An asymmetrically derivatized 1,2,3-triphospholide: Synthesis and reactivity of the 4-(2′-pyridyl)-1,2,3-triphospholide anion

摘要

Reactions between anionic heptaphosphide clusters ([P_7] ~(3-)/[HP_7]~(2-)) and 2-ethynylpyridine yielded the 4-(2′-pyridyl)-1,2,3-triphospholide anion ([P_3C _2H(2-C_5H_4N)]-; 1). This species was isolated as a compositionally pure [K(2,2,2-crypt)]~+ salt in moderate yields. Preliminary coordination studies of 1 toward Mo(CO)_6 or Mo(py)_3(CO)_3 (py = pyridine) afforded the diamagnetic piano-stool complex [{η~5-P_3C_2H(2-C _5H_4N)}Mo(CO)_3]~- (2). By contrast, reaction of 1 with Mo(COD)(CO)_4 (COD = 1,5-cyclooctadiene) yielded [{κ~2P,N-P_3C_2H(2-C_5H _4N)}Mo(CO)_4]~- (3) which readily loses a carbonyl on heating to give 2. Reaction of 2 with Mo(COD)(CO)_4 afforded the bimetallic system [{μ:η~5,κ~2P,N- P_3C_2H(2-C_5H_4N)}{Mo(CO) _3}{Mo(CO)_4}]~- (4).