Multinuclear NMR studies of the products resulting from the reaction of pyridine or 2,2'-bipyridine with [Rh4(CO)12]

摘要

The progressive addition of anhydrous pyridine,(py),to a solution of [Rh4CO)12] in CH2Cl2 under CO,even at low temperature,results in immediate disproportionation to give cis-[Rh(CO)2py2][Rh5(CO)15];further addition of pyridine results in the progressive replacement of CO's by py on the same apical rhodium in [Rh5(CO)15]~- to give cis-[Rh(CO)2py2][Rh5(CO)_(l5_x)pyx] (x = 1,2).The analogous reactions with 2,2'-bipyridine (bipy) give only [Rh(CO)2bipy][Rh5(CO)13bipy].IR and low temperature,multinuclear NMR measurements have been used to establish the structures of all the above anions and the structures of [Rh5(CO)13(bipy)] and [Rh5(CO)13py2]~- are subtly different.Under N2,[Rh4(CO)12] reacts with py to give [Rh6(CO)_(16_y),py_y] (y = 1,2).