Dppm Ligands Research Articles

Chemistry and Electrochemistry of the Heterodinuclear Complex ClPd(dppm)2PtCl: A M−M‘ Bond Providing Site Selectivity

The heterodinuclear d(9)-d(9) title compound 1, whose crystal structure has been solved, reacts with dppm [bis(diphenylphosphino)methane] in the presence of NaBF4 to generate the salt [ClPd(mu-dppm)2Pt(eta(1)-dppm)][BF4] (2a), which contains a Pt-bound dangling dppm ligand. 2a has been characterized by 1H and 31P NMR, Fourier transform Raman [nu(Pd-Pt) = 138 cm(-1)], and UV-vis spectroscopy [lambda(max)(dsigma-dsigma*) = 366 nm]. In a similar manner, [ClPd(mu-dppm)2Pt(eta(1)-dppm=O)][BF4] (2b), ligated with a dangling phosphine oxide, has been prepared by the addition of dppm=O. The molecular structure of 2b has been established by an X-ray diffraction study. 2a reacts with 1 equiv of NaBH4 to form the platinum hydride complex [(eta(1)-dppm)Pd(mu-dppm)2Pt(H)][BF4] (3). Both 2a and 3 react with an excess of NaBH4 to provide the mixed-metal d(10)-d(10) compound [Pd(mu-dppm)3Pt] (4). The photophysical properties of 4 were studied by UV-vis spectroscopy [lambda(max)(dsigma-dsigma*) = 460 nm] and luminescence spectroscopy (lambda(emi) = 724 nm; tau(e) = 12 +/- 1 micros, 77 K). The protonation of 1 and 4 leads to [ClPd(mu-dppm)2(mu-H)PtCl]+ (5) and 3, respectively. Stoichiometric treatment of 1 with cyclohexyl or xylyl isocyanide yields [ClPd(mu-dppm)2Pt(CNC6H11)]Cl (6a) and [ClPd(mu-dppm)2Pt(CN-xylyl)]Cl (6b) ligated by terminal-bound CNR ligands. In contrast, treatment of 1 with the phosphonium salt [C[triple bond]NCH2PPh3]Cl affords the structurally characterized A-frame compound [ClPd(mu-dppm)2(mu-C=NCH2PPh3)PtCl]Cl (6c), spanned by a bridging isocyanide ligand. The electrochemical reduction of 2a at -1.2 V vs SCE, as well as the reduction of 5 in the presence of dppm, leads to a mixture of products 3 and 4. Further reduction of 3 at -1.7 V vs SCE generates 4 quantitatively. The reoxidation at 0 V of 4 in the presence of Cl- ions produces back complex 2a. The whole mechanism of the reduction of 1 has been established.

Pyridine-2-thionate as a versatile ligand in Pd(ii) and Pt(ii) chemistry: the presence of three different co-ordination modes in [Pd2(μ2-S,N-C5H4SN)(μ2-κ2S-C5H4SN)(μ2-dppm)(S-C5H4SN)2

Reactions of [MCl2(L-L)], M = Pt, Pd; L-L = bis(diphenylphosphino)methane (dppm) or bis(diphenylphosphino)ethane (dppe), with NaC5H4SN in a 1 : 2 molar ratio lead to mononuclear species [M(S-C5H4SN)2(P-P)], M = Pt; L-L = dppm (1) or dppe (2) and M = Pd; L-L = dppe (3), as well as to the dinuclear [Pd2(micro2-S,N-C5H4SN)(micro2-kappa2S-C5H4SN)(micro2-dppm)(S-C5H4SN)2] (4). In contrast, reaction of [MCl2(dppm)] with NaC5H4SN in a 1 : 1 molar ratio leads to [Pd2(micro2-S,N-C5H4SN)3(micro2-dppm)]Cl (5) and trans-[Pt(S-C5H4SN)2(PPh2Me)2] (6) respectively. The latter is formed in low yield by cleavage of the dppm ligand. The dinuclear derivatives 4 and 5 present an A-frame and lantern structure, respectively. The former showing three different co-ordination modes in the same molecule with a short Pd-Pd distance of 2.9583 (9) A and the latter with three bridging S,N thionate ligands showing a shorter Pd-Pd distance of 2.7291 (13) A. Both distances could be imposed by the bridging ligands or point to some sort of metal-metal interaction.

Bis[μ-bis(diphenylphosphino)methane-κ2P:P′]bis[(1,10-phenanthroline-κ2N,N′)copper(I)] bis(tetrafluoroborate) dichloromethane disolvate

In the structure of the title complex, [Cu2(C25H22P2)2(C12H8N2)2](BF4)2·2CH2Cl2, the two Cu centres are bridged by two bis­(diphenyl­phosphino)methane (dppm) ligands to form a centrosymmetric eight-membered Cu2P4C2 ring. The coordination of polyhedron of each Cu atom is distorted tetra­hedral.

Supramolecular Assembly of Gold(I) Complexes of Diphosphines and N,N‘-Bis-4-methylpyridyl Oxalamide

We report herein the supramolecular assembly and spectroscopic and luminescent properties of gold(I) complexes of diphosphines (dppm [bis(diphenylphosphino)methane], dppp [1,3-bis(diphenylphosphino)propane], and dpppn [1,5-bis(diphenylphosphino)pentane]) and N,N'-bis-4-methylpyridyl oxalamide (L). The dppm and dppp cases form the rectangular structures, [dppm(Au(2))L](2)(ClO(4))(4) and [dppp(Au(2))L](2)(ClO(4))(4), with four gold(I) ions at the corners, as well as two L and two dppm or dppp ligands as edges, featuring 38- and 42-membered rings for the former and the latter, respectively. Remarkably, the packing of the dppp complexes shows interesting one-dimensional rectangular channels in the solid state, most likely due to intermolecular pi...pi interactions. The dpppn complex has been structurally characterized as a one-dimensional coordination polymer, {[(dpppn)(3.5)(Au(7))L(3.5)](PF(6))(7)}. The absorptions and emissions of the compounds are in general due to intraligand transitions, but aurophilic or pi...pi interactions could also make partial contributions. The dipyridyl amide system with the amides incorporated into the bridging ligands as well as the one-dimensional rectangular channels in the solid state for the dppp-based rectangle make this a promising family of metal-containing cyclic peptides in crystal engineering and molecular-recognition studies.

Bis(diphenylphosphino)methane-κ2P,P′][bis(diphenylthiophosphinyl)methane-κ2S,S′]platinum(II) bis(perchlorate) acetone solvate

The title complex, [Pt(C25H22P2)(C25H22P2S2)](ClO4)2·C3H6O or [Pt(dppm)(dppmS2)](ClO4)2·C3H6O, where dppmS2 is bis­(diphenyl­thio­phosphin­yl)methane and dppm is bis­(di­phenyl­phosphino)methane, is the first example of a platinum(II) complex containing both dppm and dppmS2 ligands. In the cation, the dppm ligand forms a non-planar four-membered chelate ring, while the dppmS2 ligand forms a six-membered chelate ring with twist–boat conformation.

Mechanisms of Concurrent Hydride Migration Processes in a Triruthenium Cluster Capped by a Phenylphosphinidene (PPh) Ligand

AbstractTwo methods were used to synthesise [Ru3(μ‐H)2(μ3‐PPh)(CO)7(μ‐dppm)] (3) (dppm = Ph2PCH2PPh2), the subject of this paper. Treatment of [Ru3(CO)10(μ‐dppm)] (1) with phenylphosphane in refluxing THF gave both [Ru3(μ‐H)(μ‐PHPh)(CO)8(μ‐dppm)] (2) and [Ru3(μ‐H)2(μ3‐PPh)(CO)7(μ‐dppm)] (3). Cluster 2 converts to 3 in refluxing THF. Alternatively the phenylphosphinidene cluster [Ru3(μ‐H)2(μ3‐PPh)(CO)9] (4), prepared by the reported method of treating [Ru3(CO)12] with phenylphosphane, reacts with dppm to produce cluster 3. The single‐crystal X‐ray structures of 2 and 3 are reported. Hydride mobility in [Ru3(μ‐H)2(μ3‐PPh)(CO)7(μ‐dppm)] (3) was analysed by variable‐temperature 1H and 31P{1H} NMR methods. The variations in the spectra with temperature could not be interpreted by a single process, several of which were explored and which gave inadequately matching computed and experimental spectra. However, the spectra were successfully analysed by two concurrent processes, both involving the migration of hydride ligands between Ru–Ru edges. The faster process leads to the exchange of the non‐equivalent phosphorus nuclei but not hydride exchange, whereas the hydrides are also exchanged in the slower process. Both processes require hydride ligand migration from one Ru–Ru edge to a vacant one. The hydride ligand bridging the same pair of ruthenium atoms as the dppm ligand is the slower to migrate. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Triosmium clusters containing bridging dppm and EPh (E = S, Te) ligands: X-ray structures of [(μ-H)Os 3(CO) 7(μ-SPh){μ 3-η 4-Ph 2PCHP(Ph)C 6H 4}], [Os 3(CO) 8(μ-SPh) 2(μ-dppm)] and [Os 3(CO) 8(μ-TePh) 2(μ-dppm)

Heating [Os 3(CO) 10(μ-dppm)] ( 1) with two equivalents of PhSSPh in toluene under reflux provided three new triosmium compounds [(μ-H)Os 3(CO) 7(μ-SPh){μ 3-η 4-Ph 2PCHP(Ph)C 6H 4}] ( 2), [Os 3(CO) 8(μ-SPh) 2(μ-dppm)] ( 3) and [(μ-H)Os 3(CO) 7(μ-η 2-SC 6H 4)(μ-SPh)(μ-dppm)] ( 4) in 20%, 21% and 26% yields, respectively. In contrast, a similar reaction of 1 with two equivalents of PhTeTePh in refluxing toluene gave the binuclear compound [Os 2(CO) 4(μ-TePh) 2(μ-dppm)] ( 6) in 15% yield, and two 50 electron isomeric compounds 5 and 7 with the formula [Os 3(CO) 8(μ-TePh) 2(μ-dppm)] in 20% and 23% yields, respectively. Thermolysis of 3 at 110 °C afforded 4 in 53% yield which on further thermolysis in refluxing octane at 128 °C gave 2 in 45% yield. Thermolysis of 3 in refluxing octane also gave 2 in 50% yield. The new compounds, 2–7, were all spectroscopically characterized, and the X-ray structures of 2, 3 and 7 have been determined. Compound 2 contains a bridging SPh ligand and a μ 3,η 4-Ph 2PCHP(Ph)C 6H 4 ligand, formed by two kinds of C–H activation, including orthometallation of a phenyl group as well as an unusual activation of the methylene group of the dppm ligand. The molecular structure of 3 reveals that two SPh groups span the open Os–Os edge of the Os 3 triangle, while the dppm ligand bridges one of the closed Os–Os edges. In compound 7, one TePh group spans the open Os–Os edge, while the other spans one of the two closed Os–Os edges and the dppm ligand bridges the third Os–Os vector.

Oxidative Addition of Methyl Iodide to a New Type of Binuclear Platinum(II) Complex: a Kinetic Study

A new organodiplatinum(II) complex cis,cis-[Me2Pt(mu-NN)(mu-dppm)PtMe2] (1), in which NN = phthalazine and dppm = bis(diphenylphosphino)methane, is synthesized by the reaction of cis,cis-[Me2Pt(mu-SMe2)(mu-dppm)PtMe2] with 1 equiv of NN. Complex 1 has a 5d(pi)(Pt) --> pi(imine) metal-to-ligand charge-transfer band in the visible region, which was used to easily follow the kinetics of its reaction with MeI. Meanwhile, the complex contains a robust bridging dppm ligand that holds the binuclear integrity during the reaction. A double MeI oxidative addition was observed, as shown by spectrophotometry and confirmed by a low-temperature 31P NMR study. The classical S(N)2 mechanism was suggested for both steps, and the involved intermediates were suggested. Consistent with the proposed mechanism, the rates of the reactions at different temperatures were slower in benzene than in acetone and large negative deltaS values were found in each step. However, some abnormalities were observed in the related rate constants and deltaS values, which were demonstrated to be due to the associative involvement of the polar acetone molecules in the reactions. The rates are almost 6 times slower in the second step as compared to the first step because of the electronic effects transmitted through the ligands and the steric effects.

Reactions of [(μ-H)Os 3(CO) 10(μ-OMe)] and [(μ-H)Os 3(CO) 9(μ-OMe)(MeCN)] with dppm, dppe, dppp, and PPh 2H: X-ray crystal structures of [(μ-H)Os 3(CO) 8(μ-OMe)(μ 2-η 2-dppm)] and [(μ-H)Os 3(CO) 9(μ-OMe)(PPh 2H)

Treatment of [(μ-H)Os 3(CO) 10(μ-OMe)] ( 1) with dppm {dppm = bis(diphenylphosphino)methane} at 110 °C gave the known compound [Os 3(CO) 10(μ 2-η 2-dppm)] ( 2) and the new compound [(μ-H)Os 3(CO) 8(μ-OMe)(μ 2-η 2-dppm)] ( 3). A similar reaction of 1 with dppe {dppe = bis(diphenylphosphino)ethane} afforded two products, [(μ-H)Os 3(CO) 8(μ-OMe)(μ 1-η 2-dppe)] ( 5) and [(μ-H)Os 3(CO) 8(μ-OMe)(μ 2-η 2-dppe)] ( 6) which differ in the mode of bonding of the dppe ligand. The reaction of 1 with dppp {dppp = bis(diphenylphosphino)propane} at 110 °C gave exclusively [(μ-H)Os 3(CO) 8(μ-OMe)(μ 2-η 2-dppp)] ( 7) which exists as two isomers in solution. Compounds 2, 3, and 5– 7 are also obtained in almost similar yields from reactions of [(μ-H)Os 3(CO) 9(μ-OMe)(MeCN)] ( 4) with the appropriate diphosphine at ambient temperature. The reaction of 1 with PPh 2H at 110 °C gave the new compounds [(μ-H)Os 3(CO) 9(μ-OMe)(PPh 2H)] ( 8) and [(μ-H) 2Os 3(CO) 7(μ-PPh 2) 2(PPh 2H)] ( 10) and the previously reported compound [(μ-H) 2Os 3(CO) 8(μ-PPh 2) 2] ( 9). The molecular structures of 3 and 8 were determined by single crystal X-ray diffraction. In compound 3, the dppm ligand bridges the same Os–Os edge as the hydride and the methoxide ligand. In 8, the PPh 2H ligand occupies a ‘pseudo’ axial site on one of the osmium atoms bearing the bridging hydride and methoxide ligand.

Addition of primary phosphines to the unsaturated triosmium cluster [(μ-H)Os 3(CO) 8{Ph 2PCH 2P(Ph)C 6H 4}]: Synthesis of triosmium clusters bearing dppm, phosphide and phosphinidene ligands via P–H bond activation

Treatment of the electronically unsaturated cluster [(μ-H)Os 3(CO) 8{Ph 2PCH 2P(Ph)C 6H 4}] ( 1) with primary phosphines PPhH 2 and PCyH 2 gives the phosphido bridged compounds [(μ-H)Os 3(CO) 8(μ-PPhH)(μ-dppm)] ( 2) and [(μ-H)Os 3(CO) 8(μ-PCyH)(μ-dppm)] ( 3), respectively, by P–H bond activation of the phosphines and demetallation of the phenyl ring of the diphosphine ligand. Thermolysis of 2 and 3 in refluxing octane at 128 °C results in the formation of the phosphinidene compounds [(μ-H) 2Os 3(CO) 7(μ 3-PPh)(μ-dppm)] ( 4) and [(μ-H) 2Os 3(CO) 7(μ 3-PCy)(μ-dppm)] ( 5), respectively, by further P–H bond cleavage of the phosphido groups. All the compounds have been characterized by infrared, 1H NMR, 31P{ 1H} NMR and mass spectroscopic data together with single-crystal X-ray diffraction studies for 4. Compound 4 consists of a triangular cluster of osmium atoms with a symmetrically capped phosphinidene ligand and a bridging dppm ligand.

Iron, silicon, tin polymetallic complexes: formation of trans, cis, cis-[Fe(CO)2(dppm-P,P)(SnClPh2)2] by silicon–tin exchange and its crystal structure

Abstract The reaction of the alkoxysilylcarbonylferrate [Fe(CO) 3 (η 1 -dppm){Si(OMe) 3 }] – 1 (dppm = Ph 2 PCH 2 PPh 2 ) with [SnCl 2 Ph 2 ] affords a Fe 2 Si 2 Sn chain complex 2 and a FeSn 2 complex 3 depending on the reaction conditions. Photochemical activation was found to trigger their transformation to another complex that has now been fully characterized by X-ray diffraction as trans, cis, cis -[Fe(CO) 2 (dppm- P,P )(SnClPh 2 ) 2 ] 6 , which results from CO elimination and chelation of the dppm ligand. To cite this article: P. Braunstein et al., C.R. Chimie 8 (2005) .

Triruthenium clusters bearing bridging dppm and capping sulfido ligands: X-ray structures of [Ru 3(CO) 6(μ 3-CO)(μ 3-S)(PPh 3)(μ-dppm)] and [Ru 3(CO) 6(μ 3-S) 2(PPh 3)(μ-dppm)

Treatment of [Ru 3(CO) 10(μ-dppm)] ( 1) with PPh 3 S at ambient temperature in THF gave the known compound [Ru 3(CO) 7(μ 3-CO)(μ 3-S)(μ-dppm)] ( 2) and the new compound [Ru 3(CO) 6(μ 3-CO)(μ 3-S)(PPh 3)(μ-dppm)] ( 3). Compound 3 can also be prepared by the room temperature reaction of 2 with PPh 3 in the presence of Me 3NO. A similar reaction of [Ru 3(CO) 7(μ 3-S) 2(μ-dppm)] ( 4) with PPh 3 afforded ( 3), [Ru 3(CO) 6(μ 3-S) 2(PPh 3)(μ-dppm)] ( 5) together with the previously reported compound [(μ-H) 2Ru 3(CO) 7(μ 3-S)(μ-dppm)] ( 6). In contrast, a similar treatment of the sulfur-selenium compound [Ru 3(CO) 7(μ 3-S)(μ 3-Se)(μ-dppm)]( 7) with PPh 3 afforded only [Ru 3(CO) 6(μ 3-S)(μ 3-Se)(PPh 3)(μ-dppm)] ( 8). Both compounds 5 and 8 exist as two isomers in solution, arising from the reversible migration of a metal–metal bond, induced by the dppm ligand. The reaction of 6 with PPh 3 under the same conditions gave [(μ-H) 2Ru 3(CO) 6(μ 3-S)(PPh 3)(μ-dppm)] ( 9). Protonation of 4 and 7 by trifluoroacetic acid gave the mono-protonated species [(μ-H)Ru 3(CO) 7(μ 3-S) 2(μ-dppm)] + ( 10) and [(μ-H)Ru 3(CO) 7(μ 3-Se)(μ 3-S)(μ-dppm)] + ( 11), respectively, isolated as their PF 6 salts. All the compounds have been characterized by spectroscopic data together with single crystal X-ray diffraction studies for 3 and 5.

Reactions of Phosphine Ligands with Iridium Complexes Leading to C(sp3)−H Bond Activation

Treatment of [Ir 2 (μ-Cl) 2 (coe) 4 ] (coe = cyclooctene) with the short-bite bifunctional N,P-donor ligand 1-benzyl-2-imidazolyldiphenylphosphine (Ph 2 PBnIm) resulted in the oxidative addition of the C(sp 3 )-H bond from thebenzyl group to the metal to give [IrHCl-{Ph 2 P(CHPh)Im}(Ph 2 PBnIm)] (1), fully characterized by an X-ray study. The related ligand 2-pyridyldiphenylphosphine (Ph 2 PPy) reacted with [Ir 2 (μ-Cl) 2 (coe) 4 ] to give the mononuclear iridium(I) complex [IrCl(Ph 2 PPy) 2 ] (2), which showed P,N-chelating and P-coordinated ligands. Addition of Ph 2 PBnIm to 2 produced the replacement of the P-coordinated Ph 2 PPy ligand along with the benzyl C-H bond addition to iridium to give [IrHCl{Ph 2 P(CHPh)Im}-(Ph 2 PPy)]. This result indicates that mononuclear complexes of the type [IrCl(Ph 2 PBnIm)-(L)] (L = P,N-chelating ligand) are the active species undergoing the C-H bond activation reaction. A related C-H bond activation process of the methylene group of dppm occurs in the reaction of [Ir 2 (μ-Cl) 2 (coe) 4 ] with dppm in toluene to give the hydrido complex with one deprotonated dppm ligand [IrHCl(Ph 2 PCHPPh 2 )(dppm)] (4). On the other hand, the hydride migrates to the methanide carbon in 4 on dissolving the complex in CD 2 Cl 2 to establish an equilibrium with [IrCl(dppm) 2 ] without H/D exchange. Protonating agents such as HBF 4 .Et 2 O and water reacted with complex 4 easily to give [IrHCl(dppm) 2 ]X (X = BF 4 , OH). The mononuclear complex 2 was found to be highly reactive. Reactions of 2 with O 2 , H 2 , and dichloromethane gave the complexes [IrCl(O 2 )(Ph 2 PPy) 2 ], [IrCl(H) 2 (Ph 2 PPy) 2 ], and [IrCl 2 (CH 2 Cl)-(Ph 2 PPy) 2 ], respectively.

Synthesis, Crystal Structure and Optical Studies of a Tetranuclear Silver(I) Complex with Bis(diphenylphosphino)methane

Silver(I), whose coordination number ranging from 2 to 4, displays a wide diversity in its structural chemistry. Many silver complexes containing silver halides and neutral ligands formulated as (AgX)mLn are well known, which exist in different molecular ratios, even for the same X and L, and show rather different crystal structures. For example, there are five kinds of structures of (AgX)mLn (X = Br, L = PPh3). As in the case of the series of (AgX)m(dppm)n 2 (dppm = bis(diphenylphosphino)methane), they also show very interesting structures. Interest in the coordination chemistry of silver-phosphorus complexes has arisen in part from their important applications as potential antitumor, free radical scavengers and catalyzer in industrial processes since the late middle of last century. By exclusion of all traces of oxygen, a new tetranuclear silver(I) complex containing dppm ligand has been synthesized and isolated, in which the metal atoms are bridged by dppm and I− anions. The synthesis, X-ray crystal structure and photophysical properties of the complex are reported.

Further reactions of some bis(vinylidene)diruthenium complexes

Whereas {Ru(dppm)Cp*} 2(μ-C CC C) ( 2) is the only product formed by deprotonation of [{Ru(dppm)Cp*} 2{μ( C CHCH C )}] + with dbu, a mixture of 2 with Ru{C CCH CH(PPh 2) 2[RuCp*]}(dppm)Cp* ( 3) and {Cp*Ru(PPh 2CHC CH–)} 2 ( 4) is obtained with KOBu t . A similar reaction with [{Ru(dppm)Cp*} 2{μ( C CMeCMe C )}] + ( 5) gave Ru{C CCMe CH(PPh 2) 2[RuCp*]}(dppm)Cp* ( 6). X-ray structures of 4, 5 and 6 confirm the presence of the 1-ruthena-2,4-diphosphabicyclo[1.1.1]pentane moiety, which is likely formed by an intramolecular attack of the deprotonated dppm ligand on C(1) of the vinylidene ligand. Protonation of {Ru(dppe)Cp*} 2(μ-C CC C) ( 8- Ru) regenerates its precursor [{Ru(dppe)Cp*} 2{μ( C CHCH C )}] 2+ ( 7- Ru). Ready oxidation of the bis(vinylidene) complex affords the cationic carbonyl [Ru(CO)(dppe)Cp*]PF 6 ( 9) (X-ray structure).

Triruthenium clusters containing bridging dppm and capping sulfido and selenido ligands: X-ray structures of [Ru 3(CO) 5(μ 3-CO)(μ 3-Se)(μ-dppm) 2], [Ru 3(CO) 6(μ 3-CO)(μ 3-Se)(μ-dppm)(η 1-Ph 2PCH 2P( [dbnd]O)Ph 2)] and [Ru 2(CO) 4(μ-SePh) 2(μ-dppm)

The reaction of [Ru 3(CO) 10(μ-dppm)] ( 1) with dppmSe at 66 °C affords [Ru 3(CO) 8(μ-dppm) 2] ( 2), [Ru 3(CO) 7(μ 3-CO)(μ 3-Se)(μ-dppm)] ( 3), [Ru 3(CO) 5(μ 3-CO)(μ 3-Se)(μ-dppm) 2] ( 4) and [Ru 3(CO) 6(μ 3-CO)(μ 3-Se)(μ-dppm)(η 1-Ph 2PCH 2P( O)Ph 2)] ( 5) in 7%, 5%, 9% and 33% yields, respectively. A similar reaction between 1 with dppmS gives [Ru 3(CO) 7(μ 3-S) 2(μ-dppm)] ( 6), [Ru 3(CO) 7(μ 3-CO)(μ 3-S)(μ-dppm)] ( 7) [Ru 3(CO) 5(μ 3-CO)(μ 3-S)(μ-dppm) 2] ( 8) and [Ru 3(CO) 6(μ 3-CO)(μ 3-S)(μ-dppm)(η 1-Ph 2PCH 2P( O)Ph 2)] ( 9) in 8%, 7%, 14% and 35% yields, respectively. Treatment of 1 with PhSeSePh at 66 °C affords the dinuclear compound [Ru 2(CO) 4(μ-SePh) 2(μ-dppm)] ( 10) in 14% yield. Thermolysis of 5 and 9in refluxing toluene at 110 °C gives 4 and 8, respectively. The molecular structures of 4, 9 and 10 have been determined by single-crystal X-ray diffraction studies. The cores of the new clusters 4, 5, 8 and 9 consist of metal triangles capped by μ 3-sulfur or selenium atoms with the bidentate ligand bridging in equatorial positions. In compounds 4 and 8, two bidentate dppm ligands bridge the Ru 3 triangle in such a way that each ligand bridges two ruthenium atoms and one Ru–Ru edge remains unbridged. Compounds 5 and 9 contain one bridging dppm ligand and one dangling dppm mono-oxide ligand Ph 2PCH 2P( O)Ph 2 coordinated to the rear metal atom at an equatorial position. The molecular structure of 10 shows classical “sawhorse” structure with two bridging SePh ligands as well as the dppm ligand.

Hexa- and triosmium carbonyl clusters bearing bridging dppm and capping sulfido ligands

Treatment of [Os 3(CO) 7(μ 3-S) 2(μ-dppm)] ( 1) with Me 3NO in toluene at 80 °C affords the trinuclear cluster [Os 3(CO) 6(μ 3-S) 2(NMe 3)(μ-dppm)] ( 2) and the hexanuclear cluster [Os 6(CO) 12(μ 3-S) 4(μ-dppm) 2] ( 3) in 30% and 51% yields, respectively. The reaction of 1 with [Os 3(CO) 10(MeCN) 2] in refluxing benzene at 80 °C gives the hexanuclear cluster [Os 6(CO) 14(μ 3-S) 2(μ-dppm)] ( 4) in 15% yield. Compound 2 reacts with CO, PPh 3 and P(OMe) 3 at room temperature to give 1, [Os 3(CO) 6(μ 3-S) 2(μ-dppm)(PPh 3)] ( 5) and [Os 3(CO) 6(μ 3-S) 2(μ-dppm){P(OMe) 3}] ( 6), respectively; in high yields indicating that the NMe 3 ligand is weakly bound. Compound 1 reacts with PPh 3 in presence of Me 3NO to afford 5, 2 and 3 in 53%, 6% and 18% yields, respectively, whereas with P(OMe) 3 1 gives only 6 in 84% yield. Compound 3 reacts with CO at 98 °C to regenerate 1 by the cleavage of the three unsupported osmium–osmium bonds. The molecular structures of 4 and 6 have been unambiguously determined by single crystal X-ray diffraction studies. The hexanuclear compound 3 appears to be a64-electron butterfly core with four triply bridging sulfido ligands and two bridging dppm ligands based on the spectroscopic and analytical data. The metal core of 4 can be described as a central tetrahedral array capped on two faces with two additional osmium atoms. The triply bridging sulfido ligands face cap the two tetrahedral arrays formed by metal capping of the two faces of the central tetrahedron. The dppm ligand bridges one edge of one of the external tetrahedral arrays. Compounds 5 and 6 are formed by the displacement of equatorial carbonyl group of 1 by a PPh 3 and P(OMe) 3 ligand respectively and their structures are comparable to that of 1.

Hexaruthenium carbonyl cluster complexes with basal edge-bridged square pyramidal metallic skeleton: efficient synthesis of 2-imidopyridine derivatives and determination of their reactive sites in carbonyl substitution reactions.

The reactions of [Ru(3)(CO)(12)] with half equivalent of 2-amino-6-methylpyridine (H(2)ampy) or 2-aminopyridine (H(2)apy) in refluxing xylene give the hexanuclear products [Ru(6)(mu(3)-H)(2)(mu(5)-eta(2)-L)(mu-CO)(2)(CO)(14)] (L = ampy, 1; apy, 2). These reactions represent the first high-yield syntheses of hexanuclear complexes with a basal edge-bridged square pyramidal metallic skeleton. Five metal atoms of these complexes are bridged by the N-donor ligand in such a way that the edge-bridging metal atom is attached to the pyridine nitrogen, while the basal atoms of the square pyramid are capped by an imido fragment that arises from the activation of both N-H bonds of the NH(2) group. The reactive sites of these complexes in CO substitution reactions have been determined by studying the reactivity of 1 with triphenylphosphine. Two kinetically controlled monosubstitutions take place on the edge-bridging metal atom in positions cis to the pyridine nitrogen, leading to a mixture of two isomers of formula [Ru(6)(mu(3)-H)(2)(mu(5)-eta(2)-ampy)(mu-CO)(2)(CO)(13)(PPh(3))] (3 and 4). On heating at 80 degrees C, these monosubstituted isomers are transformed, via a dissociative pathway, into the product of thermodynamic control (5), which has the PPh(3) ligand on the apical Ru atom. The di- and trisubstituted derivatives [Ru(6)(mu(3)-H)(2)(mu(5)-eta(2)-ampy)(mu-CO)(2)(CO)(12)(PPh(3))(2)] (6) and [Ru(6)(mu(3)-H)(2)(mu(5)-eta(2)-ampy)(mu-CO)(2)(CO)(11)(PPh(3))(3)] (7) are stepwise formed from 3-5 and PPh(3). Compound 6 has the PPh(3) ligands on the edge-bridging and apical Ru atoms, and compound 7 has an additional PPh(3) ligand on an unbridged basal Ru atom. The compound [Ru(6)(mu(3)-H)(2)(mu(5)-eta(2)-ampy)(mu-CO)(2)(CO)(12)(mu-dppm)] (8), in which a basal and the apical Ru atoms are spanned by the dppm ligand, has been isolated from the reaction of 1 with bis(diphenylphosphino)methane.

Reactions of Cu 3(dppm) 3(μ 3-OH)(ClO 4) 2 (dppm = bis-(diphenylphosphino) methane) with Soft Heterocumulenes

The reaction of [Cu 3(dppm) 3(μ 3-OH)](ClO 4) 2 ( 1) with heterocumulenes (X C S; X = NPh, NMe and S) has been studied. The μ 3-OH ligand inserts into PhNCS and MeNCS only in the presence of methanol. Insertion products are formed in accord with earlier observations made with copper(I)–aryloxides. On heating, the insertion products convert to a S bridged cluster [Cu 4(dppm) 4(μ 4-S)](ClO 4) 2 ( 8), having a tetrameric core. However, in the reaction with CS 2, 1 is converted to 8 even at room temperature in the presence of methanol. On the other hand, the dimeric complex [Cu 2(dppm) 2(CH 3CN) 4](ClO 4) 2, reacts with CS 2 to give (diphenylphosphinomethyl)-diphenylphosphine sulfide, Ph 2P–CH 2–P( S)Ph 2 (dppmS), which forms the complex [Cu(dppmS) 2]ClO 4 ( 9). A single crystal X-ray crystallographic study of 9, the first copper(I) complex of dppmS has been taken up to confirm the mono-oxidation of the dppm ligand and the nuclearity of the complex. Reactions of complex 1 with heterocumulenes and with elemental sulfur, are compared.

Addition of diphenyl diselenide (PhSeSePh) to the clusters [Os 3(CO) 10(μ-dppm)] and [(μ-H)Os 3(CO) 8{Ph 2PCH 2P(Ph)C 6H 4}]: X-ray structures of [Os 2(CO) 4(μ-SePh) 2(μ-dppm)], [Os 3(CO) 6(μ-CO)(μ-Se) 2(μ-C 6H 4)(μ-dppm)] and two isomers of [Os 3(CO) 8(μ-SePh) 2(μ-dppm)

The reaction of [Os 3(CO) 10(μ-dppm)] ( 4) with diphenyldiselenide in refluxing toluene at 110 °C affords the dinuclear compound [Os 2(CO) 4(μ-SePh) 2(μ-dppm)] ( 5), three 50 electron isomeric triosmium compounds 6, 7 and 8 with the formula [Os 3(CO) 8(μ-SePh) 2(μ-dppm)], two triosmium benzyne compounds [Os 3(CO) 6(μ-CO)(μ-η 2-Se) 2(μ-C 6H 4)(μ-dppm)] ( 9) and [Os 3(CO) 9(μ-SePh) 2(μ-η 2-C 6H 4)(μ-dppm)] ( 10) in 11%, 19%, 15%, 5%, 18% and 6% yields, respectively. Thermolysis of both 6 and 8 in refluxing toluene gives the dinuclear compound 5 in moderate yield, whereas a similar thermolysis of 7 yields 5 and 9 in 20% and 27% yields, respectively. Compound 10 converts to 9 refluxing in octane. Treatment of the unsaturated compound [(μ-H)Os 3(CO) 8{Ph 2PCH 2P(Ph)C 6H 4}] ( 11) with diphenyldiselenide in refluxing benzene gives 5, 6, 7 and 8 in 8%, 20%, 25% and 10% yields, respectively. The molecular structures of 5, 6, 7 and 9 have been determined by single crystal X-ray diffraction studies. The molecular structure of 5 shows classical “sawhorse” structure with two bridging phenylselenido ligands as well as a dppm ligand. The solid-state structure of 6 reveals that two SePh groups span the open Os–Os edges of the Os 3 triangle, while the dppm ligand bridges one of the closed Os–Os edges. In compound 7, one SePh spans the open Os–Os site, while the other spans one of the two closed Os–Os edges and the dppm ligand bridges the third Os–Os vector. Compound 9, which exists as a mixture of two isomers in solution, contains two triply bridging selenido ligands and a benzyne ligand, which are believed to have been formed by the cleavage of Se–Se bond of the PhSeSePh ligand followed by C–Se and C–H activation of the SePh group. The 54 electron compound 10 has been characterized by elemental analysis, IR, 1H NMR, 31P{ 1H} NMR and mass spectroscopic data.