Dielectric Properties of Pt(NO2acac)2 and Their Molecular Complexes with Heterocyclic N-Bases

Abstract

The dipole moments of Pt(NO₂-acac)₂ and its molecular complexes formation with heterocyclic N-bases have been studied by refractive index, Guggenheim and dielectric plot methods. The formation of charge transfer complexes Pt(NO₂-acac)₂ with heterocylic N-bases is further supported by dipole moment studies. It is found that acetylacetone has larger dipole moment than its metal chelates, which may be interpreted due to its non-planar structure. The symmetry of Pt(acac)₂ is disturbed when g-H of this chelate is replaced by the nitro group. An increase in the dipole-moment was observed in these systems after complexation. The maximum dipole moment of Pt(NO₂-acac)₂ pyridine complex was observed which indicates stronger interaction with pyridine in compa-rison to other donors. The dipole moment of these complexes has been found in consistent with those of K1 values obtained from conductometric methods. It is also observed that the value of dipole moment increases with increase in the temperature for Pt(NO₂- acac)₂-pyridine or quinoline complex. The values are greater for pyridine system at different temperatures. The dielectric titration technique has indicated 1:1 stoichiometry of these chargetransfer complexes. From this study it has been observed that more polar is the solute the larger is the expected increase in its dipole moment values. It is suggested that the interaction of Pt(NO₂-acac)₂ with N-bases is governed by dipole electrostatic attraction.