Harold R. Powell

Carbide forming and cluster build-up reactions in ruthenium carbonyl cluster chemistry

Abstract The reinvestigation of an early synthesis of hexaruthenium carbido clusters has lead to the isolation of a number of new clusters which have been fully characterised by spectroscopic and crystallographic techniques. The thermolysis of Ru 3 (CO) 12 in the presence of mesitylene (1,3,5-trimethylbenzene) at moderate temperatures yields two new clusters, [Ru 6 (μ 4 -η 2 -CO) 2 (CO) 13 (η 6 -C 6 H 3 Me 3 )] (I) and [HRu 6 (μ 4 -η 2 -CO)(CO) 13 (μ 2 -η 7 -C 6 H 3 Me 2 CH 2 )] (II), the structures and reactivity of which indicate the origin and mechanism of formation of the carbido-carbon in the hexaruthenium carbido clusters [Ru 6 C(CO) 14 (η 6 -C 6 H 3 Me 3 )] (III) and [Ru 6 C(CO) 17 ] (IV). A further product of the reaction is the decaruthenium carbido cluster dianion [Ru 10 C(CO) 24 ] 2− (V) which has the tetracapped octahedral geometry. The monohydrido-cluster anion [HRu 10 C(CO) 24 ] − (VI) may be synthesised quantitatively from V by protonation. The nature of the hydrido-ligand in VI has been investigated in the solid state by NMR spectroscopy and it has been found to be fluxional, its location being temperature dependent. The decanuclear dianion V has been found to react with mercury salts to yield the 21 metal atom cluster dianion [Ru 18 Hg 3 C 2 (CO) 42 ] 2− (VII) which consists of two tricapped octahedral nonaruthenium “subclusters” fused by a bi-facecapping (Hg 3 ) 2+ unit.

Reactions of P2Ph4 with alkyne-bridged dicobalt carbonyl complexes; crystal structures of [Co2{µ-C2(CO2Me)2}(µ-P2Ph4)(CO)4], [Co2{µ-PPh2CHCPhC(O)}(µ-PPh2)(CO)4] and [Co2{µ-PPh2C(O)CHCH}(µ-PPh2)(CO)3(PPh3)]

The reactions of P2Ph4 with a variety of substituted alkyne complexes [Co2(µ-RCCR′)(CO)6] in toluene give the complexes [Co2(µ-RCCR′)(CO)5(P2Ph4)]1(R = R′= CO2Me 1a or Ph 1b; R = Ph, R′= H 1c and [Co2(µ-RCCR′)(µ-P2Ph4)(CO)4]2(R = R′= Ph 2b; R = Ph, R′= H 2c. All three derivatives of type 1 are cleanly converted into 2 on thermolysis. An X-ray diffraction study of 2a reveals a square-planar Co2P2 core with the symmetrical alkyne perpendicular to the Co–Co bond. Further thermolysis of complexes 2 produces [Co2(µ-PPh2CRCR′)(µ-PPh2)(CO)4]3(R = R′= CO2Me 3a or Ph 3b and [Co2{µ-PPh2CRCR′C(O)}(µ-PPh2)(CO)4]4c(R = H, R′= Ph). The structure of 4c has been determined by X-ray analysis. The PPh2CHCPhC(O) ligand forms a five-membered metallacyclic ring incorporating one Co atom and is π-bonded to the other Co atom. Complexes 3a and 3b are partially converted into 4a(R = R′= CO2Me) and 4b(R = R′= Ph) on treatment with CO. This reaction is reversed by heating 4a and 4b in solution or, more slowly, on standing at room temperature. The parent acetylene complex [Co2(µ-HCCH)(CO)6] reacts with P2Ph4 differently from the substituted derivatives to give as the principal product [Co2{µ-PPh2C(O)CHCH}(µ-PPh2)(CO)4]5b. The structure of the PPh3 derivative of this complex, [Co2{µ-PPh2C(O)CHCH}(µ-PPh2)(CO)3(PPh3)]6d, has been determined by X-ray diffraction.

Synthesis and X-ray crystal structure of tris(1,2-dimethyl-3-hydroxypyrid-4-onato)iron(III)

Abstract An X-ray crystal structure analysis of the product of the reaction between FeCl3 and three equivalents of 1,2-dimethyl-3-hydroxypyrid-4-one (LH) in alkali shows it to be the tris chelate compound FeL3; the unexpected solubility in aqueous media appears to be the result of localization of negative charge on the periphery of the molecule. Crystal data: trigonal, space group P 3 (no. 147), a = b = 16.665(3), c = 6.854(1) A, U = 1648.49 A3, Z = 2, Dc = 1.383 g cm−3; 1071 reflections to give R = 0.0501 and R′ = 0.0469.

The reaction of diphenylphosphine, PPh2H, with an alkyne-bridged dicobalt carbonyl complex; the synthesis crystal structure and reactivity of the complex [CO2{μ-C(CO2Me)CHCO2Me}(μ-PPh2)(CO)4]

The reaction between [Co2(μ-C2(CO2Me)2)(CO)6] and diphenylphosphine gives the mono- and di-substituted complexes [Co2{μ-C2}(CO2Me)2(CO)6-n(PPh2H)n] [n = 1 (1), 2 (2)]. Thermolysis of (1) leads to phosphorus-hydrogen bond cleavage and formation of the phosphido-, vinyl-bridged complex [Co2{μ-C(CO2Me)CHCO2Me}(μ-PPh2(CO)4] (3) together with the trinuclear cobalt complex [Co3{μ-C2(CO2Me)2}(μ-PPh2(CO)7 (4). An X-ray diffraction study of 3 reveals that one of the methylcarboxylate substituents of the vinyl ligand is coordinated via oxygen to cobalt, forming an almost planar M-C-C-C-O five-membered metallacyclic ring. The reactions of (3) with a tertiary phosphine and with phenylacetylene are described.

Isolation and X-ray structure determination of the cluster dianion [Os20Hg(C)2(CO)48]2–, and the identification of the cluster previously reported with this stoicheiometry as [Os18Hg3(C)2(CO)42]2–

The reaction of [Os10C(CO)24]2–(3) with mercuric salts has been reinvestigated and with Hg(O2CCF3)2 it gives mixtures of two 21 metal heteronuclear cluster dianions [Os18Hg3(C)2(CO)42]2–(4) and [Os20Hg(C)2(CO)48]2–(5) together with an intermediate, [Os10C(CO)24(HgO2CCF3)](6) in varying proportions depending on reaction conditions; X-ray structure analysis of salts of [Os10C(CO)24(HgCF3)]–(6a), an analogue of (6), and of [Os20Hg(C)2(CO)48]2–(5) are reported, the latter having a previously unobserved metal framework consisting of two [Os10C(CO)24] units linked by a single mercury atom bridge; the previously reported solid state 21 metal framework, believed to be that of [Os20Hg(C)2(CO)48]2– has now been reassigned as that of the cluster dianion [Os18Hg3(C)2(CO)42]2–(4)

The heteronuclear cluster chemistry of the Group IB metals XIV. The influence of the P(CH2Ph)3 ligand on the metal framework structures adopted by mixed-metal clusters containing M{P(CH2Ph)3} (M Cu or Ag) fragments. Crystal structures of [Cu2Ru4(μ3-H)2(CO)12{μ-P(CH2Ph)2-(η2-CH2Ph)}] and [Cu2Ru4(μ3-H)2(CO)12{P(CH2Ph)3}2]

Abstract Treatment of a dichloromethane solution of the salt [N(PPh 3 ) 2 ] 2 [Ru 4 (μ-H) 2 (CO) 12 ] with two equivalents of the complex [M(NCMe) 4 ]PF 6 (M  Cu or Ag) at −30°C, followed by the addition of two equivalents of P(CH 2 Ph) 3 , affords the novel mixed-metal cluster compound [Cu 2 Ru 4 (μ 3 -H) 2 (CO) 12 {μ-P(CH 2 Ph) 2 (η 2 -CH 2 Ph)}] (77% yield) when M  Cu, whereas the expected product, [Ag 2 Ru 4 (μ 3 -H) 2 (CO) 12 {P(CH 2 Ph) 3 } 2 ] (37% yield), is obtained for M  Ag. When an acetone solution of [N(PPh 3 ) 2 ] 2 [Ru 4 (μ-H) 2 (CO) 12 ] is treated with a dichloromethane solution containing two equivalents of the compound [CuCl{P(CH 2 Ph) 3 }], in the presence of TlPF 6 , a mixture of [Cu 2 Ru 4 (μ 3 -H) 2 (CO) 12 {μ-P(CH 2 Ph) 2 (η 2 -CH 2 Ph)}] (44% yield) and [Cu 2 Ru 4 (μ 3 -H) 2 (CO) 12 {P(CH 2 Ph) 3 } 2 ] (12% yield) is produced. Single-crystal X-ray diffraction studies were performed on [Cu 2 Ru 4 (μ 3 -H) 2 (CO) 12 {μ-P(CH 2 Ph) 2 (η 2 -CH 2 Ph)}] and [Cu 2 Ru 4 (μ 3 -H) 2 (CO) 12 {P(CH 2 Ph) 3 } 2 ]. The former cluster exhibits a capped trigonal bipyramidal metal framework structure (CuCu 2.532(2), CuRu 2.585(2)–2.813(1), RuRu 2.790(1)–2.981(1) A) and the single P(CH 2 Ph) 3 group adopts a novel bidentate bonding mode by bridging the two adjacent copper atoms via bonds from its phosphorus atom (CuP 2.199(2) A) and an η 2 -CH 2 Ph ring (CuC 2.146(10) and 2.339(12) A). In marked contrast, [Cu 2 Ru 4 (μ 3 -H) 2 (CO) 12 {P(CH 2 Ph) 3 } 2 ] adopts an unusual metal core structure, which consists of a Ru 4 tetrahedron with one edge bridged by a Cu{P(CH 2 Ph) 3 } unit and a non-adjacent face capped by the second Cu{P(CH 2 Ph) 3 } group (CuRu 2.589(4)–2.724(4), RuRu 2.760(3)–2.984(4) A). Infrared and NMR spectroscopic data show that [Ag 2 Ru 4 (μ 3 -H) 2 (CO) 12 {P(CH 2 Ph) 3 } 2 ] exhibits a capped trigonal bipyramidal skeletal geometry, with the silver atoms in close contact. Thus, although the P(CH 2 Ph) 3 ligand is evidently too bulky to allow two adjacent Cu{P(CH 2 Ph) 3 } units to be accommodated in the metal skeleton of [Cu 2 Ru 4 (μ 3 -H) 2 (CO) 12 {P(CH 2 Ph) 3 } 2 ], the greater size of the silver atom relative to copper means that the analogous silver-containing species can adopt the metal framework structure which previous work suggests is preferred by clusters of this type. Variable-temperature 31 P-{ 1 H} and 1 H NMR spectroscopic studies demonstrate that all three of the new heteronuclear cluster compounds undergo a number of interesting dynamic processes in solution.

Reactions of [Os-3(CO)(10)(NCMe)(2)] with symmetric diynes and their reactivity towards [Co-2(CO)(8)]

Abstract The reaction between [Os3(CO)10(NCMe)2] and MeC2C2Me yields the known cluster [Os3(CO)9(μ-CO)(μ3-η2-MeC2C2Me)] (1) and three previously uncharacterised products [Os3(CO)9(μ-CO){μ3-η2:μ3-η1:η1:η3-MeC2C2MeOC5Me2)Os3(μ-CO)(CO)9] (2), [Os3(CO)9{μ3-η4-[(MeC2)C2(Me)]CO[(Me)C2(C2Me)]}] (3) and [Os3(CO)9{μ3-η4-[(MeC2)C2(Me)]CO[(MeC2)C2(Me)]}] (4). The structures of 2 and 3 have been determined by X-ray crystallography. Cluster 2 incorporates two linked triosmium clusters joined by an unsaturated five-membered metallacycloether ring and 3 exhibits an alkyne-functionalised metallacyclohexadieneone ring. 1–4 and [Os3(CO)9(μ-CO)(μ3-η2-PhC2C2Ph)] (5) react with [Co2(CO)8] to form products 6–11 in which one free alkyne function coordinates to a Co2(CO)6 unit in each case; the cluster [{Os3(CO)10}{Co2(CO)6}{μ3-η2-‖-(MeCC)(μ2-η2(CCMe)}] (6) has been structurally characterised. The reaction of 1 and 5 with Me3NO–MeCN leads to the replacement of one CO ligand with MeCN, the products 12 and 13 reacting with H2O to form [Os3(CO)9(μ-OH)(μ3-η1:η2:η2-RC3CHR)] (R=Me (two isomers 14, 15), Ph (16)); the X-ray structure of 16 is reported. Reaction of 3 with Me3NO–MeCN results in the substitution of a CO ligand with either a MeCN or NMe3 ligand at the metallocyclic Os atom to afford the clusters [Os3(CO)8(L)(μ3-η1:η1:η2:η2-{(MeC2)C2(Me)}2CO)] (L=NCMe (17), NMe3 (18)).

The first decaruthenium hydrido cluster: synthesis and crystal structure of [N(PPh3)2]2[Ru10C(CO)24]·C6H14 and [N(PPh3)2][HRu10C(CO)24]

Abstract X-ray structural studies of new thermolysis products from the reaction of Ru 3 (CO) 12 in heptane in the presence of 1,3,5-trimethylbenzene (mesitylene) confirm that they are the decaruthenium carbido-cluster dianion [Ru 10 C(CO) 24 ] 2− (I) and the hydrido decaruthenium carbido-cluster monoanion [HRu 10 C(CO) 24 ] − (II). Both anions have the giant tetrahedron Ru 10 metal framework, and the monohydride provides the first example of a hydrido ligand in a tetrahedral Ru 4 cavity.

The first isolation of an intermediate in the formation of a hexaruthenium carbido-cluster from the reaction of [Ru3(CO)12]: X-ray structure analyses of [Ru6(η2-µ4-CO)2(CO)13(η6-C6H3Me3)] and [HRu6(η2-µ4-CO)(CO)13(η7-µ2-C6H3Me2CH2)]

Thermolysis of [Ru3(CO)12](1) in hydrocarbons heated under reflux containing excess of 1,3,5-trimethylbenzene(mesitylene) has yielded [Ru6C(CO)14(η6-C6H3Me3)](2a) and two new hexaruthenium compounds [Ru6(η2-µ4-CO)2(CO)13(η6-C6H3Me3)](3) and [HRu6(η2-µ4-CO)(CO)13(η7-µ2-C6H3Me2CH2)](4), shown by X-ray structure analyses to have metal frameworks previously unknown in ruthenium cluster chemistry; on further thermolysis the cluster (3) gives (2a) and is therefore the first intermediate in the well established conversion of triruthenium to hexaruthenium carbido-clusters to be identified.

The synthesis and X-ray structure analysis of the dianion [Ru18(C)2(CO)42Hg3]2–, the first octadecaruthenium cluster

The heterometallic dianion [Ru18Hg3(C)2(CO)42]2– has been obtained from the decanuclear ruthenium carbido-dianion [Ru10C(CO)24]2– as its [N(PPh3)2]+ salt by reaction with mercury(II) trifluoroacetate, and has been shown by X-ray single crystal analysis to be a dimer of two tricapped octahedral Ru9 cluster fragments, linked by a bridging Hg3 triangular unit.