Coordination and Ligand Substitution Chemistry ofBis(cyclooctyne)copper(I).

Cationic bis(alkyne)copper(I) carbonyland bis(alkyne)copper(I)isocyanide complexes have been synthesized from the precursor (cyclooctyne)2CuBr. [Cu(cyclooctyne)2(CO)][SbF6] and [Cu(cyclooctyne)2(CNtBu)][SbF6] have trigonal-planar and three-coordinate copper centers. The coppercarbonyl complex [Cu(cyclooctyne)2(CO)][SbF6] displays its C–O stretching frequency in the “nonclassical”metal carbonyl region (2171 cm–1), and the analogouscopper(I) isocyanide complex [Cu(cyclooctyne)2(CNtBu)][SbF6] also has an unusually high CN stretching bandat 2230 cm–1. The reaction of 3,5-Me2C6H3NH2and 4-tBuC6H4NH2with [Cu(cyclooctyne)2(CO)][SbF6] led to CO displacement rather than additionto CO. CNtBu reacts with [Cu(cyclooctyne)2(CO)][SbF6] to afford [Cu(cyclooctyne)2(CNtBu)][SbF6]. The syntheses of [Cu(cyclooctyne)(CNtBu)2][SbF6] and [Cu(CNtBu)4][SbF6] from the (cyclooctyne)2CuBr precursor are alsoreported. [ABSTRACT FROM AUTHOR]