Competitive/co-operative interactions in acid base sandwich: role of cation vs. substituents.

摘要: The cation-π interaction can be envisaged as a lewis acid base interaction, and it is in line with Pearson's concept. critical examination of interactions between the π-acids (alkali metal cations — Li+, Na+ alkaline earth Mg2+, Ca2+) on one face tripodal Cr(CO)3 moiety other π substituted arenes demonstrates role cation substitutents manipulating them. two acids both faces arene not expectedly additive, rather shows either depreciation energy revealing competition toward or enhancement denoting cooperative effect. Among under study, Mg2+ gesture. Although substituents play meek role, they unfailingly exert their electronic effects are amply documented by excellent correlation various parameters Hammett constant σm. elusive switching λmax from UV to IR region binding arene-Cr(CO)3 complex characteristic clue that TDDFT help design ionic sensors for cations.