José M. Fernández-Colinas

Diaminogermylene and diaminostannylene derivatives of gold(I): novel AuM and AuM2 (M = Ge, Sn) complexes.

The reactions of [AuCl(THT)] (THT = tetrahydrothiophene) with 1 equiv of the group 14 diaminometalenes M(HMDS)(2) [M = Ge, Sn; HMDS = N(SiMe(3))(2)] lead to [Au{MCl(HMDS)(2)}(THT)] [M = Ge (1), Sn (2)], which contain a metalate(II) ligand that arises from insertion of the corresponding M(HMDS)(2) reagent into the Au-Cl bond of the gold(I) reagent. While compound 1 reacts with more Ge(HMDS)(2) to give the germanate-germylene derivative [Au{GeCl(HMDS)(2)}{Ge(HMDS)(2)}] (3), which results from substitution of Ge(HMDS)(2) for the THT ligand of 1, an analogous treatment of compound 2 with Sn(HMDS)(2) gives the stannate-stannylene derivative [Au{SnCl(HMDS)(2)}{Sn(HMDS)(2)(THT)}] (4), which has a THT ligand attached to the stannylene tin atom and which, in solution at room temperature, participates in a dynamic process that makes its two Sn(HMDS)(2) fragments equivalent (on the NMR time scale). A similar dynamic process has not been observed for the AuGe(2) compound 3 or for the AuSn(2) derivatives [Au{SnR(HMDS)(2)}{Sn(HMDS)(2)(THT)}] [R = Bu (5), HMDS (6)], which have been prepared by treating complex 4 with LiR. The structures of compounds 1 and 3-6 have been determined by X-ray diffraction.

Ruthenium(I) complexes containing bridging N-donor ligands: structure, synthesis and reactivity patterns

Abstract The article reviews the chemistry of binuclear ruthenium(I) complexes containing bridging N-donor ligands. The introduction is followed by a survey of compounds, which is classified in alphabetical order according to the type of organic molecule that gives rise to each particular bridging ligand (amides, diamines, imidazoles, oximes, pyrazoles, pyridines, thiazoles, triazenes, triazoles), and covers the literature published up to the end of 1992. The article finishes with some comments on structural, synthetic and reactivity aspects of this class of compound.

Steric effects in the reactions of amidinate germylenes with ruthenium carbonyl: isolation of a coordinatively unsaturated diruthenium(0) derivative

Coordinatively unsaturated germylene-bridged diruthenium(0) complexes can be prepared by treating [Ru3(CO)12] with amidinate germylenes of the type Ge(R1bzamR2)(HMDS) [R1bzamR2 = 1-R1-3-R2-benzamidinate, HMDS = N(SiMe3)2], but only when the amidinate contains just one very bulky R group (tBu) (not two).

Synthesis and reactivity of mono-, tri-, and poly-nuclear ruthenium carbonyl complexes containing the pyridine-2-thiolate ligand (pyS). Stepwise preparation of [Ru(pyS)2(CO)2] by reaction of [Ru3(CO)12] with pyridine-2-thiol

The thermal reaction of [Ru3(CO)12] with pyridine-2-thiol (pySH) gives the trinuclear complex [Ru3(µ-H)(µ3-pyS)(CO)9](1), which is subsequently converted into the polymer [{Ru(µ3-pyS)(CO)2}n](2). Further reaction of polymer (2) with pyridine-2-thiol gives the monomeric compound [Ru(pyS)2(CO)2](3). Complexes (1) and (2) contain triply bridging pyS ligands while in complex (3) both pyS ligands are chelating. These results indicate that the reactivity of [Ru3(CO)12] with pyridine-2-thiol is different to that found for [Os3(CO)12] and for [Ru3(CO)12] with 2-aminopyridine and 2-hydroxypyridine. The reactions of complexes (1)–(3) with several P-donor ligands are also described. Infrared and 1H and 31P-{1H} n.m.r. spectral data for all the compounds are presented and discussed in relation to their structures.

The addition of protons and metallic electrophiles to the electron-rich RuRu bond of [Ru2(μ,-dan)(CO)4(PiPr3)2]. X-ray structure of [Ru2(μ-AgPPh3)(μ-dan)(CO)4(PiPr3)2][BF4]·CH2Cl2 (dan=1,8-diamidonaphthalene)

Abstract The ruthenium(I) complex [Ru 2 (μ-dan)(CO) 4 (P i Pr 3 ) 2 ] ( 1 ) (dan= 1,8-diamidonaphthalene) reacts with HBF 4 ·OEt 2 , [AuCI(PPh 3 )]/TIPF 6 and AgBF 4 /PPh 3 to give the cationic complexes [Ru 2 (μ-M)(μ- dan)(CO) 4 (P i Pr 3 ) 2 ] + (M=H (2), AuPPh 3 (3), AgPPh 3 ( 4 )), while the reactions with [AuCl(tht)] (tht = tetrahydrothiophene) and AgO 2 CCF 3 give the neutral derivatives [Ru 2 (μ-M)(μ-dan)(CO) 4 (p i pr 3 ) 2 ] (M=AuCI (5), AgO 2 CCF 3 ( 6 )). Complex 1 also reacts with SnCl 2 to give [Ru 2 (μ-SnCle 2 )(μ- dan)(CO) 4 (P i Pr 3 ) 2 ] (7), hut in solution it dissociates SnCI 2 unless a large excess of the latter is present. In all cases, the added electrophiles symmetrically bridge the RuRu bond of complex 1 , as indicated by IR and NMR spectroscopies. The structure of complex 4 has been confirmed by X-ray diffraction methods.

Synthesis, characterization, reactivity, and catalytic hydrogenation activity of the hexanuclear hexahydrido carbonyl cluster compound [Ru6(μ-H)60(μ3,ν2-ampy)2(CO)14 ] (Hampy = 2-amino-6-methylpyridine)

Abstract The reaction of the 48-electron complex [Ru 3 (μ-H)(μ 3 ,ν 2 -ampy)(CO) 9 ] (1) (Hampy = 2-amino-6-methylpyridine) with molecular hydrogen (1 atm, toluene, 110°C) gives the 92-electron hexanuclear hexahydrido derivative [Ru6(μ-H) 6 ( μ 3 , ν 2 -ampy) 2 (CO) 14 ] (2). This hexanuclear compound regenerates complex 1 when exposed to carbon monoxide. However, it undergoes CO substitution instead of ligand addition when treated with PR, to give [Ru6(μ-H) 6 (μ 3 ν 2 -ampy) 2 (PR 3 ) 2 (CO) 12 ] (R = 4-tolyl ( 3a ) or Ph ( 3b )). The X-ray diffraction structure of 3a indicates that it consists of two trinuclear fragments connected to each other through two bridging hydrides, and two weak metal-metal bonds. NMR experiments (1H, 13 C, homonuclear 1H NOE, and heteronuclear indirect 13 C- 1 H correlations) indicate that 2 is isostructural with 3a . Complex 2 is an efficient catalyst precursor for the homogeneous hydrogenation of unsaturated organic molecules. A kinetic analysis of the hydrogenation of diphenylacetylene under very mild conditions ( T = 323 K, P (H 2 ) 2 , first-order in hydrogen pressure and zero-order in substrate concentration, suggesting that the active catalytic species are hexanuclear.

Synthesis and reactions with electrophiles and nucleophiles of the ruthenium(I) complex [Ru2(µ-C10H8N2)(CO)6]. Crystal structure of [Ru2(µ-C10H8N2)(CO)4{P(OPh)3}2](C10H10N2= 1,8-diaminonaphthalene)

The ruthenium(I) complex [Ru2(µ-C10H8N2)(CO)6]1(C10H10N2= 1,8-diaminonaphthalene) has been prepared by reaction of [Ru3(CO)12] with an excess of 1,8-diaminonaphthalene under carbon monoxide, at 110 °C. Complex 1 reacts with halogens, tetrafluoroboric acid and dimethyl acetylenedicarboxylate to give the triply bridged complexes [Ru2(µ-C10H8N2)(µ-X)(CO)6]+(X = 1 2, Br 3 or Cl 4)[Ru2(µ-C10H8N2)(µ-H)(CO)6]BF45 and [Ru2(µ-C10H8N2){µ-C2(CO2Me)2}(CO)6]6, respectively. The complexes [Ru2(µ-C10H8N2)(CO)4L2][L = PPhi37, PPh38, P(OPh)39 or dppm-κP12], which contain the introduced ligands trans to the Ru–Ru bond, have been prepared by reaction of 1 with an excess of the appropriate P-donor ligand L. However the reaction of 1 with an excess of trimethyl phosphite renders the trisubstituted compound [Ru2(µ-C10H8N2)(CO)3{P(OMe)3}3]10. The reaction of 1 with one equivalent of bis(diphenylphosphino)methane (dppm), at room temperature, has been found to give a mixture of oligomers containing bridging and monoco-ordinated dppm ligands. These oligomers aggregate in refluxing tetrahydrofuran to give the polymeric compound [{Ru2(µ-C10H8N2)(CO)4(µ-dppm)}n]11. The monosubstituted compound [Ru2(µ-C10H8N2)(CO)5(py)]13 has been prepared by reaction of complex 1 with pyridine (py). Infrared and 1H and 31P-{1H} NMR spectra of all the compounds are presented and discussed in relation to their structures. The crystal structure of compound 9 has been determined by X-ray diffraction methods. Crystals of 9 are monoclinic, space group P21/m, with a= 9.520(4), b= 28.073(8), c= 10.070(5)A, β= 117.15(2)° and Z= 2. The structure has been solved from diffractometer data by direct and Fourier methods and refined by fullmatrix least squares to R= 0.0658 for 3626 observed reflections. The two Ru atoms are doubly bridged by the nitrogen atoms of the deprotonated 1,8-diaminonaphthalene ligand with a short Ru–Ru separation, 2.571(1)A, consistent with a metal–metal bond.

Selective insertion of mercury(II) halides into the ruthenium–mercury bonds of trinuclear Ru2Hg clusters

The complex [Ru2(µ-dan)(CO)4(PPri3)2]1(H2dan = naphthalene-1,8-diamine) reacts with HgX2(X = Cl, Br or I) to give the trinuclear clusters [(1)HgX2] which react with HgZ2(Z = Cl, Br or I) to form the insertion products [(1)Hg(µ-Z)2HgX2] only when Z is more electronegative than X, otherwise the addition products [(1)Hg(µ-X)2HgZ2] are obtained; the X-ray structure of [(1)Hg(µ-Cl)2HgCl2] has been determined.

Deprotonation of C-Alkyl groups of cationic triruthenium clusters containing cyclometalated C-Alkylpyrazinium ligands: Experimental and computational studies

The C-alkyl groups of cationic triruthenium cluster complexes of the type [Ru3(μ-H)(μ-κ(2)N(1),C(2)-L)(CO)10](+) (HL represents a generic C-alkyl-N-methylpyrazium species) have been deprotonated to give kinetic products that contain unprecedented C-alkylidene derivatives and maintain the original edge-bridged decacarbonyl structure. When the starting complexes contain various C-alkyl groups, the selectivity of these deprotonation reactions is related to the atomic charges of the alkyl H atoms, as suggested by DFT/natural-bond orbital (NBO) calculations. Three additional electronic properties of the C-alkyl C-H bonds have also been found to correlate with the experimental regioselectivity because, in all cases, the deprotonated C-H bond has the smallest electron density at the bond critical point, the greatest Laplacian of the electron density at the bond critical point, and the greatest total energy density ratio at the bond critical point (computed by using the quantum theory of atoms in molecules, QTAIM). The kinetic decacarbonyl products evolve, under appropriate reaction conditions that depend upon the position of the C-alkylidene group in the heterocyclic ring, toward face-capped nonacarbonyl derivatives (thermodynamic products). The position of the C-alkylidene group in the heterocyclic ring determines the distribution of single and double bonds within the ligand ring, which strongly affects the stability of the neutral decacarbonyl complexes and the way these ligands coordinate to the metal atoms in the nonacarbonyl products. The mechanisms of these decacarbonylation processes have been investigated by DFT methods, which have rationalized the structures observed for the final products and have shed light on the different kinetic and thermodynamic stabilities of the reaction intermediates, thus explaining the reaction conditions experimentally required by each transformation.