Polar substituent effects on NMR chemical shifts of group 14 elements: synthesis and NMR (carbon-13, silicon-29, tin-119, and lead-207) substituent chemical shifts (SCS) of 4-substituted bicyclo[2.2.2]oct-1-ylbutanes, -trimethylsilanes, -trimethylstannanes, and -trimethyl plumbanes (M(CH3)3, M = carbon, silicon, tin, and lead) and 4-substituted bicyclo[2.2.1]hept-1-yltrimethylstannanes | doi.page