Host-guest behavior of a heavy-atom heterocycle Re4(CO)16(μ-SbPh2)2(μ-H)2 obtained from a palladium-assisted ring opening dimerization of Re2(CO)8(μ-SbPh2)(μ-H).

The heavy-atom heterocycle Pd[Re2(CO)8(μ-SbPh2)(μ-H)]2 (5) has been synthesized by the palladium-catalyzed ring-opening cyclodimerization of the three-membered heterocycle Re2(CO)8(μ-SbPh2)(μ-H) (3). The Pd atom occupies the center of the ring. The Pd atom in 5 can be removed reversibly to yield the palladium-free heterocycle [Re2(CO)8((μ-SbPh2)(μ-H)]2 (6).

Tetrarhena-heterocycle from the palladium-catalyzed dimerization of Re2(CO)8(μ-SbPh2)(μ-H) exhibits an unusual host-guest behavior.

The six-membered heavy atom heterocycles [Re(2)(CO)(8)(μ-SbPh(2))(μ-H)](2), 5, and Pd[Re(2)(CO)(8)(μ-SbPh(2))(μ-H)](2), 7, have been prepared by the palladium-catalyzed ring-opening cyclo-dimerization of the three-membered heterocycle Re(2)(CO)(8)(μ-SbPh(2))(μ-H), 3. The palladium atom that lies in the center of the heterocycle 7 was removed to yield 5. The palladium removal was found to be partially reversible leading to an unusual example of host-guest behavior.

Osmium-bismuth complexes from the reaction of Os3(CO)11(NCMe) with BiPh3.

Five new compounds were obtained from the reaction of Os(3)(CO)(11)(NCMe), 1, with BiPh(3) in hexane solution at reflux. These have been identified as Os(2)(CO)(8)(mu-BiPh), 2, Os(CO)(4)Ph(2), 3, Os(4)(CO)(14)(mu-eta(3)-O=CC(6)H(5))(mu(4)-Bi), 4, Os(4)(CO)(15)Ph(mu(4)-Bi), 5, and Os(5)(CO)(19)Ph(mu(4)-Bi), 6. Cleavage of the phenyl groups from the BiPh(3) was the dominant reaction pathway.

Synergistic behavior of bimetallic rhenium cluster catalysts: spectroscopic investigation into the nature of the active site.

Single-site Re nanoparticles were produced by anchoring dirhenium organometallic clusters on to the inner walls of mesoporous silica. The presence of oxophilic atoms (Sb or Bi) is essential to obtain well dispersed Re(0) centers. The interaction between the organometallic cluster and the silica support is critical for the generation of well-defined and isolated Re(0) single sites.

Reactions of the platinum (tri-tert-butylphosphine) group with bridging SbPh2 ligands in rhenium-antimony carbonyl complexes.

The reaction of [Re(CO)(4)(mu-SbPh(2))](2) (1) with Pt[P(t-Bu)(3)](2) in n-octane solvent at reflux (125 degrees C) has yielded two platinum-rhenium-antimony compounds, Re(2)(CO)(8)[(mu(3)-SbCH(2)CMe(2))Pt(H)P(t-Bu)(2)]P(t-Bu)(3)(mu-SbPh(2)) (2), and Re(2)(CO)(8)[Pt(CO)(CH(2)CMe(2))P(t-Bu)(2)](mu(3)-SbPh)(mu-SbPh(2)) (3), in low yields. Both products were formed by the cleavage of phenyl group(s) from one of the bridging SbPh(2) ligands in 1 and the addition of a PtP(t-Bu)(3) or Pt[P(t-Bu)(3)](2) group to the antimony atom. In both products, one of the tert-butyl groups was metalated on one of its methyl groups.

Rhenium-bismuth carbonyl cluster compounds.

The reaction of Re(2)(CO)(8)[mu-eta(2)-C(H)=C(H)Bu(n)](mu-H) with BiPh(3) in heptane solvent at reflux yielded three new compounds Re(2)(CO)(8)(mu-BiPh(2))(2), 1 (14% yield), [Re(CO)(4)(mu-BiPh(2))](3), 2 (5% yield), and Re(2)(eta(6)-C(6)H(5)Ph)(CO)(7), 3, 4.7 mg (7% yield). Compound 1 contains two Re(CO)(4) groups joined by two bridging BiPh(2) ligands in a four-membered ring.

New catalytic liquid-phase ammoxidation approach to the preparation of niacin (vitamin B3).

New highly dispersed bimetallic nanoscale catalysts based on rhenium combined with antimony or bismuth have been shown to be highly effective for the ammoxidation of 3-picoline to nicotinonitrile (precursor for vitamin B3) under mild conditions in the liquid phase.

Transformations and reactions of Re2(CO)8(mu-SbPh2)(mu-H) induced by the addition of a platinum(tri-t-butylphosphine) group.

Three products Re(2)[Pt(PBu(t)(3))](mu-SbPh(2))(CO)(8)(mu-H), 2, Re(2)[Pt(CO)(PBu(t)(3))]Ph(CO)(8)(mu(3)-SbPh)(mu-H), 3, and Re(2)[Pt(PBu(t)(3))](2)(CO)(8)(mu(4)-Sb(2)Ph(2))(mu-H)(2), 4, were obtained from the reaction of Re(2)(CO)(8)(mu-SbPh(2))(mu-H), 1, with Pt(PBu(t)(3))(2). Compound 3 was also obtained from 2 by further reaction with Pt(PBu(t)(3))(2). Compound 2 is a Pt(PBu(t)(3)) adduct of 1 formed by the insertion of the platinum atom into one of the Re-Sb bonds of 1 with formation of two Pt-Re bonds.

Bimetallic clusters of iron with palladium and platinum. Synthesis and structures of Fe2(CO)9[M(PBu(t)3)]2 (M = Pd or Pt) and Fe2(CO)8[Pt(PBu(t)3)]2(mu-H)2.

The reaction of Fe2(CO)9 with Pd(PBu(t)3)2 and Pt(PBu(t)3)2 yielded the Fe-Pd and Fe-Pt cluster complexes Fe2(CO)9[M(PBu(t)3)]2, M = Pd (8) or Pt (9). The structures of 8 and 9 are analogous and consist of nearly planar butterfly clusters of two palladium/platinum atoms in the wing-tip positions and two mutually bonded iron atoms, Fe-Fe = 2.9582(11) A in 8 and 2.