Single crystal electronic spectra and ligand field parameters of some nickel(II) amine-isothiocyanato and amine-nitrito complexes

1976 ◽  
Vol 15 (1) ◽  
pp. 203-207 ◽  
Author(s):  
Ivano. Bertini ◽  
Dante. Gatteschi ◽  
Andrea. Scozzafava
1972 ◽  
Vol 50 (16) ◽  
pp. 2603-2609 ◽  
Author(s):  
P. P. Singh ◽  
I. M. Pande

Complexes of N-allyl urea (NAU) and N-allyl thiourea (NATU) with cobalt (II) and nickel (II) halides and perchlorates have been prepared and characterized by electrical conductance, magnetic susceptibility, infrared and electronic spectra. Infrared spectra suggest coordination in NAU through oxygen and in NATU through nitrogen. The electronic spectra and magnetic susceptibility data indicate tetrahedral and octahedral stereochemistry for cobalt (II) and nickel (II) halide complexes, respectively. The various ligand field parameters Dq, B′, and β calculated for these complexes show about 25 and 11% covalency for Co (II) and Ni (II), respectively, and suggest a weak ligand field.


1976 ◽  
Vol 54 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Carlo Preti ◽  
Giuseppe Tosi

The preparation of some complexes of benzoxazole-2-thione with halides of cobalt(II) and nickel(II) is reported. The complexes of cobalt(II) and nickel(II) are tetrahedral of the type ML2X2 with the exception of NiLBr2. The complexes have been studied by means of magnetic susceptibility measurements, infrared and far ir spectra, electronic spectra, and conductivity measurements. The ligand behaves as monodentate N-bonded. The various ligand field parameters, Dq, B′, and β show about 60 and 80% of covalency in the cobalt(II) and nickel(II) complexes respectively and suggest a medium strong ligand field. The spectroscopy parameters of cobalt and nickel derivatives confirm the presence of CoN2X2 and NiN2X2 chromophores.


1978 ◽  
Vol 56 (7) ◽  
pp. 985-991 ◽  
Author(s):  
Raymond M. Morrison ◽  
Robert C. Thompson

The complexes M(4mepy)4A2 and M(H2O)2(4mepy)8A2 (where M is Ni or Co and A is PF6 or AsF6) have been prepared and their electronic spectra and magnetic properties studied. A preliminary report is made of single crystal X-ray diffraction studies on Ni(H2O)2(4mepy)8(PF6)2, Co(H2O)2(4mepy)8(PF6)2, and Co(4mepy)4(PF6)2. All of the complexes have structures involving complex cations and non-coordinated anions, consistent with extremely weak ligating abilities for both PF6− and AsF6−. Cations identified and characterized are the squashed tetrahedral [Co(4mepy)4]2+ ion, the square planar [Ni(4mepy)4]2+ ion, and the tetragonal [Co(4mepy)4((4mepy)2H2O)2]2+and [Ni(4mepy)4((4mepy)2H2O)2]2+ ions. The ligand field strength of 4-methylpyridine is found to be indistinguishable from that of pyridine in these complexes. Infrared spectra are reported and infrared criteria for establishing the presence of non-coordinated anions in PF6− and AsF6− complexes are suggested.


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