L.J. Wright

Syntheses and structures of the chalcocarbonyl complexes OsCl2(CO) (CE) (PPh3)2 (E=S,Se,Te)

The Group VI nucleophiles HE− (E = O, S, Se, Te) react with the electrophilic dichlorocarbene ligand in the complex OsCl2(CCl2)(CO)(PPh3)2 to form the corresponding chalcocarbonyl derivatives OsCl2(CO)(CE)(PPh3)2. OsCl2(CO)-(CTe)(PPh3)2 is the first reported tellurocarbonyl complex, and the compounds OsCl2(CO)(CE)(PPh3)2 constitute the first complete series of chalcocarbonyl complexes. H2O, H2S and H2Se also react with the dichlorocarbene complex to yield the corresponding chalcocarbonyl derivatives OsCl2(CO)(CE)(PPh3)2, although OsCl2(CO)(CTe)(PPh3)2 cannot be formed this way. The thiocarbonyl, dichlorocarbene complex OsCl2(CCl2)(CS)(PPh3)2 gives tractable products with H2O, H2S and H2Se, and in this way the mixed chalcocarbonyl compounds OsCl2(CS)(CE)(PPh3)2 can be isolated. X-ray crystal structure determinations have been carried out on the complexes OsCl2(CO)(CS)(PPh3)2, OsCl2(CO)(CSe)(PPh3)2 and OsCl2(CO)(CTe)(PPh3)2. The CS and CSe complexes are isostructural and crystallise in space group P1, with two molecules in unit cells of dimensions: CS a 12.837(1), b 14.302(1), c 10.452(1) A, α 92.45(1), β 97.42(1), γ 99.86(1)°; CSe a 12.846(3), b 14.341(3), c 10.462(4) A, α 92.26(2), β 97.67(2), γ 99.76(1)°. The CTe complex crystallises in space group P21/n, with four molecules in a cell of dimensions a 14.211(3), b 18.084(4), c 14.857(3) A, β 113.29(2)°. The coordinated CTe ligand in OsCl2(CO)(CTe)(PPh3)2 displays similar overall structural features to the other coordinated chalcocarbonyl ligands in that the OsCTe angle is ca. 180° and the OsCTe and CTe bonds are very short. For each of the complexes the OsCE bond length is shorter than the OsCO bond length in the same molecule, although only for the thiocarbonyl complex is the difference significant. The trans-influence of the chalcocarbonyl ligands increases in the order CO < CS ≤ CSe < CTe.

Synthesis and some reactions of a terminal carbyne complex of osmium. Crystal structures of Os(CR)Cl(CO)(PPh3)2 and Os(C[AgCl]R)Cl(CO)(PPh3)2

Abstract The reaction of two equivalents of LiR (R = p-tolyl) with the dichlorocarbene complex OsCl2(CCl2)(CO)(PPh3)2 gives the carbyne complex Os(CR)Cl(CO) (PPh3)2 (I) in good yield. X-ray crystal structure determination shows that I is mononuclear with an OsC distance of 1.78(2) A. The OsC bond reacts with electrophiles rather than nucleophiles. Thus, HCl adds to give the alkylidene complex OsCl2(CHR)(CO)(PPh3)2, Cl2 forms OsCl2(CClR)(CO)(PPh3)2 and sulphur, selenium and tellurium react to yield to corresponding dihapto-chalcoacyls Os(η2-C[X]R)Cl(CO)(PPh3)2 (X = S, Se, Te). Group Ib metal halides also add to the OsC bond to form the adducts Os(C[M X]R)Cl(CO)(PPh3)2 (MX = CuI, AgCl, AuCl). The X-ray crystal structure determination of Os(C[A gCl]R)Cl(CO)(PPh3)2 (II) suggests that this complex can be considered as a dimetallacyclopropene derivative. Crystals of I are monoclinic, space group P21/n, a 17.030(2), b 12.774(1), c 18.315(3) A, β 107.96 (1)°, V 3793.2 A3, Z = 4, Dm 1.53(1), Dc 1.54. Crystals of II are monoclinic, space group P21/n, a 13.021(2), b 23.714(2), c 12.999(2) A, β 90.556(2)°, V 4013.7 A3, Z = 4, Dm 1.705(5), Dc 1.695. The structures were solved by conventional heavy-atom methods, and refined by full-matrix least-squares employing anisotropic thermal parameters for all non-hydrogen atoms except for the carbon atoms of the phenyl rings. Phenyl hydrogen atoms were included in calculated positions. Final residuals R were 0.040 and 0.037, respectively.

Dihapto-acyl derivatives of ruthenium(II). Preparation and structure of Ru[η2-C(O)CH3] I(CO)(PPh3)2 and Ru[η2-C(O)p-tolyl]I(C0) (PPh3) 2

Abstract Reaction between Ru(CO)2(PPh3)3 and MeHgI yields Ru[η2-C(O)CH3]I(CO)(PPh3)2 which in solution exists mainly as RuCH3I(CO)2(PPh3)2 and crystal structure determination of Ru[η2-C(O)CH3]I(CO)(PPh3)2 and previously described Ru[η2-C(O)p-tolyl]I(CO) (PPh3)2 confirms that in the solid state both molecules contain dihapto-acyl ligands.

Combined decarboxylation of the formato ligand and reductive elimination of hydrido and aryl groups in the synthesis of ruthenium(0) complexes. Methylation of ruthenium(0) with formaldehyde

Abstract The formato ligand is readily introduced into the 5-coordinate complexes MRCl(CO)(PPh 3 ) 2 (M = Ru or Os, R = o -tolyl) giving 6-coordinate MR(η 2 -O 2 CH)(CO)(PPh 3 ) 2 . In the presence of excess PPh 3 thermal decarboxylation of the osmium complex leads to the stable aryl, hydride, OsRH(CO)(PPh 3 ) 3 . A similar reaction with RuR(η 2 -O 2 CH)(CO)(PPh 3 ) 2 is accompanied by reductive elimination of RH and formation of “Ru(CO)(PPh 3 ) 3 ” which as a solid is ortho -metallated, i.e. exists as Ru(C 6 H 4 P Ph 2 )H(CO)(PPh 3 ) 2 . Decarboxylation and reductive elimination in the presence of bis(diphenylphosphino)ethane (dppe) give the zerovalent Ru(CO)(dppe) 2 . “Ru(CO)(PPh 3 ) 3 ” undergoes a most unusual reaction with formaldehyde forming Ru(CH 3 )(η 2 -O 2 CH)(CO)(PPh 3 ) 2 .

A dihapto-iminoacyl derivative of ruthenium(II). Synthesis and structure of RU[η2-C(NR)R]Cl(CO)(PPh3)2

Abstract The ruthenium iminoacyl complex, Ru[C(NR)R]Cl(CO(PPh 3 ) 2 , (R  p -tolyl), which results from a migratory-insertion rearrangement of RuRCl(CO) (CNR) (PPh 3 ) 2 is shown by X-ray crystal structure analysis to contain the iminoacyl ligand attached to ruthenium through C and N in an almost symmetrical manner.

The interaction of an osmium-carbon triple bond with copper(I), silver(I) and gold(I) to give mixed dimetallocyclopropene species and the structures of Os(AgCl) (CR) Cl(CO) (PPh3)2

Abstract The osmium carbyne complex, Os(CR)Cl(CO)(PPh3)2, (R  p-tolyl) reacts with Group I halides to form the mixed dimetallocyclopropene species, Os(Cul)(C R)Cl(CO)(PPh3)2, Os(AgCl)(C R)Cl(CO)(PPh3)2, Os(AuCl)(C R)Cl(CO)(PPh3)2, and [ Os[Ag(OClO 3 )](C R)Cl(CO)(MeCN)(PPh3)2] ClO4 X-ray crystal structure determination of Os(AgCl)(C R)Cl(CO)(PPh3)2 confirms the presence of a three-membered ring and the structure can be viewed as the “acetylene-like” interaction of an osmium—carbon triple bond with AgCl. In acid solution AgCl is precipitated and an alkylidene complex results from proton addition to the carbyne ligand.

An unusual vinylidene complex from hydride addition to the aromatic ring of the tolyl—carbyne ligand in a cationic osmium carbyne complex

Abstract The cationic osmium carbyne complex [Os(CR)(CO)2(PPh3)2]+ (R = p-tolyl) reacts with Li(Et3BH) with hydride addition to the para-position of the aromatic ring of the carbyne ligand giving an unusual vinylidene complex. This formulation of the product, which was suggested by the 1H NMR data, was confirmed by an X-ray crystal structure determination.

Crystal structure of the maleic anhydride complex Ru(η2-C4H2O3)(CO)(CN-p-tolyl)(PPh3)2

Abstract The structure of the maleic anhydride complex Ru(η2-C4H2O3)(CO)(CN-p-tolyl)(PPh3)2 (1) has been determined by X-ray crystallography. Crystals of 1 are monoclinic, space group P21/c, a 9.917(1), b 20.244(3), c 20.768(3) A, β 99.80(1)°. Z = 4, Dc 1.406 g cm−3. The structure was solved by conventional Patterson and Fourier techniques and refined by full matrix least squares. The refinement converged to R = 0.061, Rw = 0.063. The geometry about ruthenium is approximately trigonal bipyramidal with the maleic anhydride and the two triphenylphosphines equatorial. The maleic anhydride coordinates to ruthenium via the alkene (C(1)C(4)) bond. The elongated C(1)C(4) bond and the values of ν(CN) and ν(CO) in the infrared spectrum suggest a strong alkene π-acceptor component in the Ru-maleic anhydride interaction.

Bis(N,N′-dimethylimidazol-2-yl­idene)mercury chlorotriiodo­mercury dimethyl sulfoxide solvate

The double mercury salt [Hg(C5H8N2)2][HgClI3]·C2H6OS was prepared and its structure characterized. The [Hg(C5H8N2)2]2+ cation lies about an inversion centre and the [HgClI3]2− anion lies on a mirror plane. Cations and anions are linked to form a one-dimensional polymer by weak Hg⋯Cl interactions [Hg⋯Cl 3.3744 (3) A]. The mercury–carbene bond distance [2.076 (7) A] is typical of a dicationic mercury–carbene species.

Catecholate spanning a metal-carbon double bond. Synthesis and crystal structure of -(2-N-methylpyrrolyl)]I(CO)(PPh3)2

Abstract Catecholate displaces chloride from both the carbene centre and the metal in Ru[CCl(2-pyrrolyl)]Cl2(CO)L2 (L = PPh3) to give Ru[C(OC 6 H 4 O )(2-pyrrolyl)]Cl(CO)L2 (A). Cations derived from A can be deprotonated to ruthenium-substituted 1-azafulvene intermediates which undergo further reactions including methylation at nitrogen to give Ru[C(OC 6 H 4 O )(2-N-methylpyrrolyl)]I(CO)L2 (E). The crystal structure of E is reported.