Triphosphines complexes

The only example of Si H M agostic interaction supported by a phosphorus bridge was discovered by Driess et al. in the complexation of a silylated triphosphine ligand to a chromium tricarbonyl complex [Eq. (20)].143,144 A bigger metal (M = Mo) or smaller substituent at silicon (R = Ph) leads to the normal triphosphine complexes. The presence of a Si H "M interaction in 59 is deduced from the lack of C3 symmetry (evident from NMR), the red shift of the IR band for the coordinated Si-H bond (1994 cm-1 vs. 2142 cm-1), and the observation of a reduced Si-H coupling (135.7 Hz for the coordinated Si-H bond vs. 210.9 and 228.6 Hz for the free Si-H bonds). The X-ray structure determination of 59 shows that one of the phosphine ligands is tilted away from the chromium atom so that the... 

In a particularly interesting application of the radical- and base-catalyzed synthesis of polyphosphine ligands (Section 3.2.2), Keiter have prepared all five possible nonchelated triphosphine complexes of W(CO)5 (35-39). 

Mesitylene-Mo(CO)3 reacts with allylphosphine in benzene to produce fac-(CO)3Mo(H2PCH2CH=CH2)3, which under the action of a free-radical initiator 2,2 -azobis(isobutyronitrile) in toluene is converted into the macrocyclic triphosphine complex/ac-(CO)3Mo(L8) [43] (Eq. 1.3). 

Reactions of isothiocyanates with the triphosphine complexes [Cu q -(Ph2PCH2)3CMe (q -BH4)] and [Cu q -(Ph2PCH2CH2)3N (ri -BH4)] proceed in a similar manner generating what are believed to be monodentate dithiocarbamate complexes. Spectroscopic data for these complexes is very similar to the bis(phosphine) complexes (219). 

Bardaji, M., Laguna, A., Orera, V.M. and Villacampa, M.D. (1998) Synthesis, Structural Characterization, and Luminescence Studies of Gold(l) and Gold(lll) Complexes with a Triphosphine Ligand. Inorganic Chemistry, 37(20), 5125-5130. 

Bardaji, M., Laguna, A., Vicente, J. and Jones, P.G. (2001) Synthesis of luminescent gold(I) and gold(III) complexes with a triphosphine ligand. Inorganic Chemistry, 40, 2675-2681. 

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