No abstract

The reaction of [Ru3(CO)12] with the lithium salt of benzophenone imine (LiNCPh2) followed by protonation with trifluoroacetic acid leads to the η1-1-azavinylidene cluster complex [Ru3(μ-H)(μ-NCPh2)(CO)10] (1). Compound 1 cannot be prepared by direct reaction of [Ru3(CO)12] with benzophenone imine under thermal conditions. Carbonyl substitution and thermolysis reactions on compound 1 and on some of its derivatives are described. Complex 1 reacts with 1 and 2 equiv of bis(diphenylphosphino)methane (dppm) at room temperature to give the substituted derivatives [Ru3(μ-H)(μ-NCPh2)(μ-dppm)(CO)8] (2) and [Ru3(μ-H)(μ-NCPh2)(μ-dppm)(dppm)(CO)7] (3), respectively. In both complexes the three bridging ligands span the same Ru−Ru edge; in addition, complex 3 contains an η1-dppm ligand occupying an equatorial site on the unique Ru atom. An X-ray structure analysis of 3·0.5CH2Cl2 is reported. Thermolysis of complex 2 in THF at reflux temperature leads to [Ru3(μ-H)(μ3-NCPh2)(μ-dppm)(CO)7] (4), a compound which contains a bridging η2-1-azavinylidene ligand interacting with the three Ru atoms. Complex 4 reacts with CO (1 atm, 18 °C) reverting to complex 2. The reaction of compound 1 with PPh3 at room temperature gives the monosubstituted derivative [Ru3(μ-H)(μ-NCPh2)(PPh3)(CO)9] (5), in which the P-donor ligand is attached to one of the two bridged Ru atoms. Thermolysis of 5 in THF at reflux temperature leads to [Ru3(μ-H)(μ3-NCPh2)(PPh3)(CO)8] (6), which, as complex 4, contains a face-bridging η2-1-azavinylidene ligand. The reaction of complex 5 with PPh3 occurs only at higher temperatures (40−70 °C) to give the asymmetrically disubstituted derivative [Ru3(μ-H)(μ-NCPh2)(PPh3)2(CO)8] (7), which has the additional PPh3 ligand attached to the unbridged Ru atom. Compound 7 is thermally unstable, undergoing an easy (40−70 °C) orthometalation reaction of a phenyl ring of the azavinylidene ligand to give the derivative [Ru3(μ-H)2(μ-NCPhC6H4)(PPh3)2(CO)7] (8). This compound reacts with CO (1 atm, 18 °C) to regenerate complex 7.

The thermal reaction of [ Ru,( CO),,] with pyridine-2-thiol (pySH) gives the trinuclear complex [R~,(p-H)(p,-pyS)(C0)~] (I), which is subsequently converted into the polymer [{Ru(p,-pyS) (CO),},](2). Further reaction of polymer (2) with pyridine-2-thiol gives the monomeric compound [Ru(pyS),(CO),](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 [Ru,(CO),,] with pyridine-2-thiol is different to that found for [Os,(CO),,] and for [Ru,(CO),,]with 2-aminopyridine and 2-hydroxypyridine. The reactions of complexes (I )-(3) with several P-donor ligands are also described. Infrared and l H and 31P-{1H} n.m.r. spectral data for all the compounds are presented and discussed in relation to their structures.It is well known that the deprotonated derivatives of 2aminopyridine, 2-hydroxypyridine, and pyridine-2-thiol (pySH) are ligands that give related complexes with many different metals.'-4 The three ligands have been studied in reactions with [Os,(CO), ,] and although their behaviour is not completely alike, it is very However, in a recent paper, we have reported the very different reactivity of 2-aminopyridine and 2hydroxypyridine with [RU,(CO),,].~ In view of these data we decided to investigate the reactions of pyridine-2-thiol with [RU~(CO)~,]. Here we describe that chemistry as well as the reactivity of the products obtained with several P-donor ligands. Results and Discussion Complexes(1)-(3)-The reaction of [ R U ~( C O ) ~, ] with pySH, in a 1 : 3 mol ratio, in refluxing toluene for 1 h, gave rise to the precipitation of the brick-red polymer [{ Ru(p,-pyS)-(CO),},] (2) (Scheme). However, a transient intermediate was detected during the first 10 min by monitoring the reaction with

The reaction of [Ru3(CO),,] with diphenyl diselenide (1 : 1 R u : Se ratio) in refluxing tetrahydrofuran gives a mixture of [Ru,(p-SePh),(CO),] 1 and [{Ru(p-SePh),(CO),},] 2 from which complex 1 can be obtained in 50% yield. Its solid-state structure has been determined by a single crystal X-ray diffraction study [monoclinic, space group P2,/n, a = 17.305( 7), b = 16.798( 5), c = 15.254(3) A, p = 101.28(2)", Z = 81 which revealed an anti configuration of the phenyl selenide bridges. infrared and variable-temperature NMR studies indicate that only the anti isomer is present in solution. The

No abstract