13C NMR-Study of 1,1-Dipotassio-2,3,4,5-Tetraphenyl-1-Silacyclopentadienide Dianion [SiC4Ph4]2−•2[K+] and 1,1-Dipotassio-2,3,4,5-Tetraphenyl-1-Germacyclopentadienide Dianion [GeC4Ph4]2−•2[K+]

Abstract

The chemical shifts in the 13C NMR spectra of 2,3,4,5-tetraphenyl-1-silacyclopentdienide dianion [SiC4Ph4]2−•2[K+] (3) and 2,3,4,5-tetraphenyl-1-germacyclopentdienide dianion [GeC4Ph4]2−•2[K+] (4) were compared to those of [SiC4Ph4]2−•2[Li+] (5), [SiC4Ph4]2−•2[Na+] (6), and [GeC4Ph4]2−•2[Li+] (7). The average polarizations in two phenyl groups of two potassium salts are decreased over 15% to 20% comparing to those of the lithium salts and sodium salt {[EC4Ph4]2−•2[M+] (E=Si, Ge, M=Li, Na) due to the effect of the counter potassium cation