Michael R. Gregg

The synthesis and structural characterization of the η1; η3-allyl bridged bimetallic complexes [η3-2-(η5-Cp)(OC)(PR3)-Fe-allyl Pt(PPh3)2]PF6 (PR3 = PPh2H, PPh2Me)

The cationic complex [η5-Cp(OC)(η2-allene)Fe(PPh2H)]PF6 reacts with Pt-(C2H4)(PPh3)2 via C2H4 substitution (rather than oxidative addition of the PH bond) to give [η3-(2-η5-Cp(OC)(PR3)Fe-allyl)Pt(PPh3)2]PF6 PR3 = PPh2H the structure of which has been determined by a single crystal X-ray diffraction study of its dimethylphenylphosphine analog [Pr3 = PMe2Ph]. Crystal data: [C53H50FeOP3 Pt+] [PF6−]·2[C6H6] is triclinic, space group P1 with a 13.504(2), b 14.044(6), c 17.759(4) A, α 98.05(2), β 108.59(1), γ 104.44(2)°, U 3002(3) A3, Z = 2, Dx 1.49 Mg m−3, λ(Mo-Kα) 0.71069 A, μ 27.6 cm−1, F(000) = 1356, T 298 K, R = 0.0527 (Rw = 0.0575) for 7731 observed (I > 3σ(I) reflections. The compound contains an ordered η2-η1-Fe, η3-Pt allyl moiety with PtC distances of 2.151(9) and 2.165(8) A to the terminal atoms and 2.272(7) A to the central atom; the FeC distance is 1.967(7) A. The plane of the allyl group is canted at an angle of 122.5° with respect to the PtP2 plane. The Pt…Fe separation is 3.794(1) A.

Observation of bridged–terminal hydrido equilibria in a series of iron–platinum bimetallic complexes

Oxidative addition of Fe(CO)4PR2H to Pt(C2H4)(PR′3)2 gives an equilibrium mixture of (OC)3Fe(µ-PR2)(µ-H)Pt(PR′3)2 and (OC)3(H)F[graphic omitted]t(PR′3)2, the first system in which an equilibration between bridge and terminal hydride bonding modes can be observed.

Metal-assisted CO labilization and intramolecular hydride transfer reactions in heterobimetallic µ-phosphido–hydrido carbonyl complexes

The oxidative addition of the P–H bond of (OC)5M(PPh2H)(M = Cr, Mo, W) to zerovalent platinum complexes initially forms heterobimetallic µ-phosphido terminal hydrido complexes which readily rearrange via bridging carbonyl and platinum–terminal carbonyl intermediates to give the µ-phosphido-µ-hydrido complexes (OC)4M(µ-PPh2)(µ-H)Pt(PR3)2.

The effect of metal–metal bonding on the regiospecificity of nucleophilic addition to carbonyl ligands in complexes of the type [(OC)4M(µ-PPh2)2Pt(PR3)] and analogues

Regiospecific nucleophilic addition of PhLi to the equatorial CO of [(OC)4[graphic ommitted]′Lx] is considered to be a direct consequence of M → M′ bonding rather than due to steric effects, and contrasts with the lack of reactivity of PhLi with cis-[(OC)4M(PR3)2] and the general observation that in octahedral systems a CO trans to CO (as opposed to PR3) is more susceptible to nucleophilic addition.

Studies pertaining to the mechanism of Pt(PCy3) addition: the reaction of MPt(μ-H)(μ-PnPr2)Pt(CO)(PCy3) with Pt(C2H4)2(PCy3)

Abstract The reaction of Pt(C 2 H 4 ) 2 (PCy 3 ) with (OC) 4 M(μ-H)(μ-P n Pr 2 )Pt(CO)(PCy 3 , ( 1 : M  Cr, Mo, W) occurs in a highly specific, kinetically controlled manner to give MPt 2 (μ 2 M  Pt -CO)(η 2 Pt  Pt -H)(μ 2 M  Pt -P n Pr 2 )(CO) 4 (PCy 3 ) 2 ( 5 ), as the first formed trimer. The trimer 5 (M  Mo, W) isomerizes to give MPt 2 (μ 2 Pt  Pt -CO) ((μ 2 M  Pt H)(μ 2 M  Pt -P n Pr 2 )(CO) 4 )PCy 3 ) 2 ( 6 ) which in turn isomerizes to MPt 2 μ 2 M  Pt CO)(μ 2 M  Pt (μ 2 Pt  Pt -P n Pr 2 )(CO) 4 (PCy 3 ) 2 ( 7 , as the final isolable product. These results provide a detailed insight into the mechanism of “Pt(PCy 3 ) addition”, a cluster assembly process.