Monomeric and extended oxo-centered triruthenium clusters (original) (raw)
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Inorganica Chimica Acta, 1992
The reaction of [RuB(CO),J with RPH, (R=phenyl or cyclohexyl) has been re-examined and the involvement of the trinuclear clusters [Ru&-H)+-PHR)(CO),,,], [RusH&-PR)(CO),], [Ru,H,(b-PR)(CO),(PH,R)] and [Ru,H&PHR)z(CO),] in the formation of the b&capped compound [Ru&.Q-PR)~(CO)~] has been explored. The single-crystal X-ray structures of [Ru&H)&-PPh)(C0)8(PHzPh)] and [Ru3(~-H)(~-PHPh)3(C0)7] are presented. The latter compound was obtained as a single isomer whereas there are four isomers present in solutions of the PHCy analogue (Cy =cyclohexyl). In an unsuccessful attempt to hydrogenate [Ru&-PR)~(CO)~] to reform one of the isomers, [Ru,H&PHR)r(CO),] or [Ru~H&-PR)(CO)~(PH~R)], we obtained instead a mixture of the known compound [Ru&-PR)&L~-PR)~(~O) ,* and the hydrogenated form of this, [Ru6H&-] PR)&L~-PR)~(CO)~~]. The structures of these hexanuclear clusters are related, both being based on distorted trigonal prismatic Ru, arrangements, but the distortions are very different and the average Ru-Ru distances in the go-valence electron dihydride are longer than in the 88-valence electron non-hydride compound. We have identified a restricted rotation about the P-Ph bonds for the CL,-ligands but not the pa-ligands which is interpreted in terms of clashes of the ortho-phenyl hydrogen atoms with CO ligands.
A hexanuclear ruthenium cluster with a boat configuration of the Ru 6 core
Polyhedron, 1994
Whereas thermolysis of the cluster [Ru,(yH)(p,-pyS)(CO),] (pyS = pyridine-2-thionato, C5H4NS) in refluxing hexane gave a trimer of trinuclear clusters, [{Ru3(p3-WP~-PYWC~)~},I, in refluxing n-decane under an atmosphere of CO, various hexanuclear clusters were formed of which the compound [Ru~(~~-S)(~-SH)(~~-~~S)(~-CO)~(CO)~~] has been characterized by X-ray diffraction. The compound consists of two Ru, units linked by two Ru-Ru bonds and a pyramidal p4-S ligand. Monodentate,' chelating,' and doubly2 and triply3 bridging coordination modes of the pyridine-2thionato ligand (pyS) are well documented. Recently, this group reported a novel cluster condensation process in which a p3-pyS ligand makes an additional M-S bond and in doing so links trinuclear clusters through p4-bridges.4 Thus, thermolysis of the cluster [Ru,(p-H)&pyS)(CO),] in refluxing hexane leads to double decarbonylation and trimerization to give [ { Ru&-H)(~~-~~S) (CO),},] (Scheme 1; hydride and CO ligands omitted from the Ru, cluster). We believed that by carrying out the thermolysis of [Ru3(p-H)(p3-pyS)(CO),] under an atmosphere of CO, loss of CO and trimerization would be inhibited and C-S bond cleavage would occur instead to give the cluster [Ru,(yH) (p3-S) (p-2-pyridyl) (CO),]. There is a direct precedent for this type of C-S cleavage in the conversion of [OS&-H)(p,-RN=CHS)(CO),] to [OS,@-H)(~~-S)(~-RN=CH)(CO)~].~ We were hoping that the triruthenium compound formed in this way could subsequently be induced to undergo a trimerization reaction through p4-S bridges. However, the reaction did not follow this pathway, but instead gave a series of hexanuclear products.
Ruthenium Carbonyl Cluster Complexes with Oxygen Ligands. Part 2
Journal of The Chemical Society-dalton Transactions, 1994
The reaction between 4-methoxyphenol and Ru,(CO)~~ in cyclohexane has been investigated and found to afford a hexaruthenium 'raft' cluster Ru,(p-H)&-q7-0C~H~OMe-4)(CO& (3a), together with tetraruthenium clusters incorporating three (Ru&-OC,H,OMe-4),(@lX~-OCsH.,OMe-4XCO),, (3bN or four (Ru&-OC,H,OMe-4),(LL-OC,H,OMe-4),(CO~u, (3~)) aryloxo ligands; similarly, reaction of Ru,(CO),, with 2-naphthol afforded the analogous Ru,(~~-H)~(IL~-~'-OC~~H~XCO)~~ &I), Ru&-0C,,H7)2(11-CIX~-OC10H7MC0)10 (4b) and Ru.,(~~-OC~~H~)~(~-OC~~H~)~(CO~~,, (4e). The source of chloride in 3b and 4b is believed to be carbon tetrachloride contaminant in the cyclohexane. An X-ray diffraction study reveals that 3b contains an Ru,(CO), unit linked to an Ru(CO), moiety by two asymmetric triply-bridging and one asymmetric doubly-bridging 4methox-yphenoxo ligands, and an asymmetric doubly-bridging chloro ligand; this interaction is strongly suggestive of a higher oxidation state ruthenium linked to a trinuclear cluster of formally zero oxidation state. The dynamic 13C NMR spectra of 4c have been recorded, and are consistent with restricted rotation about the Ar-0 linkage of the p+oordinated naphthoxo ligands at low temperature.
European Journal of Inorganic Chemistry, 1999
The tetrahedral cluster anion [Ru 3 Ir(CO) ] -(1) reacts with neutral hydrido clusters [HRu 2 Ir(CO) 9 (RCϵCRЈ)] (10: R = RЈ = Ph; 11: R = RЈ = Et; 12: R = Ph; RЈ = Me; 13: R = RЈ = Me). internal alkynes RCϵCRЈ to afford the alkyne derivatives [Ru 3 Ir(CO) 11 (RCCRЈ)] -(2: R = RЈ = Ph; 3: R = RЈ = Et; 4: R = The protonation of the butterfly anions 2 and 3, however, gives rise to the formation of the neutral tetrahedral clusters Ph; RЈ = Me; 5: R = RЈ = Me) which have a butterfly arrangement of the Ru 3 Ir skeleton in which the alkyne is [HRu 3 Ir(CO) 11 (RCCRЈ)] (14: R = RЈ = Ph and 15: R = RЈ = Et), respectively. The analogous clusters [HRu 3 Ir(CO) 11 -coordinated in a µ 4 -η 2 fashion. Under CO pressure they undergo fragmentation to give the trinuclear cluster anions (PhCCCH 3 )] (16) and [HRu 3 Ir(CO) 11 (CH 3 CCCH 3 )] (17) are only accessible from the reaction of the neutral cluster [Ru 2 Ir(CO) 9 (RCCRЈ)] -(6: R = RЈ = Ph; 7: R = RЈ = Et; 8: R = Ph; RЈ = Me; 9: R = RЈ = Me), in which the alkyne ligand is [HRu 3 Ir(CO) 13 ]
Organometallics, 1995
Thermolysis of Rua(/Z-H)(/z-NC5H4)(CO)Io in refluxing chlorobenzene affords [Ru2(/z-H)(/z-NC5H4)2(CO)4(NC5Hs)2][RUlo (/z-H)(/z6-C)(CO)24] (la) in excellent yield. The results of a structural study of la are consistent with the hydride occupying an edge-bridging site at an apex of the "giant tetrahedron". Thermolysis of Ru3(/z-H)(/z-NCsH4)(CO)Io with [PPh4][BF4] in chlorobenzene affords the cluster [PPh4][Rujo(/z-H)(/z6-C)(CO)24] (lb) in moderate yield. Compound la reacts immediately with l equiv, of triphenylphosphine at room temperature to afford the monosubstituted cluster [Ru 2(/z-H)(/z-NC5 H 4)2(CO)4(NC 5 H 5)2 ][Ru to(/z-H)(/z6-C)(CO)23(PPh3) ] (2a) in high yield; the crystal structure of 2a and NMR studies show that ligand substitution occurs at the apical ruthenium associated with the hydride ligand. Further reaction with triphenylphosphine at room temperature affords successively the complexes [Rulo(/z-H)(/z6-C)(CO)24_x(PPh3)~]-with x = 2 (3a) and 3 (4a); the tetrasubstituted cluster (x = 4, 5c) is obtained as its [Ru2(/z-H)(/z-NCsH4)2(CO)4(PPh3)2] + salt following a short reflux in acetone. In each case, substitution occurs at the apical ruthenium atoms. Hydride and CO fluxionality in the five cluster anions was investigated by ~3C EXSY experiments. Compound la exhibits complete hydride fluxionality between the four apices at low temperature, while 5e shows similar behaviour at room temperature. CO fluxionality increases with phosphine substitution, reaching a maximum at the bis-substituted cluster, and becoming less facile on the trisand tetrakis-substituted cluster anions. Compound lb reacts in a similar manner with triphenylphosphine to form an analogous series of complexes. Attempted metathesis of preformed la by reaction with [PPN]Cl was unsuccessful; instead, conversion to [PPN]2[Ru10(/z6-C)(CO)24] occurs.