Vinyliden-Übergangsmetallkomplexe XXVI. Synthese und struktur kationischer Carbonyl-, Alken-, Vinyliden-, Alkinyl- und Alkin-Rhodiumkomplexe mit der Baueinheit trans-[Rh(P iPr 3) 2

Abstract

The complex trans-[Rh(CO)(NH 3)(PiPr 3) 2]PF 6 ( 2) was prepared from [(η 3-C 3H 5)Rh(P iPr 3) 2] ( 1), NH 4PF 6 and CO or from 1 and NH 4PF 6 in presence of an excess of methanol. With an excess of CO, the dicarbonyl and tricarbonyl compounds trans-[Rh(CO) 2(P iPr 3) 2]PF 6 ( 3) and [Rh(CO) 3(P iPr 3) 2]PF 6 ( 4) were obtained. Displacement of one CO ligand in 3 by pyridine and acetone led to the formation of trans-[Rh(CO)(py)P iPr 3) 2]PF 6 ( 5a) and trans-[Rh(CO) (OCMe 2(P iPr 3) 2]PF 6 ( 6), respectively. Treatment of 1 with [pyH]BF 4 and pyridine gave trans-[Rh(py) 2(P iPr 3) 2]BF 4 (7); in presence of H 2 the dihydrido complex [RhH 2(py) 2(P iPr 3) 2]BF 4 ( 8) was formed. The reaction of 1 with NH 4PF 6 and ethylene produced trans [Rh(C 2H 4(NH 3(P iPr 3) 2]PF 6(9) whereas with methylvinylketone and acetophenone the octahedral hydridorhodium(III) complexes [RhH(η 2-CHCHC(O)CH 3 (NH 3(P iPr 3) 2]PF 6( 11) and [RhH(η2-C 6H 4C(O)CH 3(NH 3(P ipr 3) 2]PF 6 ( 13) were obtained. The synthesis of the cationic vinylidenerhodium(I) compounds trans-[Rh(CCHR)(py)(P iPr 3) 2]BF 4 ( 14–16) and trans-[Rh(CCHR)(NH 3)(P iPr 3) 2]PF6 ( 17–19) was achieved either on treatment of 1 with [pyH]BF 4 or NH 4PF 6 in presence of 1-alkynes or by ethylene displacement from 9 by HCCR. With tert-butylacetylene as substrate, the alkinyl(hydrido)rhodium(III) complex [RhH(CC tBu)(NH 3)(OCMe 2)(P iPr 3) 2]PF 6 ( 20) was isolated which in CH 2Cl 2 solution smoothly reacted to give 19 (R  tBu). The cationic but-2-yne compound trans-[Rh(MeCCMe)(NH 3)(P i Pr 3) 2]PF 6 ( 21) was prepared from 1, NH 4PF 6 and C 2Me 2. The molecular structures of 3 and 14 were determined by X-ray crystallography; in both cases the square-planar coordination around the metal and the trans disposition of the phosphine ligands was confirmed.