TRANSITION METAL TRIS(1-PYRAZOLYL)BORATES CONTAINING NITROSO AND ARYLAZO LIGANDS

Anions RB(pz)3M(CO)3-, obtained by the reaction of RB(pz)3- with group VIb hexacarbonyls, react with nitrosating agents to yield the orange nitroso compounds RB(pz)3M(CO)2NO which have been converted to the green, very stable RB(pz)3M- (NO)2Cl compounds (M = Mo, W). Reaction of HB(3,5-(CH3)2pz)3M(CO)2NO (M = Mo, W) with ClNO produces the stable monomeric derivatives HB(3,5-(CH3)2pz)3MCl2NO which have a 16-electron configuration. The reaction of RB-(pz)3M(CO)3- with diversely substituted aryldiazonium salts yields the metal-arylazo compounds RB(pz)3M(CO)2N=NAr (M = Mo, W) of remarkable thermal and chemical stability. Their 19F shielding parameters (for Ar = m- or p-fluorophenyl) have been studied. © 1969, American Chemical Society. All rights reserved.