Browsing by Author "Daya S. Pandey"

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Nickel and copper complexes based on tridentate nitrogen donor ligand 2,6-bis-(1-phenyliminoethyl) pyridine: Synthesis, spectral and structural characterization
(Elsevier S.A., 2007) Manoj Trivedi; Daya S. Pandey; Qiang Xu
The reaction of CuCl2 · 2H2O with 2,6-bis(1-phenyliminoethyl)pyridine (referred hereafter as L) in 1:1 molar ratio in methanol or acetronitrile at room temperature afforded distorted trigonal-bipyramidal complex [Cu(κ3-L)Cl2]. On the other hand, the reaction of NiCl2 · 6H2O with 2 equivalents of L gave an octahedral complex [Ni(κ3-L)2]2+, which was isolated as [Ni(κ3-L)2][BF4]2 using NH4BF4. The complexes have been characterized by elemental analyses, FAB-MS, IR, EPR and electronic spectral studies. Molecular structures of both the [Cu(κ3-L)Cl2] (1) and [Ni(κ3-L)2](BF4)2 (2) have been determined by single crystal X-ray analyses. Weak interaction studies on 1 and 2 revealed stabilisation of the crystal packing by inter and intra-molecular C-H⋯X (X = F, Cl, π) interactions. In complex 2 ortho C-H bond from phenyl rings leads to unexpected C-H⋯π interaction with nickel α,α′-diimine chelate ring. This provides structural support for metalloaromaticity in the chelate ring of complex 2. © 2007 Elsevier B.V. All rights reserved.
Reactions and structural studies of 4-(1H-benzimidazole-2-yl)-benzonitrile with metal nitrates
(Indian Chemical Society, 2012) Rampal Pandey; Daya S. Pandey
One pot synthesis of 4-(1H-benzimidazole-2-yl)-benzonitrile (1) under mild reaction conditions and metal-organic hybrid of 4-CN-BIBH with CoII salt have been reported for the first time. In the metal-organic hybrid [Co(NO3)2.4H2O, (4-CN-BIBH)] (3), there is no interaction between the metal and 4-CN-BIBH through dative bonds. 4-CN-BIBH afforded solvated species 4-CN-BIBH. DMSO, (2) in dimethylsulfoxide and reacted with CuII, ZnII, CdII and NiII nitrates to form [(4-CN-BIBH2).NO3] (4) and M(OH)(NO 3).(H2O)x-1. Formation of [(4-CN-BIBH 2).NO3] has been supported by theoretical studies.
Ruthenium complexes containing pyridine-2-carbaldehyde azine as a synthon in the synthesis of bi-/trimetallic complexes
(Wiley-VCH Verlag, 2008) Sudhakar D. Dwivedi; Ashish K. Singh; Sanjay K. Singh; Sanjeev Sharma; Manish Chandra; Daya S. Pandey
Ruthenium complexes [(η5-C5H5) Ru(PPh3)(κ2-paa)]PF6 (paa = pyridine-2-carbaldehyde azine) and [(η5-C5H 5)Ru(κ1-dppm)-(κ2-paa)]BF 4 [dppm = bis(diphenylphosphanyl)methane] have been employed as a synthon in the synthesis of homo/hetero bi-/trimetallic complexes. It is the uncoordinated N,N-donor site on paa in complex [(η5-C 5H5)Ru(PPh3)-(κ2-paa)]PF 6, and N,N-donor site on paa and pendant phosphorus in [(η5-C5H5)Ru(κ1-dppm) (κ2-paa)]BF4 that allows for their incorporation into bi-/trimetallic systems. The resulting complexes have been characterized by analytical, spectral and electrochemical studies. Molecular structures of homobimetallic complex [(PPh3)(θ5-C 5H5)Ru(μ-paa)Ru(θ6-C 10H14)Cl](PF6)2 and hetero-bimetallic complex [(PPh3)(θ5-C 5H5)-Ru(μ-paa)Rh(θ5-C 5Me5)Cl](PF6)2 have been authenticated crystallographically. Complexes exhibit absorptions throughout the visible region and complicated electrochemical behaviour. Metal-based Ru II/RuIII oxidations in the bimetallic complexes do not vary as in the trimetallic complexes. © Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Ruthenium(II) polypyridyl complexes: Potential precursors, metalloligands, and topo II inhibitors
(2008) Sanjeev Sharma; Sanjay K. Singh; Daya S. Pandey
Neutral and cationic mononuclear complexes containing both group 15 and polypyridyl ligands [Ru(κ3-tptz)(PPh3)-Cl 2] [1; tptz = 2,4,6-tris(2-pyridyl)-1,3,5-thazine], [Ru(κ3-tptz)(κ2-dppm)CI]BF4 [2; dppm = bis(diphenylphosphino)-methane], [Ru(κ3-tptz)(PPh 3)(pa)]Cl (3; pa = phenylalanine), [Ru(κ3-tptz) (PPh3)(dtc)]Cl (4; dtc = diethyldithiocarbamate), [Ru(κ3-tptz)(PPh3)(SCN)2] (5) and [Ru(κ3-tptz)(PPh3)(N3)2] (6) have been synthesized. Complex 1 has been used as a metalloligand in the synthesis of homo- and heterodinuclear complexes [Cl2(PPh 3)Ru(μ-tptz)Ru-(η6-C6H 6)Cl]BF4 (7), [Cl2(PPh3)Ru(μ- tptz)Ru(η6-C10H14)Cl]PF6 (8), and [Cl2(PPh3)Ru(μ-tptz)Rh(η5-C 5Me5)Cl]BF4 (9). Complexes 7-9 present examples of homo- and heterodinuclear complexes in which a typical organometallic moiety [(η6-C6H6)RuCl]+, [(η6-C10H14)RuCl]+, or [(η5-C5Me5)RhCl]+ is bonded to a ruthenium(II) polypyridine moiety. The complexes have been fully characterized by elemental analyses, fast-atom-bombardment mass spectroscopy, NMR ( 1H and 31P), and electronic spectral studies. Molecular structures of 1-3, 8, and 9 have been determined by single-crystal X-ray diffraction analyses. Complex 1 functions as a good precursor in the synthesis of other ruthenium-(II) complexes and as a metalloligand. All of the complexes under study exhibit inhibitory effects on the Topoisomerase II-DNA activity of filarial parasite Setaria cervi and β-hematin/hemozoin formation in the presence of Plasmodium yoelii lysate. © 2008 American Chemical Society.
Small Organic Non–gelators Evincing Radical Control over Morphology and Rheology of a Weak Metallogel
(Wiley-Blackwell, 2016) Arnab Biswas; Sujay Mukhopadhyay; Roop S. Singh; Daya S. Pandey
Two arrays of “Inorganic-Organic Mixed Gels” (IOMGs) based on terpyridyl complexes have been synthesized combining progelator/non-gelators with easily available, inexpensive and non-reactive small organic non-gelators (SOnGs). This new class of multicomponent gels displays radical changes in morphological patterns and enormous enhancement in their viscoelastic properties relative to weak metallogel (ZTP2G) derived from the progelator only. It has been unequivocally shown that twisting or coiling in gels diminishes as well as their viscoelastic strengths with simple alteration of heteroatoms, their number and positions in SOnGs. Multicomponent gelation is quite complicated considering the susceptibility of anion triggered metallogels towards various external stimuli which has been profoundly outdone. The present approach may be extremely beneficial for negating limitations in the usage of weak metallogels with promising efficacy in specified areas. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Synthetic, spectral and structural studies of ruthenium(II) compounds based on 2,6-diacetylpyridinemonoxime
(2008) Manoj Trivedi; Sanjay K. Singh; Daya S. Pandey; Ru-Qiang Zou; Manish Chandra; Qiang Xu
Reaction of the ruthenium complexes [RuCl2(EPh3)3] (E = P, As), [(η5-C5H5)RuCl(EPh3)2] (E = P, As), [(η5-C5Me5)RuCl(PPh3)2] and [(η5-C9H7)RuCl(PPh3)2] with 2,6-diacetylpyridinemonoxime (dapmoH) have been investigated. Compounds with the formulations [Ru(κ3-dapmoH)Cl(PPh3)2]PF6 (1), [Ru(κ3-dapmoH)Cl(PPh3)2]BF4 (2) and [Ru(κ3-dapmoH)Cl(AsPh3)2]Cl (3) have been isolated and fully characterized by elemental analyses, IR, NMR, electronic, emission spectral and electrochemical studies. Molecular structures of the complexes [Ru (κ3 -dapmoH) Cl (PPh3)2] PF6 · H2 O (1) and [Ru (κ3 -dapmoH) Cl (PPh3)2] BF4 · 1.5 H2 O (2) have been determined by single crystal X-ray diffraction studies. A structural feature of interest for both the compounds is that the counter anions in 1 and 2 play vital role in the self-assembly of cages through intermolecular weak interactions in which water dimers or trimers are encapsulated. Compounds 1 and 2 strongly emit upon excitation at their respective MLCT transitions. © 2007 Elsevier B.V. All rights reserved.
Tuned helical array of RhIII/IrIII Cp* complexes with polypyridyl ligands
(Wiley-VCH Verlag, 2006) Sanjay K. Singh; Manish Chandra; Santosh K. Dubey; Daya S. Pandey
Reactions of the chloro-bridged dimeric complexes [{(η5- C5Me5)M(μ-Cl)Cl}2] (M = Rh, Ir) with the polypyridyl ligands 2,3-di(2-pyridyl)pyrazine (dpp) and 2,4,6-tri(2-pyridyl)-1, 3,5-triazine (tptz) in the presence of ammonium tetrafluoroborate gave the mononuclear complexes [(η5-C5Me5) MCl(κ2-dpp)]BF4 [M = Rh (1), Ir (2)] and [(η5-C5Me5)MCl(κ2-tptz)] BF4 [M = Rh (3), Ir (4)]. The complexes have been characterised by elemental analysis, FAB-MS, ESMS, IR, NMR, electronic and emission spectroscopic studies and the molecular structures of 1, 2 and 3 have been crystallographically determined. Structural studies on the complexes revealed the presence of helical superstructures resulting from C-H⋯X (X = N, F, Cl and π) interactions. © Wiley-VCH Verlag GmbH & Co. KGaA, 2006.