trinuclear Zn(II) Complex with N,N,O-donor Schiff Base Ligands and Bridging Acetates

A new centrosymmetric trinuclear Zn(II) complex [Zn3L2(CH3COO)4] (1) has been synthesized by the reaction of Zn(CH3COO)2 · 2H2O with a tridentate N,N,O-donor Schiff base ligand HL [C5H4NC(CH3)=NC6H4(OH)] and systematically characterized by elemental analysis, FT-IR, UV/Vis and thermal methods. Single crystal X-ray structure analysis reveals that three Zn(II) centers are in two different coordination environments. Two terminal Zn(II) centers adopt a distorted squarepyramidal geometry leaving the central Zn(II) in a distorted octahedral environment. Two adjacent metal centers are connected through single μ2-phenolato as well as double μ-acetato-O,O´ syn-syn bridges. Fluorescence properties of the complex as compared to the ligand indicate that the former can serve as a potential photoactive material. Graphical Abstract Synthesis, Structure and Fluorescence Properties of a Trinuclear Zn(II) Complex with N,N,O-donor Schiff Base Ligands and Bridging Acetates

Synthesis, Characterisation and Crystal Structure of a Copper(II) Dichromate Complex with the N,N’-Bis(2-pyridylmethylene)butane- 1,4-diamine Schiff Base Ligand

The new complex Cu[L1]Cr2O7has been synthesised with the N,N′-bis(2-pyridylmethylene) butane-1,4-diamine Schiff base L1, [NC5H4CH=N(CH2)4N=CHC5H4N], and characterised with elemental analyses and different spectroscopic and electrochemical studies. The structure of the new complex has been established by single crystal X-ray diffraction. The complex crystallises in the monoclinic system with space group P21/c having cell parameters a = 14.7(5), b = 9.22(2), c = 16.2(5) Å , β = 116.9(1)°, and Z = 4. The Cr2O72− unit is bonded through one terminal oxygen donor end to the central Cu(II) chelated by the Schiff base ligand.