A Comparative Nuclear Magnetic Resonance Study of the Solvation of CuClO4 in Binary Mixtures of Acetonitrile with Pyridine and Picolines at 298 K

作者：Gill Dip Singh^*; Rana Dilbag Singh; Chauhan Mohinder Singh

来源：Zeitschrift fur Naturforschung Section A-A Journal of Physical Sciences, 2012, 67(5): 303-307.

DOI：10.5560/ZNA.2012-0032

• Cu-63 NMR
• Pyridine
• Picolines
• Chemical Shift
• Linewidth
• Quadrupole Coupling Constant

Cu-63 nuclear magnetic resonance (NMR) and viscosity studies of 0.064 M CuClO4 solutions have been reported in binary mixtures of acetonitrile (AN) with pyridine (Py) and 2, 3, and 4-picolines (2,3,4-Pic) at 298 K using a Bruker 500 MHz NMR spectrometer and an Ubbelohde viscometer, respectively. Chemical shift delta and linewidth Delta for the Cu-63 signals have been recorded referenced to a 0.064 M CuClO4 solution in anhydrous AN. The copper quadrupole coupling constants (e(2)Qq/h) have been calculated in all cases. The variation of the delta and e(2)Qq/h values as a function of mol fraction of the co-solvent show that all these bases interact with Cu+ more strongly than AN. They replace AN from the Cu+ complexed with AN in the form [Cu(AN)(4)](+) and form a mixed complex of the type [Cu(AN)(4) - x(S)x](+) (x = 1 - 4) where S stands for the base. At relatively high mole fraction of the co-solvents, the mixed solvated complex gradually changes to a more symmetrical complex of the type [Cu(S)(4)](+) which remains stable in the solution. The solvating effect of 2-Pic and 4-Pic is observed to be stronger than that of Py and 3-Pic.

• 出版日期2012-5