Scott D. Woodgate

Reaction between the thiocarbonyl complex, Os(CS)(CO)(PPh3)3, and propyne: crystal structure of a new sulfur-substituted osmabenzene

Abstract Reaction between Os(CS)(CO)(PPh 3 ) 3 and propyne gives a complex mixture of products from which can be isolated the simple oxidative addition product Os(CCMe)H(CS)(CO)(PPh 3 ) 2 ( 1 ) and the osmabenzene Os(η 2 -C[S]CMeCHCHC Me)(CO)(PPh 3 ) 2 ( 2 ), where the two propyne molecules in the osmabenzene ring have linked tail-to-tail. Treatment of 1 with HCl gives, as the ultimate product, the propenylthioacyl complex, Os(η 2 -C[S]CHCHMe)Cl(CO)(PPh 3 ) 2 ( 3 ). The crystal structures of compounds 1 – 3 have been determined.

Syntheses and reactions of the carbyne complexes, M(CR)Cl(CO)(PPh3)2 (M=Ru, Os; R=1-naphthyl, 2-naphthyl). The crystal structures of [Os(C-1-naphthyl)(CO)2(PPh3)2]ClO4, Os(CH-2-naphthyl)Cl2(CO)(PPh3)2, and Os(2-naphthyl)Cl(CO)2(PPh3)2

Abstract Treatment of the dichlorocarbene-containing complex, Os(CCl2)Cl2(CO)(PPh3)2 with two equivalents of 1-naphthyllithium or two equivalents of 2-naphthyllithium in the presence of N,N,N′,N′-tetramethylethylenediamine (tmeda) gives the corresponding carbyne-containing complexes Os(CR)Cl(CO)(PPh3)2 (R=1-naphthyl (1); R=2-naphthyl (2)). Similar treatment of Ru(CCl2)Cl2(CO)(PPh3)2 with two equivalents of phenyllithium or 1-naphthyllithium yields Ru(CR)Cl(CO)(PPh3)2 (R=Ph (3); R=1-naphthyl (4)). When 1, 2, 3 and 4 are carbonylated in the presence of AgClO4 the corresponding carbyne-containing cations [M(CR)(CO)2(PPh3)2]ClO4 are formed (M=Os, R=1-naphthyl (5); M=Os, R=2-naphthyl (6); M=Ru, R=Ph (7); M=Ru, R=1-naphthyl (8)). When Ru(CPh)Cl(CO)(PPh3)2 is added to an acetonitrile solution containing two equivalents of AgClO4 in the absence of CO the complex [Ru(CPh{AgOClO3})(NCMe)(CO)(PPh3)2]ClO4 (9) can be isolated. Addition of LiCl to 9 yields the complex Ru(CPh{AgCl})Cl(CO)(PPh3)2 (10). The acids HX react with the neutral carbyne complexes 1, 2, 3 or 4 to form the corresponding carbene complexes M(CHR)ClX(CO)(PPh3)2 (M=Os, R=1-naphthyl, X=Cl (11); M=Os, R=2-naphthyl, X=Cl (12); M=Ru, R=Ph, X=Cl (13); M=Ru, R=1-naphthyl, X=Cl (14); M=Os, R=1-naphthyl, X=ClO4 (15); M=Os, R=1-naphthyl, X=F (16)). Treatment of complexes 1 or 2 with PhICl2 leads to corresponding monochlorocarbene-containing complexes Os(CClR)Cl2(CO)(PPh3)2 (R=1-naphthyl (17); R=2-naphthyl (18)) which subsequently rearrange on addition of aqueous base to give the σ-naphthyl, dicarbonyl complexes OsRCl(CO)2(PPh3)2 (R=1-naphthyl (19); R=2-naphthyl (20)). The single crystal X-ray structures of [Os(C-1-naphthyl)(CO)2(PPh3)2]ClO4, Os(CH-2-naphthyl)Cl2(CO)(PPh3)2, and Os(2-naphthyl)Cl(CO)2(PPh3)2 have been determined.

Silatranyl, hydride complexes of osmium(II) and osmium(IV): crystal structure of Os(Si{OCH2CH2}3N)H3(PPh3)3

Abstract Reaction between Os(CO) 2 (PPh 3 ) 3 and the silatrane, HSi{OCH 2 CH 2 } 3 N, gives the osmium(II) silatranyl, hydride complex Os(Si{OCH 2 CH 2 } 3 N)H(CO) 2 (PPh 3 ) 2 ( 1 ), as a mixture of three isomers, the structures of which were determined by NMR spectroscopy. Reaction between OsH 4 (PPh 3 ) 3 and the silatrane, HSi{OCH 2 CH 2 } 3 N, gives the osmium(IV) silatranyl, trihydride complex Os(Si{OCH 2 CH 2 } 3 N)H 3 (PPh 3 ) 3 ( 2 ). The crystal structure of 2 has been determined and all three hydride ligands located. The three hydrides all make close approaches to the silicon atom but the distances between silicon and each of the hydrides suggests that any Si⋯H interactions must be weak. The interatomic distance between Si and N in the silatranyl ligand is large and the nitrogen atom has near planar geometry. Compound 2 can be methylated or protonated at nitrogen giving the complexes [Os(Si{OCH 2 CH 2 } 3 NMe)H 3 (PPh 3 ) 3 ]I ( 3 ), and [Os(Si{OCH 2 CH 2 } 3 NH)H 3 (PPh 3 ) 3 ]CF 3 SO 3 ( 4 ), respectively.

Tris(N-pyrrolyl)phosphine complexes of osmium(II) and osmium(0)

Abstract Reaction between OsHCl(CO)(PPh3)3 and the powerful π-accepting ligand tris(N-pyrrolyl)phosphine, P(NC4H4)3, results in replacement of the PPh3 ligand trans to hydride giving OsHCl(CO)[P(NC4H4)3](PPh3)2 (1). The analogue of 1 with Cl replaced by p-tolyl, OsH(p-tolyl)(CO)[P(NC4H4)3](PPh3)2 (3), is accessible by thermal decarboxylation of Os(p-tolyl)(η2-O2CH)(CO)(PPh3)2 (2) in the presence of P(NC4H4)3. Complex 3, despite having cis-hydride and p-tolyl ligands, is resistant to reductive elimination of toluene. Osmium(0) complexes containing P(NC4H4)3 are conveniently prepared by replacement of one PPh3 ligand from Os(CO)(CE)(PPh3)3 (E=O, S) to give Os(CO)(CE)[P(NC4H4)3](PPh3)2 (4, E=O; 5, E=S). Structure determination of 4 confirms a trigonal bipyramidal geometry with the PPh3 ligands in the axial positions and the π-accepting P(NC4H4)3 ligand in the expected equatorial site.

Syntheses and reactions of coordinatively unsaturated silyl, aryl osmium(II) complexes and the crystal structures of Os[Si(OEt)3]R(CO)(PPh3)2 and Os[Si(OEt)3]R(CO)2(PPh3)2 (R=phenyl or o-tolyl)

Abstract Reaction between OsPhCl(CO)(PPh 3 ) 2 and HSi(OEt) 3 gives the five-coordinate complex, Os[Si(OEt) 3 ]Cl(CO)(PPh 3 ) 2 ( 1 ), the crystal structure of which reveals a square pyramidal geometry with the triethoxysilyl ligand at the apical site and the two triphenylphosphine ligands arranged mutually trans . Addition of CO gives the six-coordinate complex, Os[Si(OEt) 3 ]Cl(CO) 2 (PPh 3 ) 2 ( 2 ), but this addition is thermally reversible. The chloride ligand in 1 is replaced easily and reaction with LiR gives the stable, five-coordinate complexes, Os[Si(OEt) 3 ]R(CO)(PPh 3 ) 2 ( 3a , R=phenyl; 3b , R= o -tolyl). Crystal structure determinations for 3a and 3b reveal a coordination geometry almost unchanged from that of 1 with Cl replaced by phenyl and o -tolyl, respectively. Addition of CO to 3a and 3b gives the six-coordinate complexes, Os[Si(OEt) 3 ]R(CO) 2 (PPh 3 ) 2 ( 4a , R=phenyl) ( 4b , R= o -tolyl). Crystal structure determinations for 4a and 4b confirm octahedral geometry for each compound. Despite having adjacent aryl and silyl ligands neither 3a , 3b nor 4a , 4b show any tendency to undergo reductive elimination of RSi(OEt) 3 . IR, 1 H-, 13 C- and 29 Si-NMR data for all new complexes are presented.

Phenyl derivatives of mercury functionalised in the 2-position with either a formyl or a vinyl group. Crystal structures of Hg[C6H4(CHO)-2]Cl and Hg[C6H4(CHCH2)-2]2

Abstract A convenient preparation of Hg[C 6 H 4 (CH 2 OH)-2]Cl ( 1 ) involves treatment of dilithiated benzyl alcohol with HgCl 2 . 1 is smoothly oxidised to Hg[C 6 H 4 (CHO)-2]Cl ( 2 ) by reaction with pyridinium chlorochromate (PCC). The crystal structure of 2 reveals a two coordinate linear arrangement at mercury supplemented by weaker interactions with the aldehyde oxygen atoms both intramolecularly and intermolecularly. Treatment of 2 with NaI effects symmetrisation with the formation of Hg[C 6 H 4 (CHO)-2] 2 ( 3 ). Reaction between 3 and the Wittig reagent Ph 3 PCH 2 results in the formation of Hg[C 6 H 4 (CHCH 2 )-2] 2 ( 4 ). The crystal structure of 4 has been determined.

Syntheses and structural studies of five- and six-coordinate o-halophenyl derivatives of ruthenium(II) and osmium(II)

Abstract Reaction between MHCl(CO)(PPh3)3 (M=Ru, Os) and the o-halophenyl mercury compounds, Hg(C6H4X-2)2 (X=Cl, Br, I) gives the five co-ordinate complexes, M(C6H4X-2)Cl(CO)(PPh3)2 (1a M=Ru, X=Cl; 1b M=Ru, X=Br; 2a M=Os, X=Cl; 2b M=Os, X=Br; 2c M=Os, X=I). In these complexes there is a significant bonding interaction between the coordinatively unsaturated metal centre and the o-halo-substituent on the σ-bound phenyl group as revealed by crystal structure determinations of 2a, 2b, and 2c. Each of the five-coordinate complexes readily adds CO forming the corresponding six-coordinate dicarbonyl complexes, M(C6H4X-2)Cl(CO)2(PPh3)2 (5a M=Ru, X=Cl; 5b M=Ru, X=Br; 6a M=Os, X=Cl; 6b M=Os, X=Br; 6c M=Os, X=I). Crystal structure determination of 6a confirms regular octahedral geometry for these six-coordinate complexes with no interaction between the metal centre and the o-halo-substituent on the σ-bound phenyl group. The complexes 1a, b, 2a–c, 5a, b, 6a–c, are potentially precursors of benzyne complexes through reduction (removal of ClX) but all attempts at reduction were unsuccessful. The related thiocarbonyl complexes, Os(C6H4X-2)Cl(CS)(PPh3)2 (7a X=Cl; 7b X=Br) and Os(C6H4X-2)Cl(CO)(CS)(PPh3)2 (8a X=Cl; 8b X=Br), have been prepared similarly beginning with OsHCl(CS)(PPh3)3. The crystal structure of 8a has been determined. Both 8a and 8b undergo a slow migratory-insertion reaction upon heating to yield the corresponding η2-thioacyl complexes, Os(η2-C[S]C6H4X-2)Cl(CO)(PPh3)2 (9a X=Cl; 9b X=Br), the crystal structures of both of which have been determined. Once the o-halophenyl group is no longer directly bonded to the metal, as in 9a and 9b, normal reactivity returns to the o-halo substituent and 9b undergoes lithium–bromine exchange when treated with n-butyllithium and the resulting lithiated material, when treated with SnnBu3Cl, gives Os(η2-C[S]C6H4SnnBu3-2)Cl(CO)(PPh3)2 (10).

Vinylidene complexes of osmium(0) derived from 1-naphthyl- or 2-naphthyl-carbyne complexes by hydride addition to the naphthyl substituents. The crystal structure of Os(CC10H8)(CO)2(PPh3)2

Abstract When treated with lithium triethylborohydride, the cationic carbyne complexes [Os(–CR)(CO)2(PPh3)2]+(R=1-naphthyl, 1; R=2-naphthyl, 2) form 3 and 4, respectively, which both have the formula Os(C11H8)(CO)2(PPh3)2. NMR studies of these two isomeric vinylidene complexes show that the product derived from the 1-naphthyl carbyne cation involves attack at the naphthyl ring in the position para to the carbyne carbon to give 3, while that derived from the 2-naphthyl carbyne cation involves attack at the naphthyl ring in the position ortho to the carbyne carbon to give 4. The structure of 4 has been confirmed by an X-ray crystal structure determination. Addition of HCl to the vinylidene complexes 3 or 4 results in the formation of the corresponding naphthylmethyl complexes, Os(CH2R)Cl(CO)2(PPh3)2 (R=1-naphthyl, 5; R=2-naphthyl, 6).

Carbonyl-chlorido(1-methyl-sulfanylpenta-1,3-dien-1-yl-5-yl-idene)bis-(triphenyl-phosphane)osmium(II).

The crystal structure of the title compound, [Os(C6H7S)Cl(C18H15P)2(CO)], confirms the formulation as an osmabenzene. There is a slightly distorted octahedral coordination environment at the OsII ion, with the triphenylphosphane ligands mutually trans and the chloride cis to the carbon bearing the –SMe substituent. Within the metallacyclic ring, the C—C distances are appropriate for aromatic bonds and the two Os—C distances are shorter than typical Os—C single bonds. The maximum deviation from the least-squares plane through the osmabenzene ring occurs for the carbon bearing the SMe substituent [0.1037 (18) Å].