A new synthetic route to ligands of the general composition R2PCH2ER '(2) (E = P, As) and some rhodium complexes derived thereof

Symmetrical and unsymmetrical bis(phosphino)methanes R2PCH2PR'(2) (8-16) as well as the arsino(phosphino) analogues R'2AsCH2PR2 (21-25) with bulky alk yl, cycloalkyl or aryl groups R and R' were prepared from the stannylated p hosphines R2PCH2SnR "(3) (3-5, 6, 7) via metalation with MeLi or PhLi in th e presence of tetramethylethylenediamine and subsequent treatment with R-2' PCl or R'2AsCl, respectively. Compound 25 [R' = Cy, R = (R)-menthyl] is the first arsino(phosphino)methane which has been structurally characterized. The bis(phosphino)methanes R2PCH2PR2 (R = Pr-i 17, Cy 18) and R2PCH2PR'(2), (12, 19, 20) were also obtained by thermal reaction of R2PCH2SnPh3 and the corresponding chlorophosphine R2PCl or R'2PCl in the absence of solvent. T he bis(cyclooctene) derivative [RhCl(C8H14)(2)](2) 26 reacted with excess ( Pr2PCH2PPr2i)-P-i to give [Rh(kappa(2)P,P'-(P2PCH2PPr2i)-P-i)(2)]Cl 27, whi le treatment of 26 with Ph2PCH2PPr2i yielded the chloro-bridged dimer [RhCl (kappa(2)P,P'-Ph2PCH2PPr2i)](2) 28. The reaction of the cationic species [R h(C8H14)(2)(OCMe2)(2)]PF6 29 with Cy2PCH2PPr2i in benzene or toluene afford ed the half-sandwich-type complexes [(eta(6)-C6H6)Rh(kappa(2)P,P'-Cy2PCH2PP r2i)]PF6 30, [(eta(6)-C6H5CH3)Rh(kappa(2)P,P'-Cy2PCH2PPr2i)]PF6 31, of whic h the latter was characterized by X-ray crystallography.