Studies on the Effect of Positive and Negative Charges on the (77)Se NMR Shifts of Selenones and Selenenyls of N-heterocyclic Carbenes of Imidazolium-4,5-dicarboxylates

正负电荷对咪唑鎓-4,5-二羧酸盐N-杂环卡宾的硒酮和硒烯基的(77)Se NMR位移的影响研究