Arsines monodentate tertiary

Complexes with monodentate tertiary phosphines, arsines and stibines 108... 

There is an extensive chemistry of tertiary phosphine rhodium(III) complexes. However, there are comparatively few complexes of monodentate tertiary arsines, although the complexes of ditertiary arsines are more numerous. There are virtually no tertiary stibine complexes. The two main preparative routes to the complexes described in this section are (i) direct reaction pf the ligands with rhodium trichloride, which usually yields trichloro complexes and (ii) oxidative addition to rhodium(I) tertiary phosphine complexes, which gives rise to more diverse products of the type [RhXYZ(PRj) ], Metathetical reactions on the complexes prepared by either method (i) or (ii) have been used to prepare most of the remaining compounds. 

The second (and final) set of reactions which will concern us in this section are those in which acetonitrile solutions of the salts (Bui,N)2Re2X8 (X = Cl or Br) are converted to the centro-symmetric halogen-bridged dimers Re2Xe(LL)2(il) by l,2-bis(diphen-ylphosphino)ethane and l-diphenylphosphino-2-diphenylarsinoethane (33,3, 35). This behavior contrasts with the substitution using monodentate tertiary phosphines and arsines which gives rise to Re2X6(PR3)2 ... 

Unless stated otherwise, X = anion (usually halide) L = monodentate tertiary phosphine, arsine, or phosphite S = solvent. 

Pentacarbonyliron and Fe2(CO)9 react with monodentate tertiary phosphines, arsines, and stibines to give substitution products of the general formula Fe(CO)j (ER3) . Usually substitution does not proceed beyond n = 2 ... 

Complexes with monodentate tertiary phosphines, arsines and stibines Complexes with alkyl and aryl phosphites as ligands Complexes with bidentate tertiary phosphines, arsines and stibines... 

Chelate complexes could only be prepared in the case of platinum(II) as the metal ion, while the group V atom alone acted as a donor toward palladium(II) and mercury(II). The coordinated olefin in the chelate complexes was found to be readily displaced by monodentate ligands such as tertiary arsines, -toluidine and the thiocyanate ion. It was suggested by these workers that chelation would take place more readily if the olefinic phosphine or arsine were subject to greater steric restrictions than was the pentenyl ligand. 

The halo ligands of these complexes can be replaced by other anionic ligands.918 One of the mutually trans tertiary arsine ligands can be replaced by other monodentate ligands such as pyridine (equation 215). Two ligands can be replaced by bidentate nitrogen ligands (equation 216) 1014 these latter products are discussed below in Section 48.6.3.6. 

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