Simulation of polydimethylsiloxane copolymers with nickel(ii) 2,6-pyridinecarboxamide complexes

A number of structural models of Ni^II-2,6-pyridinedicarboxamide-polydimethylsiloxane with different ratio of dimethylsiloxane units and pyridinedicarboxamide moieties coordinating Ni^II, as well as with varying copolymer regularities were obtained in the modified PCFF force field. For this purpose, the missing force field parameters were calculated for the Ni^II⋯N and Ni^II⋯O bonds and the corresponding torsion angles of the Ni^II-2,6-pyridinedicarboxamide complex. The helical structure was adopted as the basic structure for modeling macromolecules. The comparison of structural fragments of the the copolymer showed that the regular structures have lower potential energy than the irregular ones, the structures with a fewer number of dimethylsiloxane units retain their helical shape better, and an increase in the frequency of occurrence of nickel complexes leads to a denser arrangement of the turns of the polymer helix.