Reactions of N,C,N-chelated pnictinidenes with Rh(I) and Ir(I) complexes: Coordination vs. Transmetalation

Abstract The reaction of N,C,N -chelated pnictinidenes ArE(I) [where Ar = C 6 H 3 -2,6-(CH=N t -Bu) 2 , E = As ( 1 ) and Sb ( 2 )] with dimeric complexes [(COD)M(μ-Cl)] 2 (where COD = 1,5-cyclooctadiene, M = Rh or Ir) gave pnictinidene complexes [ArEM(Cl) (COD)] [where E = As, M = Ir ( 3 ) and E = Sb, M = Ir ( 4 ), Rh ( 6 )] that were characterized by the help of 1 H and 13 C NMR spectroscopy and in the case of 3 and 6 also with the single-crystal X-ray diffraction analysis. However, the complex [ArAsRh(Cl) (COD)] ( 5 ) could not be isolated and exists only in an equilibrium with starting compounds in solution. The treatment of other Rh(I) precursors, such as [(COT) 2 Rh (μ-Cl)] 2 (COT = cyclooctene), with 1 or 2 led to the rhodium (III) pincer complex ArRhCl 2 ( 7 ) as a results of a transmetalation. Complex 7 was completely characterized including the single-crystal X-ray diffraction analysis. Finally, the reactivity toward the rhodium(I) carbonyl complex [(CO) 2 Rh (μ-Cl)] 2 was studied. In the case of the stibinidene 1 , an insoluble material was obtained, while the arsinidine derivative cis -[ArAsRh(Cl) (CO) 2 ] ( 8 ) could be isolated and characterized by NMR and IR spectroscopy.