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1.
Joy Chakraborty Brajagopal Samanta Andrei S. Batsanov Joan Ribas M. Salah El Fallah Samiran Mitra 《Structural chemistry》2006,17(4):401-407
A ligand–metal–ligand type co-ordination polymer [Ni (C6H12N4)(NCS)2(H2O)2]
n
has been synthesised under controlled hydrothermal conditions. Here 1,3,5,7-tetraazatricyclo[3.3.1]decane [or hexamethylenetetramine (hmt)] has been used as a μ-(N,N′) bidentate spacer molecule. The prepared polymeric complex has been characterised by elemental and spectral analyses. The structure has been confirmed by a single crystal X-ray diffraction study. Magneto-structural correlation has been drawn from cryomagnetic susceptibility measurements (2–300 K) which unequivocally reflects very weak magnetic spin interactions among the long distant octahedral Ni(II) metal centres mediated by hmt and weak hydrogen bonding interactions between the adjacent zigzag one-dimensional polymeric chains carrying into a two-dimensional infinite polymeric framework. 相似文献
2.
Brajagopal Samanta Joy Chakraborty C. R. Choudhury S. K. Dey D. K. Dey S. R. Batten P. Jensen Glenn P. A. Yap Samiran Mitra 《Structural chemistry》2007,18(1):33-41
We have reported herein the synthesis of three new Cu(II) complexes of tri- and tetradentate Schiff base ligands containing
N3 or N4 donor set along with terminal NNN− or SCN− ligands: [L1Cu(NCS)]ClO4 (1), [L2Cu(NCS)2] (2) and [L3Cu(NNN)]ClO4 (3) [L1 = NC5H4C(CH3)=N(CH2)3N=C(CH3)C5H4N, L2= Me2N–(CH2)3–N=C(CH3)C5H4N and L3 = NC5H4CH=N–(CH2)4–N=CHC5H4N]. The complexes have been systematically characterised by elemental, spectroscopic and electrochemical techniques. Antimicrobial
activities of the Schiff base ligands and their metal complexes have been studied using the disc diffusion method on the strains
of Candida tropicalis and Bacillus megaterium. Structures of all the complexes have been unequivocally established from single crystal X-ray diffraction analyses that
show the monomeric units containing a five-coordinated copper center in highly distorted square pyramidal geometry with thiocyanate
or azide anion coordinated as terminal ligand. The complexes 1 and 3 crystallise in monoclinic (P21/c) and 2 in triclinic (P-1) space group, respectively. 相似文献
3.
Talukder P Datta A Mitra S Rosair G El Fallah MS Ribas J 《Dalton transactions (Cambridge, England : 2003)》2004,(24):4161-4167
A new tridentate Schiff base ligand HL (L = C14H19N2O), derived from the condensation of benzoylacetone and 2-dimethylaminoethylamine in a 1:1 ratio, reacts with copper(ii) acetate and cyanate, thiocyanate or azide, to give rise to several end-to-end polymeric complexes of formulae [CuL(mu(1,3)-NCO)]n 1, [CuL(mu(1,3)-NCS)]n 2 and the complex 3 has two crystallographically independent units of formula [CuL(N3)] in the asymmetric unit cell. Complex 3 exists in dimeric form rather than as a polymeric chain. Compound 1 is the first report of a singly end-to-end cyanate bridged polymeric chain of Cu(II) with a Schiff base as a co-ligand. There are many examples of double NCS bridged polymeric chains, but fewer singly bridged ones such as compound 2. We have characterized these complexes by analytical, spectroscopic, structural and variable temperature magnetic susceptibility measurements. The coordination geometry around the Cu(II) centers is distorted square pyramidal for 1 and 2 and square planar for complex 3. The magnetic susceptibility data show slight antiferromagnetic coupling for the polymers having J values -0.19 and -0.57 cm(-1) for complexes 1 and 2 respectively. The low values of J are consistent with the equatorial-axial disposition of the bridges in the polymers. 相似文献
4.
Subhra Basak Soma Sen Sambuddha Banerjee Samiran Mitra Georgina Rosair M.T. Garland Rodriguez 《Polyhedron》2007
Three new dinuclear Zn(II) complexes [Zn(L)(μ1,1-N3)Zn(L)(N3)] · 1.5H2O (1), [Zn(L)(μ1,1-NCO)Zn(L)(NCO)] · 1.5H2O (2) and [Zn(L)(μ1,1-NCS)Zn(L)(NCS)(OH2)] (3) have been synthesized from a potentially tetradentate N2O2-donor Schiff base ligand LH, [LH = (OCH3)(OH)C6H3CHN(CH2)2N(CH3)2], which is the condensation product of o-vanillin and 2-dimethylaminoethylamine. All the three complexes 1, 2 and 3 have been characterized by elemental analysis, IR and 1H NMR spectroscopy, TGA and fluorescence studies. Finally, their structures have been established by the single crystal X-ray diffraction method. Structural studies reveal that in complexes 1, 2 and 3 the two Zn(II) centers are held together by a μ2-phenolato oxygen atom and also by an end-on pseudohalide nitrogen (azide for 1; cyanate for 2; thiocyanate for 3) atom. Among the two deprotonated Schiff base ligands present in each complex, one acts as a tetradentate ligand (N2O2 donor set) while the other acts as a tridentate ligand (N2O donor set), having a non-coordinated methoxy group. All the synthesized complexes display intraligand 1(π–π∗) fluorescence and can potentially serve as photoactive materials. 相似文献
5.
Anamika Das Christoph Marschner Joan Cano Judith Baumgartner Joan Ribas M. Salah El Fallah Samiran Mitra 《Polyhedron》2009
Two new dicyanamido-bridged di- and polynuclear complexes of Co(II), [Co(dca)(tptz)(H2O)]2·2(ClO4) (1) and [Co(dca)2(imz)2]n (2) [dca, dicyanamide; tptz, 2,4,6-tris(2-pyridyl)1,3,5-triazine; and imz, imidazole] have been synthesized and characterized structurally, as well as magnetically. The X-ray single crystal structure determination of complex 1 shows that two symmetry related octahedral Co(II) ions are separated by dca ligand and other coordination sites are satisfied by tptz and aquo ligands. Each dinuclear unit is associated with each other by intramolecular hydrogen bonding interactions, giving rise to a 1D chain structure. On the other hand complex 2 is a 1D coordination polymer having [Co(II)(imz)2] units connected by double bridging dca ligands. These 1D chains interact through face-to-face π–π stacking interactions of the imz rings extending the dimensionality to a 2D supramolecular network. The variable temperature (300–2 K) magnetic measurements of both compounds reveal that dicyanamide exhibits a weak antiferromagnetic interaction between the metal centers. 相似文献
6.
Chakraborty A Kar S Nath DN Guchhait N 《The journal of physical chemistry. A》2006,110(44):12089-12095
A donor-acceptor substituted aromatic system (E)-3-(4-Methylamino-phenyl)-acrylic acid methyl ester (MAPAME) has been synthesized, and its photophysical behavior obtained spectroscopically has been compared with the theoretical results. The observed dual fluorescence from MAPAME has been assigned to emission from locally excited and twisted intramolecular charge transfer states. The donor and acceptor angular dependency on the ground and excited states potential energy surfaces have been calculated both in vacuo and in acetonitrile solvent using time dependent density functional theory (TDDFT) and TDDFT polarized continuum model (TDDFT-PCM), respectively. Calculation predicts that a stabilized twisted excited state is responsible for red shifted charge transfer emission. 相似文献
7.
Amitabha Datta Nirmal Kumar Karan Samiran Mitra Volker Gramlich 《Journal of chemical crystallography》2003,33(7):579-583
The nickel(II) complex [Ni(C4H3NCH=N–(CH2)3–N=CHC4H3N)], (1) containing the symmetrical N4 tetradentate Schiff base ligand, which is the 2:1 condensation product of pyrrole-2-carboxaldehyde and 1,3-diaminopropane respectively, was prepared. Structural investigation shows that it is monomeric, having space group P21/c, a = 7.989(7), b = 17.406(14), c = 9.193(5) Å, = 90, = 100.39(6), = 90, and Z = 4. The coordination geometry around the nickel atom is slightly distorted square planar and the conformation of the six-membered ring containing the metal,azomethine nitrogens and three carbon atoms of the connecting 1,3-diaminopropane is a symmetric boat. 相似文献
8.
Sutapa Sen Manas K. Saha Tarakranjan Gupta Aswini K. Karmakar Parimal Kundu Samiran Mitra Michael B. Hursthouse K. M. Abdul Malik 《Journal of chemical crystallography》1998,28(10):771-777
The compound [Cu(phen)(O2CCF3)2]n (phen = 1,10-phenanthroline) has been synthesized and its crystal structure determined. It crystallizes in monoclinic space group C2/c, with a = 19.229(7), b = 11.281(5), c = 7.621(2) Å, = 104.305(12)°, and Z = 4. The crystal structure is polymeric, being built from infinite zigzag chains of trifluoroacetate bridged copper(II), with the phenanthroline ligands being stacked between the chains. The variable-temperature (13–300 K) magnetic susceptibility and ESR data are reported and a weak ferromagnetic exchange interaction is observed with the exchange parameter estimated as J = 2.9 cm–1. 相似文献
9.
Aurkie Ray Sambuddha Banerjee Georgina M. Rosair Volker Gramlich Samiran Mitra 《Structural chemistry》2008,19(3):459-465
A nickel(II) and a cobalt(III) complex of two different potentially tetradentate Schiff bases with different binding modes
have been synthesised. The nickel(II) complex [NiL1] · CH3OH (1) was formed, on reacting the metal salt with a perfectly symmetrical N2O2 tetradentate Schiff base ligand H
2
L
1
, which is the 1:2 condensation product of 1,3-diamino propane and 2-hydroxyacetophenone. The cobalt(III) complex [Co(HL2)3] · (ClO4)3 · H2O (2) was synthesised using an asymmetric N2O2 tetradentate Schiff base ligand HL
2
on condensing N,N-dimethyl-1,3-diamino propane with o-vanillin in 1:1 mmol ratio. Although both Schiff bases are N2O2 functionalised, they showed variation in their coordinative property with nickel(II) and cobalt(III) ions. Both the complexes
were characterised by IR spectroscopy and cyclic voltammetry and their single crystal structures clearly indicate that 1 is a mononuclear species whereas 2 is a hydrogen-bonded dimer. 相似文献
10.
Thakurta S Chakraborty J Rosair G Tercero J El Fallah MS Garribba E Mitra S 《Inorganic chemistry》2008,47(14):6227-6235
Two new Cu(II) linear trinuclear Schiff base complexes, [Cu3(L)2(CH3COO)2] (1) and [Cu3(L)2(CF3COO)2] (2), have been prepared using a symmetrical Schiff base ligand H2L [where H2L = N,N'-bis(2-hydroxyacetophenone)propylenediimine]. Both of the complexes have been characterized by elemental analyses, Fourier transform IR, UV/vis, and electron paramagnetic resonance spectroscopy. Single-crystal X-ray structures show that the adjacent Cu(II) ions are linked by double phenoxo bridges and a mu(2)-eta(1):eta(1) carboxylato bridge. In each complex, the central copper atom is located in an inversion center with distorted octahedral coordination geometry, while the terminal copper atoms have square-pyramidal geometry. Cryomagnetic susceptibility measurements over a wide range of temperature exhibit a distinct antiferromagnetic interaction of J = -36.5 and -72.3 cm(-1) for 1 and 2, respectively. Density functional theory calculations (B3LYP functional) and continuous-shape measurement (CShM) studies have been performed on the trinuclear unit to provide a qualitative theoretical interpretation of the antiferromagnetic behavior shown by the complexes. 相似文献