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1.
Three new polyamine Ni(II) complexes, namely [Ni(trien)(phen)](BF4)2 1, [Ni(trien)(bipy)](ClO4)2 2 and [Ni(trien)(en)](ClO4)2 3 [trine = triethylenetetramine, phen = 1,10-phenanthroline, bipy = 2,2′-bipyridyl, en = ethylenediamine] have been synthesized and characterized by physico-chemical and spectroscopic methods. Complexes 1 and 2 crystallize in monoclinic space group P21/c, and possess a distorted octahedral geometry. Significant hydrogen bonding interactions are found in both complexes.  相似文献   

2.
Three complexes of a dithiocarbamate ligand (dbpdtc = benzyl(4-(benzylamino)phenyl)dithiocarbamate), namely [Ni(dbpdtc)2] (1), [Ni(dbpdtc)(NCS)(PPh3)] (2) and [Ni(dbpdtc)(PPh3)2]ClO4 (3) have been prepared. The complexes were characterized by IR, electronic spectroscopy and cyclic voltammetry. A single-crystal X-ray structural analysis was carried out for complex 1 and showed that the nickel is in a distorted square planar environment with a NiS4 chromophore. For the two mixed ligand complexes, the thioureide ν C–N values were shifted to higher wavenumbers compared to [Ni(dbpdtc)2], suggesting increased strength of the thioureide bond due to the presence of the π-accepting phosphine. Electronic spectral studies suggest square planar geometries for the complexes. Cyclic voltammetry showed easier reduction of nickel(II) to nickel(I) in the mixed ligand complexes compared to [Ni(dbpdtc)2].  相似文献   

3.
Four new mixed ligand nickel(II) complexes viz., [Ni(tren)(phen)](ClO4)2 (1), [Ni(tren)(bipy)](ClO4)2 (2), [Ni(SAA)(PMDT)] · 2H2O (3) and [Ni(SAA)(TPTZ)] (4) (tren = tris(2-aminoethylamine), phen = 1,10-phenanthroline, bipy = 2,2′-bipyridine, SAA = salicylidene anthranilic acid, PMDT = N,N,N′,N″,N″-pentamethyldiethylenetriamine, TPTZ = 2,4,6-tri(2-pyridyl)-1,3,5-triazine) have been synthesized and characterized by means of elemental analysis, spectroscopic, magnetic susceptibility and cyclic voltammetric measurements. Single crystal X-ray analysis of [Ni(tren)(phen)](ClO4)2 (1) and [Ni(SAA)(PMDT)] · 2H2O (3) has revealed the presence of a distorted octahedral geometry. Superoxide dismutase activity of these complexes has also been measured.  相似文献   

4.
A series of novel octahedral nickel(II) dithiocarbamate complexes involving bidentate nitrogen-donor ligands (phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine) or a tetradentate ligand (cyclam = 1,4,8,11-tetraazacycloteradecane) of the composition [Ni(BzMetdtc)(phen)2]ClO4 (1), [Ni(Pe2dtc)(phen)2]ClO4 (2), [Ni(Bzppzdtc)(phen)2]ClO4 · CHCl3 (3), [Ni(Bzppzdtc)(phen)2](SCN) (4), [Ni(BzMetdtc)(bpy)2]ClO4 · 2H2O (5), [Ni(Pe2dtc)(cyclam)]ClO4 (6), [Ni(BzMetdtc)2(cyclam)] (7), [Ni(Bz2dtc)2(cyclam)] (8) and [Ni(Bz2dtc)2(phen)] (9) (BzMetdtc = N,N-benzyl-methyldithiocarbamate(1-) anion, Pe2dtc = N,N-dipentyldithiocarbamate(1-) anion, Bz2dtc = N,N-dibenzyldithiocarbamate(1-) anion, Bzppzdtc = 4-benzylpiperazinedithiocarbamate(1-) anion), have been synthesized. Spectroscopic (electronic and infrared), magnetic moment and molar conductivity data, and thermal behaviour of the complexes are discussed. Single crystal X-ray analysis of 3 and 8 confirmed a distorted octahedral arrangement in the vicinity of the nickel atom with a N4S2 donor set. They represent the first X-ray structures of such type complexes. The catalytic influence of complexes 2, 3, 6, and 7 on graphite oxidation was studied and discussed.  相似文献   

5.
Three dinuclear terephthalato-bridged nickel(II) complexes [Ni(rac-L)]2(μ-TPA)(ClO4)2 (1), [Ni(RR-L)]2(μ-TPA)(ClO4)2 (2), and [Ni(SS-L)]2(μ-TPA)(ClO4)2 (3) (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, TPA = terephthalic acid) have been synthesized and characterized. Single-crystal X-ray diffraction analyses revealed that the Ni(II) atoms have six-coordinated distorted octahedral environments, and the terephthalato ligand bridges two Ni(II) centres in a bis bidentate fashion to form dimers in all three complexes. The monomers of {[Ni(RR-L)]2(μ-TPA)}2+ and {[Ni(SS-L)]2(μ-TPA)}2+ are connected through intermolecular hydrogen bonds to generate 1D right-handed and left-handed helical chains, respectively. The racemic character of 1 and the homochiral natures of 2 and 3 are confirmed by the results of CD spectroscopy.  相似文献   

6.

Abstract  

Three copper(II), one zinc(II), and one ferrous(II) complexes having 3-bromo or 3,8-dibromo-1,10-phenanthroline ligand with different metal/ligand molar ratios, formulated as [Cu(3-bromo-phen)(ClO4)(C3H7NO)2(H2O)](ClO4) (1), [Cu(3,8-dibromo-phen)(ClO4)(C3H7NO)2(H2O)](ClO4) (2), [Cu(3,8-dibromo-phen)(ClO4)(H2O)3](ClO4)(H2O)3 (3), [Zn(3,8-dibromo-phen)2(H2O)2](ClO4)2(H2O)2 (4), and [Fe(3,8-dibromo-phen)3](ClO4)2(H2O)(CH4O)(C3H6O)2 (5) (phen = 1,10-phenanthroline), have been synthesized and characterized in this paper. X-ray single-crystal diffraction studies reveal the different crystallographic symmetry and packing fashions between neighboring phen rings in 1:1 Cu(II) complexes 13 due to the alteration of bromo substituent 1,10-phenanthroline ligands and coordinated or free solvent molecules. Additionally, in 1:2 Zn(II) and 1:3 Fe(II) complexes 4 and 5, continuous π–π stacking and alternating π–π and dimeric p–π stacking are found.  相似文献   

7.
The two new nickel(II) complexes, [Ni(HL)(L)](NO3)?H2O (1) and [Ni(L)2] (2) (where HL/L = N′-[(E)-phenyl(pyridin-2-yl)methylidene]benzohydrazide), have been synthesized and characterized by elemental analysis, spectroscopic, magnetic susceptibility, and cyclic voltammetric measurements. Single-crystal X-ray analysis of [Ni(HL)(L)](NO3)?H2O (1) and [Ni(L)2] (2) has revealed the presence of a distorted octahedral geometry around nickel(II). The X-ray and spectral characterizations have confirmed the existence of the keto-enol form of the ligands in the complexes. The electronic structures and spectral properties of the ligands and the complexes have been explained by DFT and TDDFT calculations. Superoxide dismutase activity of these complexes has also been measured.  相似文献   

8.
Abstract  Two new nickel(II) complexes, namely [Ni(BPSE)](BF4) 1, and [Ni (5-BST)CH3OH]ClO4 2 [BPSE = 2-benzoylpyridinesalicylidene ethylenediamine, 5-BST = 5-bromosalicylidene-tris(2-aminoethyl)amine] have been synthesized and characterized using various physico-chemical methods. The magnetic and spectroscopic data indicate a distorted square planar geometry for complex 1, while complex 2 is assigned a distorted octahedral geometry. Complex 1 crystallized in the triclinic space group P-1. Complex 2 adopts an octahedral geometry with space group symmetry P 21/n. The superoxide dismutase activity of these complexes has been measured. Graphical Abstract  This paper describes three new nickel (II) complexes viz; [Ni(BPSE)](BF4) 1, [Ni(BSE)] 2 and [Ni (5-BST) CH3OH] ClO4 3 [BPSE = 2-benzoylpyridine salicyledene-ethylenediamine, BSE = bis(salicylaldehyde) ethylenediamine, 5-BST = 5-bromosalicyledene-tris(2-amino ethyl) amine]. The magnetic and spectroscopic data indicate a distorted square planar geometry for complex 1 and 2, while the comlplex 3 is assigned a distorted octahedral geometry. Superoxide dismutase activity of these complexes have also been measured. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

9.
Three novel unsymmetric tridentate ligands, namely, ptmi (ptmi = 3-(1,10-phenanthroline-2-yl)-as-triazino[5,6-f]-5-methoxyisatin), pti (pti = 3-(1,10-phenanthroline-2-yl)-as-triazino-[5,6-f]isatin), ptni (ptni = 3-(1,10-phenanthroline-2-yl)-as-triazino[5,6-f]-5-nitroisatin), and their complexes [Ru(tpy)(ptmi)](ClO4)2 (tpy = 2,2′:6′,2″-terpyridine) (1), [Ru(tpy)(pti)](ClO4)2 (2), and [Ru(tpy)(ptni)](ClO4)2 (3) were prepared and characterized by elemental analysis, 1H NMR, ES–MS. The electrochemical behaviors were studied by cyclic voltammetry. The DNA-binding properties of these complexes were investigated by the spectroscopic method, viscosity measurements, and thermal denaturation. Theoretical studies on these complexes were also performed with the density functional theory (DFT) method. The experimental results showed that these complexes bind to calf thymus (CT-DNA) in an intercalative mode. The order of DNA-binding affinities (A) of these complexes is A(1) < A(2) < A(3). The trend in the DNA-binding affinities of this series of complexes can be reasonably explained by the DFT calculations.  相似文献   

10.
Co(II), Ni(II) and Cu(II) nitrate complexes with btmpp, namely ([Co(btmpp)(H2O)2(NO3)]NO3 (1), [Ni(btmpp)(H2O)(NO3)]NO3 (2) and [Cu(btmpp)(MeOH)(NO3)]NO3 (3), where btmpp = 2,6-bis(3,4,5-trimethyl-N-pyrazolyl)pyridine), have been synthesized and characterized by physicochemical and spectroscopic methods. The crystal structure of complex 1 has been determined by single crystal diffraction at 100K. In all the complexes, btmpp is coordinated in a tridentate mode through its nitrogen atoms. One of the nitrates in complex 1 is terminally bonded to the metal center through the oxygen atom, whereas the other one is out of the coordination sphere. The Co(II) atom in complex 1 is hexa-coordinated with a CoN3O3 distorted octahedral environment. Decomposition of three complexes was analyzed thermogravimetrically. All three complexes decompose similar to explosive material.  相似文献   

11.
2-(2-Pyridyl)benzimidazole (PBI) was synthesized by solvent-free aldol condensation and complexed with nickel(II) and copper(II) nitrate and perchlorate salts by simple reactions at room temperature. The transition metal complexes [Ni(PBI)2NO3](NO3) (1), [Ni(PBI)3](ClO4)2·1.5H2O (2), [Cu(PBI)2NO3](NO3) (3), and [Cu(PBI)3](ClO4)2·3H2O (4) (PBI = 2-(2-pyridyl)benzimidazole) were synthesized in good yield and structurally characterized by X-ray crystallography, infrared absorption spectroscopy, and elemental analysis. Complexes 1 and 3 are isostructural, crystallizing in the same space group P21/c. Both the nickel(II) and copper(II) atoms have distorted square pyramidal geometries. The metal centers in these complexes are coordinated by two molecules of the bidentate ligand (PBI) and an O-atom of the coordinated nitrate anion. Complexes 2 and 4 are also isostructural but do not crystallize in the same space group: P-1 for 2 and Pccn for 4. The geometry around both the nickel(II) and the copper(II) centers is distorted octahedral. Here, the metal atoms are coordinated by three molecules of 2-(2-pyridyl)benzimidazole. The copper(II) complex 4 has 2-fold symmetry with one of the three PBI ligands being positionally disordered about the 2-fold axis. Intermolecular N–H···O hydrogen bonds, involving the NH H-atom and an O-atom of the coordinated nitrate anion, are observed in all four complexes. In 1 and 3, this gives rise to the formation of centrosymmetric dimer-like structures that are decorated by hydrogen-bonded nitrate anions. In 2 and 4 the perchlorate anions and the water molecules of crystallization are involved in N–H···O and O–H···O hydrogen bonds bridging two symmetry-related cations, thus forming cyclic arrangements. In the case of complex 4, this leads to the formation of two-dimensional hydrogen-bonded networks parallel to plane (011). Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

12.
The synthesis of a new Schiff base containing 1,10-phenanthroline-2,9-dicarboxaldehyde and 2-aminobenzenethiol subunits is described. The reaction of 1,10-phenanthroline-2,9-dicarboxaldehyde with 2-aminobenzenethiol leads to the isolation of 2,9-bis(2-benzothiazolinyl)-1,10-phenanthroline (I) which undergoes rearrangement when reacted with cobalt, nickel, copper or zinc ions to produce complexes of the tautomeric Schiff base 2,9-bis[2-(2-mercaptophenyl)-2-azaethene]-1,10-phenanthroline (L). The [Cu(L)ClO4][ClO4] and [M(L)X2] complexes (where M = Co(II), Ni(II) and Zn(II) and X = Br) were characterized by physical and spectroscopic measurements which indicated that the ligand is acting probably as a tetradentate N4 chelating agent.  相似文献   

13.
Five novel nickel(II) complexes have been successfully synthesized with a heterocyclic ligand, Opdac, [Ni(Opdac)2]Cl2 (1), [Ni(Opdac)2(CH3OH)2]Br2(CH3OH)2 (2), [Ni(Opdac)2]I2 (3), [Ni(Opdac)2NO3]NO3 (4) and [Ni(Opdac)2ClO4]ClO4 (5) where Opdac = 4-(1-H-1,3-benzimidazole-2-yl)-1,5-dimethyl-2-phenyl-1-2-dihydro-3-H-pyrazol-3-one. All the complexes were characterized by elemental analysis, molar conductivity, CHN analysis, magnetic susceptibility measurements, spectroscopic studies and TG/DTA methods. In all the complexes, Opdac acts as a bidentate ligand coordinating to Ni(II) ion via the benzimidazole imine nitrogen and the pyrazolone oxygen atoms. The complexes 1 and 3 have a tetrahedral geometry while 2, 4 and 5 have an octahedral geometry around the Ni(II) center.  相似文献   

14.
The XRD structure and the influence of the conformation in the molecular orbitals of the pteridine-benzoylhydrazone ligand (BZLMH = benzoylhydrazone of 6-acetyl-1,3,7-trimethyllumazine, lumazine = (1H,3H)-pteridin-2,4-dione) have been studied. Complexes of BZLMH with nickel(II), zinc(II) and mercury(II) have been prepared and spectroscopically characterized by IR, NMR and fluorescence spectroscopy; also XRD studies have allowed to establish two different coordinative patterns in the complexes [Ni3(BZLMH)3(OH)(H2O)(CH3CN)2](ClO4)5 · 2H2O · CH3CN (2) and [Zn(NO3)(BZLMH)(H2O)](NO3) (3). Compound (2) is a trinuclear hydroxo-centered complex with a central hydroxo group bridging the three nickel(II) ions. The [Ni33-OH)]5+ core is planar with the benzoylhydrazone ligands coordinated in the bis-bidentate [O(4),N(5)]-[N(61),O(63)] mode. The zinc(II) compound displays a BPT coordination geometry in which the BZLMH ligand acts in a tridentate fashion using N(5), N(61) and O(63) donor atoms. Fluorescence spectroscopic properties of benzoylhydrazone (BZLMH) are studied and the fluorescence band shift and changes in intensity is modulated by complexation with different metal ions (Ni2+, Zn2+ and Hg2+), so the binding is signaled such a possible cause.  相似文献   

15.
Reactions of M(NO3)2?·?xH2O [M?=?Co(II), Ni(II), and Cu(II)] with N,N,N′,N′-tetraalkylpyridine-2,6-dicarboxamides(O-daap) in CH3CN yield [Co(O-dmap)(NO3)2] (1), [Co(O-deap)(NO3)2] (2), [Co(O-dpap)(NO3)2] (3), [Ni(O-dmap)(H2O)3](NO3)2] (4), [Ni(O-deap)(H2O)2(NO3)](NO3)] (5), [Cu(O-deap)(NO3)2] (6), and [Cu(O-dpap)(NO3)2] (7). X-ray crystal structures of 1, 2, 4, 5, and 7 reveal that O-daap ligands coordinate tridentate to each metal, O–N–O, with nitrate playing a vital role in molecular and crystal structures of all the complexes. The coordination geometry in the two Co(II) complexes, 1 and 2, is approximately pentagonal bipyramidal with nitrate bonded in a slightly unsymmetrical bidentate chelating mode. [Ni(dmap)(H2O)3](NO3)2 (4) and [Ni(deap)(H2O)2(NO3)](NO3) (5) exhibit octahedral geometry, the former containing uncoordinated nitrate while the latter has one nitrate coordinated unidentate and the other nitrate outside the coordination sphere. The Cu(II) in [Cu(dpap)(NO3)2] (7) occupies a distorted square pyramidal geometry and is linked to two unidentate nitrates, although one nitrate is also involved in a weak interaction with the metal through its other oxygen. IR spectra and other physical studies are consistent with their crystal structural data. O-dmap?=?N,N,N′,N′-tetramethylpyridine-2,6-dicarboxamides; O-deap?=?N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamides; and O-dpap?=?N,N,N′,N′-tetraisopropylpyridine-2,6-dicarboxamides.  相似文献   

16.
The potentially pentadentate chelate 2,6-diacetylpyridine-bis(N-methyl-S-methyldithiocarbazate) (Nmedapsme) has been synthesized and structurally characterized by X-ray diffraction. Its reactions with nickel(II) salts did not lead to pentadentate coordinated ligand complexes but ternary complexes of general formula, [Ni(Nmedapsme)(nmesme)L]X·H2O (L = Br, I; X = I, BF4) where Nmedapsme binds as a tridentate and nmesme = N-methyl-S-methyldithiocarbazate. The related ternary nickel(II) complexes of formula, Ni(Nmedapsme)(nmetsc)Br2 has also been prepared and characterized. X-ray crystal structures of [Ni(Nmedapsme)(nmesme)I]I·H2O and [Ni(Nmedapsme)(nmesme)Br]BF4·H2O revealed that, in these complexes, the Nmedapsme ligand acts as a tridentate NNN donor while the distal S-donors are not coordinated. The bidentate (NS) ligand, nmesme coordinates to the nickel(II) ion via the amino nitrogen and the thione sulfur atoms, the sixth coordination site is occupied by an anion. In both complexes, the nickel(II) ion adopts a distorted octahedral configuration. The complex [Cu(nmesme)2(ONO2)]NO3 was obtained from an unsuccessful attempt to complex copper(II) with Nmedapsme. Hydrolysis of the parent Schiff base Nmedapsme occurred during complexation. An X-ray crystallographic structure analysis shows that the complex, [Cu(nmesme)2(ONO2)]NO3 has an approximately square-pyramidal geometry with the two nmesme ligands coordinated to the copper(II) ion as NS bidentate chelating agents via the amino nitrogen and thione sulfur atoms and the fifth coordination position of copper(II) is occupied by a monodentate nitrate ligand.  相似文献   

17.
The syntheses and crystal structures of four new divalent transition metal complexes of the types [Cu2(dien)2(nic)](ClO4)3 · MeOH (nic = anion of nicotinic acid; dien = diethylenetriamine), 1; [Cu(dien)(nic)]2(nic)2, 2; [Cu(dien)(nic)]2(BF4)2 · 2MeOH, 3 and [Ni(dien)(nic)(H2O)]4(NO3)4 · 2MeOH, 4, are reported, which were prepared by the reactions of diethylenetriamine and nicotinic acid with Cu(ClO4)2 · 6H2O, Cu(OAc)2 · H2O, Cu(BF4)2 · 6H2O and Ni(NO3)2 · 6H2O in MeOH, respectively. These complexes were characterized by single-crystal X-ray diffraction method and elemental analyses. In the cation of complex 1, one nicotinate ligand bridges two Cu(II) metal centers through the pyridyl nitrogen atom and one of the carboxylate oxygen atoms. The cations of complexes 2 and 3 form the twelve-membered metallocycles, involving two Cu(II) ions that are bridged by two nicotinate ligands. The cation of complex 4 forms a tetranuclear cage with the four Ni(II) metal centers bridged by four nicotinate ligands and each Ni(II) metal center adopts the distorted octahedral geometry. Their thermal properties have been investigated by using differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA).  相似文献   

18.
The synthetic investigation of the NiII/M(NO3)3·6H2O/di-2-pyridyl ketone [(py)2CO] tertiary reaction system in EtOH has yielded triangular Ni2M cationic complexes (M = lanthanide, Y). The reaction between Ln(NO3)3·6H2O, Ni(ClO4)2·6H2O, (py)2CO and base (1:3:3:3) in EtOH under gentle heating gave the isostructural complexes [Ni2Ln{(py)2C(OEt)(O)}3{(py)2C(OH)(O)}(NO3)(H2O)](ClO4)2 (Ln = Gd, 2; Ln = Tb, 3) in high yields. The ligands (py)2C(OEt)(O) and (py)2C(OH)(O) are the monoanions of the hemiketal and gem-diol derivatives of (py)2CO, respectively, formed in situ in the presence of the metal ions. The cations of 2 and 3 consist of one 8-coordinate LnIII and two distorted octahedral NiII atoms in an essentially isosceles, triangular arrangement capped by a central μ3 atom of the unique 3.3011 (Harris notation) (py)2C(OH)(O) ligand. Each metal-metal edge is bridged by the deprotonated O atom of one 2.2011 (py)2C(OEt)(O) ligand. The isostructural complexes [Ni2M{(py)2C(OEt)(O)}4(NO3)(H2O)]2[M(NO3)5](ClO4)2 (M = Y, 4 ; M = Tb, 5 ; M = Dy, 6) were prepared by the 1:1 reaction of the mononuclear “metalloligand” [Ni(O2CMe){(py)2CO}{(py)2C(OH)2}](ClO4) (1) and M(NO3)3·6H2O in EtOH under mild heating in moderate to good yields. The structures of the dications of 4-6 are similar to those in 2 and 3, the only difference being the replacement of the unique 3.3011 (py)2C(OH)(O) ligand of the latter by one 3.3011 (py)2C(OEt)(O) group in the former. The YIII, TbIII and DyIII atoms in [M(NO3)5]2− are coordinated by five bidentate chelating nitrato groups. Characteristic IR bands of the complexes are discussed in terms of the known structures and the coordination modes of the ligands. Variable temperature, solid-state direct current magnetic susceptibility and magnetization studies were carried out on dried samples of 2-4. The data indicate ferromagnetic Ni?Ni and Ni?Gd exchange interactions, and an ST = 11/2 ground state for 2. Complex 3 is characterized by a high-spin ground state while the ferromagnetic Ni?Ni interaction for 2 is independently supported by the study of 4. No out-of-phase, alternating current susceptibility signals have been detected for 3 that would be indicative of SMM behavior.  相似文献   

19.
20.
Abstract

Six new nickel complexes of two dithiocarbamate ligands (cyfdtc = N-cyclohexyl-N- furfuryldithiocarbamate and bztpedtc = N-benzyl-N-[2-thiophenylethyl]dithiocarbamate) namely, (Ni[cyfdtc]2) (1), (Ni[bztpedtc]2) (2), (Ni[cyfdtc][NCS][PPh3]) (3), (Ni[bztpedtc] [NCS][PPh3]) (4), (Ni[cyfdtc][PPh3]2)ClO4 (5), and (Ni[bztpedtc][PPh3]2)ClO4 (6) have been prepared and characterized using IR, electronic, and NMR (1H and 13C) spectra. A single crystal X-ray structural analysis was carried out for complex 3 and showed that nickel is in a distorted square planar arrangement with the NiS2PN chromophore. The shift in νC?N of the heteroleptic complexes to higher frequencies compared with the parent complex is assigned to mesomeric delocalization of electron density from the

dithiocarbamate ligand toward the metal atom, which increases the contribution of polar thioureide form in mixed ligand complexes. Electronic spectral studies suggest square planar geometry for the complexes. In the 13C NMR spectra, the upfield shift of NCS2 carbon signal for 3 and 4 from the chemical shift value of 1 and 2 is due to effect of PPh3 on the mesomeric drift of electron density toward nickel throughout thioureide C?N bond.  相似文献   

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