PMe2 Ph Research Articles

Intermolecular versus intramolecular C–H activation reaction in the thermolysis of [Ru(Me)Cp*(PMe 2Ph) 2] (Cp* = η 5-C 5Me 5): formation and crystallographic characterisation of [Ru(Ph)Cp*(PMe 2Ph) 2

Thermolysis of the ruthenium complex [Ru(Me)Cp*(PMe 2Ph) 2] ( 1) (Cp* = η 5-C 5Me 5) in benzene gives methane and [Ru(Ph)Cp*(PMe 2Ph) 2] ( 2), which is converted slowly to ▪( 3) through the loss of benzene. 2 was structurally characterised by single-crystal X-ray diffraction experiments. DFT calculations were performed in order to understand the behaviour of the ruthenium complex 1 towards inter- or intra-molecular C–H bond activation reactions.

Synthesis and non-linear optical properties of (η 5-pentaphenylcyclopentadienyl)dicarbonylruthenium(II) σ-alkenyl complexes

The complexes [Ru{( Z)-HC CHPh}(CO) 2(η 5-C 5Ph 5)] ( 1) and [Ru{( Z)-HC CHC 6H 4NO 2}(CO) 2(η 5-C 5Ph 5)] ( 2) have been synthesized and their identity confirmed by single-crystal X-ray diffraction studies. Reaction of 2 with PMe 2Ph and Me 3NO in tetrahydrofuran afforded [Ru{( Z)-HC CHC 6H 4NO 2}(CO)(PMe 2Ph)(η 5-C 5Ph 5)] ( 3). Cyclic voltammetry confirms the expected increase in ease of oxidation on proceeding from 2 to 1 and from 2 to 3. Hyper-Rayleigh scattering studies at 1064 nm reveal a dramatic increase in quadratic non-linearity on co-ligand replacement of CO by PMe 2Ph, in proceeding from 2 to 3. Z-scan studies at 800 nm are consistent with significant contribution from two-photon states, and with an increase in γ real on co-ligand replacement of CO by PMe 2Ph in proceeding from 2 to 3.

Structural and spectroscopic studies of three-coordinate copper(I) supported by bis(phosphino)borate ligands

The bis(phosphino)borates [( p- t BuPh) 2B(CH 2PPh 2) 2][ASN] ( 1[ASN]; ASN = 5-azonia-spiro[4.4]nonane), [Ph 2B(CH 2P i Pr 2) 2]Li(THF) 2 ( 2[Li]), and [(3,5-Me 2Ph) 2B(CH 2P t Bu 2) 2] − ( 3[Li] and 3[Tl]) react with copper(I) reagents to generate anionic and neutral complexes. Reaction of 1[ASN] with CuI provides the 1:1 adduct [[( p- t BuPh) 2B(CH 2PPh 2) 2]CuI][ASN] ( 4). CuCl reacts with 3[Li] in THF to afford [[(3,5-Me 2Ph) 2B(CH 2P t Bu 2) 2]CuCl][Li(THF) 4] ( 5), along with a minor byproduct, the three-coordinate bis(phosphine) adduct {(3,5-Me 2Ph)B(CH 2P t Bu 2) 2}CuCl ( 6). An analogous neutral complex, {PhB(CH 2P t Bu 2) 2}CuCl ( 7), can be synthesized directly by reacting CuCl with the neutral phosphino borane PhB(CH 2P t Bu 2) 2. Reaction of the substituted copper(I) halide Me 2S · CuBr with 3[Tl] provides the anionic dimer complex [{[(3,5-Me 2Ph) 2B(CH 2P t Bu 2) 2]Cu} 2(μ-Br)]Tl ( 8). The neutral solvent adducts [Ph 2B(CH 2P i Pr 2) 2]Cu(NCCH 3) ( 9) and [(3,5-Me 2Ph) 2B(CH 2P t Bu 2) 2]Cu(NCCH 3) ( 10) are prepared by the reactions between [Cu(CH 3CN) 4][PF 6] and 2[Li] or 3[Li], respectively. Neutral 10 is a useful precursor to several other neutral species via substitution of the labile acetonitrile ligand, including [(3,5-Me 2Ph) 2B(CH 2P t Bu 2) 2]Cu(PMe 2Ph)( 11), [(3,5-Me 2Ph) 2B(CH 2P t Bu 2) 2]Cu(S PMe 3) ( 12), [(3,5-Me 2Ph) 2B(CH 2P t Bu 2) 2] Cu(2,6-lutidine) ( 13), and [(3,5-Me 2Ph) 2B(CH 2P t Bu 2) 2]Cu(CN t Bu) ( 14). Attempts to isolate a neutral monocarbonyl adduct, [(3,5-Me 2Ph) 2B(CH 2P t Bu 2) 2]Cu(CO) ( 15), are frustrated by the high lability of the CO ligand. The solid-state crystal structures of complexes 6, 8, 9, 10, and 11 have been determined and are described.

Synthesis, characterization and molecular structure of the [(η 6-C 6Me 6)Ru(μ-N 3)(N 3)] 2 complex and its reactions with some monodentate ligands

The reaction of complex [(η 6-C 6Me 6)Ru(μ-Cl)Cl] 2 ( 1) with sodium azide yielded complexes of the composition [(η 6-C 6Me 6)Ru(μ-N 3)(N 3)] 2 ( 2) and [(η 6-C 6Me 6)Ru(μ-N 3)(Cl)] 2 ( 3), depending upon the reaction conditions. Complex 3 with excess of sodium azide in ethanol yielded complex 2. Complexes 2 and 3 undergo substitution reactions with monodentate ligands such as PPh 3, PMe 2Ph and AsPh 3 to yield monomeric complexes. The structure of complex 2 was determined by X-ray crystallography. All these complexes were characterized by micro analytical data and by FT-IR and FT-NMR spectroscopy. Complex 2 crystallizes in the monoclinic space group P2 1/ n with a = 8.5370(11) Å, b = 16.192(2) Å, c = 10.4535(13) Å and β = 110.877(2)°.

Synthesis and characterization of new sulfide aggregates of the type [{Pt 2(μ 3-S) 2(P–P) 2}M(C 6F 5) 2] (M=Ni, Pd, Pt; P–P=2PPh 3, 2PMe 2Ph, dppf)

The reaction of [Pt 2(μ-S) 2(P–P) 2] (P–P=2PPh 3, 2PMe 2Ph, dppf) [dppf=1,1 ′-bis(diphenylphosphino)ferrocene] with cis-[M(C 6F 5) 2(PhCN) 2] (M=Ni, Pd) or cis-[Pt(C 6F 5) 2(THF) 2] (THF=tetrahydrofuran) afforded sulfide aggregates of the type [{Pt 2(μ 3-S) 2(P–P) 2}M(C 6F 5) 2] (M=Ni, Pd, Pt). X-ray crystal analysis revealed that [{Pt 2(μ 3-S) 2(dppf) 2}Pd(C 6F 5) 2], [{Pt 2(μ 3-S) 2(PPh 3) 2}Ni(C 6F 5) 2], [{Pt 2(μ 3-S) 2(PPh 3) 2}Pd(C 6F 5) 2] and [{Pt 2(μ 3-S) 2(PMe 2Ph) 2}Pt(C 6F 5) 2] have triangular M 3S 2 core structures capped on both sides by μ 3-sulfido ligands. The structural features of these polymetallic complexes are described. Some of them display short metal–metal contacts.

Comparative reactivity studies of dppf-containing CpRu II and (C 6Me 6)Ru II complexes towards different donor ligands (dppf=1,1 ′-bis(diphenylphosphino)ferrocene)

[CpRu(dppf)Cl] (Cp=η 5-C 5H 5) ( 1) and [(HMB)Ru(dppf)Cl]PF 6 ((HMB)=η 6-C 6Me 6) ( 3) react with different donor ligands to give rise to N-, P- and S-bonded complexes. The stoichiometric reactions of 1 and 3 with NaNCS give the mononuclear complexes [CpRu(dppf)(NCS)] ( 2) and [(HMB)Ru(dppf)(NCS)]PF 6 ( 4), respectively, in yields above 80%, while 3 also gives a dppf-bridged diruthenium complex [(HMB)Ru(NCS) 2] 2(μ-dppf) ( 5) in 67% yield from reaction with four molar equivalents of NaNCS. Compound 5 is also obtained in 70% yield from the reaction of 4 with excess NaNCS. With CH 3CN in the presence of salts, both 1 and 3 give their analogous solvento derivatives [CpRu(dppf)(CH 3CN)]BPh 4 ( 6) and [(HMB)Ru(dppf)(CH 3CN)] (PF 6) 2 ( 7). With phosphines, the reaction of 1 gives chloro-displaced complexes [(CpRu(dppf)L]PF 6 (L =PMe 3 ( 8), PMe 2Ph( 9)), whereas the reaction of 3 with PMe 2Ph leads to substitution of dppf, giving [(HMB)Ru(PMe 2Ph) 2Cl] PF 6 ( 10). The reaction of 1 with NaS 2CNEt 2 gives a dinuclear dppf-bridged complex [{CpRu(S 2CNEt 2)} 2(μ-dppf)] ( 11), whereas that of 3 results in loss of the HMB ligand giving a mononuclear complex [Ru(dppf)(S 2CNEt 2) 2] ( 12). With elemental sulfur S 8, 1 is oxidized to give a dinuclear CpRu III dppf-chelated complex [{CpRu(dppf)} 2(μ-S 2)](BPh 4)Cl ( 13), whereas 3 undergoes oxidation at the ligand, giving a dppf-displaced complex [(HMB)Ru(CH 3CN) 2Cl]PF 6 ( 14) and free dppfS 2. The structures of 1, 2, 5– 9, 11, 13 and 14 were established by X-ray single crystal diffraction analyses. Of these, 5 and 11 both contain a dppf-bridge between Ru II centers, while 13 is a dinuclear CpRu III disulfide-bridged complex; all the others are mononuclear. All complexes obtained were also spectroscopically characterized.

Phosphanylalkylcyclopentadienyl ligands: synthesis, molecular structures and catalytic properties of [{(η 5-C 5H 4)CMe 2PHR}CrCl 2(PMe 2Ph)] (R=Ph, [formula omitted

Li[(C 5H 4)CMe 2PHPh] reacted with [CrCl 3(THF) 3] with formation of a mixture of products, among which only [{(η 5-C 5H 4)CMe 2PPh}CrCl] 2 ( 1) could be isolated. However, when [CrCl 3(PMe 2Ph) 3] was treated with Li[(C 5H 4)CMe 2PHR], the complexes [{(η 5-C 5H 4)CMe 2PHR}CrCl 2(PMe 2Ph)] (R=Ph ( 2), t Bu ( 3)) were obtained in moderate yield. Complexes 1 and 2 were characterised by X-ray crystallography, 1–3 by IR spectroscopy. In the solid state, a phosphanido-bridged dimer is observed for 1, while 2 and 3 are monomeric complexes without coordination of the phosphanyl group of the cyclopentadienyl ring. 2 and 3 were also characterised by mass spectrometry and NMR and UV–Vis spectroscopy, and their magnetic moments were determined. 2 and 3 were studied in the catalytic polymerisation of ethylene with methylalumoxane (MAO) as cocatalyst.

Synthesis and characterization of tertiaryphosphinecobalt(III) Schiff base complexes and their thermodynamic study with organic bases in different solvents

The [Co(acacen)(PMe 2Ph)]ClO 4 · H 2O (acacen=bis(acetylacetone)ethylene diimine) was synthesized and characterized. The equilibrium constants and the thermodynamic parameters were measured spectrophotometrically for 1:1 adduct formation of [Co(acacen)L]ClO 4 · H 2O, where (L=PBu 3, PMe 2Ph) as acceptors with H 2NR (R= n-propyl, n-butyl, sec-butyl) as donors, in ethanol and butanol solvents in constant ionic strength ( I=0.01 M NaClO 4) and at various temperatures T=(288 to 308) K. The trend of the reactivity of five-coordinate cobalt(III) Schiff base complexes toward a given amine donor according to the axial ligand is as follow: PMe 2Ph > PBu 3. Also the trend of the reactivity of the donors (amines) toward a given cobalt(III) Schiff base complex is as follow: n-propylamine > n-butylamine > sec-butylamine. The trend of the reactivity of a given cobalt(III) Schiff base complexes toward a given amine donor according to the solvent is as follow: butanol > ethanol.

Ruthenium hydride complexes with a heteroscorpionate ligand derived from methane: 2-phenoxy-bis(pyrazol-1-yl)methane. The hemilabile role of the ligand in substitution and proton transfer reactions

The complex [RuH(κ 3-bpzmPhO)(cod)] ( 1) was synthesized by the reaction of [RuH(cod)(NH 2NMe 2) 3][BPh 4] with the potassium salt of 2-phenoxy-bis(pyrazol-1-yl)methane (bpzmPhOK). This ligand adopts a κ 3- N, N, O coordination on the metal center that is reminiscent of the situation usually observed in trispyrazolylborate complexes. Complex 1 exists in solution as a mixture of two diastereoisomers that are in equilibrium. The reaction of 1 with different phosphines (PMe 3, PMe 2Ph, PMePh 2 and PPh 3) has been studied. The reaction product depends not only on the nature of the phosphine but also on the complex:L ratio and the temperature. Diphosphine derivatives of stoichiometries [RuH(κ 1- O-bpzmPhO)(cod)L 2] (L=PMe 3, PMe 2Ph) and [RuH(κ 3-bpzmPhO)L 2] (L=PMe 3, PMe 2Ph, PMePh 2, PPh 3) were prepared. Similarly, tetraphosphine derivatives of formula [ cis- O, H-RuH(κ 1- O-bpzmPhO)L 4] (L=PMe 3, PMe 2Ph) were obtained. The complex with PMe 2Ph can be transformed into the respective trans isomer by heating the solution. The reaction of 1 with five equivalents of PMe 3 gives rise to a pentaphosphine derivative with complete decoordination of the anionic bpzmPhO ligand. This ligand exhibits hemilabile behavior that involve a reversible coordination of the pyrazole fragments. Proton transfer reactions from HBF 4 to 1 have also been studied both in acetone-d 6 and in methanol-d 4. In all of these processes the proton is selectively transferred to the oxygen of the bpzmPhO ligand, which remains coordinated through at least the N-donor centers. Three hydride derivatives are formed in these reactions and they differ either in the relative orientation of the ligands or in the coordination of the OH group of the ligand.

Solid state structure and fluxionality in solution of [H 4Ru 4(CO) 11L] (L=P(C 6F 5) 3, PMe 2Ph, P(OMe) 3 and P(OEt) 3): two different structures

The monosubstituted [H 4Ru 4(CO) 11L] derivatives where L=P(C 6F 5) 3, PMe 2Ph, P(OMe) 3 and P(OEt) 3 (compounds 1 to 4, respectively) were synthesized, the crystal structure of 1, 2 and 4 were determined by X-ray diffraction (that of compound 3 had been determined previously but not fully reported so we obtained it again) and their dynamical behavior studied by 1H, 31P and 19F NMR. The structures of compounds 1, 3 and 4 show the common tetrahedral structure with four long (hydride bridged) and two short metal–metal bonds with the P-donor ligand transoid to an unbridged Ru–Ru bond. The structure of 2 is different since the M–M bonds to the Ru atom bonded to the phosphine, are all hydride-bridged. The variable temperature NMR studies of 1, 2 and 3 show dynamical behaviour similar to what had been reported for compound 4. However we propose that some of the structures involved in the equilibrium have the phosphorus substituent transoid to a bridged Ru–Ru bond.

Synthesis and characterisation of iron and cobalt complexes with phosphinothiolate ligands

Neutral iron complexes of a series of arenephosphinothiol proligands, Ph x P(ArSH) 3− x , ( x=0–2, Ar=C 6H 4, C 6H 3SiMe 3) have been synthesised. Compounds [Fe{2-(Ph 2PO)C 6H 4S} 3] ( 1), [Fe{2-(Ph 2P)-6(Me 3Si)C 6H 3S} 3] ( 2), [Fe{2-(Ph 2PO)-6(Me 3Si)C 6H 3S} 3] ( 3) and [Fe 2{PhP(C 6H 4S-2) 2} 3] ( 4) were obtained most conveniently by the electrochemical oxidation of an iron anode in a cell containing an acetonitrile solution of the corresponding proligand. [Fe{2-(Ph 2P)C 6H 4S} 2(CO) 2] ( 5) was obtained by the addition of the appropriate proligand to an acetonitrile solution of FeCl 2 saturated with CO. The reaction of FeCl 2 with PhP(C 6H 4SH-2) 2 in methanol in the presence of CO and bis-diphenylphosphinoethane (dppe) gave [Fe{PhP(C 6H 4S-2) 2}(dppe)(CO)] ( 6) in good yield. The reaction of FeCl 2 with the potentially tetradentate P(C 6H 4SH-2) 3 proligand in presence of PMe 2Ph or dppe allows the synthesis of [Fe{P(C 6H 4S-2) 3}(PMe 2Ph) 2] ( 7) and [Fe{P(C 6H 4S-2) 3}(dppe)] ( 8). Corresponding reactions of the phosphinothiolates with CoCl 2 in the presence of CO and/or phosphine ligands gave [CoCl{PhP(C 6H 4S-2) 2}(dppe)] ( 9), [Co{PhP(C 6H 4S-2) 2}(dppe)(CO)]BPh 4 ( 10), [Co{PhP(C 6H 4S-2) 2}(dppe) ] ( 11), [Co(P(C 6H 4S-2) 3L] (L=dppe, 12, L=PMe 2Ph, 13. The X-ray crystal structures of complexes 2, 4, 7 and 8, are discussed.

The substitution chemistry of a useful new synthon with neutral donor ligands. The reactions of [TcCl 3(NNPh 2)(PPh 3) 2] with phosphine ligands. The X-ray crystal structures of [TcCl 2(NNPh 2)(PMe 2Ph) 3][PF 6], [TcCl(NNPh 2)(dppe) 2][PF 6] 2 and [TcCl 2(NNPh 2)(TRIPHOS)][BPh 4

The reaction of (Bu 4N)[TcOCl 4] with 1,1-diphenylhydrazine .HCl and PPh 3 in refluxing MeOH yields the neutral, Tc(III) isodiazene complex [TcCl 3(NNPh 2)(PPh 3) 2]. The reaction of this complex with PMe 2Ph in MeOH yields the cationic complex [TcCl 2(NNPh 2)(PMe 2Ph) 3] + which is isolated as the hexafluorophosphate salt. The X-ray structure of this complex shows a meridional arrangement of phosphine ligands with the diphenylisodiazene ligand and a chloride in the axial sites. The Tc–N(1) bond length is 1.741(3) Å, while N(1)–N(2) is 1.287(4) Å and the Tc–N(1)–N(2) bond angle is 176.4(3)°, which reflects the multiple bonding through out the zwitterionic isodiazene moiety. The distorted octahedral geometry results from the steric congestion associated with the three phosphine ligands in the equatorial plane. In the reaction of [TcCl 3(NNPh 2)(PPh 3) 2] with a three molar excess of dppe, {dppe=1,2 bis(diphenylphosphino)ethane} the dicationic isodiazene complex [TcCl(NNPh 2)(dppe) 2] 2+ is isolated as the bis hexafluorophosphate salt. The X-ray structure of this dication shows an equatorial arrangement of phosphine ligands with the isodiazene ligand and chloride in the axial positions. The Tc–N(1) bond length is 1.758(7) Å and the N(1)–N(2) bond length is 1.312(9) Å again reflecting the multiple bonding throughout the M–N–N framework. The Tc–N(1)–N(2) bond angle is 179.7(9)° which is indicative of sp 2 hybridization on the β-nitrogen atom. The reaction of [TcCl 3(NNPh 2)(PPh 3) 2] with TRIPHOS {TRIPHOS=bis(2-diphenylphosphinoethyl)phenylphosphine} yields the cationic product, structurally analogous to the Tris–PMe 2Ph cation described above, [TcCl 3(NNPh 2)(TRIPHOS)] +, which is isolated as the tetraphenylborate salt. The bonding constraints put on the coordination geometry by the tridentate ligand cause significant distortion from an ideal octahedron. The Tc–N(1) bond length is 1.752(3) Å and the N(1)–N(2) bond length is 1.286(4) Å, and the Tc–N(1)–N(2) bond angle is 176.2(3)°, again reflecting the multiple bonding throughout the isodiazene M–N–N linkage and the sp 2 hybridization on the β-nitrogen atom.

Platination of [3-X-7,8-Ph 2-7,8- nido-C 2B 9H 8] 2− (X=Et, F) : Synthesis and characterisation of slipped and 1,2→1,7 isomerised products

The reaction of the labelled carborane ligand [3-Et-7,8-Ph 2-7,8- nido-C 2B 9H 8] 2− with a source of {Pt(PMe 2Ph) 2} 2+ affords non-isomerised 1,2-Ph 2-3,3-(PMe 2Ph) 2-6-Et-3,1,2- closo-PtC 2B 9H 8 ( 1). The analogous reaction between [3-F-7,8-Ph 2-7,8- nido-C 2B 9H 8] 2− and {Pt(PMe 2Ph) 2} 2+ yields 1,8-Ph 2-2,2-(PMe 2Ph) 2-4-F-2,1,8- closo-PtC 2B 9H 8 ( 3). Compound 1 has a heavily slipped structure ( Δ 0.72 Å), which to some degree obviates the need for C atom isomerisation. However, that it is a kinetic product of the reaction is evident from the fact that it reverts to isomerised 1,8-Ph 2-2,2-(PMe 2Ph) 2-4-Et-2,1,8- closo-PtC 2B 9H 8 ( 2) slowly at room temperature but more rapidly with gentle warming. The heteroatom and labelled-B atom positions in the isomerised compounds 2 and 3 may be explained most simply by the rotation of a CB 2 face of an intermediate based on the structure of 1. Compounds 1– 3 were characterised by a combination of spectroscopic and crystallographic techniques.

Catalytic cleavage of the SiSi bond of methylchlorodisilanes with nucleophiles: evidences for a stabilised silylene reaction intermediate

The methylchlorodisilanes MeCl 2SiSiCl 2Me, MeCl 2SiSiClMe 2 and MeCl 2SiSiMe 3 disproportionate in the presence of nucleophilic catalysts into the methylchlorosilanes MeSiCl 3, Me 2SiCl 2, Me 3SiCl and the polysilanes Si n Me n Cl n+2 , Si n Me n+1 Cl n+1 and Si n Me n+2 Cl n ( n=3–5). Qualitative kinetic studies of the disproportionation reveal that the catalytic activities of the nucleophiles are ranked according to: phosphine oxides (OPnBu 3, OP(NMe 2) 3)>chlorides (nBu 4NCl, nBu 4PCl)>phosphines (PnBu 3, PiPr 3, PMe 2Ph, P(NMe 2) 3, PCy 3, PPh 3)>phosphites (P(OPh) 3). For the PR 3 compounds, a correlation is observed between the π acceptor character the activity for the disproportionation, the lower π acceptor the nucleophile, the higher the rate. A two step mechanism is proposed which involves the formation of an intermediate followed by condensation with the substrate disilane to afford the polysilanes. Investigation of the reaction of the intermediate with hydrogen as a test reaction provides evidences for the condensation step to be rate limiting in the disproportionation. That result, combined with the fact that poor π acceptor nucleophiles (phosphine oxides, chlorides and trialkylphosphines) are more active disproportionation catalysts, supports the description of the intermediate as a stabilised silylene.

Reduction of the NO + ligand in ‘half-sandwich’ ruthenium derivatives

The reduction of the tetrafluoroborate salts of the ruthenium nitrosyl dicationic [Ru(η 5-C 5R 5)(NO)(L) 2] 2+ (R=Me, L=PMe 3, 1a; PMe 2Ph, 1b; R=H, L=PPh 3, 2d) and monocationic complexes [Ru(Me)Cp*(NO)L] + (L=PMe 3, 3a; PMe 2Ph, 3b) (Cp*=η 5-C 5Me 5) has been studied by electrochemical and spectroscopic (IR, NMR, EPR) techniques. The nitrosyl complexes 1a, 1b and 2d exhibit two successive one-electron cathodic processes due to the sequential reduction of coordinated NO + to NO and NO −, respectively. Chemical reduction yields products of rearrangement of the intermediates which have been spectroscopically characterized. EPR studies and theoretical calculations show that in the first one-electron reduction product the electron interacts with the NO nitrogen atom and that the RuNO moiety presents significant distortion from linearity. The X-ray structure of the related [Ir(Me) 2Cp*(NO)]BF 4 has been determined.

Two types of tetrasubstitution in [H 4Ru 4(CO) 12]: spectroscopic characterization and crystal structure determination of [H 4Ru 4(CO) 8(PMe 2Ph) 4] and [H 2Ru 4(CO) 9(PMe 2Ph) 4

Two tetrasubstituted tetranuclear ruthenium clusters containing dimethylphenylphosphine [H 4Ru 4(CO) 8(PMe 2Ph) 4] and [H 2Ru 4(CO) 9(PMe 2Ph) 4] were prepared and characterized spectroscopically as well as by X-ray crystallography. Both compounds show a structure based on the usual 60-electron tetrahedral framework with each ruthenium atom being bonded to one phosphine ligand. In the case of the nonacarbonyl derivative, one of the ruthenium atoms has one terminal carbonyl group and is also bonded to two semibridging carbonyl groups; two other metal–metal bonds are bridged by the hydride groups. In the case of the octacarbonyl compound all the ruthenium atoms are bonded to two terminal carbonyls and to two bridging hydrides. NMR spectroscopical information of [H 4Ru 4(CO) 8(PMe 2Ph) 4] suggests the presence of two isomers in solution which we propose to have D 2d and C s symmetries. The observation of the NMR properties gives some observations about conditions that favour coupling between substituents in different ruthenium atoms.

Facile introduction of bridging MPh 2 groups (MGe, Sn, Pb) into platinum–pentaruthenium and hexaruthenium carbido carbonyl cluster complexes

The reactions of PtRu 5(CO) 16(μ 6-C) ( 1) with Ph 3GeH and Ph 3SnH afforded the trimetallic cluster complexes PtRu 5(CO) 15(μ-GePh 2)(μ 6-C) ( 4) and PtRu 5(CO) 15(μ-SnPh 2)(μ 6-C) ( 5), respectively, in good yields. Both the compounds consist of an octahedral cluster of one platinum and five ruthenium atoms with an interstitial carbido ligand in the center. The bridging CO ligand in 1 was replaced by a bridging GePh 2 group in 4 and a bridging SnPh 2 group in 5. The lead homologue PtRu 5(CO) 15(μ-PbPh 2)(μ 6-C) ( 6) was obtained from the reaction of 1 with Pb 2Ph 6. The reaction of PtRu 5(CO) 15(PMe 2Ph)(μ 6-C) ( 2) with Ph 3SnH yielded the phosphine derivative of 5, PtRu 5(CO) 14(μ-SnPh 2)(PMe 2Ph)(μ 6-C) ( 7). Compound 7 was obtained in a higher yield from the reaction of 5 with PMe 2Ph. The reaction of Ru 6(CO) 14(η 6-C 6H 6)(μ 6-C) ( 3) with Ph 3SnH yielded the new hexaruthenium complex Ru 6(CO) 13(μ-SnPh 2)(η 6-C 6H 6)(μ 6-C) ( 8) containing a bridging SnPh 2 ligand. Evidence for benzene formation in the formation of compound 5 indicates the fate of the phenyl group that was cleaved from the tin atom in that reaction.

Reaction chemistry of [Pd 2(μ-OH) 2L 4] 2+ with aryl amines. : Structures of [Pd 2(μ-OH){μ-NH( p-tol)}(PPh 3) 4](BF 4) 2, [Pd(η 3-CH 2C(NH( p-tol)CH 2)(PPh 3) 2](BF 4), and [Pd(PMe 2Ph) 2(μ-PF 2O 2)] 2(PF 6) 2

The reaction of [Pd 2(μ-OH) 2(PPh 3) 4](BF 4) 2 ( 1) with aromatic amines (aniline and p-toluidine) in dichloromethane yields the dinuclear complexes [Pd 2(μ-OH)(μ-NHAr)(PPh 3) 4](BF 4) 2 ( 2) (Ar=Ph, p-tol). The same reaction in acetone gives the palladium(II) allyl complex, [Pd(η 3-CH 2C(NH p-tol)CH 2)(PPh 3) 2](BF 4) ( 3). An attempt to prepare the PMe 2Ph analog of 1 as the PF 6 − salt yielded instead [Pd(PMe 2Ph) 2(μ-PF 2O 2)] 2(PF 6) 2 ( 7).The structures of 2 (Ar= p-tol), 3, and 7 have been determined by X-ray diffraction methods.

Synthesis, structural characterisation and reactivity of molybdenum half-sandwich complexes containing keto- and amido-phosphines

The keto-functionalised N-pyrrolyl phosphine ligand PPh 2NC 4H 3{C(O)CH 3-2} L 1 reacts with [MoCl(CO) 3(η 5-C 5R 5)] (R=H, Me) to give [MoCl(CO) 2( L 1 -κ 1 P)(η 5-C 5R 5)] (R=H 1a; Me 1b). The phosphine ligands PPh 2CH 2C(O)Ph ( L 2 ) and PPh 2CH 2C(O)NPh 2 ( L 3 ) react with [MoCl(CO) 3(η 5-C 5R 5)] in an analogous manner to give the compounds [MoCl(CO) 2(L-κ 1 P)(η 5-C 5R 5)] (L= L 2 , R=H 2a, Me 2b; L= L 3 , R=H 3a, Me 3b). Compounds 1– 3 react with AgBF 4 to give [Mo(CO) 2(L-κ 2 P, O)(η 5-C 5R 5)]BF 4 (L= L 1 , R=H 4a, Me 4b; L= L 2 , R=H 5a, Me 5b; L= L 3 , R=H 6a, Me 6b) following displacement of chloride. The X-ray crystal structure of 4a revealed a lengthening of both Mo–P and CO bonds on co-ordination of the keto group. The lability of the co-ordinated keto or amido group has been assessed by addition of a range of phosphines to compounds 4– 6. Compound 4a reacts with PMe 3, PMe 2Ph and PMePh 2 to give [Mo(CO) 2( L 1-κ 1 P)(L)(η 5-C 5H 5)]BF 4 (L=PMe 3 7a; PMe 2Ph 7b; PMePh 2 7c) but does not react with PPh 3, 5a reacts with PMe 2Ph, PMePh 2 and PPh 3 to give [Mo(CO) 2( L 2-κ 1 P)(L)(η 5-C 5H 5)]BF 4 (L=PMe 2Ph 8b; PMePh 2 8c; PPh 3 8d), and 6a reacts with PMe 3, PMe 2Ph, PMePh 2 and PPh 3 to give [Mo(CO) 2( L 3-κ 1 P)(L)(η 5-C 5H 5)]BF 4 (L=PMe 3 10a; PMe 2Ph 10b; PMePh 2 10c; PPh 3 10d). No reaction was observed for the pentamethylcyclopentadienyl compounds 4b– 6b with PMe 3, PMe 2Ph, PMePh 2 or PPh 3. These results are consistent with the displacement of the co-ordinated oxygen atom being influenced by the steric properties of the P, O-ligand, with PPh 3 displacing the keto group from L 2 but not from the bulkier L 1 . In the reaction of [Mo(CO) 2( L 2 -κ 2 P, O)(η 5-C 5H 5)]BF 4 ( 5a) with PMe 3 the phosphine does not displace the keto group, instead it acts as a base, with the only observed molybdenum-containing product being the enolate compound [Mo(CO) 2{PPh 2CHC(O)Ph-κ 2 P, O}(η 5-C 5H 5)] 9. Compound 9 can also be formed from the reaction of 2a with BuLi or NEt 3, and a single crystal X-ray analysis has confirmed the enolate structure.

CH and PC bond activations of PMe 2Ph ligands by an octahedral Ru 6 cluster

The compound Ru 6(CO) 15(PMe 2Ph) 2(μ 6-C) ( 1) was obtained from the reaction of Ru 6(CO) 17(μ 6-C) with PMe 2Ph. Compound 1 exists in solution as a mixture of two slowly interconverting isomers. It is decarbonylated by treatment with Me 3NO·2H 2O to yield two new products Ru 6(CO) 13(μ-PMe 2)(μ 3-η 3-Me 2PC 6H 4)(μ 6-C) ( 2) and Ru 6(CO) 14(PMe 2Ph)(μ-η 2-MePhPCH 2)(μ 6-C)(μ-H) ( 3). Compound 2 is also obtained from 1 by thermal decarbonylation at 127 °C together with two additional compounds: Ru 6(CO) 14(μ-PMe 2)(μ-η 2-MePhPCH 2)(μ 6-C) ( 4) and Ru 6(CO) 12(μ-PMe 2) 2(μ 3-η 2-C 6H 4)(μ 6-C) ( 5). Compound 2 reacts reversibly with CO to form the CO adduct Ru 6(CO) 14(μ-PMe 2)(μ-η 2-Me 2PC 6H 4)(μ 6-C) ( 6). The structures of compounds 1– 6 were established crystallographically. All contain octahedral Ru 6 clusters with a carbido ligand in the center. Except for 1, all contain phosphine ligands in various stages of degradation. Compound 2 contains one bridging PMe 2 ligand formed by loss of a phenyl ring from a PMe 2Ph ligand and a bridging η 3-Me 2PC 6H 4 ligand formed by ortho-metallation of the phenyl ring of the second PMe 2Ph ligand. Compound 3 contains a bridging η 2-MePhPCH 2 ligand formed by metallation of one of the methyl groups of a PMe 2Ph ligand. Compound 4 contains a bridging PMe 2 and a bridging η 2-MePhPCH 2 ligand. Compound 5 contains two bridging PMe 2 ligands and a bridging (μ 3-η 2-C 6H 4) benzyne ligand fromed by cleavage of a phenyl ring from one of the PMe 2Ph ligands. Compound 6 contains one bridging PMe 2 ligand and a bridging η 2-Me 2PC 6H 4 ligand formed by ortho-metallation of the phenyl ring of one of the PMe 2Ph ligands.