Richard D. Adams

•Oxidative addition of gold methyl bonds to pentaruthenium cluster complex.•CO insertion forms acetyl ligands.•Formation of acetone by elimination of bridging acetyl ligand and a σ-methyl ligand.The reaction of Ru5(μ5-C)(CO)15, 1 with MeAu(PPh3) yielded two major products: Ru5(μ5-C)(CO)14(μ-η2-O=CMe)[μ-Au(PPh3)], 5 (30% yield) and Ru5(μ5-C)(CO)13(μ-η2-O=CMe)(Me)[μ-Au2(PPh3)2], 6 (31% yield) and one minor product Ru5(μ5-C)(CO)14(μ-η2-O=CMe)(η1-O=CMe)[μ-Au2(PPh3)2], 7 (2% yield). Compound 6 was also obtained independently in 39% yield by the addition of MeAu(PPh3) to 5. Compound 7 was also obtained independently in 63% yield by the addition of CO to 6. The PPh3 derivative of 5, Ru5(μ5-C)(CO)13(PPh3)(μ-η2-O=CMe)[μ-Au(PPh3)], 8 was obtained in 76% yield by the reaction of 5 with PPh3. Compound 6 eliminates acetone when heated to yield the digold complex Ru5(μ5-C)(CO)11(μ-CO)2[μ-Au(PPh3)]2, 9. Compound 9 reacts with MeAu(PPh3) to yield the tetragold compound Ru5(μ5-C)(CO)11(μ-CO)2[μ-Au(PPh3)]4 10. All products have been characterized by single crystal X-ray diffraction analyses. Compounds 5 and 6 contain a bridging acetyl ligand formed by the combination of the methyl group with a CO ligand in opened Ru5 clusters. Compound 7 contains both a bridging acetyl ligand and a terminally-coordinated acetyl ligand.Ru5(μ5-C)(CO)15 adds two equivalents of MeAuPPh3 to yield the complex Ru5(μ5-C)(CO)13(μ-η2-O=CMe)(Me)[μ-Au2(PPh3)2], 6 which contains a bridging acetyl ligand and a σ-methyl ligand. When heated, 6 eliminates acetone to yield the digold complex Ru5(μ5-C)(CO)11(μ-CO)3[μ-Au(PPh3)]2, 9.Download high-res image (171KB)Download full-size image

Open Pentaruthenium Cluster Complexes Formed from the Addition of Benzoic Acid to Ru5(C)(CO)15

Co-reporter:Richard D. Adams;Mitchell Smith;Jonathan Tedder

Journal of Cluster Science 2017 Volume 28( Issue 2) pp:695-702

Publication Date(Web):2017 March

DOI:10.1007/s10876-016-1056-1

Two isomers of Ru5(C)(CO)14(O2CC6H5)(μ-H): Ru5(C)(CO)14(η2-O2CC6H5)(μ-H), 2 and Ru5(C)(CO)14(μ-O2CC6H5)(μ-H), 3 were obtained from the reaction of Ru5(C)(CO)15 with benzoic acid (PhCO2H). Both compounds were characterized structurally by X-ray diffraction analysis. Compound 2 contains an opened pentaruthenium cluster with a chelating benzoate ligand on the ruthenium atom that was opened. Compound 3 contains an opened pentaruthenium cluster with a benzoate ligand on that bridges a pair of ruthenium atoms which are not mutually bonded. Compound 2 can be converted partially to 3 and 3 partially back to 2 and they form a 1.54/1.0 ratio (3/2) at equilibrium in solution at 95 °C.

Formyl C-H activation in N,N-Dimethylformamide by a dirhenium carbonyl complex

Co-reporter:Richard D. Adams, Poonam Dhull

Journal of Organometallic Chemistry 2017 Volumes 849–850(Volumes 849–850) pp:

Publication Date(Web):1 November 2017

DOI:10.1016/j.jorganchem.2017.03.009

•Activation of the formyl CH bond in N,N-dimethylformamide at a dirhenium center.•Synthesis of a C,O bridged carboxamido ligand.•Decarbonylation of N,N-dimethylformamide at a dirhenium center.The reaction of Re2(CO)8[μ-η2-C(H)=C(H)Bun](μ-H), 1 with N,N-dimethylformamide (DMF) at 70 C for 6 h has yielded three new compounds: Re2(CO)8(μ-η2-O=CNMe2)(μ-H), 2, (16% yield), Re2(CO)7(NHMe2)(μ-η2-O=CNMe2)(μ-H), 3, (30% yield), Re2(CO)9(NHMe2), 4 (14% yield). Compounds 2 and 3 contain a C,O-η2-bridging formamido (O=CNMe2) ligand and a bridging hydrido ligand that were formed by the elimination of hexene from 1 and the oxidative addition of the formyl C-H bond of the DMF to the dirhenium group of 1. Compound 3 also contains an NHMe2 ligand that was apparently formed by the decarbonylation of DMF and the transfer of the formyl hydrogen atom to the NMe2 group. Compound 4 contains a similarly formed NHMe2 ligand. Compound 2 was also obtained by the reaction of 3 with CO and compound 3 was obtained by the reaction of 2 with DMF. Compound 4 was obtained independently in a high yield by the reaction of Re2(CO)9(NCMe) with NHMe2. Compounds 2, 3 and 4 were characterized structurally by single-crystal X-ray diffraction analyses.Activation of the formyl C-H in dimethylformamide by a dirhenium carbonyl complex leads to the formation of a bridging formamido ligand.Download high-res image (112KB)Download full-size image

Synthesis and Reactivity of Electronically Unsaturated Dirhenium Carbonyl Compounds Containing Bridging Gold-Carbene Groups

Co-reporter:Richard D. Adams, Poonam Dhull, Vitaly Rassolov, and Yuen Onn Wong

Inorganic Chemistry 2016 Volume 55(Issue 20) pp:10475-10483

Publication Date(Web):September 27, 2016

DOI:10.1021/acs.inorgchem.6b01714

The electronically unsaturated compounds Re2(CO)8[μ-Au(NHC)](μ-Ph), 1, and Re2(CO)8[μ-Au(NHC)]2, 2, were obtained from the reaction of Re2(CO)8[μ–η2-C(H)═C(H)Bun](μ-H) with MeAu(NHC), NHC = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene. Compound 1 was converted to the new compound Re2(CO)8[μ-Au(NHC)](μ-H), 3, by reaction with H2. Addition of CO to 3 yielded the new compound Re2(CO)9[Au(NHC)](μ-H), 4, which contains a terminally coordinated Au(NHC) group on one of the rhenium atoms, and the hydrido ligand was shifted to bridge the Re–Au bond. The mechanism of the formation of 4 was established by DFT computational analyses. Compound 3 also reacted with C2H2 by an addition with insertion into the Re–H bonds to yield the compound Re2(CO)8[μ-Au(NHC)](μ-C2H3), 5, which contains a σ–π coordinated, bridging C2H3 ligand. The stereochemistry of the insertion was found to proceed preferentially with a cis- (syn-) stereochemistry. Compound 1 reacted with HCl to yield Re2(CO)8[μ-Ph](μ-H), 6, and ClAu(NHC) by selective removal of the bridging Au(NHC) group. All new compounds were characterized by single-crystal X-ray diffraction analyses.

Opening of Carborane Cages by Metal Cluster Complexes: The Reaction of a Thiolate-Substituted Carborane with Triosmium Carbonyl Cluster Complexes

Co-reporter:Richard D. Adams, Joseph Kiprotich, Dmitry V. Peryshkov, and Yuen Onn Wong

Inorganic Chemistry 2016 Volume 55(Issue 16) pp:8207

Publication Date(Web):August 3, 2016

DOI:10.1021/acs.inorgchem.6b01403

The reaction of Os3(CO)10(NCMe)2 with closo-o-(1-SCH3)C2B10H11 has yielded the complex Os3(CO)9[μ3-η3-C2B10H9(SCH3)](μ-H)2, 1, by the loss of the two NCMe ligands and one CO ligand from the Os3 cluster and the coordination of the sulfur atom and the activation of two B–H bonds with transfer of the hydrogen atoms to the cluster. Reaction of 1 with a second equivalent of Os3(CO)10(NCMe)2 yielded the complex Os3(CO)9(μ-H)[(μ3-η3-1,4,5-μ3-η3-6,10,11-C2B10H8S(CH3)]Os3(CO)9(μ-H)2, 2, that contains two triosmium triangles attached to the same carborane cage. The carborane cage was opened by cleavage of two B–C bonds and one B–B bond. The B–H group that was pulled out of the cage became a triply bridging group on one of the Os3 triangles but remains bonded to the cage by two B–B bonds. When heated to 150 °C, 2 was transformed into the complex Os3(CO)9(μ-H)[(μ3-η3-μ3-η3-C2B10H7S(CH3)]Os3(CO)9(μ-H), 3, by the loss of two hydrogen atoms and a rearrangement that led to further opening of the carborane cage. Reaction of 1 with a second equivalent of closo-o-(1-SCH3)C2B10H11 has yielded the complex Os3(CO)6)(μ3-η3-C2B10H9-R-SCH3) (μ3-η3-C2B10H10-S-SCH3)(μ-H)3, 4a, containing two carborane cages coordinated to one Os3 cluster. Compound 4a was isomerized to the compound Os3(CO)6(μ3-η3-C2B10H9-R-SCH3)(μ3-η3-C2B10H10-R-SCH3)(μ-H)3, 4b, by an inversion of stereochemistry at one of the sulfur atoms by heating to 174 °C.

Iridium–bismuth carbonyl cluster complexes

Co-reporter:Richard D. Adams, Gaya Elpitiya

Journal of Organometallic Chemistry 2016 Volume 812() pp:115-122

Publication Date(Web):15 June 2016

DOI:10.1016/j.jorganchem.2015.08.001

•Synthesis of high nuclearity iridium-bismuth clusters by condensation reactions.•Quadruply bridging bismuth ligands in square pyramidal metal clusters.•Synthesis and structures of phosphine substitution products.The compound Ir3(CO)9(μ3-Bi), 1 loses CO when heated and condenses to form the hexairidium compoun Ir6(CO)13(μ3-Bi)(μ4-Bi), 2. Compounds 1 and 2 react with PPh3 to form the PPh3 derivatives Ir3(CO)9-n(PPh3)n(μ3-Bi), 3 – 5, n = 1-3 and Ir6(CO)12(PPh3)(μ3-Bi)(μ4-Bi), 6, respectively. Compound 4 loses CO and converts to the o-metallated product Ir3(CO)6(PPh3)(μ-C6H4PPh2)(μ-H)(μ3-Bi), 7. Compound 1 reacts with Ru3(CO)10(NCMe)2 to yield the bimetallic cluster complex Ir3Ru4(CO)18(μ3-Bi), 9. The structures of all new products were established by single-crystal X-ray diffraction analyses. The hexairidium products 2 and 6 contain square pyramidal Ir5 clusters with a quadruply bridging bismuth ligand across the square base and a triply bridging bismuth ligand on one of the Ir3 triangles. The sixth Ir grouping is a capping group on one of the remaining Ir3 triangles. Compound 9 contains an octahedral Ir3Ru3 cluster with a Ru(CO)3 group capping an Ir3 triangle and a triply bridging bismuth ligand on one of the IrRu2 triangles.

Multicenter transformations of the methyl ligand in CH3Os3Au carbonyl cluster complexes: Synthesis, characterization and DFT analyses

Co-reporter:Richard D. Adams, Zhongwen Luo, Mingwei Chen, Vitaly Rassolov

Journal of Organometallic Chemistry 2016 Volume 812() pp:95-107

Publication Date(Web):15 June 2016

DOI:10.1016/j.jorganchem.2015.07.041

•Multicenter C–H bond transformations of a methyl group at a triosmium center.•Synthesis of osmium-gold cluster complexes with bridging acetyl and bridging methylidyne ligands.•Computational analyses of agostically coordinated bridging methyl and bridging methylene ligands.•CO induced cluster opening reactions.Os3(CO)11(NCCH3) and Os3(CO)10(NCCH3)2 react with (CH3)AuPPh3 to yield the new Os3Au cluster complexes, Os3(CO)10(μ-OCCH3) (AuPPh3), 1 and Os3(CO)9(μ-η3-CH) (μ-H)2(μ-AuPPh3), 2 containing bridging acetyl and bridging methylidyne ligands, respectively, by two competing reaction pathways: 1) a methyl migration/CO insertion pathway that produces a complex with a bridging acetyl ligand. and 2) C–H bond cleavage transformations via a series of decarbonylated intermediates containing an agostically coordinated bridging methyl group, a bridging methylene group, a triply bridging methylidyne ligand and bridging hydride ligands. It has also been found that carbon monoxide can induce shifts of the bridging hydride ligands back to methylidyne ligand in 2 with subsequent cleavage of Os–Au and Os–Os bonds to yield two open cluster complexes (CH3)Os3(CO)12AuPPh3, 4 and (CH3)Os2(CO)8AuPPh3, 5 having terminally coordinated methyl ligands. The open cluster complex 4 can be converted back to 1 and 2 via decarbonylation process by using either thermal or irradiation treatments. The CO dissociation mechanisms related to the CH bond transformation processes were studied by DFT computational analyses. It has been demonstrated that the Os3Au(CH3) cluster provides a robust platform to studying multicenter C–H bond transformations and for C–C bond formation via methyl migration/CO insertion processes.

High nuclearity clusters containing methyl groups. Synthesis and structures of pentaosmium-gold carbonyl cluster compounds

Co-reporter:Richard D. Adams, Zhongwen Luo

Journal of Organometallic Chemistry 2016 Volume 812() pp:108-114

Publication Date(Web):15 June 2016

DOI:10.1016/j.jorganchem.2015.07.022

•Synthesis and structural characterizations of gold-pentaosmium carbonyl cluster complexes.•Os5(CO)14(CH3)(μ3-AuPPh3)3 is a high nuclearity cluster containing a terminal methyl ligand.•The activation of CH3Au(PPh3) by [Au(PPh3)][NO3].The compounds Os5(CO)15(μ3-AuPPh3)2, 2 and Os5(CO)14[μ4-Au3(PPh3)3](μ3-AuPPh3), 3 were obtained from the reaction of [PPN]2[Os5(CO)15] using [Au(PPh3)][NO3]. Compound 2 contains two triply-bridging Au(PPh3) groups. Compound 3 contains one triply-bridging Au(PPh3) group and a quadruply-bridging Au3(PPh3)3 group. When the same reaction was performed in the presence of CH3Au(PPh3), the new trigold compound Os5(CO)14(CH3)(μ3-AuPPh3)3, 4 was obtained. Compound 4 contains three triply-bridging Au(PPh3) groups and one methyl group coordinated to one of the apical osmium atoms of the trigonal bipyramidal pentaosmium cluster. Compound 4 was not obtained by the direct reaction of 2 with CH3Au(PPh3) but it was obtained when [Au(PPh3)][NO3] was added to the reaction solutions. Cationic digold species such as [CH3Au2(PPh3)2]+ have been proposed as a possible mechanism for the activation of CH3Au(PPh3) by [Au(PPh3)][NO3]. Compound 4 was also obtained albeit in a lower yield from the reaction of Os6(CO)18 with MeAu(PPh3) following treatment with Me3NO. Each of the pentaosmium products was characterized structurally by a single-crystal X-ray diffraction analysis.

Binuclear Aromatic CH Bond Activation at a Dirhenium Site

Co-reporter:Dr. Richard D. Adams;Dr. Vitaly Rassolov;Dr. Yuen Onn Wong

Angewandte Chemie 2016 Volume 128( Issue 4) pp:1346-1349

Publication Date(Web):

DOI:10.1002/ange.201508540

Abstract

The electronically unsaturated dirhenium complex [Re₂(CO)₈(μ-H)(μ-Ph)] (1) has been found to exhibit aromatic C−H activation upon reaction with N,N-diethylaniline, naphthalene, and even [D₆]benzene to yield the compounds [Re₂(CO)₈(μ-H)(μ-η¹-NEt₂C₆H₄)] (2), [Re₂(CO)₈(μ-H)(μ-η²-1,2-C₁₀H₇)] (3), and [D₆]-1, respectively, in good yields. The mechanism has been elucidated by using DFT computational analyses, and involves a binuclear C−H bond-activation process.

Synthesis and characterization of an iridium–bismuth metallaheterocycle

Co-reporter:Richard D. Adams, Gaya Elpitiya

Polyhedron 2016 Volume 103(Part A) pp:131-134

Publication Date(Web):8 January 2016

DOI:10.1016/j.poly.2015.08.044

Heavy atom metallaheterocycles are an emerging family of new complexes that exhibit new structures and interesting chemical properties. In this work, the iridium–bismuth heterocyclic complex, [Ir4(CO)10(μ-BiPh2)(μ-H)]2, 1 has been obtained from the reaction of [PPN][HIr4(CO)11] with Ph2BiCl. Compound 1 was structurally characterized and was found to contain two centrosymmetrically-related Ir4(CO)10(μ-H) clusters linked by two bridging BiPh2 ligands positioned on opposite sides of a planar six-membered Ir4Bi2 ring.The iridium–bismuth complex [Ir4(CO)10(μ-BiPh2)(μ-H)]2,1 was obtained from the reaction of [HIr4(CO)11]− anion with Ph2BiCl. Complex 1 contains a planar, six-membered Ir4Bi2 ring composed of two tetrahedral [HIr4(CO)11] clusters linked by two bridging BiPh2 ligands.

Binuclear Aromatic CH Bond Activation at a Dirhenium Site

Co-reporter:Dr. Richard D. Adams;Dr. Vitaly Rassolov;Dr. Yuen Onn Wong

Angewandte Chemie International Edition 2016 Volume 55( Issue 4) pp:1324-1327

Publication Date(Web):

DOI:10.1002/anie.201508540

Abstract

Cage Opening of a Carborane Ligand by Metal Cluster Complexes

Co-reporter: Richard D. Adams;Joseph Kiprotich; Dmitry V. Peryshkov;Dr. Yuen Onn Wong

Chemistry - A European Journal 2016 Volume 22( Issue 19) pp:6501-6504

Publication Date(Web):

DOI:10.1002/chem.201601075

Abstract

The reaction of Os₃(CO)₁₀(NCMe)₂ with closo-o-C₂B₁₀H₁₀ has yielded two interconvertible isomers Os₃(CO)₉(μ₃-4,5,9-C₂B₁₀H₈)(μ-H)₂ (1 a) and Os₃(CO)₉(μ₃-3,4,8-C₂B₁₀H₈)(μ-H)₂ (1 b) formed by the loss of the two NCMe ligands and one CO ligand from the Os₃ cluster. Two BH bonds of the o-C₂B₁₀H₁₀ were activated in its addition to the osmium cluster. A second triosmium cluster was added to the 1 a/1 b mixture to yield the complex Os₃(CO)₉(μ-H)₂(μ₃-4,5,9-μ₃-7,11,12-C₂B₁₀H₇)Os₃(CO)₉(μ-H)₃ (2) that contains two triosmium triangles attached to the same carborane cage. When heated, 2 was transformed to the complex Os₃(CO)₉(μ-H)(μ₃-3,4,8-μ₃-7,11,12-C₂B₁₀H₈)Os₃(CO)₉(μ-H) (3) by a novel opening of the carborane cage with loss of H₂.

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)

Co-reporter:Michael B. Hall;Justin R. Walensky

Inorganic Chemistry 2015 Volume 54(Issue 7) pp:3536-3544

Publication Date(Web):March 10, 2015

DOI:10.1021/acs.inorgchem.5b00080

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).

The Addition of Gold and Tin to Bismuth–Triiridium Carbonyl Complexes

Co-reporter:Richard D. Adams;Gaya Elpitiya

Inorganic Chemistry 2015 Volume 54(Issue 16) pp:8042-8048

Publication Date(Web):August 6, 2015

DOI:10.1021/acs.inorgchem.5b01261

The reaction of Ir3(CO)9(μ3-Bi) with PhAu(NHC) (1), where NHC = 1,3-bis(2,6-diisopropylphenylimidazol-2-ylidene), has yielded the compound Ir3(CO)8(Ph)(μ3-Bi)[μ-Au(NHC)] (2) by the loss of one CO ligand and the oxidative addition of the Au–C (phenyl) bond of 1 to one of the iridium atoms. The Au(NHC) group bridges one of the Ir–Bi bonds of the cluster. On the basis of X-ray crystal structural analysis and molecular orbital and quantum theory of atoms in molecules calculations, the Au–Bi interaction was determined to be substantial and is comparable in character to the Ir–Bi and Ir–Ir bonds in this cluster. Compound 2 reacts with 2 equiv of HSnPh3 to yield the compound Ir3(CO)7(SnPh3)2(μ3-Bi)[μ-Au(NHC)](μ-H) (3), which contains two terminally coordinated SnPh3 ligands. Compound 3 reacts with H2O to yield the compound Ir3(μ3-Bi)(CO)7[μ-Ph2Sn(OH)SnPh2][μ-Au(NHC)] (4) by cleavage of a phenyl ring from each of the SnPh3 ligands and formation of a bridging OH group between the two tin atoms to form a chelating Ph2Sn(OH)SnPh2 ligand.

New rhenium carbonyl cluster complexes containing bridging hydrocarbyl and bridging mercury groups

Co-reporter:Richard D. Adams, Yuen Onn Wong

Journal of Organometallic Chemistry 2015 Volume 784() pp:109-113

Publication Date(Web):15 May 2015

DOI:10.1016/j.jorganchem.2015.01.008

•Synthesis and structures of mercury-bridged rhenium complexes containing bridging phenyl and alkenyl ligands.•Molecular dimerization by bridging Hg–I groupings.•Spiro-mercury atom bridges two dirhenium groupings.The new rhenium–mercury complexes [Re2(CO)8(μ-HgI)(μ-η1-C6H5)]2, 2 and [Re2(CO)8[μ-HCC(H)C4H9]2(μ4-Hg), 3 were obtained from the reactions of Re2(CO)8[μ-Au(PPh3)](μ-η1-C6H5), 1 with HgI2 and of Re2(CO)8[μ-HCC(H)C4H9](μ-H) with Hg(C6H5)2, respectively. In the solid state compound 2 is dimer of Re2(CO)8(μ-HgI)(μ-η1-C6H5) that held together by iodide ligands that asymmetrically bridge between the two mercury atoms. Each dirhenium group is formally electronically unsaturated and contains one bridging η1-C6H5 ligand. Compound 3 contains two Re2(CO)8[μ-HCC(H)C4H9]2 groups held together by a quadruply bridging spiro-structured mercury atom.The rhenium-mercury complexes [Re2(CO)8(μ-HgI)(μ-η1-C6H5)]2, 2 and [Re2(CO)8[μ-HCC(H)C4H9]2(μ4-Hg), 3 were obtained from the reactions of Re2(CO)8[μ-Au(PPh3)](μ-η1-C6H5), 1 with HgI2 and from Re2(CO)8[μ-HCC(H)C4H9](μ-H) with Hg(C6H5)2.

Bridging phenyl ligands. Unsaturated mercury-triosmium carbonyl cluster complexes containing bridging phenyl ligands

Co-reporter:Richard D. Adams, Zhongwen Luo, Yuen Onn Wong

Journal of Organometallic Chemistry 2015 Volume 784() pp:46-51

Publication Date(Web):15 May 2015

DOI:10.1016/j.jorganchem.2014.08.009

•Replacement of gold phosphine groups with mercuric halide groups.•Unsaturated triosmium cluster complexes containing bridging phenyl ligands.•Transformation of bridging phenyl ligands into bridging benzyne ligands.The gold phosphine group in the complex Os3(CO)10(μ-η1-Ph)(μ-AuPPh3), 1 can be replaced by mercury halide groups by reactions with mercury halides. The reaction of 1 with HgI2 yielded the new compound [Os3(CO)10(μ-η1-Ph)(μ-HgI)]4, 2 in 19% yield. The reaction of 1 with HgCl2 yielded the new compound Os4(CO)13(μ-η1-Ph)(μ-Cl)3, 3 in 18% yield. When heated to reflux in cyclohexane solvent, compound 2 was converted into the compound [Os3(CO)9(μ3-C6H4)(μ-H)(μ3-Hg)]2Os(CO)4, 4 in 11% yield. All new compounds were characterized by single-crystal X-ray diffraction analyses. Compound 2 is a tetramer of the unit “Os3(CO)10(μ-η1-Ph)(μ-HgI)” that is held together by a cubane-like Hg4I4 core having D2 symmetry. Each triosmium cluster is formally electronically unsaturated and contains one edge-bridging phenyl ligand. Compound 3 contains a Os3(CO)10(μ-η1-Ph)(μ-Hg) cluster, but in this case the Hg atom bridges to an additional Os(CO)3 group via three bridging chloride ligands. Compound 4 contains two Os3(CO)9(μ3-C6H4)(μ-H)(μ3-Hg) clusters that are linked by a bridging Os(CO)4 group. Each Os3 cluster in 4 contains a triply bridging C6H4 benzyne ligand and one bridging hydrido ligand.The gold phosphine group in Os3(CO)10(μ-η2-Ph)(μ-AuPPh3), 1 can be replaced by reactions with HgI2 and HgCl2 to yield the compounds [Os3(CO)10(μ-Ph)(μ-HgI)]4, 2 and Os4(CO)13(μ-Ph)(μ-Cl)3, 3 respectively. When heated 2 is transformed into the benzyne containing complex [Os3(CO)9(μ3-C6H4)(μ-H)(μ3-Hg)]2Os(CO)4, 4.

Foreword to special issue on International Symposium on Bioorganometallic Chemistry (ISBOMC'14)

Co-reporter:Richard D. Adams, Christian G. Hartinger

Journal of Organometallic Chemistry 2015 Volume 782() pp:1

Publication Date(Web):15 April 2015

DOI:10.1016/j.jorganchem.2015.02.040

Facile cleavage of phenyl groups from BiPh3 in its reactions with Os3(CO)10(NCMe)2 and evidence for localization of π-bonding in a bridging benzyne ligand

Co-reporter:Richard D. Adams, Yuwei Kan, Qiang Zhang

Journal of Organometallic Chemistry 2014 Volume 751() pp:475-481

Publication Date(Web):1 February 2014

DOI:10.1016/j.jorganchem.2013.07.027

•Facile cleavage of phenyl rings from BiPh3.•Partial π-bonding localization in a bridging benzyne ligand.•Spiro-bismuth atom bridges metal atoms.Three new compounds were obtained from the reaction of Os3(CO)10(NCMe)2, 1 with BiPh3 in a methylene chloride solution at reflux. These have been identified as Os3(CO)10(μ3-C6H4), 3, Os3(CO)10Ph(μ-η2- OCPh), 4, and HOs6(CO)20(μ-η2-C6H4)(μ4-Bi), 6. Two other products Os2(CO)8(μ-BiPh), 2, and HOs5(CO)18(μ-η2-C6H4)(μ4-Bi), 5 were obtained previously from the reaction of Os3(CO)11(NCMe) with BiPh3. Cleavage of the phenyl groups from the BiPh3 was the dominant reaction pathway and two of the products 3 and 4 contain rings but no bismuth. Each of the new compounds was characterized structurally by single-crystal X-ray diffraction methods. Compound 3 contains a triply-bridging benzyne (C6H4) ligand that exhibits a pattern of alternating long and short C–C bonds that can be attributed to partial localization of the π-bonding in the C6 ring. The localization in the π-bonding in the ring is supported by DFT calculations. Compound 4 contains a triangular cluster of three osmium atoms with a bridging benzoyl ligand and a terminally coordinated phenyl ligand. Compound 6 contains six osmium atoms divided into two groups of four and two and the two groups are linked by a spiro-bridging bismuth atom. The group of two osmium atoms contains a bridging C6H4 ligand. When heated, compound 4 was converted into 3 and the compound Os3(CO)10(μ-η2-OCPh)2, 7. Compound 7 contains two bridging benzoyl ligands.Five products Os2(CO)8(μ-BiPh), 2, Os3(CO)10(μ3-C6H4)–, 3, Os3(CO)10Ph(μ-η2-OCPh), 4, HOs5(CO)18(μ-η2-C6H4)(μ4-Bi), 5 and HOs6(CO)20(μ-η2-C6H4)(μ4-Bi), 6 were obtained by the facile cleavage of phenyl groups from BiPh3 in its reaction of Os3(CO)10(NCMe)2, 1 with BiPh3. A fifth compound Os3(CO)10(μ-η2-OCPh)2,7 was obtained by thermal transformation of 3.

Preface

Co-reporter:Claudio Pettinari, Richard D. Adams

Journal of Organometallic Chemistry 2014 Volume 771() pp:1

Publication Date(Web):15 November 2014

DOI:10.1016/j.jorganchem.2014.09.014

Facile CH Bond Formation by Reductive Elimination at a Dinuclear Metal Site

Co-reporter:Dr. Richard D. Adams;Dr. Vitaly Rassolov;Yuen Onn Wong

Angewandte Chemie 2014 Volume 126( Issue 41) pp:11186-11189

Publication Date(Web):

DOI:10.1002/ange.201406219

Abstract

The electronically unsaturated dirhenium complex [Re₂(CO)₈(µ-AuPPh₃)(µ-Ph)] (1) was obtained from the reaction of [Re₂(CO)₈{µ-η²-C(H)C(H)nBu}(µ-H)] with [Au(PPh₃)Ph]. The bridging {AuPPh₃} group was replaced by a bridging hydrido ligand to yield the unsaturated dirhenium complex [Re₂(CO)₈(µ-H)(µ-Ph)] (2) by reaction of 1 with HSnPh₃. Compound 2 reductively eliminates benzene upon addition of NCMe at 25 °C. The electronic structure of 2 and the mechanism of the reductive elimination of the benzene molecule in its reaction with NCMe were investigated by DFT computational analyses.

Facile CH Bond Formation by Reductive Elimination at a Dinuclear Metal Site

Co-reporter:Dr. Richard D. Adams;Dr. Vitaly Rassolov;Yuen Onn Wong

Angewandte Chemie International Edition 2014 Volume 53( Issue 41) pp:11006-11009

Publication Date(Web):

DOI:10.1002/anie.201406219

Abstract

Iridium–Bismuth Cluster Complexes Yield Bimetallic Nano-Catalysts for the Direct Oxidation of 3-Picoline to Niacin

Co-reporter:Richard D. Adams, Mingwei Chen, Gaya Elpitiya, Matthew E. Potter, and Robert Raja

ACS Catalysis 2013 Volume 3(Issue 12) pp:3106

Publication Date(Web):November 18, 2013

DOI:10.1021/cs400880k

The reaction of Ir3(CO)9(μ3-Bi), 1, with BiPh3 has yielded a iridium–bismuth cluster complex Ir5(CO)10(μ3-Bi)2(μ4-Bi), 2. The first examples of bimetallic iridium–bismuth nanoparticles have been subsequently synthesized from 1 and 2, and these have been securely anchored onto the inner walls of mesoporous silica. These isolated, bimetallic iridium–bismuth nanoparticles display a superior catalytic performance, when compared to their analogous monometallic counterparts and equivalent physical mixtures, in the C–H activation of 3-picoline to yield niacin.Keywords: anchored nanoparticles; catalytic synergy; C−H activation; iridium−bismuth; nanocluster; niacin; selective oxidation

Biosketch of Professor F.G.A. Stone

Co-reporter:Richard D. Adams, Thomas D. McGrath

Journal of Organometallic Chemistry 2013 730() pp: 2

Publication Date(Web):

DOI:10.1016/j.jorganchem.2013.01.003

Synthesis and structures of new tetrairidium carbonyl clusters containing phenylgermanium ligands

Co-reporter:Richard D. Adams, Mingwei Chen

Journal of Organometallic Chemistry 2013 733() pp: 21-27

Publication Date(Web):

DOI:10.1016/j.jorganchem.2013.02.035

Special issue on Organometallic Chemistry of the Main Group Elements

Co-reporter:Richard D. Adams, Narayan S. Hosmane

Journal of Organometallic Chemistry 2013 747() pp: 1

Publication Date(Web):

DOI:10.1016/j.jorganchem.2013.07.007

Tetraruthenium carbonyl complexes containing germyl and stannyl ligands from the reactions of Ru4(CO)13(μ-H)2 with HGePh3 and HSnPh3

Co-reporter:Richard D. Adams, Yuwei Kan, Vitaly Rassolov, Qiang Zhang

Journal of Organometallic Chemistry 2013 730() pp: 20-31

Publication Date(Web):

DOI:10.1016/j.jorganchem.2012.08.021

Dynamic Rotation of Bridging Aryl Ligands in Unsaturated Metal Carbonyl Cluster Complexes

Co-reporter:Richard D. Adams, Vitaly Rassolov, and Qiang Zhang

Organometallics 2013 Volume 32(Issue 6) pp:1587-1590

Publication Date(Web):February 22, 2013

DOI:10.1021/om400059c

Variable-temperature NMR studies of the compound Os3(CO)10(μ-η1-C6H5)(μ-AuPPh3) (1) have revealed a dynamic process of hindered rotation of the bridging phenyl ligand about the metal–metal bond. The activation parameters for the process, ΔH⧧ = 73.33(42) kJ/mol and ΔS⧧ = −2.66(1.25) J/(K mol), were determined by analysis of variable-temperature 1H NMR spectra. A density functional theory analysis has provided a mechanism that involves a shift of the ligand out of the bridging position with the formation of an agostic interaction of one of the ortho-positioned CH bonds of the phenyl ring to the neighboring metal atom. The related compound Os3(CO)10(μ-η1-Py)(μ-AuPPh3) (2; Py = 2-C15H9) was synthesized and was found to exhibit a similar rotation of the bridging pyrenyl ligand about the metal–metal bond: ΔH⧧ = 70.93(61) kJ/mol and ΔS⧧ = −6.98(1.83) J/(K mol).

Semibridging Phenyl Ligands in Iridium–Copper and Iridium–Silver Cluster Compounds: Synthesis, Structures, and Bonding

Co-reporter:Richard D. Adams, Mingwei Chen, Gaya Elpitiya, Xinzheng Yang, and Qiang Zhang

Organometallics 2013 Volume 32(Issue 8) pp:2416-2426

Publication Date(Web):April 3, 2013

DOI:10.1021/om400133w

Reactions of the tetrairidium anion [Ir4(CO)11(Ph)]– (1) with [Cu(NCMe)4][BF4] and Ag[NO3] have yielded the new iridium–copper and iridium–silver complexes Ir4(CO)11(μ-η1-Ph)[μ3-Cu(NCMe)] (2) and [Et4N][{Ir4(CO)11Ph}2(μ4-Ag)] (3), respectively. Compound 2 consists of a tetrahedral Ir4 cluster with a Cu(NCMe) group bridging one of the Ir3 triangular faces of the cluster and a semibridging η1-phenyl ligand that is σ–π-coordinated as a bridge across one of the Ir–Cu bonds. The complex anion of 3 contains two Ir4(CO)11Ph anions linked by a single quadruply bridging silver atom that has adopted a bow-tie geometry between the four iridium atoms. It contains two terminally coordinated σ-phenyl ligands. Compound 3 reacts with a second equivalent of Ag[NO3] to yield the uncharged complex [Ir4(CO)11]2(μ4-Ag)(μ-Ag)(μ3-Ph)(μ-Ph) (4), which contains two Ir4(CO)11 clusters linked by a quadruply bridging silver atom and one triply bridging Ph ligand. The second Ag atom in 4 is an edge bridge on one of the Ir4 clusters, and the second Ph ligand bridges an Ir–Ag bond to it. When it is dissolved in NCMe, compound 4 is split in two and adds 1 equiv of NCMe to the Ag atom in each half to form the compound Ir4(CO)11(η1-Ph)[μ3-Ag(NCMe)] (5; 73% yield). Unlike 2, the phenyl ligand in 5 is terminally coordinated. The NCMe ligand is coordinated to the Ag atom. When 4 was treated with PPh3, the complex Ir4(CO)11(μ-η1-Ph)[μ3-Ag(PPh3)] (6) was obtained in 87% yield. The cluster of 6 is structurally similar to that of 5 except that the phenyl ligand has adopted a semibridging coordination to the silver atom, similar to that found between the phenyl ligand and the copper atom in 2. All of the new products were characterized by single-crystal X-ray diffraction analyses. The bonding of the bridging phenyl ligands to the clusters in 2 and 4 was analyzed by DFT computational methods.

Structures and Bonding of η2-Bridging CO Ligands and Their Influence on the Structures and Rearrangements of Higher Nuclearity Metal Carbonyl Cluster Complexes

Co-reporter:Richard D. Adams and Qiang Zhang

Organometallics 2013 Volume 32(Issue 18) pp:5171-5179

Publication Date(Web):September 9, 2013

DOI:10.1021/om400722z

Three products were obtained from the reaction of IrRu3(CO)13(μ3-H) with P(But)3 in a hexane solution at reflux for 30 min. These have been identified as IrRu3(CO)12[P(But)3](μ-H) (1; 15% yield), IrRu2(CO)9[P(But)3](μ-H) (2; 29% yield), and IrRu3(CO)10(μ3-η2-CO)[P(But)3]2(μ-H) (3; 19% yield). Compound 1 is simply a P(But)3 derivative of IrRu3(CO)13(μ3-H). Compound 2 is electronically unsaturated and has a vacant coordination site located on the iridium atom. Compound 3 contains a butterfly tetrahedral cluster of four metal atoms with a rare η2 triply bridging CO ligand. Compound 3 reacts with Ru(CO)5 to yield the higher nuclearity cluster complex IrRu4(CO)12(μ4-η2-CO)[P(But)3]2(μ3-H) (4), which contains five metal atoms arranged in the form of an iridium-capped butterfly tetrahedron of four ruthenium atoms. Compound 4 contains a η2-quadruply bridging CO ligand. Compound 4 reacts with CO to yield the compound IrRu4(CO)14P(But)3(μ4-η2-CO)(μ-H), 5 which contains five metal atoms in the form of a spiked-tetrahedron. Compound 5 also contains a η2 quadruply bridging CO ligand. Compound 5 was converted to 2 in 36% yield by removal of two of the Ru groups by treatment with CO at 70 °C/10 atm. All of the new products were characterized structurally by single-crystal X-ray diffraction analyses. The η2-coordinated bridging CO ligands serve as four-electron donors. The nature of the bonding of the different types of η2-bridging CO ligands to the metal atoms in these clusters was investigated by DFT computational methods.

Unsaturated Triosmium Carbonyl Cluster Complexes with Bridging Aryl Ligands: Structures, Bonding, and Transformations

Co-reporter:Richard D. Adams, Vitaly Rassolov, and Qiang Zhang

Organometallics 2013 Volume 32(Issue 21) pp:6368-6378

Publication Date(Web):October 11, 2013

DOI:10.1021/om4007399

Reactions of Os3(CO)10(NCMe)2, 1, with the series of aryl-gold complexes ArylAu(PPh3) [Aryl = phenyl = Ph, 2-naphthyl = 2-Np (2-C10H7) and 1-pyryl (1-C16H10)] have provided the series of electronically unsaturated triosmium complexes Os3(CO)10(μ-η1-Ar)(μ-AuPPh3) [2, Ar = phenyl = Ph; 3, Ar = 2-naphthyl = 2-Np (2-C10H7); and Ar = 4 and 5, 2-pyryl and 4-pyryl], containing bridging η1-Ar ligands and a bridging Au(PPh3) group that bridges the same unsaturated Os–Os bond in the 46-electron cluster complex. All new compounds were characterized by single-crystal X-ray diffraction analyses. A DFT computational analysis of 2 has revealed that bonding of the bridging phenyl ligand to the metal atoms consists of a combination of delocalized σ-bonding between the ipso-carbon atom and the two proximate metal atoms and π-donation from the π-orbitals of the ring to those same metal atoms. There is no significant metal to ring π-back-bonding. Compound 3 exists as two isomers, 3a and 3b. Compound 3a contains a μ-η1-2-Np ligand. Compound 3b contains a μ-η2-2-Np ligand. The pyryl complexes 4 and 5 also exist as two isomers. These differ by the point of attachment of the η1-Ar ligand to the metal atoms. When heated to reflux in an octane solution (125 °C), compounds 2, 3, 4, and 5 were decarbonylated and converted to the corresponding aryne complexes Os3(CO)9(μ3-Ar)(μ-AuPPh3)(μ-H), 6–9, which contain a triply bridging aryne ligand formed by the loss of one CO ligand from the complex and by a CH cleavage on the bridging Ar ligand. A mechanism for the transformation of 3b into the naphthyne complex 7 was established by DFT computational analyses.

Studies of the Structures and Bonding of Gold-Bridged Dirhenium Carbonyl Cluster Complexes

Co-reporter:Richard D. Adams, Yuen Onn Wong, and Qiang Zhang

Organometallics 2013 Volume 32(Issue 24) pp:7540-7546

Publication Date(Web):November 21, 2013

DOI:10.1021/om4010127

The compounds Re2(CO)8(μ-AuPPh3)2, 1, a dimer of Re(CO)4(μ-AuPPh3), and ax,ax-Re2(CO)8(PPh3)2 were obtained from UV–vis radiation-induced decarbonylation of the compound Re(CO)5[Au(PPh3)]. Compound 1 contains two rhenium atoms bridged by two AuPPh3 groups. The complex has 32 valence electrons and is formally unsaturated by the amount of two electrons. The Re–Re bond distance in 1 is unusually short (Re–Re = 2.9070(3) Å), as found by a single-crystal structural analysis. The nature of the metal–metal bonding in 1 was investigated by DFT computational analyses, which have provided evidence not only for σ-bonding but also significant complementary π-bonding directly between the two rhenium atoms. The electronic structure of Re2(CO)8(μ-H)2, 2, was similarly analyzed and is compared with that of 1. Compound 1 is intensely colored due to low-energy, metal-based electronic transitions between the HOMO and HOMO-2 and the LUMO. Compound 1 reacts with I2 to yield Re2(CO)8(μ-AuPPh3)(μ-I), 3, and the known compound Re2(CO)8(μ-I)2, 4, by substitution of the bridging AuPPh3 groups with bridging iodide ligands. Compound 3 is electronically saturated, 34 valence electrons, and contains a formal Re–Re single bond: Re–Re = 3.2067(5) Å. Compound 3 was also in a high yield (83%) from the reaction of Re2(CO)8(μ-H)(μ-CH═CHC4H9) with Au(PPh3)I. The Re–Re bonding in compounds 3, 4, and Re2(CO)10 was also analyzed computationally, and this bonding was compared with their bonding in 1 and 2.

Synthesis and Transformations of Triosmium Carbonyl Cluster Complexes Containing Bridging Aryl Ligands

Co-reporter:Richard D. Adams, Vitaly Rassolov, and Qiang Zhang

Organometallics 2012 Volume 31(Issue 8) pp:2961-2964

Publication Date(Web):April 11, 2012

DOI:10.1021/om300235n

The reaction of Os3(CO)10(NCMe)2 (1) with C6H5Au(PPh3) has yielded the complex Os3(CO)10(μ,η1-C6H5)(μ-AuPPh3) (2), which contains an bridging η1-phenyl ligand and a Au(PPh3) group that bridges the same unsaturated Os–Os bond in the 46-electron cluster complex. When it was heated to reflux in an octane solution (125 °C), compound 2 was decarbonylated and converted to the complex Os3(CO)9(μ3-C6H4)(μ-AuPPh3)(μ-H) (3), which contains a triply bridging benzyne ligand by a CH cleavage on the bridging phenyl ring. The reaction of Os3(CO)10(NCMe)2 with (1-C10H7)Au(PPh3) (1-C10H7 = 1-naphthyl) yielded the complex Os3(CO)10(μ-2-C10H7)(μ-AuPPh3) (4), which exists as two isomeric forms in the solid state. A 1,2-hydrogen shift in the naphthyl ligand occurred in the formation of 4. The green isomer 4a is structurally similar to 2 and contains a bridging η1-2-naphthyl ligand and a bridging Au(PPh3) group and is electronically unsaturated overall. The pink isomer 4b contains a bridging η2-2-naphthyl ligand and a bridging Au(PPh3) group and is electronically saturated. The pink isomer is found in hexane solution and was converted to the complex Os3(CO)9(μ3-C10H6)(μ-AuPPh3)(μ-H) (5) when heated to reflux in octane (125 °C) for 30 min. Compound 5 contains a triply bridging 1,2-naphthyne ligand.

Synthesis and Structures of Iridium–Gold Carbonyl Cluster Compounds Containing Methyl and σ-Aryl Ligands

Co-reporter:Richard D. Adams and Mingwei Chen

Organometallics 2012 Volume 31(Issue 17) pp:6457-6465

Publication Date(Web):August 27, 2012

DOI:10.1021/om300678c

The compounds Ir4(CO)11(R)(μ-AuPPh3) (3, R = C6H5; 4, R = CH3; 5, R = 2-C16H10) were obtained from the reactions of [NEt4][Ir4(CO)11Br] with (R)Au(PPh3) (R = C6H5, CH3, 1-C16H10) at 25 °C by the loss of Br– and the oxidative addition of the Au–C bond of the (R)Au(PPh3) to the Ir4 cluster. Each compound contains a tetrahedral Ir4 cluster with an Au(PPh3) group bridging one of the six Ir–Ir bonds and a R group coordinated to one of the Au-bridged Ir atoms. The reaction of (CH3)Au(PPh3) with [PPN][HIr4(CO)11] yielded compound 4 and the higher nuclearity compound Ir4(CO)9(CH3)2(AuPPh3)4 (6). The reaction of PhAu(PPh3) with [PPN][HIr4(CO)11] yielded compound 3 and the higher nuclearity compounds Ir4(CO)9(PPh3)(Ph)(AuPPh3)3 (7) and Ir4(CO)9(Ph)2(AuPPh3)4 (8). Compounds 6 and 8 both contain butterfly Au4(PPh3)4 clusters bridging a triangular face of a tetrahedral Ir4 cluster and a CH3 group or Ph group, respectively, on two neighboring Ir atoms. Compound 7 contains a triangular (AuPPh3)3 group bridging a triangular face of a tetrahedral Ir4 cluster. Compounds 6 and 8 were obtained in better yields from the reactions of Ir4(CO)11(AuPPh3)2 with (CH3)Au(PPh3) and PhAu(PPh3), respectively. Compound 7 was obtained independently in high yield by the reaction of Ir4(CO)10(PPh3)(AuPPh3)2 with PhAu(PPh3). All of the new products were characterized by single-crystal X-ray diffraction analyses.

Synthesis and Characterizations of Bismuth-Bridged Triiridium Carbonyl Complexes Containing Germyl/Germylene and Stannyl/Stannylene Ligands

Co-reporter:Richard D. Adams, Mingwei Chen, Gaya Elpitiya, and Qiang Zhang

Organometallics 2012 Volume 31(Issue 20) pp:7264-7271

Publication Date(Web):October 9, 2012

DOI:10.1021/om300813t

The reaction of Ir3(CO)9(μ3-Bi) with Ph3GeH yielded the compound Ir3(CO)6(GePh3)3(μ3-Bi)(μ-H)3 (1). When 1 was heated to reflux in hexane, it was transformed into the compound Ir3(CO)6(μ-GePh2)3(μ3-Bi) (2), which contains three bridging GePh2 ligands by loss of 3 equiv of benzene. The reaction of Ir3(CO)9(μ3-Bi) with Ph3SnH yielded the compounds Ir3(CO)6(SnPh3)3(μ3-Bi)(μ-H)3 (3) and Ir3(CO)6(μ-SnPh2)3(μ3-Bi) (4), respectively. Compounds 1–4 were characterized crystallographically. Compounds 1 and 3 each have three terminally coordinated EPh3 (E = Ge, Sn) ligands in equatorial coordination sites, one on each of the iridium atoms. In solution compounds 1 and 3 exist as two isomers. The major isomer has the structure found in the solid state. The two isomers interconvert rapidly on the NMR time scale by tripodal, trigonal-twist rearrangement mechanisms: for 1, ΔH⧧ = 66.6 kJ/mol and ΔS⧧ = 1.58 J/(K mol), and for 3, ΔH⧧ = 65.6 kJ/mol and ΔS⧧ = −1.4 J/(K mol). The molecular orbitals and UV–vis spectra of 2 were calculated and analyzed by ADF DFT computational treatments. The visible spectrum is dominated by transitions from the Ir–Bi bonding orbitals HOMO-3 and HOMO-4 to an Ir–Ir antibonding orbital, the LUMO, in the Ir3 core of the complex.

Osmium–Germanium and Osmium–Germanium–Gold Carbonyl Cluster Complexes: Syntheses, Structures, Bonding, and Reactivity

Co-reporter:Richard D. Adams, Yuwei Kan, and Qiang Zhang

Organometallics 2012 Volume 31(Issue 24) pp:8639-8646

Publication Date(Web):December 11, 2012

DOI:10.1021/om301074w

Reactions of Os3(CO)10(NCMe)2 with HGePh3 have yielded the compounds Os3(CO)10(NCMe)(GePh3)(μ-H) (1) and Os3(CO)10(GePh3)2(μ-H)2 (2) by the sequential replacement of the NCMe ligands and the oxidative addition of the GeH bonds of one and two HGePh3 molecules, respectively, to the osmium atoms of the cluster. Compound 2 exists as two isomers in solution at low temperatures which interconvert rapidly on the 1H NMR time scale at room temperature. When it was heated, 1 was transformed into the pentaosmium complex Os5(CO)17(μ-GePh2) (3), which exhibits a planar raft structure with one bridging GePh2 ligand. Compound 1 reacts with the compound PhAu(PPh3) to yield the compound Os3(CO)8(μ-CO)(μ-O═CPh)(μ-GePh2)(μ-AuPPh3) (4), which contains a bridging O═CPh ligand and a Au(PPh3) group that bridges an Os–Ge bond. A minor product, Os(CO)4(GePh3)(AuPPh3) (5), was also obtained in this reaction. Compound 4 was also obtained from the reaction of 1 with CH3Au(PPh3). Compound 4 reacted with PhC2Ph to yield the complex Os3(CO)7(μ-GePh2)(μ-AuPPh3)[μ-(O)CPhCPhCPh)] (6), which contains a novel bridging oxametallacycle formed by the coupling of PhC2Ph to the bridging O═CPh ligand in 4 and is another example of a Au(PPh3) group that bridges an Os–Ge bond. The bonding of the bridging Au(PPh3) group to the Os–Ge bonds in 4 and 6 was investigated by DFT computational analyses.

Foreword

Co-reporter:Richard D. Adams, Claudio Pettinari

Journal of Organometallic Chemistry 2012 714() pp: 1

Publication Date(Web):

DOI:10.1016/j.jorganchem.2012.02.023