Thermochemistry of adducts of zinc(II) dialkyldithiocarbamate with 2,2′-bipyridine

The enthalpies of dissolution of adducts, Zn(II) dialkyldithiocarbamate and bipy, Zn(S2CNR2)(2). C10H8N2, (R=C2H5, n-C3H7, n-C4H9, i-C4H9 and n-C5H11), in acetone were measured and the following thermochemical parameters for the adducts determined: the standard enthalpies for the Lewis acid/base reaction (Delta(r)H(theta)), the standard enthalpies of formation (Delta(f)H(theta)), the standard enthalpies of decomposition (Delta(D)H(theta)), the lattice standard enthalpies (Delta(M)H(theta)) and the standard enthalpies of the Lewis acid/base reactions in the gas phase (Delta(r)H(theta)(g)). The mean standard enthalpies of the zinc-nitrogen bonds have been estimated and range from 54 to 138 kJ mol(-1). The standard enthalpies of sublimation of the adducts were determined by differential scanning calorimetry and estimation methods. The thermodynamics of adduct formation between Zn(II) dialkyldithiocarbamate and bipyridine in acetone solution was determined by calorimetric titration. The results indicate the following order of the enthalpy changes for the interaction: Et<Pr-n<Pe(n)<Bu-n<Bu-i. (C) 2000 Elsevier Science B.V. All rights reserved.