Subrata Kumar Dey

First report of singly phenoxo-bridged copper(II) dimeric complexes: synthesis, crystal structure and low-temperature magnetic behaviour study

Three singly phenoxo-bridged dinuclear Cu(II) complexes [Cu2(L)2(SCN)(H2O)](ClO4) n1, [Cu2(L)2(N3)(H2O)](ClO4) n2, [Cu2(L)2(NCO)(H2O)](ClO4) n3 n(HL is the Schiff base ligand derived from O-vanillin and 2-aminomethyl ethylenediamine) have been synthesised and characterised by infrared, UV-Vis spectra, electrochemical study and single crystal X-ray diffraction study. In all the complexes (1–3), there are two geometrically different square pyramidal copper(II) centres, with N3O2 and N2O3 donor sets for the two Cu(II) centres. In the dimeric unit, the copper atoms are held together by only one distinct rare μ2-phenolate oxygen of one Schiff base. The Cu–Cu distances are 3.291(2), 3.244(1) and 3.244(1) nA for complexes 1, 2 and 3, respectively, and the Cu–O–Cu angles are found to be 111.5(1), 109.3(2), 109.6(1)° for complexes 1, 2 and 3, respectively. Variable temperature magnetic susceptibility study on the complexes 1,2 and 3 indicate the presence of antiferromagnetic coupling between the Cu(II) centres with 2J values −109.8, −103.9 and −95.9 cm−1, respectively.

Synthesis and structural characterization of [Ni(Me2NCH2CH2CH2N=CHC6H4O)2]

The synthesis, properties, and X-ray crystal structure of a Ni(II) complex of the tridentate Schiff base ligand Me2NCH2CH2CH2N=CHC6H4OH(LH) are described. The complex crystallizes in the monoclinic space group P21/c, with a = 10.180(2), b = 15.169(3), c = 15.293(4) Å, β = 106.69(2)°, and Z = 4. The Ni atom shows a distorted fac-octahedral geometry, with the two Ni—N(Me2) bonds being significantly longer than the two Ni—N(imino) bonds, 2.284(9), 2.310(9) vs. 2.051(2), 2.055(2) Å.

Synthesis and structural studies of selenocyanato-bridged polymeric and molecular complexes of cadmium(II): presence of both end-to-end and end-on coordination

Abstract Two new complexes, having one two-dimensional zig–zag polymeric network [Cd2(dmen)2(SeCN)4]n (1) and one molecular packing structure [Cd(dmen)2(SeCN)2] (2) (where dmen=N,N-dimethyl ethylenediamine), have been synthesised and characterised by infrared spectra and single crystal X-ray diffraction study. The different arrangements of selenocyanate anions result in two dimensional zig–zag polymeric sheet with the formation of two different rings, one having an eight-membered nearly hexagonal ring and another having a pseudo 16-membered ring for 1 and a molecular complex 2 with four independent molecules, having a total of 16 molecules per cell. The coordination environment in both the complexes is distorted octahedral. In the selenocyanato-bridged polymeric complex the cadmium(II) ions are linked by end-to-end coordination whereas in the molecular complex the cadmium(II) ions are bridged by end-on coordination only.

A new cyanato-bridged polymeric complex [Cd3(NCO)6(NH2CH2C5H4N)3]n with a zig–zag ladder shaped structure

Abstract A new cyanato-bridged polymeric complex [Cd3(NCO)6(NH2CH2C5H4N)3]n has been synthesized and characterized by X-ray crystallography. There are three cadmium atoms, three chelated 2-(aminomethyl)pyridine and six end-on bridging cyanato groups in the asymmetric unit. Each Cd atom is bonded to one chelated C5H4NCH2NH2 base and four μ2-NCO groups in a distorted octahedral environment. Three such independent CdN6 octahedra share their bridging edges to produce a zig–zag ladder shaped polymeric network extending along a.

Experimental Measurements of Wind-Resistant Support in a Circular Stack Design

Higher capacities of power plants together with increased awareness on environmental considerations have led to taller height of stacks. It is seen that strong wind can result in falling of stacks. So aerodynamic considerations of stacks is very important in order to save the falling of stacks. One stack is not enough in industries and power sectors and two or three stacks are required for proper operation of the unit. It is very important to arrange the stacks in proper way to resist their downfall. The present experimental study concentrates on the mutual effect of three nearby stacks on each other at three different arrangements, viz. linear, side-by-side and triangular. The experiments find out the directions of resultant forces acting on the stacks in different configurations so that proper arrangement of supports can be made with respect to the wind directionality obtained from local meteorological data. The other conclusions that could be drawn from these experiments are: (a) the second stack in along wind linear arrangement experiences the most drag and hence is much more susceptible to falling down with high gusts, whereas the last stack experiences the least drag and hence less prone to the downfall. (b) In side-by-side arrangement, although the middle one experiences maximum drag, the lift forces on the right and left stacks are far greater and hence the resultant force on them are much more in comparison to the middle one. (c) In the triangular arrangement also, the lift force being so pronounced on the right and left corner stacks, the resultant force on them will be much higher in comparison to that on the front stack sitting at the apex of the triangle. Thus, this study is important in studying the effect of wind force on three stacks in different arrangements and is very helpful in placing the supports in proper places in order to avoid failing of stack-like structures due to wind.© 2006 ASME

Isolation and characterisation of a novel thermally stable octahedral bicarbonato complex of bis(2-picolylamine)copper(II): identification of rare monodentate coordination

A novel bicarbonate complex, [Cu(C5H4NCH2NH2)2(OCO2H)2] (1), has been synthesised under controlled pH and characterised by IR, UV-Vis spectroscopy, magnetic moment and thermal analysis; the coordination environment around the metal centre is elongated octahedral with two chelated bidentate amines in the square plane and the axial sites are occupied by two monodentate bicarbonate ligands.