The Structure and Stability of Ni(II) Complexes of Thiourea and Related Ligands

1975 ◽  
Vol 53 (5) ◽  
pp. 633-643 ◽  
Author(s):  
D. R. Eaton ◽  
K. Zaw
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Resonance ◽  
Exchange Rates ◽  
Relative Stability ◽  
Ligand Exchange ◽  
Metal Ion ◽  
Proton Magnetic Resonance ◽  
Conductivity Measurements ◽  
Square Planar ◽  
Ethylene Thiourea

A number of Ni(II) complexes of thiourea, N-methylthiourea, N,N′-dimethylthiourea, N-naphthylthiourea, N,N′-diethylthiourea, and ethylene thiourea have been studied in acetone solution by proton magnetic resonance, magnetic susceptibility measurements, and conductivity measurements. In solution these complexes have tetrahedral, square planar, and octahedral geometries. In many cases equilibria between compounds with different geometries exist. Such equilibria have been studied as a function of temperature. The factors determining the relative stability of Ni(II) compounds with different geometries are discussed. In the present series of compounds it is concluded that the charge on the metal ion has the predominant influence in determining geometry. Some qualitative results on ligand exchange rates and mechanisms are also reported.

scholarly journals Metal ion promoted synthesis of pentaazamacrocyclic complexes of a few first row transition metal series derived from 2,6-diaminopyridine

2005 ◽  
Vol 70 (11) ◽  
pp. 1273-1281
Author(s):  
Ali Khan ◽  
Shabana Tabassum ◽  
Nishat Begum ◽  
Poonam Chingsubam
Keyword(s):  
Magnetic Susceptibility ◽  
Transition Metal ◽  
1H Nmr ◽  
Elemental Analysis ◽  
Metal Ion ◽  
Condensation Reaction ◽  
Spectroscopic Techniques ◽  
Conductivity Measurements ◽  
Template Condensation ◽  
Square Planar

Anew series of dichloro/dinitrato (2,6,9,13,18-pentaazacbicyclo [12.3.1]octadeca -1(18),14,16-triene) metal(II) [MLX2](M = Mn(II), Co(II), Ni(II) and Zn(II); X = Cl or NO3) and (2,6,9,13,18-pentaazacyclo[12.3.1]octadeca-1(18),14,16-triene) copper(II) dichloride/dinitrate [CuL]X2 (X = Cl or NO3) have been synthesized by the template condensation reaction of 2,6-diaminopyridine with 1,2-diaminoethane and 1,3-dibromopropane. The complexes were studied by elemental analysis, magnetic susceptibility and conductivity measurements. Various spectroscopic techniques, viz. IR, 1H-NMR, EPR, UV/Vis, were used to establish their structures. Except for the complexes of copper(II), which are square planar, all other complexes have octahedral structures.

THE INTERACTION OF SILICON TETRAFLUORIDE WITH METHANOL

1963 ◽  
Vol 41 (6) ◽  
pp. 1477-1484 ◽  
Author(s):  
J. P. Guertin ◽  
M. Onyszchuk
Keyword(s):  
Hydrogen Bonding ◽  
Magnetic Resonance ◽  
Absorption Band ◽  
Hydrogen Bonds ◽  
Infrared Spectrum ◽  
Proton Magnetic Resonance ◽  
Methanol Solution ◽  
Silicon Tetrafluoride ◽  
Conductivity Measurements ◽  
Bond Stretching

Silicon tetrafluoride reacts with methanol in a 1:4 mole ratio, forming the complex SiF4.4CH3OH, which freezes to a glass at about −20° and is completely dissociated in the gaseous phase at 25°. Conductivity measurements show clearly that it is a very weak electrolyte in methanol solution. Its infrared spectrum does not contain an Si—O bond stretching absorption band. Proton magnetic resonance measurements provide strong evidence of hydrogen bonding between silicon tetrafluoride and methanol. These results indicate that the structure of the complex requires tetracovalent rather than hexacovalent silicon and strong hydrogen bonds between methanol and each of the four fluorine atoms.

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