Ruthenium(II) and ruthenium(IV) complexes containing kappa1-P-, kappa2-P,O-, and kappa3-P,N,O-iminophosphorane-phosphine ligands Ph2PCH2P[=NP(=O)(OR)2]Ph2 (R = Et,Ph): synthesis,reactivity, theoretical studies,and catalytic activity in transfer hydrogenation of cyclohexanone

[(Ru(eta(6)-p-cymene)(mu-Cl)Cl)(2)] and [(Ru(eta(3):eta(3)-C(10)H(16))(mu-Cl)Cl)(2)] react with Ph(2)PCH(2)P[=NP(=O)(OR)(2)]Ph(2) (R = Et (1a), Ph (1b)) affording complexes [Ru(eta(6)-p-cymene)Cl(2)(kappa(1)-P-Ph(2)PCH(2)P[=NP(=O)(OR)(2)]Ph(2))] (R = Et (2a), Ph (2b)) and [Ru(eta(3):eta(3)-C(10)H(16))Cl(2)(kappa(1)-P-Ph(2)PCH(2)P[=NP(=O)(OR)(2)]Ph(2))] (R = Et (6a), Ph (6b)). While treatment of 2a with 1 equiv of AgSbF(6) yields a mixture of [Ru(eta(6)-p-cymene)Cl(kappa(2)-P,O-Ph(2)PCH(2)P[=NP(=O)(OEt)(2)]Ph(2))][SbF(6)] (3a) and [Ru(eta(6)-p-cymene)Cl(kappa(2)-P,N-Ph(2)PCH(2)P[=NP(=O)(OEt)(2)]Ph(2))][SbF(6)] (4a), [Ru(eta(6)-p-cymene)Cl(kappa(2)-P,O-Ph(2)PCH(2)P[=NP(=O)(OPh)(2)]Ph(2))][SbF(6)] (3b) and [Ru(eta(3):eta(3)-C(10)H(16))Cl(kappa(2)-P,O-Ph(2)PCH(2)P[=NP(=O)(OR)(2)]Ph(2))][SbF(6)] (R = Et (7a), Ph (7b)) are selectively formed from 2b and 6a,b. Complexes [Ru(eta(6)-p-cymene)(kappa(3)-P,N,O-Ph(2)PCH(2)P[=NP(=O)(OR)(2)]Ph(2))][SbF(6)](2) (R = Et (5a), Ph (5b)) and [Ru(eta(3):eta(3)-C(10)H(16))(kappa(3)-P,N,O-Ph(2)PCH(2)P[=NP(=O)(OR)(2)]Ph(2))][SbF(6)](2) (R = Et (8a), Ph (8b)) have been prepared using 2 equiv of AgSbF(6). The reactivity of 3-5a,b has been explored allowing the synthesis of [Ru(eta(6)-p-cymene)X(2)(kappa(1)-P-Ph(2)PCH(2)P[=NP(=O)(OR)(2)]Ph(2))] (R = Et, Ph; X = Br, I, N(3), NCO (9-12a,b)). The catalytic activity of 2-8a,b in transfer hydrogenation of cyclohexanone, as well as theoretical calculations on the models [Ru(eta(6)-C(6)H(6))Cl(kappa(2)-P,N-H(2)PCH(2)P[=NP(=O)(OH)(2)]H(2))]+ and [Ru(eta(6)-C(6)H(6))Cl(kappa(2)-P,O-H(2)PCH(2)P[=NP(=O)(OH)(2)]H(2))]+, has been also studied.     

Silver(I) complexes of N-thiophosphorylated bis(iminophosphorane) ligands: from monomers to polymers

Treatment of diphosphines Ph(2)P(CH2)nPPh2 (n = 1, 2, 4, 6) and [Fe(eta5-C(5)H(4)PR'2)2] (R' = Ph, (i)Pr) with a two-fold excess of (RO)2P(=S)N3 (R = Et, Ph) results in the high-yield formation of the N-thiophosphorylated bis(iminophosphorane) derivatives (CH2)n[P{=NP(=S)(OR)2}Ph2]2 and Fe(eta5-C(5)H(4)[P{=NP(=S)(OR)2}R'2])2, respectively. The reactions of these ligands with AgSbF(6) in a 1 : 1 molar ratio have been investigated. The resulting silver(I) complexes, derived from the selective coordination of the P=S units, have been characterized by IR, NMR and MS (FAB) spectroscopy and, in selected cases, by X-ray crystallography. Monomeric, dimeric and polymeric solid-state structures, depending on the nature of the ligand backbone, have been found.     

Synthesis of beta-P,N aminophosphines and coordination chemistry to Pd(II). X-ray structures of [PdCl2(Ph2PCH(Ph)NHPh-kappaP,kappaN)] and PdCl(eta3-C3H5)(Ph2PCH2CH(Ph)NHPh-kappaP)

The reaction of the C=N bond in PhCH=NPh with the carbanionic species Ph2PCH2-, leading to the N-phenyl beta-aminophosphine Ph2PCH2CH(Ph)NHPh, L1, is described. This molecule reacts with different organic electrophiles to afford related compounds Ph2PCH2CH(Ph)NPhX (X = SiMe3, L2; COPh, L4), [Ph2MePCH2CH(Ph)NHPh]+(I-), L3, and [Ph2PCH2CH(Ph)N(Ph)CO]2, L5, containing two amido and two phosphino functions. The coordination properties of L1, L2, and L4 have been studied in palladium chemistry. The X-ray structure of [PdCl2(Ph2PCH2CH(Ph)NHPh-kappaP,kappaN)] shows the bidentate coordination mode for the L1 ligand with equatorial C(Ph)-N(Ph) phenyl groups. [PdCl2(Ph2PCH2CH(Ph)NHPh-kappaP,kappaN)] crystallizes at 298 K in the space group P2(1)/n with cell parameters a = 10.689(2) A, b = 21.345(3) A, c = 12.282(2) A, beta = 90.294(12) degrees, Z = 4, D(calcd) = 1.526. The reaction between 2 equiv of L1 and [PdCl(eta3-C3H5)]2 affords the [PdCl(eta3-C3H5)(Ph2PCH2CH(Ph)NHPh-kappaP)] complex in which an unexpected N-H.Cl intramolecular interaction has been observed by an X-ray diffraction analysis. [PdCl(eta3-C3H5)(Ph2PCH2CH(Ph)NHPh-kappaP)] crystallizes at 298 K in the monoclinic space group Cc with cell parameters a = 10.912(1) A, b = 17.194(2) A, c = 14.169(2) A, beta = 100.651(9) degrees, Z = 4, D(calcd) = 1.435. Neutral and cationic alkyl or allyl palladium chloride complexes containing L1 are also reported as well as a neutral allyl palladium chloride complex containing L4. Variable-temperature 31P[1H] NMR studies on the allyl complexes show that the eta3/eta1 allyl interconversion is enhanced by a positive charge and also by a N-H.Cl intramolecular interaction.     

Enolphosphato-phosphines: a new class of P,O ligands

The new bifunctional ligands Ph(2)PCH[double bond]CPh[OP(O)(OR)(2)] (1) (1a, R = Et; 1b, R = Ph) represent the first examples of P,O derivatives resulting from the association of a phosphine moiety and an enolphosphate group. The Z stereochemistry about the double bond provides a favorable situation for these ligands to act as P,O-chelates. Neutral and cationic Pd(II) complexes have been synthesized and characterized, in which 1a or 1b acts either as a P-monodentate ligand or a P,O-chelate, via coordination of the oxygen atom of the P[double bond]O group. In the latter case, it has been observed that phosphines 1a and 1b can display a hemilabile behavior, owing to successive dissociation and recoordination of the O atom. Competition experiments revealed that phosphine 1a presents a higher chelating ability than 1b, a feature ascribed to the more electrodonating properties of the ethoxy groups in 1a compared to the phenoxy groups in 1b. P,O-Chelation affords seven-membered metallocycles, which is unusual for P,O-chelates. Complexes trans-[PdCl(2)[Ph(2)PCH[double bond]C(Ph)OP(O)(OPh)(2)](2)] (2b), [PdCl[Ph(2)PCHdouble bond]C(Ph)OP(O)(OEt)(2)](mu-Cl)](2) (3a), [complex--see text] (8a'), and [complex--see text] (10a) have been structurally characterized. Interestingly, the seven-membered rings in 8a' and 10a adopt a sofa conformation with the double bond lying almost perpendicular to the plane containing the Pd, the two P, and the two O atoms.     

Novel ruthenium(ii) complexes containing the N-phosphorylated iminophosphorane-phosphine ligand Ph(2)PCH(2)P{[double bond, length as m-dash]NP([double bond, length as m-dash]O)(OEt)(2)}Ph(2): a new coordination mode of its methanide anion

The reactivity of complex [Ru(eta(6)-p-cymene)(kappa(3)P,N,O-Ph(2)PCH(2)P{[double bond, length as m-dash]NP([double bond, length as m-dash]O)(OEt)(2)}Ph(2))][SbF(6)](2) towards a variety of mono- and bidentate neutral ligands has been studied, allowing the high-yield synthesis of the novel half-sandwich Ru(ii) derivatives [Ru(eta(6)-p-cymene)(L)(kappa(2)P,O-Ph(2)PCH(2)P{[double bond, length as m-dash]NP([double bond, length as m-dash]O)(OEt)(2)}Ph(2))][SbF(6)](2) (L = N[triple bond, length as m-dash]CMe , N[triple bond, length as m-dash]CEt , PMe(3), PMe(2)Ph , PMePh(2), PPh(3), P(OMe)(3), P(OEt)(3), P(OPh)(3), py , kappa(1)P-dppm , kappa(1)P-dppe ), as well as the octahedral species [Ru(Ninsertion markN)(2)(kappa(2)P,O-Ph(2)PCH(2)P{[double bond, length as m-dash]NP([double bond, length as m-dash]O)(OEt)(2)}Ph(2))][SbF(6)](2) (Ninsertion markN = bipy , phen ). Deprotonation of complexes ,, upon treatment with an excess of NaOH in CH(2)Cl(2), generates the monocationic derivatives [Ru(Ninsertion markN)(2)(kappa(2)P,N-Ph(2)PC(H)[double bond, length as m-dash]P{NP([double bond, length as m-dash]O)(OEt)(2)}Ph(2))][Cl] (Ninsertion markN = bipy , phen ) in which the methanide anion adopts an unprecedented kappa(2)P,N bidentate coordination mode. The structures of compounds , and have been determined by single-crystal X-ray diffraction methods.     

The synthesis, structure and dynamic behaviour of disubstituted alkenylphosphine derivatives of [Rh6(CO)16

A series of [Rh(6)(CO)(16)] substituted derivatives containing Ph(2)P(alkenyl) ligands has been synthesized starting from the [Rh(6)(CO)(16-x)(NCMe)(x)](x= 1, 2) clusters and Ph(2)P((CH(2))(n)CH=CH(2))(n= 2, 3) phosphines. It was shown that the terminal alkenyl substituents in these phosphines easily undergo isomerization in the coordination sphere of the hexarhodium complexes to give the allyl -CH(2)CH=C(H)R (R = Me and Et) fragments coordinated through the double bond of the rearranged organic moieties. The solid-state structure of two clusters, [Rh(6)(CO)(14)(mu2,kappa3-Ph(2)PCH(2)CH=C(H)CH(3))](4) and [Rh(6)(CO)(14)(mu2,kappa3-Ph(2)PCH(2)CH=C(H)CH(2)CH(3))](8), was established by X-ray crystallography. Solution structures of the products obtained were also characterized by IR and NMR ((1)H, (31)P, (1)H-(1)H COSY and (1)H-(1)H NOE) spectroscopy. It was shown that 4 and 8 exist in solution as mixtures of three isomers (A, B and C), which differ in the conformation of the coordinated allyl fragment. A similar (two species, A and B) equilibrium was found to occur in the solution of the [Rh(6)(CO)(14)(mu2,kappa3-Ph(2)PCH(2)CH=CH(2))](2) cluster. The dynamic behaviour of 2, 4 and 8[Rh(6)(CO)(14)(mu2,kappa3-Ph(2)PCH=CH(2))] has been studied using VT (31)P and (1)H-(1)H NOESY NMR spectroscopy, rate constants and activation parameters of the (A<-->B) isomerization processes were determined. It was shown that the most probable mechanism of this isomerization involves a dissociative [Rh6(CO)(14)(kappa1-Ph(2)P(alkenyl))] intermediate and re-coordination of the double bond to the same metal atom where the process started from. The conversion of the A and B species in and into the third isomer very likely occurs through the transfer of an allyl hydrogen atom onto the rhodium skeleton to give eventually cis conformation of the coordinated allyl fragment.     

Diphosphines possessing electronically different donor groups: synthesis and coordination chemistry of the unsymmetrical Di(N-pyrrolyl)phosphino-functionalized dppm analogue Ph2PCH2P(NC4H4)2

The unsymmetrical diphosphinomethane ligand Ph(2)PCH(2)P(NC(4)H(4))(2) L has been prepared from the reaction of Ph(2)PCH(2)Li with PCl(NC(4)H(4))(2). The diphenylphosphino group can be selectively oxidized with sulfur to give Ph(2)P(S)CH(2)P(NC(4)H(4))(2) 1. The reaction of L with [MCl(2)(cod)] (M = Pd, Pt) gives the chelate complexes [MCl(2)(L-kappa(2)P,P')] (2, M = Pd; 3, M = Pt) in which the M-P bond to the di(N-pyrrolyl)phosphino group is shorter than that to the corresponding diphenylphosphino group. However, the shorter Pd-P bond is cleaved on reaction of 2 with an additional 1 equiv of L to give [PdCl(2)(L-kappa(1)P)(2)] 4. Complex 4 reacts with [PdCl(2)(cod)] to regenerate 2, and with [Pd(2)(dba)(3)].CHCl(3) to give the palladium(I) dimer [Pd(2)Cl(2)(mu-L)(2)] 5, which exists in solution and the solid state as a 1:1 mixture of head-to-head (HH) and head-to-tail (HT) isomers. The palladium(II) dimer [Pd(2)Cl(2)(CH(3))(2)(mu-L)(2)] 6, formed by the reaction of [PdCl(CH(3))(cod)] with L, also exists in solution as a mixture of HH and HT isomers, although in this case the HT isomer prevails at low temperature and crystallizes preferentially. Complex 6 reacts with TlPF(6) to give the A-frame complex [Pd(2)(CH(3))(2)(mu-Cl)(mu-L)(2)]PF(6) 7. The reaction of L with [RuCp*(mu(3)-Cl)](4) leads to the dimer [Ru(2)Cp*(2)(mu-Cl)(2)(mu-L)] 8, for which the enthalpy of reaction has been measured. The reaction of L with [Rh(mu-Cl)(cod)](2) gives a mixture of compounds from which the dimer [Rh(2)(mu-Cl)(cod)(2)(mu-L)]PF(6) 9 can be isolated. The crystal structures of 2.CHCl(3), 3.CH(2)Cl(2), 4, 5.(1)/(4)CH(2)Cl(2), 6, 7.2CH(2)Cl(2), 8, and 9.CH(2)Cl(2) are reported.     

A series of dinuclear homo- and heterometallic complexes with two or three bridging sulfido ligands derived from the tungsten tris(sulfido) complex [Et(4)N][(Me(2)Tp)WS(3)] (Me(2)Tp = hydridotris(3,5-dimethylpyrazol-1-yl)borate)

The generation of heterobimetallic complexes with two or three bridging sulfido ligands from mononuclear tris(sulfido) complex of tungsten [Et(4)N][(Me(2)Tp)WS(3)] (1; Me(2)Tp = hydridotris(3,5-dimethylpyrazol-1-yl)borate) and organometallic precursors is reported. Treatment of 1 with stoichiometric amounts of metal complexes such as [M(PPh(3))(4)] (M = Pt, Pd), [(PtMe(3))(4)(micro(3)-I)(4)], [M(cod)(PPh(3))(2)][PF(6)] (M = Ir, Rh; cod = 1,5-cyclooctadiene), [Rh(cod)(dppe)][PF(6)] (dppe = Ph(2)PCH(2)CH(2)PPh(2)), [CpIr(MeCN)(3)][PF(6)](2) (Cp = eta(5)-C(5)Me(5)), [CpRu(MeCN)(3)][PF(6)], and [M(CO)(3)(MeCN)(3)] (M = Mo, W) in MeCN or MeCN-THF at room temperature afforded either the doubly bridged complexes [Et(4)N][(Me(2)Tp)W(=S)(micro-S)(2)M(PPh(3))] (M = Pt (3), Pd (4)), [(Me(2)Tp)W(=S)(micro-S)(2)M(cod)] (M = Ir, Rh (7)), [(Me(2)Tp)W(=S)(micro-S)(2)Rh(dppe)], [(Me(2)Tp)W(=S)(micro-S)(2)RuCp] (10), and [Et(4)N][(Me(2)Tp)W(=S)(micro-S)(2)W(CO)(3)] (12) or the triply bridged complexes including [(Me(2)Tp)W(micro-S)(3)PtMe(3)] (5), [(Me(2)Tp)W(micro-S)(3)IrCp][PF(6)] (9), and [Et(4)N][(Me(2)Tp)W(micro-S)(3)Mo(CO)(3)] (11), depending on the nature of the incorporated metal fragment. The X-ray analyses have been undertaken to clarify the detailed structures of 3-5, 7, and 9-12.     

Concise syntheses of tridentate PNE ligands and their coordination chemistry with palladium(II) : a solution- and solid-state study

A straightforward methodology for the high-yielding synthesis of the di-functionalised phosphines {Ph2P(CH2)2NC4H8E, E = NMe (1), O (2), S (3)}via base-catalysed Michael addition is described. Reaction of the functionalised tertiary phosphines 1-3 with PdCl2(MeCN)2 affords complexes in which the ligands are bound in a tridentate fashion, namely [PdCl(kappa3-PNE)]Cl (6a, 8) as the predominant products. A kappa2-PN coordination mode was also identified crystallographically for ligand following its reaction with PdCl2(MeCN)2, which afforded [PdCl2(-kappa2-PN)] (6b) in ca. 5% yield. Conductivity studies of solutions of 6a are consistent with an ionic formulation, however the poor solubility of and precluded their study in a similar fashion. Analysis of bulk samples of [PdCl2(1)] (6) and [PdCl2(3)] (8) by 15N and 31P NMR spectroscopy in the solid state as consistent with exclusive tridentate binding of the PNE ligands. An X-ray crystallographic study has probed the coordination of in the unusual salt [PdCl(-kappa3-PNN)]2[Mg(SO4)2(OH2)4] (10) prepared by treating a methanolic solution of with excess MgSO4. No data could be obtained to support the transformation of 6a into 6b on addition of excess chloride. In contrast, 6a reacts regioselectively with the water-soluble phosphine Cy2PCH2CH2NMe3Cl to afford the cis-diphosphine complex cis-[PdCl(Cy2PCH2CH2NMe3Cl)(1-kappa2-PN)]Cl2 (9). Reaction of 1 with PdCl(Me)(COD) results in the formation of the kappa2-PN dichloride complex [PdCl(Me)(1-kappa(2)-PN)] (11). Attempts to prepare [Pd(Me)(MeCN)(-kappa2-PN)][PF6] (12) through reaction of 11 with NaPF6 in MeCN led to decomposition. Treatment of PdMe2(TMEDA) with 1 at low temperature initially affords [PdMe2(1-kappa2-NN)], which isomerises to afford [PdMe(2)(1-kappa(2)-PN)] (13); at temperatures greater than 10 degrees C complex 13 decomposes rapidly.     

A new type of tweezer complex involving a rhenium-rhenium multiple bond that enforces an unusual structure in a dipalladium(II) unit

The substitution of the mu-acetato ligands in cis-Re(2)(mu-O(2)CCH(3))(2)Cl(2)(mu-dppm)(2) (1, dppm = Ph(2)PCH(2)PPh(2)) and trans-Re(2)(mu-O(2)CCH(3))(2)Cl(2)(mu-dppE)(2) (2, dppE = Ph(2)PC(=CH(2))PPh(2)) by [4-Ph(2)PC(6)H(4)CO(2)](-) occurs with retention of stereochemistry to give cis-Re(2)(mu-O(2)CC(6)H(4)-4-PPh(2))(2)Cl(2)(mu-dppm)(2) (3) and trans-Re(2)(mu-O(2)CC(6)H(4)-4-PPh(2))(2)Cl(2)(mu-dppE)(2) (6), respectively. The uncoordinated phosphine groups in complexes 3 and 6 have been used to form mixed-metal assemblies with Au(I) and Pd(II), including the Re(2)Pd(2) complex cis-Re(2)(mu-O(2)CC(6)H(4)-4-PPh(2))(2)Cl(2)(mu-dppm)(2)(Pd(2)Cl(4)) (5), in which the planar [(P)ClPd(mu-Cl)(2)PdCl(P)] unit has the unusual cis structure. The crystal structures of 3 and 5 have been determined.     

Unexpected metal-induced isomerisms and phosphoryl migrations in Pt(II) and Pd(II) complexes of the functional phosphine 2-(bis(diphenylphosphino)methyl)-oxazoline

The reaction of the functional diphosphine 1 [1 = 2-(bis(diphenylphosphino)methyl-oxazoline] with [PtCl(2)(NCPh)(2)] or [PdCl(2)(NCPh)(2)], in the presence of excess NEt(3), affords [Pt{(Ph(2)P)(2)C···C(···NCH(2)CH(2)O)}(2)] ([Pt(1(-H)-P,P)(2)], 3a) and [Pd{(Ph(2)P)(2)C···C(···NCH(2)CH(2)O)}(2)] ([Pd(1(-H)-P,P)(2)], 3b), respectively, in which 1(-H) is (oxazoline-2-yl)bis(diphenylphosphino)methanide. The reaction of 3b with 2 equiv of [AuCl(tht)] (tht = tetrahydrothiophene) afforded [Pd(1(-H)-P,N)(2)(AuCl)(2)] (4), as a result of the opening of the four-membered metal chelate since ligand 1(-H), which was P,P-chelating in 3b, behaves as a P,N-chelate toward the Pd(II) center in 4 and coordinates to Au(I) through the other P donor. In the absence of a base, the reaction of ligand 1 with [PtCl(2)(NCPh)(2)] in MeCN or CH(2)Cl(2) afforded the isomers [Pt{(Ph(2)P)(2)C═C(OCH(2)CH(2)NH)}(2)]Cl(2) ([Pt(1'-P,P)(2)]Cl(2) (5), 1' = 2-(bis(diphenylphosphino)methylene)-oxazolidine) and [Pt{(Ph(2)P)(2)C═C(OCH(2)CH(2)NH)}{Ph(2)PCH═C(OCH(2)CH(2)N(PPh(2))}]Cl(2) ([Pt(1'-P,P)(2'-P,P)]Cl(2) (6), 2' = (E)-3-(diphenylphosphino)-2-((diphenylphosphino)methylene)oxazolidine]. The P,P-chelating ligands in 5 result from a tautomeric shift of the C-H proton of 1 to the nitrogen atom, whereas the formation of one of the P,P-chelates in 6 involves a carbon to nitrogen phosphoryl migration. The reaction of 5 and 6 with a base occurred by deprotonation at the nitrogen to afford 3a and [Pt{(Ph(2)P)(2)C···C(···NCH(2)CH(2)O)}{Ph(2)PCH═COCH(2)CH(2)N(PPh(2))}]Cl ([Pt(1(-H)-P,P)(2'-P,P)]Cl (7)], respectively. In CH(2)Cl(2), an isomer of 3a, [Pt{Ph(2)P)(2)C···C(···NCH(2)CH(2)O)}{Ph(2)PC(PPh(2))═COCH(2)CH(2)N}] ([Pt(1(-H)-P,P)(1(-H)-P,N)] (8)), was obtained as a side product which contains ligand 1(-H) in two different coordination modes. Complexes 3b·4CH(2)Cl(2), 4·CHCl(3), 6·2.5CH(2)Cl(2), and 8·CH(2)Cl(2) have been structurally characterized by X-ray diffraction.     

Kinetic and mechanistic study of the Pt(II) versus Pt(IV) effect in the platinum-mediated nitrile-hydroxylamine coupling

The metal-mediated coupling between coordinated EtCN in the platinum(II) and platinum(IV) complexes cis- and trans-[PtCl(2)(EtCN)(2)], trans-[PtCl(4)(EtCN)(2)], a mixture of cis/trans-[PtCl(4)(EtCN)(2)] or [Ph(3)PCH(2)Ph][PtCl(n)(EtCN)] (n = 3, 5), and dialkyl- and dibenzylhydroxylamines R(2)NOH (R = Me, Et, CH(2)Ph, CH(2)C(6)H(4)Cl-p) proceeds smoothly in CH(2)Cl(2) at 20-25 degrees C and the subsequent workup allowed the isolation of new imino species [PtCl(n){NH=C(Et)ONR(2)}(2)] (n = 2, R = Me, cis-1 and trans-1; Et, cis-2 and trans-2; CH(2)Ph, cis-3 and trans-3; CH(2)C(6)H(4)Cl-p, cis-4 and trans-4; n = 4, R = Me, trans-9; Et, trans-10; CH(2)Ph, trans-11; CH(2)C(6)H(4)Cl-p, trans-12) or [Ph(3)PCH(2)Ph][PtCl(n){NH=C(Et)ONR(2)}] (n = 3, R = Me, 5; Et, 6; CH(2)Ph, 7; CH(2)C(6)H(4)Cl-p, 8; n = 5, R = Me, 13; Et, 14; CH(2)Ph, 15; CH(2)C(6)H(4)Cl-p, 16) in excellent to good (95-80%) isolated yields. The reduction of the Pt(IV) complexes 9-16 with the ylide Ph(3)P=CHCO(2)Me allows the synthesis of Pt(II) species 1-8. The compounds 1-16 were characterized by elemental analyses (C, H, N), FAB-MS, IR, (1)H, (13)C{(1)H}, and (31)P{(1)H} NMR (the latter for the anionic type complexes 5-8 and 13-16) and by X-ray crystallography for the Pt(II) (cis-1, cis-2, and trans-4) and Pt(IV) (15) species. Kinetic studies of addition of R(2)NOH (R = CH(2)C(6)H(4)Cl-p) to complexes [Ph(3)PCH(2)Ph][Pt(II)Cl(3)(EtCN)] and [Ph(3)PCH(2)Ph][Pt(IV)Cl(5)(EtCN)] by the (1)H NMR technique revealed that both reactions are first order in (p-ClC(6)H(4)CH(2))(2)NOH and Pt(II) or Pt(IV) complex, the second-order rate constant k(2) being three orders of magnitude larger for the Pt(IV) complex. The reactions are intermolecular in nature as proved by the independence of k(2) on the concentrations of added EtC triple bond N and Cl(-). These data and the calculated values of Delta H++ and Delta S++ are consistent with the mechanism involving the rate-limiting nucleophilic attack of the oxygen of (p-ClC(6)H(4)CH(2))(2)NOH at the sp-carbon of the C triple bond N bond followed by a fast proton migration.     

Spontaneous formation of heteroligated PtII complexes with chelating hemilabile ligands

The spontaneous formation of the heteroligated complex [PtCl(kappa(2)-Ph(2)PCH(2)CH(2)SMe)(Ph(2)PCH(2)CH(2)SPh)]Cl (8 a) by a novel ligand rearrangement process has been observed. By using the weak-link approach, the relative arrangement of the alkyl and aryl groups can be controlled by abstraction of chloride from 8 a to form the closed complex [Pt(kappa(2)-Ph(2)PCH(2)CH(2)SMe)(kappa(2)-Ph(2)PCH(2)CH(2)SPh)][BF(4)](2) (5) and reopening using halide ions to form semi-open complexes [PtX(kappa(2)-Ph(2)PCH(2)CH(2)SMe)(Ph(2)PCH(2)CH(2)SPh)]BF(4) (8 b; X=Cl(-)) and (8 c; X=I(-)). Analogous procedures using Ph(2)PCH(2)CH(2)SMe and 1,4-(Ph(2)PCH(2)CH(2)S)(2)C(6)H(4) lead to heteroligated bimetallic complexes 7 and 9, illustrating that this ligand rearrangement process can be used as a tool for the assembly of complementary metallosupramolecular structures.     

Molecular triangle of palladium(II) and its anion binding properties

The ligand 4(3H)-pyrimidone (Hpm) forms the complexes trans-[PdCl(2)(Hpm)(2)] and [Pd(PP)(Hpm)(2)](CF(3)SO(3))(2) (PP = Ph(2)PCH(2)PPh(2) or Ph(2)P(CH(2))(3)PPh(2)), with the neutral ligand (Hpm), and a bowl-like molecular triangle, [(Pd(bu(2)bipy)(mu-pm))(3)](3+) (bu(2)bipy = 4,4'-di-tert-butyl-2,2'-bipyridine), with the deprotonated ligand (pm). This triangular complex acts as a host for binding of several anionic guests.     

Formation of P-C bonds under unexpectedly mild conditions. Phosphoryl migration and metal coordination of diphenylphosphinomethyl-oxazolines and -thiazolines

The heterocycles 2-methyl-2-oxazoline (mox) and 2-methyl-2-thiazoline (mth) react with Ph2PCl under mild conditions, in the presence of NEt3 which promotes their phosphorylation by stabilization of their enamino tautomers mox(e) and mth(e), respectively, and which also behaves as HCl scavenger. Depending on the reaction conditions, three different phosphine ligands were obtained in good yields from mox: the monophosphine Ph2PCH2C=NCH2CH2O (1ox) and the isomeric diphosphines Ph2PCH=COCH2CH2NPPh2 (2ox) (X-ray structure) and (Ph2P)2CHC=NCH2CH2O (3ox). The formation of these ligands involves phosphoryl migration reactions, which were studied by NMR spectroscopy. The synthesis and the X-ray structures of the corresponding diphenylphosphinothiazolines Ph2PCH2C=NCH2CH2S (1th) and Ph2CH=CSCH2CH2NPPh2 (2th) are also reported but the thiazoline analog of the geminal diphosphine 3ox was not observed. The metal complexes [Pt(3ox-H)2] x 4 CH2Cl2 (4 x 4 CH2Cl2), [Pt(Me)I(1ox)] (5), [Pt(Me)2(1ox)] (7), [Pd(dmba-C,N)(1th)]OTf x 0.25 Et2O (8 x 0.25 Et2O), [Pd(dmba-C,N)(1th-H)] (9), and [9 x {Pd(dmba-C,N)Cl}] x 2.5 C6H6 (10 x 2.5 C6H6) have been prepared and structurally characterized by X-ray diffraction.     

On the reaction of Ph2PNHPPh2 with RNCS (R=Et, Ph, p-NO2C6H4): preparation of the zwitterionic ligand EtNHC(S)Ph2P==NPPh2C(S)NEt (HSNS) and the zwitterionic metalate [(SNS)Rh(CO)

The reaction of Ph(2)PNHPPh(2) (PNP) with RNCS (Et, Ph, p-NO(2)(C(6)H(4))) gives addition products resulting from the attack of the P atoms of PNP on the electrophilic carbon atom of the isothiocyanate. When PNP is reacted with EtNCS in a 1:2 molar ratio, the zwitterionic molecule EtNHC(S)PPh(2)==NP(+)Ph(2)C(S)N(-)Et (HSNS) is obtained in high yield. HSNS can be protonated (H(2)SNS(+)) or deprotonated (SNS(-)), behaving in the latter form as an S,N,S-donor pincer ligand. The reaction of HSNS with [(acac)Rh(CO)(2)] (acac=acetylacetonate) affords the zwitterionic metalate [(SNS)Rh(CO)]. Other products can be obtained depending on the R group, the PNP/RNCS ratio (1:1 or 1:2), and the reaction temperature. The proposed product of the primary attack of PNP on RNCS, Ph(2)PN==PPh(2)C(S)NHR (A), cannot be isolated. Reaction of A with another RNCS molecule leads to 1:2 addition compounds of the general formula RNHC(S)PPh(2)==NP(+)Ph(2)C(S)N(-)R (1), which can rearrange into the non-zwitterionic product RNHC(S)PPh(2)==NP(S)Ph(2) (2) by eliminating a molecule of RNC. Two molecules of A can react together, yielding 1:1 PNP/RNCS zwitterionic products of the formula RNHCH[PPh(2)==NP(S)Ph(2)]PPh(2)==NP(+)Ph(2)C(S)N(-)R (3). Compound 3 can then rearrange into RNHCH[PPh(2)==NP(S)Ph(2)](2) (4) by losing a RNC molecule. When R=Et (a), compounds 1 a, 2 a (HSNS), and 4 a have been isolated and characterized. When R=Ph (b), compounds 2 b and 4 b can be prepared in high yield. When R=p-NO(2)C(6)H(4) (c), only compound 3 c is observed and isolated in high yield. The crystal structures of HSNS, [(SNS)Rh(CO)], and of the most representative products have been determined by X-ray diffraction methods.     

Self-assembly of polymer and sheet structures in palladium(II) complexes containing carboxylic acid substituents

A series of complexes trans-[PdCl(2)L(2)] has been prepared by the reaction of [PdCl(2)(PhCN)(2)] and/or Na(2)[PdCl(4)] with L = pyridine or quinoline ligands having one or two carboxylic acid groups. These complexes can form 1-D polymers through O-H.O hydrogen bonding between the carboxylic acid groups, as demonstrated by structure determinations of [PdCl(2)(NC(5)H(4)-4-COOH)(2)], [PdCl(2)(NC(5)H(4)-3-COOH)(2)], and [PdCl(2)(2-Ph-NC(9)H(5)-4-COOH)(2)]. In some cases, solvation breaks down the O-H.O hydrogen-bonded structures, as in the structures of [PdCl(2)(NC(5)H(4)-3-COOH)(2)].2DMSO and [PdCl(2)(2-Ph-NC(9)H(5)-4-COOH)(2)].4DMF, while pyridine-2-carboxylic acid underwent deprotonation to give the chelate complex [Pd(NC(5)H(4)-2-C(O)O)(2)]. The complexes trans-[PdCl(2)L(2)], L = pyridine-3,5-dicarboxylic acid or 2,6-dimethyl pyridine-3,5-dicarboxylic acid, self-assembled to give 2-D sheet structures, with hydrogen bonding between the carboxylic acid groups mediated by solvate methanol or water molecules. In the cationic complexes [PdL'(2)L(2)](2+) (L'(2) = Ph(2)PCH(2)PPh(2), Ph(2)P(CH(2))(3)PPh(2); L = pyridine carboxylic acid; anions X(-) = CF(3)SO(3)(-)), hydrogen bonding between the carboxylic acid groups and anions or solvate acetone molecules occurred, and only in one case was a polymeric complex formed by self-assembly.     

Lithium-palladium complex supported by phosphonatophosphine and chloride ligands

The reaction of the phosphonatophosphine ligand Ph2PCH(SiMe3)P(O)(OEt)2 with [PdCl2(COD)] in the presence of LiCl afforded the neutral, mixed-metal complex [LiPd2CI5{mu-Ph2PCH2P(O)(OEt)2}2] in which the Li(+) cation is tetrahedrally coordinated by the PO bonds and two Pd-bound Cl atoms.     

Unusual reactivity of a sterically hindered diphosphazane ligand, EtN{P(OR)(2)}(2), (R = C(6)H(3)(Pr(I))(2)-2,6) towards (eta(3)-allyl)palladium precursors

The reactivity of (eta(3)-allyl)palladium chloro dimers [(1-R-eta(3)-C(3)H(4))PdCl](2) (R = H or Me) towards a sterically hindered diphosphazane ligand [EtN{P(OR)(2)}(2)] (R = C(6)H(3)(Pr(i))(2)-2,6), has been investigated under different reaction conditions. When the reaction is carried out using NH(4)PF(6) as the halide scavenger, the cationic complex [(1-R-eta(3)-C(3)H(4))Pd{EtN(P(OR)(2))(2)}]PF(6) (R = H or Me) is formed as the sole product. In the absence of NH(4)PF(6), the initially formed cationic complex, [(eta(3)-C(3)H(5))Pd{EtN(P(OR)(2))(2)}]Cl, is transformed into a mixture of chloro bridged complexes over a period of 4 days. The dinuclear complexes, [(eta(3)-C(3)H(5))Pd(2)(mu-Cl)(2){P(O)(OR)(2)}{P(OR)(2)(NHEt)}] and [Pd(mu-Cl){P(O)(OR)(2)}{P(OR)(2)(NHEt)}](2) are formed by P-N bond hydrolysis, whereas the octa-palladium complex [(eta(3)-C(3)H(5))(2-Cl-eta(3)-C(3)H(4))Pd(4)(mu-Cl)(4)(mu-EtN{P(OR)(2)}(2))](2), is formed as a result of nucleophilic substitution by a chloride ligand at the central carbon of an allyl fragment. The reaction of [EtN{P(OR)(2)}(2)] with [(eta(3)-C(3)H(5))PdCl](2) in the presence of K(2)CO(3) yields a stable dinuclear (eta(3)-allyl)palladium(I) diphosphazane complex, [(eta(3)-C(3)H(5))[mu-EtN{P(OR)(2)}(2)Pd(2)Cl] which contains a coordinatively unsaturated T-shaped palladium center. This complex exhibits high catalytic activity and high TON's in the catalytic hydrophenylation of norbornene.     

Versatility of dithiophosphates in the syntheses of copper(I) complexes with bis(diphenylphosphino)alkanes: abstraction of chloride from dichloromethane

Reactions of [Cu(CH(3)CN)(4)]X (X = PF(6), BF(4)) with bis(diphenylphosphino)methane (dppm = Ph(2)PCH(2)PPh(2)) and ammonium dialkyldithiophosphates, (NH(4))[S(2)P(OR)(2)] (R = Et, (i)Pr), yield a series of novel Cu(I) polynuclear complexes, trinuclear [Cu(3)(mu-dppm)(3)(mu(3)-Cl){S(2)P(OEt)(2)}] (PF(6)) 1 and [Cu(3)(mu-dppm)(2){S(2)P(OR)(2)}(2)](PF(6)) (R = Et, 2; (i)Pr, 3), tetranuclear [Cu(4)(mu-dppm)(2) {S(2)P(OEt)(2)}(4)] 4, and hexanuclear [Cu(6)(mu-dppm)(2)(mu(4)-Cl){S(2)P(O(i)()Pr)(2)}(4)](BF(4)) 5. Similarly, the reaction of [Cu(2)(mu-L-L)(2)(CH(3)CN)(2)](PF(6))(2) (L-L, dppm, dppe = Ph(2)PCH(2)CH(2)PPh(2)) with (NH(4))[S(2)P(OR)(2)] yields dinuclear [Cu(2)(mu-dppm)(2){S(2)P(OR)(2)}(2)] 6 (R= (i)Pr, 6A; Et, 6B), trinuclear [Cu(3)(mu-dppe)(3)(mu-Cl)(2){S(2)P(O(i)Pr)(2)}] 9, and polymeric [Cu(mu(2)-dppe){S(2)P(OR)(2)}](n) (R = Et, 7; (i)Pr, 8) complexes. The formation of 1 and 5 involved the abstraction of chloride from dichloromethane when the Cu/S(2)P(OR)(2) ratio exceeded 1, but when ratio was 1:1, no Cl abstraction occurred, as in compound 4. Compound 9, however, was obtained as a 12% byproduct in the synthesis of 8 using a 1:1:1 ratio of Cu/dppe/S(2)P(O(i)Pr)(2). The chloride binds to Cu atoms in a mu(3)-Cl mode by capping one face of the Cu(3) triangle of cluster 1. A mu(4)-Cl caps a single tetragonal face of the trigonal prism of cluster 5, and in the cluster 9, two chlorides bond in mu(2)-Cl modes. Both clusters 2 and 3 exhibit the mu(3)-S mode of bonding for dtp ligands. Only cluster 5 exhibited close Cu...Cu contacts (2.997-3.0238 A). All of compounds were characterized by single-crystal X-ray diffraction and pertinent crystallographic data for 1, 5, and 9 are are follows: (1) C(79)H(76)ClCu(3)F(6)O(2)P(8)S(2), triclinic, P, a = 11.213(1) A, b = 14.142(1) A, c = 25.910(2) A, alpha = 95.328(2) degrees , beta = 99.594(2) degrees , gamma = 102.581(2) degrees , V = 3918.2(6) A(3), Z = 2; (5) C(74)H(100)BClCu(6)F(4)O(8)P(8)S(8), monoclinic, P2(1)/n, a = 25.198(4) A, b = 15.990(3) A, c = 25.421(4) A, beta = 106.027(3) degrees , V = 9845(3)A(3), Z = 4; (9) C(84)H(86)Cl(2)Cu(3)O(2)P(7)S(2), monoclinic, C2/c, with a = 24.965(3) A, b = 17.058(2) A, c = 20.253(2) A, beta = 95.351(4) degrees , V = 8587.4(17)A(3), Z = 4.