Addition Of PPh Research Articles

Introduction of ferrocene-containing [2]rotaxanes onto siloxane, silsesquioxane and polysiloxanes via click chemistry

The reaction of N(3)(CH(2))(3)Si(OTMS)(3) (TMS = SiMe(3)) with a dialkylammonium having hexynyl group 1, [FcCH(2)NH(2)CH(2)C(6)H(4)-4-O(CH(2))(4)C≡CH]PF(6) (Fc = Fe(C(5)H(4))(C(5)H(5))), in the presence of dibenzo[24]crown-8-ether (DB24C8) and [Cu{Fe(CN)(4)}]PF(6) catalyst yielded the [2]rotaxane containing the dialkylammonium unit terminated by a bulky silyl group. Azides with a silsesquioxane group react similarly to form the corresponding [2]rotaxanes having a bulky silsesquioxane end group. The azide-functionalized polysiloxane, [-O-SiMe{(CH(2))(3)N(3)}-](n)[-O-SiMe(2)-](m) also undergoes a click reaction with 1 to produce the side chain polyrotaxane. Cyclic voltammograms of these rotaxanes and 1 [(DB24C8)1] show the Fe(II)/Fe(III) redox at the same potential, but with different current depending on their molecular weights. Addition of PdCl(2)(MeCN)(2) to a solution of the side-chain polyrotaxane forms gel which regenerates the sol upon addition of PPh(3).

Study of the different behaviour of thiazolin and thiazin indazole derivatives with palladium(II) acetate

The study of the reactivity of the ligands 2-(indazol-1-yl)-2-thiazoline ( 1) and 2-(indazol-1-yl)-1,3-thiazine ( 2) with palladium(II) acetate has allowed the isolation of different compounds. For the thiazolin indazole derivative ( 1) a cyclopalladated compound: (μ-OAc) 2[Pd( k 2- C, N-TnInA)] 2 ( 1a) with a bidentate [C(sp 2,phenyl),N] − ligand and a central “Pd(μ-OAc) 2Pd” unit was obtained. Treatment of the dimeric compound 1a with sodium acetylacetonate produced the mononuclear compound [Pd( k 2- O, O′-acac)( k 2- C, N-TnInA)] ( 1c). The reaction of 1a with LiCl followed by the addition of PPh 3 gave the compound [PdCl(PPh 3)( k 2- C, N-TnInA)] ( 1e) where the acetate groups were replaced by Cl − and PPh 3 ligands, and with the PPh 3 in a cis-arrangement to the metallated carbon atom. The solid-state structure of 1e was determined by single-crystal X-ray diffraction methods. The reaction of 2 with palladium(II) acetate produced, in contrast to ligand 1, the complex cis-[Pd(OAc) 2( k 2- N, N′-TzIn)] ( 2a) with a bidentate [ N, N′] ligand. Compound 2a reacted with LiCl giving cis-[PdCl 2( k 2- N, N′-TzIn)] ( 2b), where the acetate groups were exchanged by chloride ligands. DFT calculations suggest that the most favoured compound obtained from the reaction between 1 and palladium(II) acetate should be the cyclopalladated one, while for 2 the formation of the [ N, N′] coordinated complex is less unfavoured.

Mixed-metal cluster synthesis: [Re(CO) 3(μ-S 2NC 7H 4)] 2 as a precursor for tri- and tetranuclear 2-mercaptobenzothiolato capped clusters

The readily prepared [Re 2(CO) 6(μ-S 2NC 7H 4) 2] ( 1) reacts with Group 8 trimetallic carbonyl clusters to yield new mixed-metal tri- and tetranuclear clusters. With [Os 3(CO) 10(NCMe) 2] at 80 °C the tetranuclear mixed-metal cluster [Os 3Re(CO) 13(μ 3-C 7H 4NS 2)] ( 2) is the only isolated product. With Ru 3(CO) 12 products are dependent upon the reaction temperature. At 80 °C, a mixture of tetranuclear mixed-metal [Ru 3Re(CO) 13(μ 3-C 7H 4NS 2)] ( 5) and the triruthenium complex [Ru 3(CO) 9(μ-H)(μ 3-C 7H 4NS 2)] ( 4) results, while at 110 °C a second tetranuclear mixed-metal cluster, [Re 2Ru 2(CO) 12(μ 4-S)(μ-C 7H 4NS)(μ-C 7H 4NS 2)] ( 3), resulting from carbon–sulfur bond scission, is the major product. Reaction of 1 With Fe 3(CO) 12 at 80 °C furnishes the trinuclear mixed-metal cluster [Fe 2Re(CO) 8(μ-CO) 2(μ 3-C 7H 4NS 2)] ( 6). The reactivity of 6 has been probed with the aim of identifying any metal-based selectivity for carbonyl substitution. Addition of PPh 3 in presence of Me 3NO at 25 °C gives both the mono- and bis(phosphine)-substituted derivatives [Os 3Re(CO) 12(PPh 3)(μ 3-C 7H 4NS 2)] ( 7) and [Os 3Re(CO) 11(PPh 3) 2(μ 3-C 7H 4NS 2)] ( 8). In 7 the PPh 3 ligand occupies an axial site on wingtip osmium, while in 8 one PPh 3 ligand is equatorially coordinated to wingtip osmium and the other is bonded to a hinge osmium. New complexes have been characterized by a combination of spectroscopic data and single crystal X-ray diffraction studies.

The effect of the central donor in bis(benzimidazole)-based cobalt catalysts for the selective cis-1,4-polymerisation of butadiene

A series of bis(benzimidazole)-based cobalt(II) dichloride complexes containing a range of different central donors has been synthesized and characterized. The nature of the central donor affects the binding of the ligand to the cobalt centre and determines the coordination geometry of the metal complexes. All complexes have been shown to catalyse the polymerization of butadiene, in combination with MAO as the co-catalyst, to give cis-1,4-polybutadiene with high selectivity. The nature of the central donor has a marked influence on the polymerization activity of the catalysts, but does not affect the polymer microstructure. The addition of PPh(3) generally increases the polymerization activity of these cobalt catalysts and results in predominantly (60-70%) 1,2-vinyl-polybutadiene.

Copper Halide‐Bridged Ruthenium Telluride Carbonyl Complexes: Discovery of the Semiconducting Cluster Chain Polymer {[PPh4]2[Te2Ru4(CO)10Cu4Br2Cl2]⋅THF}∞

A new series of Te-Ru-Cu carbonyl complexes was prepared by the reaction of K(2)TeO(3) with [Ru(3)(CO)(12)] in MeOH followed by treatment with PPh(4)X (X=Br, Cl) and [Cu(MeCN)(4)]BF(4) or CuX (X=Br, Cl) in MeCN. When the reaction mixture of K(2)TeO(3) and [Ru(3)(CO)(12)] was first treated with PPh(4)X followed by the addition of [Cu(MeCN)(4)]BF(4), doubly CuX-bridged Te(2)Ru(4)-based octahedral clusters [PPh(4)](2)[Te(2)Ru(4)(CO)(10)Cu(2)X(2)] (X=Br, [PPh(4)](2)[1]; X=Cl, [PPh(4)](2)[2]) were obtained. When the reaction mixture of K(2)TeO(3) and [Ru(3)(CO)(12)] was treated with PPh(4)X (X=Br, Cl) followed by the addition of CuX (X=Br, Cl), three different types of CuX-bridged Te-Ru carbonyl clusters were obtained. While the addition of PPh(4)Br or PPh(4)Cl followed by CuBr produced the doubly CuBr-bridged cluster 1, the addition of PPh(4)Cl followed by CuCl led to the formation of the Cu(4)Cl(2)-bridged bis-TeRu(5)-based octahedral cluster compound [PPh(4)](2)[{TeRu(5)(CO)(14)}(2)Cu(4)Cl(2)] ([PPh(4)](2)[3]). On the other hand, when the reaction mixture of K(2)TeO(3) and [Ru(3)(CO)(12)] was treated with PPh(4)Br followed by the addition of CuCl, the Cu(Br)CuCl-bridged Te(2)Ru(4)-based octahedral cluster chain polymer {[PPh(4)](2)(Te(2)Ru(4)(CO)(10)Cu(4)Br(2)Cl(2)).THF}(infinity) ({[PPh(4)](2)[4].THF}(infinity)) was produced. The chain polymer {[PPh(4)](2)[4].THF}(infinity) is the first ternary Te-Ru-Cu cluster and shows semiconducting behavior with a small energy gap of about 0.37 eV. It can be rationalized as resulting from aggregation of doubly CuX-bridged clusters 1 and 2 with two equivalents of CuCl or CuBr, respectively. The nature of clusters 1-4 and the formation and semiconducting properties of the polymer of 4 were further examined by molecular orbital calculations at the B3LYP level of density functional theory.

Synthesis of the sterically crowded cycloheptatrienyl complexes [M(CO)(PPh 3) 2(η-C 7H 7)] + (M = Mo or W): X-ray crystal structures of [W(CO)(PPh 3) 2(η-C 7H 7)][BF 4] and [W(CO) 2(PPh 3)(η-C 7H 7)][BF 4] · CH 2Cl 2

The first examples of complexes of the sterically crowded, bis(triphenylphosphine) auxiliary M(PPh 3) 2(η-C 7H 7) (M = Mo or W) have been synthesised. [Mo(CO)(PPh 3) 2(η-C 7H 7)][PF 6] ( 1) was obtained by low-temperature reaction of [MoMe(CO)(PPh 3)(η-C 7H 7)] with [Ph 3C][PF 6] in the presence of PPh 3. The tungsten analogue [W(CO)(PPh 3) 2(η-C 7H 7)][BF 4] ( 3) was formed by reaction of [WI(CO)(PPh 3)(η-C 7H 7)] with Ag[BF 4] in acetone followed by addition of PPh 3. An X-ray crystallographic structural comparison of complex 3 with its mono-phosphine counterpart, [W(CO) 2(PPh 3)(η-C 7H 7)][BF 4] · CH 2Cl 2 ( 4) reveals that the principal structural differences between 3 and 4 resulting from replacement of a carbonyl ligand by PPh 3 are: (i) an increase in the sum of the angles between the tripodal ligands and (ii) an elongation of the W–PPh 3 bond length (from 2.4950(12) Å in 4 to 2.5360(6) and 2.5496(6) Å in the bis(phosphine) complex 3).

The PPh 3 ligand modified Rh/SiO 2 catalyst for hydroformylation of olefins

A novel family of hybrid catalyst with high turnover frequency (TOF) and high selectivity towards aldehydes for hydroformylation of olefins could be successfully approached through direct coordination with the PPh 3 ligand to the highly dispersed Rh metal particle precursors. A further advantage is that the catalyst is easily prepared and recyclable. The results revealed that hydroformylation of olefins to aldehydes dominantly took place on the surface of PPh 3 ligand modified Rh metal particles of the hybrid catalyst. It was found that the formation of chemical coordination bond between the Rh metal particles and the lone-pair electron of PPh 3 was evident through the TG and 31P NMR measurement. Moreover, the addition of PPh 3 onto the Rh/SiO 2 exert a significant influence on the adsorption state of reactant CO, H 2 and C 2H 4 on the PPh 3–Rh/SiO 2 sample, which probably lead to good catalytic performances for hydroformylation of olefins.

Synthesis and characterisation of saturated and unsaturated triruthenium clusters containing electronically symmetrical and asymmetrical alkynes

The synthesis and characterisation of μ 3-η 2-alkynyl triruthenium clusters, [Ru 3(μ 3-η 2-R 1-4-C 6H 4CCR 2)(μ-dppm)(μ-CO)(CO) 7] ( 1, saturated), [Ru 3(μ 3-η 2-R 1-4-C 6H 4CCR 2)(μ-dppm)(CO) 7] ( 2, unsaturated) and [Ru 3(μ 3-η 2-R 1-4-C 6H 4CCR 2)(μ-dppm)(PPh 3)(CO) 7] ( 3, saturated) containing symmetrical and asymmetrical alkynes in which R 1 and R 2 are electron donor or electron withdrawing groups in the para position of the aromatic ring(s) or R 2 is ferrocenyl, are reported. Clusters 1 were obtained from the reactions of [PPN][Ru 3(μ-Cl)(CO) 10] with R 1-4-C 6H 4CCR 2 and dppm. Clusters 1 were successfully decarbonylated to give unsturated clusters 2, with the exception of the FcCCC 6H 4-4-NO 2 containing cluster, which is stable. Novel adducts 3 were obtained in high yields by addition of PPh 3 to unsaturated clusters 2. Clusters 1– 3 were characterised by analytical and spectroscopic data, and structures were proposed on the basis of systematic 31P NMR studies and correlations with X-ray structural data of related compounds available in the literature. Saturated compounds 1 contain a CO and a dppm ligands bridging the same edge, which is also parallel to the μ 3-η 2-alkyne, as opposed to the structure previously proposed for the PhCCPh and other derivatives, and established by X-ray crystallography for the PhCCCCPh cluster derivative, in which the dppm ligand bridges a different edge. Unsaturated compounds 2 exhibit the same structure established for the PhCCPh derivative in the solid state, with the alkyne bonded in the μ 3-η 2-mode perpendicular to the Ru 2 edge supported by the dppm ligand. Because the dppm phosphorus chemical shifts were sensitive to the alkyne electronic asymmetry, it was possible to show that clusters containing electronically asymmetrical alkynes exist in two inseparable isomeric forms, which differ with respect to the alkyne orientation. Similarly to their osmium analogues, saturated compounds 3 exist as inseparable mixtures of isomers that differ with respect to the position of the bridging CO and dppm ligands, and in the cases of asymmetrical alkyne derivatives, also with respect to the orientation of the alkyne. This work has established, therefore, that μ-CO and dppm ligand positions respective to the μ 3-η 2-alkyne in saturated clusters 1 and 3 are sensitive both to the nature of the coordinated alkyne and to the presence of a PPh 3 in place of a CO ligand on the metal frame.

NMR investigation of platinum–diphosphine complexes in [BMIM][PF 6] ionic liquid

The formation of platinum–diphosphine complexes of catalytic importance was investigated in [BMIM][PF 6] (BMIM=butyl-methyl-imidazolium cation) ionic liquid by NMR for the first time. Both the PtCl(SnCl 3)(bdpp) and Pt(SnCl 3) 2(bdpp) complexes (where bdpp=2,4-bis(diphenylphosphino)pentane) were identified in the insertion reaction of tin(II)chloride into the PtCl bond of PtCl 2(bdpp) complex. The addition of PPh 3 to PtCl 2(bdpp) resulted in the formation of [Pt(bdpp)(PPh 3)Cl] + complex cation as a minor component, which turned to be a major component in the presence of tin(II)chloride while it forms trichlorostannate counterion. Both types of reactions show high similarity with those obtained in conventional organic solvents. As a serious disadvantage of the use of [BMIM][PF 6] as ionic liquid, the partial decomposition of the hexafluorophosphate counterion in the presence of the smallest amount of water (and tin(II)chloride) is also discussed.

Synthesis, characterization and X-ray structure of trans-[Pd(COOCH 3)(H 2O)(PPh 3) 2](TsO), a possible intermediate in the catalytic hydroesterification of olefins (TsO= p-toluenesulfonate)

The complex trans-[Pd(COOCH 3)(H 2O)(PPh 3) 2](TsO) ( I) has been synthesized by reacting trans-[Pd(COOCH 3)Cl(PPh 3) 2] with AgTsO in methanol. It has been characterized by IR, 1H and 31P NMR spectroscopy. Crystals of trans-[Pd(COOCH 3)(H 2O)(PPh 3) 2](TsO)·(CH 3OH) ( II) have been obtained by re-crystallization of I in methanol. The structure of the complex has been determined by X-ray analysis. It shows a slightly distorted square planar conformation around the central palladium. The coordinated water molecule and the clathrated methanol form a contact with the uncoordinated TsO − anion, suggesting hydrogen bond interaction. Since I is a possible intermediate in the catalytic hydroesterification of olefins, its catalytic activity in the hydroesterification of ethylene has been tested at 100 °C under 45 atm of a 1/1 mixture of ethylene and CO in methanol as solvent, also in the presence of PPh 3 and TsOH. Without addition of PPh 3 and TsOH, I affords to traces of methylpropionate together with Pd(0) complexes and Pd metal. The same results are obtained when complex I is tested in the presence of PPh 3, except that in this case formation of palladium metal is avoided. Using the system I/PPh 3/TsOH=1/6/8, a TOF (mol of ester/mol Pd∗h) of 1800 h −1 is obtained. We propose that the role of the acid TsOH is to favor the formation of a Pd–hydride intermediate and/or to reactivate the Pd(0) species, stabilized by the excess of PPh 3, via an oxidative addition of the acid. Since the acid does not favor the formation of Pd–alkoxy species we suggest that complex I plays only a minor role in catalysis and that this occurs via a Pd–hydride species.

Regioselective palladation of 2-oxazolinyl-[2.2]paracyclophanes.: Synthesis of planar-chiral phosphines

Palladations of the diastereomeric 4-(4- tert-butyl-2-oxazolinyl)-[2.2]paracyclophanes ( S, R p )- 3 and ( S, S p )- 3 have been investigated. Exclusive ortho-palladation occurs, when ( S, R p )- 3 is treated with Pd(OAc) 2 in glacial acetic acid. In contrast, ( S, S p )- 3 affords products from either metallation in the ortho or the benzylic position of the [2.2]paracyclophane skeleton depending on the reaction conditions. Upon treatment of the resulting complexes with LiCl followed by addition of PPh 3 mononuclear chloro{4-(2-oxazolinyl)-[2.2]paracyclophane,5- C,3- N}(triphenylphosphine)palladium(II) complexes ( S, S p )- 7, ( S, R p )- 7, and ( S, S p )- 9 have been obtained. The solid state structures of ( S, S p )- 7 and ( S, R p )- 7 have been determined by X-ray diffraction analysis. Reaction of ortho-palladated complexes ( S, S p )- 7 and ( S, R p )- 7 with KPPh 2 gives the corresponding planar-chiral phosphines ( S, S p )- 11 and ( S, R p )- 11, respectively. From benzyl substituted complex ( S, S p )- 9 bromo derivative ( S, S p )- 12 was obtained.

Synthesis and reactions of triphenylsilanethiolato complexes of manganese(II), iron(II), cobalt(II), and nickel(II).

Reactions of Fe[N(SiMe(3))(2)](2) with 1 and 2 equiv of Ph(3)SiSH in hexane afforded dinuclear silanethiolato complexes, [Fe(N(SiMe(3))(2))(mu-SSiPh(3))](2) (1) and [Fe(SSiPh(3))(mu-SSiPh(3))](2) (2), respectively. Various Lewis bases were readily added to 2, generating mononuclear adducts, Fe(SSiPh(3))(2)(L)(2) [L = CH(3)CN (3a), 4-(t)BuC(5)H(4)N (3b), PEt(3) (3c), (LL) = tmeda (3d)]. From the analogous reactions of M[N(SiMe(3))(2)](2) (M = Mn, Co) and [Ni(NPh(2))(2)](2) with Ph(3)SiSH in the presence of TMEDA, the corresponding silanethiolato complexes, M(SSiPh(3))(2)(tmeda) [M = Mn (4), Co (5), Ni (6)], were isolated. Treatment of 3a with (PPh(4))(2)[MoS(4)] or (NEt(4))(2)[FeCl(4)] resulted in formation of a linear trinuclear Fe-Mo-Fe cluster (PPh(4))(2)[MoS(4)(Fe(SSiPh(3))(2))(2)] (7) or a dinuclear complex (NEt(4))(2)[Fe(2)(SSiPh(3))(2)Cl(4)] (8). On the other hand, the reaction of 3a with [Cu(CH(3)CN)(4)](PF(6)) gave a cyclic tetranuclear copper cluster Cu(4)(SSiPh(3))(4) (9), where silanethiolato ligands were transferred from iron to copper. Silicon-sulfur bond cleavage was found to occur when the cobalt complex 5 was treated with (NBu(4))F in THF, and a cobalt-sulfido cluster Co(6)(mu(3)-S)(8)(PPh(3))(6) (10) was isolated upon addition of PPh(3) to the reaction system. The silanethiolato complexes reported here are expected to serve as convenient precursors for sulfido cluster synthesis.

Synthesis, structures, and properties of a series of four-, five-, and six-coordinate cobalt(III) triazacorrole complexes: the first examples of transition metal corrolazines.

The syntheses of the first transition metal corrolazine complexes, in which the meso carbon atoms of a corrole framework have been replaced by N atoms, are reported. Metalation of the corrolazine [(TBP)(8)CzH(3)] (TBP = 4-tert-butylphenyl) (1) with Co(acac)(2) gives [(TBP)(8)CzCo(III)] (2) in good yield. Addition of PPh(3) to 2 in pyridine results in the formation of [(TBP)(8)CzCo(III)(PPh(3))] (3), which was characterized by X-ray crystallography. Likewise, addition of an excess of pyridine to 2 in CH(2)Cl(2) followed by slow diffusion of MeOH gives [(TBP)(8)CzCo(III)(py)(2)] (4) as a crystalline solid, which was also characterized by X-ray crystallography. The crystal structures of 3 and 4 reveal that the corrolazine cavity is significantly smaller ( approximately 0.1 A) than their regular corrole analogues. Characterization of 2-4 by UV-vis spectroscopy reveals some interesting features in the absorption spectra of these compounds, including a dramatic red-shift of the Soret band. In addition, binding of pyridine to 2 was evaluated quantitatively by UV-vis titration, revealing a formation constant of beta(2) = 9.0 x 10(7) M(-)(2), which is larger than any of the regular Co(III) corrole analogues.

Heterodimetallic palladium(II) compounds containing terdentate [Csp 2(ferrocene),N,N′] − ferrocenyl ligands

The reaction of the novel ferrocenyl Schiff base containing an amino group as pendant arm: [(η 5-C 5H 5)Fe{(η 5-C 5H 4)CHNCH 2CH 2CH 2NMe 2}] ( 1) with palladium(II) salts is reported. Treatment of 1 with the stoichiometric amount of Na 2[PdCl 4] produced: cis-[Pd{(η 5-C 5H 5)Fe{(η 5-C 5H 4)CHNCH 2CH 2CH 2NMe 2}Cl 2] ( 2). However, when the reaction is performed in the presence of sodium acetate it leads to mixtures of 2 and [Pd{[(η 5-C 5H 3)CHNCH 2CH 2CH 2NMe 2]Fe(η 5-C 5H 5)}Cl] ( 3). Compound 3 arises from the activation of the σ[Csp 2 (ferrocene)H] bond. Further treatment of 3 with deuteriated pyridine (py- d 5) or triphenylphosphine (PPh 3) produced the cleavage of the PdN(amine) bond and the formation of the neutral compounds: [Pd{[(η 5-C 5H 3)CHNCH 2CH 2CH 2NMe 2]Fe(η 5-C 5H 5)}Cl(L)], with L=py- d 5 ( 4) or PPh 3 ( 5). The reaction of 3 with Tl[BF 4] in acetone followed by the addition of PPh 3 yielded [Pd{[(η 5-C 5H 3)CHNCH 2CH 2CH 2NMe 2]Fe(η 5-C 5H 5)}(PPh 3)][BF 4] ( 6). NMR-studies reveal that the ligand acts as a neutral bidentate (N,N′) group, in 2, as a monoanionic bidentate [Csp 2 (ferrocene), N] −, in 4 and 5 or terdentate [Csp 2 (ferrocene),N,N′] − ligand, in 3 and 6. The X-ray crystal structures of 2 and 3 are also reported and confirm the mode of binding of the ligand to the palladium.

Stereoselective oxidative addition of methyl iodide to chiral cyclometallated platinum(II) compounds derived from ( R)-(+)-1-(1-naphthylethylamine). Crystal structure of [PtMe{3-( R)-(C 10H 7)CHMeNCHC 4H 2S}PPh 3

The reaction of 3-( R)-(C 10H 7)CHMeNCHC 4H 3S ( 2a) with [Pt 2Me 4(μ-SMe 2) 2] in acetone gave the new chiral cyclometallated platinum(II) compound [PtMe{3-( R)-(C 10H 7)CHMeNCHC 4H 2S}SMe 2] ( 3a). Addition of PPh 3 produced compound [PtMe{3-( R)-(C 10H 7)CHMeNCHC 4H 2S}PPh 3] ( 4a) which was characterized by X-ray diffraction methods. While oxidative addition of methyl iodide to 3a gave two pairs of diastereomers, the analogous reaction for 4a produced only one diastereomer of the platinum(IV) compound [PtMe 2I{3-( R)-(C 10H 7)CHMeNCHC 4H 2S}PPh 3] ( 7a). Subsequent isomerization of the resulting platinum(IV) compound gave a new pair of diastereomers in relative amounts 90 and 10%. Analogous proportions of final diastereomers were obtained for the oxidative addition of methyl iodide to the new chiral compounds [PtMe{3-( R)-(C 10H 7)CHMeNCHAr}PPh 3] (Ar=C 6H 4 ( 4b), 2-FC 6H 3 ( 4c), 2-CF 3C 6H 3 ( 4d)). The reaction of [Pt 2Me 4(μ-SMe 2) 2] with imines ( R)-(C 10H 7)CHMeNCH(2-BrC 6H 4) ( 2e) and ( R)-(C 10H 7)CHMeNCH(2,6-Cl 2C 6H 3) ( 2f) produced intramolecular oxidative addition to yield platinum(IV) compounds with some degree of stereoselectivity.

Platinum complexes of ( R)- N, N-bis(2-(diphenylphosphino)ethyl)-1-phenyl-ethylamine: their synthesis and characterisation

Both neutral and ionic platinum complexes of ( R)- N, N-bis(2-diphenylphosphinoethyl)-1-phenyl-ethylamine (PNP) were synthesised. In the reaction of PtCl 2(PhCN) 2 and PNP cis-PtCl 2(η 2-P,P-PNP) ( 1) was formed coordinating PNP as a P,P-bidentate ligand. Diastereotopic phosphorus atoms were observed in 31P NMR upon addition of SnCl 2 to the parent complex ( 1) due to the formation of [PtCl(PNP)][SnCl 3] ( 2a). The formation of similar complex cations, [PtX(PNP)] + (where X=I ( 4), CN ( 5)) containing PNP as a terdentate ligand was also observed when KI and KCN was added in the presence of SnCl 2, which formed trichlorostannate counterion. The addition of PPh 3 to 1 resulted in the partial formation of [Pt(PPh 3)(PNP)] 2+ ( 3), which could be accomplished upon addition of SnCl 2. The catalytic activity of the platinum–PNP system in the hydroformylation of styrene is low.

Reaction of rhenium alkynyl carbene complexes with tertiary phosphines produces dihydrophospholium rhenium complexes by a formal CH insertion process

Abstract Addition of PPh 2 CH 3 to the alkynyl carbene complex Cp(CO) 2 ReC(Tol)(CCPh) ( 1a ) led to formation of the dihydrophospholium complex Cp(CO) 2 Re[CC(Ph)PPh 2 CH 2 CH(Tol)] ( 4 ). When the reaction was monitored by low temperature NMR spectroscopy, initial phosphine addition to the carbene carbon atom of 1a to give σ-propargyl complex Cp(CO) 2 ReC(PPh 2 CH 3 )(Tol)CCPh ( 5 ) was observed at −78°C. Upon warming to −20°C, 5 rearranged to the σ-allenyl complex Cp(CO) 2 Re(Tol)CCC(Ph)(PPh 2 CH 3 ) ( 6 ) via phosphine dissociation and readdition. Upon further warming to room temperature, 6 rearranged to 4 . A protonation-deprotonation mechanism for the conversion of 6 to 4 is supported by the observation that reaction of 6 with DOTf produces the cationic allene complex Cp(CO) 2 Re[η 2 -2,3-(Tol)DCCC(Ph)(PPh 2 CH 3 )]OTf ( 11 - d ), which is converted to 4 - d upon treatment with KO- t -Bu. The reaction of 1a with Ph 2 PCHCH 2 led to the formation of the cyclopropane Cp(CO) 2 Re[CC(Ph)PPh 2 CHCH 2 C(Tol)] ( 8 ).

Dimerization of terminal alkynes catalyzed by indenyl ruthenium(II) complexes

The indenyl ruthenium complexes [Ru(η 5-C 9H 7)X(dppm)] (X=H, 1; CCPh, 2; ( E)-CHCHPh, 3), [Ru(η 5-C 9H 7)X(PPh 3) 2] (X=H, 4; CCPh, 5), [Ru(η 5-C 9H 7)X(dppe)] (X=H, 6; CCPh, 7), [Ru(η 5-C 9H 7)Cl(COD)] ( 8), (dppm=bis(diphenylphosphino)methane; dppe=1,2-bis(diphenylphosphino)ethane; COD=1,5-cyclooctadiene) catalyze the dimerization of phenylacetylene to ( E)- and ( Z)-1,4-diphenylbut-1-en-3-yne. The cyclopentadienyl complex [Ru(η 5-C 5H 5)H(dppm)] ( 9) is inactive. The activity of the complexes depending on phosphine follows the order dppm>bis-PPh 3>dppe, after 13 h. The catalysis is less efficient for the aliphatic 1-octyne than for phenylacetylene. Addition of PPh 3 to complexes 5 and 8 enhances the conversion to the dimerization products. The isomeric distribution of E and Z enynes is dependent on different factors, such as temperature, reaction time, substrate to catalyst molar ratio, nature of σ-ligand. The isomers ( E) and ( Z)-1,4-diphenylbut-1-en-3-yne are synthesized on a semipreparative scale by catalysis of either complex 4 or 5, and can be separated from the isomeric mixture by standard methods. The procedure represents a one pot preparation of the two isomers starting from one terminal alkyne by CH activation.

Synthesis and structure of a dinuclear cobalt carbonyl derivative containing methyldithioformate as a five-electron donor ligand

Dicobalt octacarbonyl reacts with an excess of (MeSCS 2) 2 to form several sulfur-containing cobalt carbonyl derivatives; on addition of PPh 3, the complex Co 2(CO) 2(PPh 3) 2(1,3-η-S 2CSMe)(μ-1,2-η-SCSMe) ( 1) could be isolated from the reaction mixture. The structure of complex 1 was determined by X-ray crystallography; it contains a methyl dithioformate ligand in which the ligand donates five electrons to the cluster and the CS group is bound perpendicular to the Co 2 core.

The coordination behaviour of the squarate anion in rhodium(I) chemistry

Preparation of the neutral [Rh 2(μ-sq) (COD) 2] ( 1) (sq=squarate) and ionic [Rh(phen) (COD)] [Rh(sq) (COD)] ( 2) and [Rh(dppe) 2] 2[sq] ( 3) complexes is reported. Complex [Rh 2(μ-sq) (CNR) 4] ( 4) (R = p-tosylmethylisocyanide) has been prepared by substitution of the diolefinic ligands of complex 1. Carbonylation of compounds 1 and 2 gave [Rh 2(μ-sq) (CO) 4] (5) and [Rh(phen) (CO) 2] [Rh(sq) (CO) 2] ( 6), respectively. Compound [Rh 2(μ-sq) (CO) 2(PPh 3) 2] ( 7) was prepared by addition of PPh 3 to complex 5. Complex 7 undergoes oxidative addition of molecular iodine leading to the rhodium(III) compound [Rh 2(μ-sq) [ 4 (CO) 2 (PPh 3) 2] ( 8).