Dinuclear ruthenium and iron complexes containing palladium and platinum with tri-tert-butylphosphine ligands: synthesis, structures, and bonding

The reaction of Pd(PBu(t)(3))(2) with Ru(CO)(5) yielded the dipalladium-diruthenium cluster complex Ru(2)(CO)(9)[Pd(PBu(t)(3))](2), 10. The reaction of Pt(PBu(t)(3))(2) with Ru(CO)(5) at room temperature afforded the diplatinum-diruthenium cluster complex Ru(2)(CO)(9)[Pt(PBu(t)(3))](2), 12, and the monoplatinum-diruthenium cluster PtRu(2)(CO)(9)(PBu(t)(3)), 11. All three complexes contain a diruthenium group with bridging Pd(PBu(t)(3)) or Pt(PBu(t)(3)) groups. Compound 11 can be converted to 12 by reaction with an additional quantity of Pt(PBu(t)(3))(2). The reaction of 12 with hydrogen at 68 degrees C yielded the dihydrido complex Pt(2)Ru(2)(CO)(8)(PBu(t)(3))(2)(micro-H)(2), 13. This complex contains a Ru(2)Pt(2) cluster with hydride ligands bridging two of the Ru-Pt bonds. The reaction of Fe(2)(CO)(9) with Pt(PBu(t)(3))(2) yielded the platinum-diiron cluster complex PtFe(2)(CO)(9)(PBu(t)(3)), 14, which is analogous to 11. All new complexes were characterized crystallographically. Molecular orbital calculations of 10 reveal an unusual delocalized metal-metal bonding system involving the Pd(PBu(t)(3)) groups and the Ru(2)(CO)(9) group.     

Addition of Pt(PBu(t)(3)) groups to Ru(5)(CO)(12)(eta(6)-C(6)H(6))(mu(5)-C). Synthesis, structures, and dynamical activity

The reaction of Ru(5)(CO)(12)(eta(6)-C(6)H(6))(mu(5)-C), 7, with Pt(PBu(t)(3))(2) yielded two products Ru(5)(CO)(12)(eta(6)-C(6)H(6))(mu(6)-C)[Pt(PBu(t)(3))], 8, and Ru(5)(CO)(12)(eta(6)-C(6)H(6))(mu(6)-C)[Pt(PBu(t)(3))](2), 9. Compound 8 contains a Ru(5)Pt metal core in an open octahedral structure. In solution, 8 exists as a mixture of two isomers that interconvert rapidly on the NMR time scale at 20 degrees C, DeltaH() = 7.1(1) kcal mol(-1), DeltaS() = -5.1(6) cal mol(-)(1) K(-)(1), and DeltaG(298)(#) = 8.6(3) kcal mol(-1). Compound 9 is structurally similar to 8, but has an additional Pt(PBu(t)(3)) group bridging an Ru-Ru edge of the cluster. The two Pt(PBu(t)(3)) groups in 9 rapidly exchange on the NMR time scale at 70 degrees C, DeltaH(#) = 9.2(3) kcal mol(-)(1), DeltaS(#) = -5(1) cal mol(-)(1) K(-)(1), and DeltaG(298)(#) = 10.7(7) kcal mol(-1). Compound 8 reacts with hydrogen to give the dihydrido complex Ru(5)(CO)(11)(eta(6)-C(6)H(6))(mu(6)-C)[Pt(PBu(t)(3))](mu-H)(2), 10, in 59% yield. This compound consists of a closed Ru(5)Pt octahedron with two hydride ligands bridging two of the four Pt-Ru bonds.     

Lewis acid-base interactions between metal atoms and their applications for the synthesis of bimetallic cluster complexes

A series of new palladium-ruthenium cluster complexes have been prepared by adding Pd(PBu(t)(3)) fragments to the ruthenium-ruthenium bonds of ruthenium carbonyl complexes. Reaction of Pd(PBu(t)(3))(2) with Ru(3)(CO)(12) yielded the tripalladium adduct Ru(3)(CO)(12)[Pd(PBu(t)(3))](3) 1. Compound 1 contains three Pd(PBu(t)(3)) groups symmetrically disposed with each one acting as a bridge across one Ru-Ru bond of the former Ru(3)(CO)(12) molecule. Reaction of Pd(PBu(t)(3))(2) with Ru(6)(CO)(17)(C) yielded the dipalladium adduct Ru(6)(CO)(17)(C)[Pd(PBu(t)(3))](2) 2. Compound 2 exists as two isomers in the solid state. One isomer has Pd(PBu(t)(3)) groups bridging two edges of the Ru(6) octahedron. The other isomer has a Pd(PBu(t)(3)) group bridging one edge of the Ru(6) octahedron, and the other is a triple bridge. The reaction of Pd(PBu(t)(3))(2) with Ru(CO)(5) yielded the dipalladium-diruthenium complex Ru(2)(CO)(9)[Pd(PBu(t)(3))](2) 3, a dipalladium adduct of the unstable molecule Ru(2)(CO)(9).     

Rhodium cluster complexes containing bridging phenylgermanium ligands

The reaction of Rh(4)(CO)(12) with Ph(3)GeH at 97 degrees C has yielded the first rhodium cluster complexes containing bridging germylene and germylyne ligands: Rh(8)(CO)(12)(mu(4)-GePh)(6), 9, and Rh(3)(CO)(5)(GePh(3))(mu-GePh(2))(3)(mu(3)-GePh)(mu-H), 10. When the reaction is performed under hydrogen, the yield of 9 is increased to 42% and no 10 is formed. Compound 9 contains a cluster of eight rhodium atoms arranged in the form of a distorted cube. There are six mu(4)-GePh groups bridging each face of this distorted cube. Four of the rhodium atoms have two terminal carbonyl ligands, while the remaining four rhodium atoms have only one carbonyl ligand. Compound 10 contains a triangular cluster of three rhodium atoms with one terminal GePh(3) ligand, three bridging GePh(2) ligands, and one triply bridging GePh ligand. There is also one hydrido ligand that is believed to bridge one of the Rh-Ge bonds. Compound 9 reacted with PPhMe(2) at 25 degrees C to give the tetraphosphine derivative Rh(8)(CO)(8)(PPhMe(2))(4)(mu(4)-GePh)(6), 11. The structure of 11 is similar to 9 except that a PPhMe(2) ligand has replaced a carbonyl ligand on each the four Rh(CO)(2) groups. Compound 10 reacted with CO at 68 degrees C to give the complex Rh(3)(CO)(6)(mu-GePh(2))(3)(mu(3)-GePh), 12. Compound 12 is formed by the loss of the hydrido ligand and the terminal GePh(3) ligand from 10 and the addition of one carbonyl ligand. All compounds were fully characterized by IR, NMR, elemental, and single-crystal X-ray diffraction analyses.     

Activation of metal hydride complexes by tri-tert-butylphosphine-platinum and -palladium groups

The compounds HM(CO)4SnPh3, M = Os (10), Ru (11) are activated in the presence of Pt(PBut3)2 and Pd(PBu(t)3)2 toward the insertion of PhC2H into the M-H bond. The compounds PtOs(CO)4(SnPh3)(PBu(t)3)[mu-HCC(H)Ph], 12, and PtOs(CO)4(SnPh3)(PBu(t)3)[mu-H2CCPh], 13, were obtained from the reaction of 10 with PhC2H in the presence of Pt(PBu(t)3)2. Compounds 12 and 13 are isomers containing alkenyl ligands formed by the insertion of the PhC2H molecule into the Os-H bond at both the substituted and unsubstituted carbon atoms of the alkyne. Both compounds contain a Pt(PBu(t)3) group that is bonded to the osmium atom and a bridging alkenyl ligand that is pi-bonded to the osmium atom. The reaction of 11 with PhC2H in the presence of Pt(PBu(t)3)2 yielded the products PtRu(CO)4(SnPh3)(PBu(t)3)[mu-HC2(H)Ph], 14, and PtRu(CO)4(SnPh3)(PBut3)[mu-H2C2Ph], 15, which are also isomers similar to 12 and 13. The reaction of 11 with PhC2H in the presence of Pd(PBu(t)3)2 yielded the product PdRu(CO)4(SnPh3)(PBu(t)3)[mu-H2C2Ph], 16. Compound 16 contains a Pd(PBu(t)3) group bonded to the ruthenium atom and a bridging H2C2Ph ligand that is pi-bonded to the palladium atom. Compound 10 reacted with Pt(PBu(t)3)2 in the absence of PhC2H to yield the compound PtOs(CO)4(SnPh3)(PBu(t)3)(mu-H), 17. Compound 17 is a Pt(PBu(t)3) adduct of 10. It contains a Pt-Os bond with a bridging hydrido ligand. Compound 17 reacted with PhC2H to yield 12. Compound 12 reacted with PhC2H to yield the compound PtOs(CO)3(SnPh3)(PBu(t)3)[mu-HCC(Ph)C(H)C(H)Ph], 18. Compound 18 contains a bridging 2,4-diphenylbutadienyl ligand, HCC(Ph)C(H)C(H)Ph, that is pi-bonded to the osmium atom and sigma-bonded to the platinum atom. Fenkse-Hall molecular orbitals of 17 were calculated. The LUMO of 17 exhibits an empty orbital on the platinum atom that appears to be the most likely site for PhC2H addition prior to its insertion into the Os-H bond.     

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 2.9100 (9) A in 9. Compound 8 decomposes to form the mononuclear iron compound Fe(CO)4(PBu(t)3) (11) when heated at 68 degrees C. The reaction of Pt(PBu(t)3)2 with Fe2(CO)9 in the presence of hydrogen at 127 degrees C yielded the dihydrido complex Fe2(CO)8[Pt(PBu(t)3)]2(mu-H)2 (10). Compound 10 contains a closed Fe2Pt2 tetrahedral cluster with hydrido ligands bridging two of the Fe-Pt bonds. Compounds 8, 9, and 10 were structurally characterized crystallographically.     

Platinum-osmium cluster complexes from the addition of Pt(PBut3) groups to Os3(CO)12

Three new compounds, PtOs(3)(CO)(12)(PBu(t)(3)) (10), Pt(2)Os(3)(CO)(12)(PBu(t)(3))(2) (11), and Pt(3)Os(3)(CO)(12)(PBu(t)(3))(3) (12), have been obtained from the reaction of Pt(PBu(t)(3))(2) with Os(3)(CO)(12) (9). The products were formed by the sequential addition of 1-3 Pt(PBu(t)(3)) groups to the three Os-Os bonds of the metal cluster of Os(3)(CO)(12). In solution, compounds 10-12 interconvert among themselves by intermolecular exchange of the Pt(PBu(t)(3)) groups. When 11 is treated with PPh(3), the mono- and bis(PPh(3)) derivatives of 9, Os(3)(CO)(11)(PPh(3)) and Os(3)(CO)(10)(PPh(3))(2), were obtained by elimination of the Pt(PBu(t)(3)) groups together with one and two CO ligands, respectively. When heated, compound 11 was transformed into the new compound Pt(2)Os(3)(CO)(10)(PBu(t)(3))(PBu(t)(2)CMe(2)CH(2))(mu-H) (13) by the loss of two CO ligands and a metalation of one of the methyl groups of one of the PBu(t)(3) ligands. Compounds 10-13 have been characterized by single-crystal X-ray diffraction analyses.     

Remarkable dynamical opening and closing of platinum and palladium pentaruthenium carbido carbonyl cluster complexes

The reaction of Ru(5)(CO)(15)(mu(5)-C), 1, with Pt(PBu(t)(3))(2) at room temperature yielded the mixed-metal cluster complex PtRu(5)(CO)(15)(PBu(t)(3))(C), 2, in 52% yield. Compound 2 consists of a mixture of two interconverting isomers in solution. One isomer, 2A, can be isolated by crystallization from benzene/octane solvent. The second isomer, 2B, can be isolated by crystallization from diethyl ether. Both were characterized crystallographically. Isomer 2A consists of a square pyramidal cluster of five ruthenium atoms with a phosphine-substituted platinum atom spanning the square base. Isomer 2B consists of a square pyramidal cluster of five ruthenium atoms with a phosphine-substituted platinum atom on an edge on the square base. The two isomers interconvert rapidly on the NMR time scale at 40 degrees C, deltaG(313)++ = 11.4(8) kcal mol(-1), deltaH++ = 8.8(5) kcal mol(-1), deltaS++ = -8.4(9) cal mol(-1) K(-1). The reaction of Pd(PBu(t)(3))(2) with compound 1 yielded two new cluster complexes: PdRu(5)(CO)(15)(PBu(t)(3))(mu(6)-C), 3, in 50% yield and Pd(2)Ru(5)(CO)(15)(PBu(t)(3))(2)(mu(6)-C), 4, in 6% yield. The yield of 4 was increased to 47% when an excess of Pd(PBu(t)(3))(2) was used. In the solid state compound 3 is structurally analogous to 2A, but in solution it also exists as a mixture of interconverting isomers; deltaG(298)++ = 10.6(6) kcal mol(-1), deltaH++ = 9.7(3) kcal mol(-1), and deltaS++ = -3(1) cal mol(-1) K(-1) for 3. Compound 4 contains an octahedral cluster consisting of one palladium atom and five ruthenium atoms with an interstitial carbido ligand in the center of the octahedron, but it also has one additional Pd(PBu(t)(3)) grouping that is capping a triangular face of the ruthenium cluster. The Pd(PBu(t)(3)) groups in 4 also undergo dynamical interchange that is rapid on the NMR time scale at 25 degrees C; deltaG(298)++ = 11(1) kcal mol(-1), deltaH++ = 10.2(4) kcal mol(-1), and deltaS++ = -3(2) cal mol(-1) K(-1) for 4.     

Addition of palladium and platinum tri-tert-butylphosphine groups to Re-Sn and Re-Ge bonds

The reaction of Re2(CO)8[mu-eta2-C(H)=C(H)Bu(n)](mu-H) with Ph3SnH at 68 degrees C yielded the new compound Re2(CO)8(mu-SnPh2)2 (10) which contains two SnPh2 ligands bridging two Re(CO)(4) groups, joined by an unusually long Re-Re bond. Fenske-Hall molecular orbital calculations indicate that the bonding in the Re2Sn2 cluster is dominated by strong Re-Sn interactions and that the Re-Re interactions are weak. The 119Sn M?ssbauer spectrum of 10 exhibits a doublet with an isomer shift (IS) of 1.674(12) mm s(-1) and a quadrupole splitting (QS) of 2.080(12) mm s(-1) at 90 K,characteristic of Sn(IV) in a SnA2B2 environment. The IS is temperature dependent, -1.99(14) x 10(-4) mm s(-1) K(-1); the QS is temperature independent. The temperature-dependent properties are consistent with the known Gol'danskii-Kariagin effect. The germanium compound Re2(CO)8(mu-GePh2)2 (11) was obtained from the reaction of Re2(CO)8[mu-eta2-C(H)=C(H)Bu(n)](mu-H) with Ph3GeH. Compound 11 has a structure similar to that of 10. The reaction of 10 with Pd(PBu(t)3)2 at 25 degrees C yielded the bis-Pd(PBu(t)3) adduct, Re2(CO)8(mu-SnPh2)2[Pd(PBu(t)3)]2 (12); it has two Pd(PBu(t)3) groups bridging two of the four Re-Sn bonds in 10. Fenske-Hall molecular orbital calculations show that the Pd(PBu(t)3) groups form three-center two-electron bonds with the neighboring rhenium and tin atoms. The mono- and bis-Pt(PBu(t)3) adducts, Re2(CO)8(mu-SnPh2(2)[Pt(PBu(t)3)] (13) and Re2(CO)8(mu-SnPh2)2[Pt(PBu(t)3)]2 (14), were formed when 10 was treated with Pt(PBu(t)3)2. A mono adduct of 11, Re2(CO)8(mu-GePh2)2[Pt(PBu(t)3)] (15), was obtained similarly from the reaction of 11 with Pt(PBu(t)3)2.     

Unsaturated platinum-rhenium cluster complexes. Synthesis, structures and reactivity

Two new compounds PtRe3(CO)12(PBut3)(micro-H)3, 9, and PtRe2(CO)9(PBut3)(micro-H)2, 10, were obtained from the reaction of Pt(PBut3)2 with Re3(CO)12(micro-H3), 8, at room temperature. Compound 9 contains a butterfly cluster of four metals formed by the insertion of the platinum atom from a Pt(PBut3) group into one of the hydride-bridged metal-metal bonds of 8. The three hydrido ligands are bridging ligands across each of three new Pt-Re bonds. Compound 10 contains a triangular PtRe2 cluster with two hydrido ligands; one bridges a Pt-Re bond, and the other bridges the Re-Re bond. The new compound Pt2Re2(CO)7(PBut3)2(micro-H)2, 11, was obtained from the reaction of 8 with Pt(PBut3)2 in hexane at reflux. Compound 11 was also obtained from 10 by reaction with an additional quantity of Pt(PBut3)2. Compound 11 contains a tetrahedral cluster of four metal atoms with two dynamically active hydrido ligands. A CO ligand on one of the two platinum atoms also exchanges between the two platinum atoms rapidly on the NMR time scale. Compound 11 is electronically unsaturated and was found to add hydrogen at room temperature to form the tetrahydrido cluster complex, Pt2Re2(CO)7(PBut3)2(micro-H)4, 12. Compound 12 has a structure similar to 11 but contains one triply bridging hydrido ligand, two edge bridging hydrido ligands, and one terminal hydrido ligand on one of the two platinum atoms. A kinetic isotope effect D/H of 1.5(1) was determined for the addition of H2 to 11. Hydrogen can be eliminated from 12 by heating to 97 degrees C or by the application of UV-vis irradiation at room temperature. Compound 12 adds CO at room temperature to yield the complex Pt2Re2(CO)8(PBut3)2(micro-H)4, 13, which contains a planar cluster of four metal atoms with a Pt-Pt bond and four edge bridging hydrido ligands. Compounds 11 and 12 react with Pt(PBut3)2 to yield the known five metal cluster complexes Pt3Re2(CO)6(PBut3)3(micro-H)2, 14, and Pt3Re2(CO)6(PBut3)3(micro-H)4, 15, respectively. Density functional calculations confirm the hydride positions in the lowest energy structural isomers of 11 and 12 and suggest a mechanism for H2 addition to 11 that occurs on the Pt atom with the lower coordination number.     

Mechanism of protonation of [Pt(3)(mu-PBu(t)(2))3(H)(CO)2], yielding the hydride-bridged [Pt(3)(mu-PBu(t)(2))2(mu-H)(PBu(t)(2)H)(CO)2]OTf (Tf=CF(3)SO(2)), and the spectroscopic and theoretical characterization of a kinetic intermediate

The reaction of the Pt(I)Pt(I)Pt(II) triangulo cluster Pt(3)(micro-PBu(t)()(2))(3)(H)(CO)(2) (1) with TfOH (Tf = CF(3)SO(2)) affords the hydride-bridged cationic derivative [Pt(3)(mu-PBu(t)()(2))(2)(mu-H)(PBu(t)()(2)H)(CO)(2)]OTf (2). With TfOD the reaction gives selectively [Pt(3)(mu-PBu(t)(2))(2)(mu-D)(PBu(t)(2)H)(CO)(2)]OTf (2-D(1)), implying that the proton is transferred to a metal center while a P-H bond is formed by the reductive coupling of one of the bridging phosphides and the terminal hydride ligand of the reagent. The reaction proceeds through the formation of a thermally unstable kinetic intermediate which was characterized at low temperatures, and was suggested to be the CO-hydrogen-bonded (or protonated) [Pt(3)(mu-PBu(t)(2))(3)(H)(CO)(2)].HOTf (3). An ab initio theoretical study predicts a hydrogen-bonded complex or a proton-transfer tight ion pair as a possible candidate for the structure of the kinetic intermediate.     

Heteronuclear rhodium, palladium, platinum, and gold organoimido complexes from dinuclear organoamido rhodium precursors

Treatment of the organoamido complexes [Rh(2)(mu-4-HNC(6)H(4)Me)(2)(L(2))(2)] (L(2) = 1,5-cyclooctadiene (cod), L = CO) with nBuLi gave solutions of the organoimido species [Li(2)Rh(2)(mu-4-NC(6)H(4)Me)(2)(L(2))(2)]. Further reaction of [Li(2)Rh(2)(mu-4-NC(6)H(4)Me)(2)(cod)(2)] with [Rh(2)(mu-Cl)(2)(cod)(2)] afforded the neutral tetranuclear complex [Rh(4)(mu-4-NC(6)H(4)Me)(2)(cod)(4)] (2), which rationalizes the direct syntheses of 2 from [Rh(2)(mu-Cl)(2)(cod)(2)] and Li(2)NC(6)H(4)Me. Reactions of [Li(2)Rh(2)(mu-4-NC(6)H(4)Me)(2)(CO)(4)] with chloro complexes such as [Rh(2)(mu-Cl)(2)(CO)(4)], [MCl(2)(cod)] (M = Pd, Pt), and [Ru(2)(mu-Cl)(2)Cl(2)(p-cymene)(2)] afforded the homo- and heterotrinuclear complexes PPN[Rh(3)(mu-4-NC(6)H(4)Me)(2)(CO)(6)] (5; PPN=bis(triphenylphosphine)iminium), [(CO)(4)Rh(2)(mu-4-NC(6)H(4)Me)(2)M(cod)] (M = Pd (6), Pt(7)) and [(CO)(4)Rh(2)(mu-4-NC(6)H(4)Me)(2)Ru(p-cymene)] (8), while the reaction with [AuCl(PPh(3))] gave the tetranuclear compound [(CO)(4)Rh(2)(mu--4-NC(6)H(4)Me)(2)[Au(PPh(3))](2)] (9). The structures of complexes 6, 8, and 9 were determined by X-ray diffraction studies. The anion of 5 reacts with [AuCl(PPh(3))] to give the butterfly cluster [[Rh(3)(mu-4-NC(6)H(4)Me)(2)(CO)(6)]Au(PPh(3))] (10), in which the Au atom is bonded to two rhodium atoms. Reaction of the anion of 5 with [Rh(cod)(NCMe)(2)](BF(4)) gave the tetranuclear complex [Rh(4)(mu-4-NC(6)H(4)Me)(2)(CO)(6)(cod)] (11) in which the Rh(cod) fragment is pi-bonded to one of the arene rings, while the reaction of the anion of 5 with [PdCl(2)(cod)] afforded the heterotrinuclear complex 6 through a metal exchange process.     

Insertion of a bis(phosphine)platinum group into the S-S bond of Mn(2)(CO)(7)(mu-S(2))

The reaction of Mn(2)(CO)(7)(mu-S(2)), 1, with Pt(PPh(3))(2)(PhC(2)Ph) yielded the new complex, Mn(2)(CO)(6)Pt(PPh(3))(2)(mu(3)-S)(2), 3, by loss of CO and insertion of a Pt(PPh(3))(2) group into the S-S bond of 1. Complex 3 was characterized crystallographically and was found to consist of an open Mn(2)Pt cluster with one Mn-Mn bond, 2.8154(14) A, one Mn-Pt bond, 2.9109(10) A, and two triply bridging sulfido ligands. Compound 3 reacts with CO to form adduct Mn(2)(CO)(6)(mu-CO)Pt(PPh(3))(2)(mu(3)-S)(2), 4. Compound 4 also contains an open Mn(2)Pt cluster with two triply bridging sulfido ligands but has only one metal-metal bond, Mn-Mn = 2.638(2) A. Under nitrogen, compound 4 readily loses CO and reverts back to 3.     

Synthesis and structural characterization of two novel heterometallic clusters: [Rh4Pt2(CO)11(dppm)2] and [Ru2Rh2Pt2(CO)12(dppm)2

Two novel heterometallic octahedral clusters [Rh(4)Pt(2)(CO)(11)(dppm)(2)](1) and [Ru(2)Rh(2)Pt(2)(CO)(12)(dppm)(2)](2) were synthesized by the reaction of [Rh(2)Pt(2)(CO)(6)(dppm)(2)] with [Rh(6)(CO)(14)(NCMe)(2)] and Ru(3)(CO)(12), respectively. Solid state structures of 1 and 2 have been established by a single crystal X-ray diffraction study. Two dppm ligands in 1 are bonded to one platinum and three rhodium atoms, which form an equatorial plane of the Rh(4)Pt(2) octahedron. Two rhodium and two platinum atoms bound to the diphosphine ligands in 2 are nonplanar to give an octahedral C2 symmetric Ru(2)Rh(2)Pt(2)(dppm)2 framework. The (31)P NMR investigation of and (1D, (31)P COSY, (31)P-[(103)Rh] HMQC) and simulation of 1D spectral patterns showed that in both clusters the structures of the M(6)(PP)(2) fragments found in the solid state are maintained in solution.     

Anionic platinum complexes with 2-pyridylphosphines as ligands for rhodium: synthesis of zwitterionic Pt-Rh organometallic compounds

Bimetallic zwitterionic platinum(II)-rhodium(I) complexes of the type [(C(6)F(5))(3)Pt(micro-PPy(n)Ph(3)(-)(n)Rh(CO)(2))] and [(C(6)F(5))(3)Pt(micro-PPy(n)Ph(3)(-)(n)())Rh(diene))] (n = 2, 3; Py = 2-pyridyl) have been prepared. The P end of the bridging ligands (micro-PPy(n)Ph(3)(-)(n)) is always coordinated to the Pt center, while the N-donor ends chelate the Rh atom, giving metallacycles comparable to pyrazolylborate-Rh complexes. These metallacycles can adopt two conformations, either with the Pt complex in pseudoaxial position approaching the Rh center or with the Pt complex in a remote position. The preferred conformation depends on the steric hindrance at the rhodium center. In less sterically demanding Rh-carbonyl complexes the Pt moiety gets close to the Rh moiety as this brings closer the opposite charges of the zwitterion. For diene complexes mixtures of conformers are obtained. The X-ray structures of [(C(6)F(5))(3)Pt(micro-PPhPy(2))Rh(COD)] (COD = 1,5-cyclooctadiene) and [(C(6)F(5))(3)Pt(micro-PPhPy(2))Rh(CO)(2)] are reported.     

High-nuclearity iridium carbonyl clusters containing phenylgermyl ligands: synthesis, structures, and reactivity

The reaction of Ir4(CO)12 with Ph3GeH at 97 degrees C has yielded the new tetrairidium cluster complexes Ir4(CO)7(GePh3)(mu-GePh2)2[mu3-eta3-GePh(C6H4)](mu-H)2 (10) and Ir4(CO)8(GePh3)2(mu-GePh2)4 (11). The structure of 10 consists of a tetrahedral Ir4 cluster with seven terminal CO groups, two bridging GePh2) ligands, an ortho-metallated bridging mu3-eta3-GePh(C6H4) group, a terminal GePh3 ligand, and two bridging hydrido ligands. Compound 11 consists of a planar butterfly arrangement of four iridium atoms with four bridging GePh2 and two terminal GePh3 ligands. The same reaction at 125 degrees C yielded the two new triiridium clusters Ir3(CO)5(GePh3)(mu-GePh2)3(mu3-GePh)(mu-H) (12) and Ir3(CO)6(GePh3)3(mu-GePh2)3 (13). Compound 12 contains a triangular Ir3 cluster with three bridging GePh2), one triply bridging GePh, and one terminal GePh3 ligand. The compound also contains a hydrido ligand that bridges one of the Ir-Ge bonds. Compound 13 contains a triangular Ir3 cluster with three bridging GePh2 and three terminal GePh3 ligands. At 151 degrees C, an additional complex, Ir4H4(CO)4(mu-GePh2)4(mu4-GePh)2 (14), was isolated. Compound 14 consists of an Ir4 square with four bridging GePh2, two quadruply bridging GePh groups, and four terminal hydrido ligands. Compound 12 reacts with CO at 125 degrees C to give the compound Ir3(CO)6(mu-GePh2)3(mu3-GePh) (15). Compound 15 is formed via the loss of the hydrido ligand and the terminal GePh3 ligand and the addition of one carbonyl ligand to 12. All compounds were fully characterized by IR, NMR, single-crystal X-ray diffraction analysis, and elemental analysis.     

Disulfides of manganese carbonyl. Synthesis of Mn(2)(CO)(7)(mu-S2) and its reactions with tertiary phosphines and arsines

The reaction of Mn(2)(CO)(9)(NCMe) with thiirane yielded the sulfidomanganese carbonyl compounds Mn(2)(CO)(7)(mu-S(2)), 2, Mn(4)(CO)(15)(mu(3)-S(2))(mu(4)-S(2)), 3, and Mn(4)(CO)(14)(NCMe)(mu(3)-S(2))(mu(4)-S(2)), 4, by transfer of sulfur from the thiirane to the manganese complex. Compound 3 was obtained in better yield from the reaction of 2 with CO, and compound 4 is obtained from the reaction of 2 with NCMe. The reaction of 2 with PMe(2)Ph yielded the tetramanganese disulfide Mn(4)(CO)(15)(PMe(2)Ph)(2)(mu(3)-S)(2), 5, and S=PMe(2)Ph. The reaction of 5 with PMe(2)Ph yielded Mn(4)(CO)(14)(PMe(2)Ph)(3)(mu(3)-S)(2), 6, by ligand substitution. The reaction of 2 with AsMe(2)Ph yielded the new complexes Mn(4)(CO)(14)(AsMe(2)Ph)(2)(mu(3)-S(2))(2), 7, Mn(4)(CO)(14)(AsMe(2)Ph)(mu(3)-S(2))(mu(4)-S(2)), 8, Mn(6)(CO)(20)(AsMe(2)Ph)(2)(mu(4)-S(2))(3), 9, and Mn(2)(CO)(6)(AsMe(2)Ph)(mu-S(2)), 10. Reaction of 2 with AsPh(3) yielded the monosubstitution derivative Mn(2)(CO)(6)(AsPh(3))(mu-S(2)), 11. Reaction of 7 with PMe(2)Ph yielded Mn(4)(CO)(15)(AsMe(2)Ph)(2)(mu(3)-S)(2), 12. The phosphine analogue of 7, Mn(4)(CO)(14)(PMe(2)Ph)(2)(mu(3)-S(2))(2), 13, was prepared from the reaction of Mn(2)(CO)(9)(PMe(2)Ph) with Me(3)NO and thiirane. Compounds 2-9 and 11-13 were characterized by single-crystal X-ray diffraction. Compound 2 contains a disulfido ligand that bridges two Mn(CO)(3) groups that are joined by a Mn-Mn single bond, 2.6745(5) A in length. A carbonyl ligand bridges the Mn-Mn bond. Compounds 3 and 4 contain four manganese atoms with one triply bridging and one quadruply bridging disulfido ligand. Compounds 5 and 6 contain four manganese atoms with two triply bridging sulfido ligands. Compound 9 contains three quadruply bridging disulfido ligands imbedded in a cluster of six manganese atoms.     

Homoleptic hexa and penta gallylene coordinated complexes of molybdenum and rhodium

The reactions of molybdenum(0) and rhodium(I) olefin containing starting materials with the carbenoid group 13 metal ligator ligand GaR (R = Cp*, DDP; Cp* = pentamethylcyclopentadienyl, DDP = HC(CMeNC(6)H(3)-2,6-(i)Pr(2))(2)) were investigated and compared. Treatment of [Mo(η(4)-butadiene)(3)] with GaCp* under hydrogen atmosphere at 100 °C yields the homoleptic, hexa coordinated, and sterically crowded complex [Mo(GaCp*)(6)] (1) in good yields ≥50%. Compound 1 exhibits an unusual and high coordinated octahedral [MoGa(6)] core. Similarly, [Rh(GaCp*)(5)][CF(3)SO(3)] (2) and [Rh(GaCp*)(5)][BAr(F)] (3) (BAr(F) = B{C(6)H(3)(CF(3))(2)}(4)) are prepared by the reaction of GaCp* with the rhodium(I) compound [Rh(coe)(2)(CF(3)SO(3))](2) (coe = cyclooctene) and subsequent anion exchange in case of 3. Compound 2 features a trigonal bipyramidal [RhGa(5)] unit. In contrast, reaction of excess Ga(DDP) with [Rh(coe)(2)(CF(3)SO(3))](2) does not result in a high coordinated homoleptic complex but instead yields [(coe)(toluene)Rh{Ga(DDP)}(CF(3)SO(3))] (4). The common feature of 2 and 4 in the solid state structure is the presence of short CF(3)SO(2)O···Ga contacts involving the GaCp* or rather the Ga(DDP) ligand. Compounds 1, 2, and 4 have been fully characterized by single crystal X-ray diffraction, variable temperature (1)H and (13)C NMR spectroscopy, IR spectroscopy, mass spectrometry, as well as elemental analysis.