Formation of a Polynuclear Cobalt(II) Complex on a Polydentate Nanoplatform of Carboxylated Boltorn H20

A method of synthesis of a polynuclear cobalt(II) complex with carboxylated Boltorn H20, a hyperbranched polyol of second generation, has been suggested. The logarithm of stability constant and the composition of the complex species BH20(OC(O)CH2CH2COO)12Co12 in a 50% acetone solution have been calculated from the electronic absorption spectra: logβ = 13.7 ± 0.2 and the composition M : L = 12 : 1. The IR spectroscopy and NMR (13C and 1H) point to the coordination of Co(II) ions not only at the surface of the molecule but also near its core.