Browsing by Author "Valderrama, M"

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    Bis(diphenylphosphino)amine and their dichalcogenide derivatives as ligands in rhodium(III), iridium(III), and ruthenium(II) complexes.: Crystal structures of [(η5-C5Me5)MCl{η2-(SePPh2)2N}] (M = Rh, Ir)
    (2000) Valderrama, M; Contreras, R; Lamata, MP; Viguri, F; Carmona, D; Lahoz, FJ; Elipe, S; Oro, LA
    Reaction of the dimers [{(eta(5)-C5Me5)MCl}(2)(mu-Cl)(2)] (M = Rh, Ir) or [{(eta(6)-arene)RuCl}(2)(mu-Cl)(2)] (arene = p-(MeC6H4Pr)-Pr-i, C6Me6) with NH(PPh2)(2) in the presence of AgA (A = BF4, PF6) leads to the mononuclear cationic complexes [(eta(5)-C5Me5)MCl{eta(2)- (PPh2)(2)NH}]A (M = Rh (1), Ir (2)) or [(eta(6)-arene)RuCl{eta(2)-(PPh2)(2)NH}]A (arene = p-(MeC6H4Pr)-Pr-i (3), C6Me6 (4)). Similar reactions using the chalcogenide derivatives NH(EPPh2)(2) (E = S, Se) yield the neutral complexes [(eta(5)-C5Me5)RhCl{eta(2)-(EPPh2)(2)N}] (E = S (5), Se (6)), [(eta(5)-C5Me5)IrCl{eta(2)-(EPPh2)(2)N}] (E = S (7), Se (8)), [(eta(6)-arene)RuCl{eta(2)-(SPPh2)(2)N}] (arene = C6H6 (9), p-(MeC6H4Pr)-Pr-i (10)) and [(eta(6)-arene)RuCl{eta(2)-(SePPh2)(2)N)}] (arene = C6Me6 (11), p-(MeC6H4Pr)-Pr-i (12)). Chloride abstraction from complexes 5-8 with AgPF6 in the presence of PPh3 gives the cationic complexes [(eta(5)-C5Me5)Rh{eta(2)-(EPPh2)(2)N}(PPh3)]PF6 (E = S (13), Se (14)) and [(eta(5)-C5Me5)Ir{eta(2)-(EPPh2)(2)N}(PPh3)]PF6 (E = S (15), Se (16)). Complexes 13-16 can also be synthesised from the starting dinuclear complexes, AgPF6, NH(EPPh2)(2) and PPh3. Using this alternative synthetic route the related ruthenium complexes [(eta(6)-C6Me6)Ru{eta(2)-(EPPh2)(2)N}(C5H5N)] BF4 (E = S (17), Se (18)) can be prepared. All described compounds have been characterised by microanalysis and NMR (H-1, P-31) and IR spectroscopy. The crystal structures of the neutral complexes [(eta(5)-C5Me5)MCl{eta(2)-(SePPh2)(2)N}] (M = Rh (6), Ir (8)) have been determined by X-ray diffraction methods. Both complexes exhibit analogous pseudo-octahedral molecular structures with a C5Me5 group occupying three coordination positions and a bidentate chelate Se,Se'-bonded ligand and a chloride atom completing the coordination sphere. (C) 2000 Elsevier Science S.A. All rights reserved.
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    Bis(diphenylphosphino)methylamine as chelate ligand in pentamethylcyclopentadienylrhodium(III) and iridium(III) complexes.: Crystal structure of [(η5-C5Me5)RhCl(η2-P,P′-(PPh2)2NMe}]BF4
    (2003) Valderrama, M; Contreras, R; Boys, D
    Reactions of the dimers [{(eta(5) -C5Me5)MCl(mu-Cl)}(2)] (M = Rh, Ir) with the ligand NMe(PPh2)(2) in 1:2 molar ratio afford the mononuclear cationic complexes [(eta(5)-C5Me5)MCl{eta(2)-P,P'-(Ph2P)(2)NMe}]Cl (M = Rh 1, Ir 2). Similar iodide complexes, [(eta(5)- C5Me5)MCl{eta(2)-P,P'-(Ph2P)(2)NMe}]I (M = Rh 3, Ir 4), can be prepared by N-functionalization of co-ordinated dppa ligand in complexes [(eta(5) -C5Me5)MCl{eta(2)-P,P'-(Ph2P)(2)NH}]BF4. The tetrafluoroborate derivatives, [(eta(5)-C5Me5)MCl{eta(2)-P,P'- (Ph2P)(2)NMe}]BF4 (M = Rh 5, Ir 6) are prepared by reaction of complexes 1-4 with AgBF4 in acetone. All the compounds described are characterised by microanalysis, IR and NMR (H-1, P-31{H-1}) spectroscopy. The crystal structure of complex 5 is determined by X-ray diffraction methods. The complex exhibits a pseudo-octahedral molecular structure with a C5Me5 group occupying three co-ordination positions and a bidentate chelate P,P'-bonded ligand and a chloride atom completing the coordination sphere. (C) 2002 Elsevier Science B.V. All rights reserved.
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    C-Pt(IV) activation in new trimethylplatinum(IV) complexes: nucleophilic attack at metal-carbon bond
    (ELSEVIER SCIENCE SA, 2003) Romero, P; Valderrama, M; Contreras, R; Boys, D
    Reaction of the tetranuclear complex [Me3PtI](4) with the ligand o-Ph2P(E)C6H4SMe (E = S, Se) in a 1:4 molar ratio yields the mononuclear neutral complexes [Me3PtI(eta(2)-MeSC6H4P(E)Ph-2-S,S)] (E = S(1), Se(2)). Iodide abstraction from these compounds with AgPF6 in the presence of a ligand L (PPh3, py) leads to cationic complexes of the type [Me3Pt(eta(2)-MeSC6H4P(E)Ph-2-E,S)L]PF6 [E = S, L = PPh3 (3), Py (4); E = Se, L = Py (5)]. However, using complex 2 and the ligand PPh3 under identical conditions induces a reductive elimination reaction affording the Pt(II) complex [MePt(eta(2)-MeSC6H4PPh2-P,S)(PPh3)]PF6 (6). Reactions of complexes 3 and 4 with NaI reveal a nucleophilic attack of the iodide to one of the methyl groups bonded to the platinum center generating a series of subsequent side reactions. Complex [Me3Pt{eta(2)-MeSC6H4P(S)Ph-2-S,S}(py)]PF6.CH2Cl2 (4) was additionally characterised by X-ray diffraction. The platinum atom exhibits a distorted octahedral coordination, bonded to three methyl carbon atoms in a facial arrangement; a bidentate chelate S,S'-bonded ligand and a nitrogen atom of the pyridine ligand complete the metal coordination sphere. (C) 2003 Elsevier Science B.V. All rights reserved.
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    Chelating properties of the anionic iridium(III) complex [(eta(5)-C(5)Me(5))IrCl{PO(OMe)(2)}(2)](-). Synthesis of bi- and trinuclear derivatives
    (1996) Valderrama, M; Campos, P
    The synthesis and properties of new neutral complexes of the type [(eta(5)S-C(5)Me(5))IrX{PO(OMe)(2)} {P(OH)(OMe)(2)}] (X=Cl, I) and their thallium derivatives. [(eta(5)-C(5)Me(5))IrX{PO(OMe)(2)}Tl-2] are described. The potentially bidentate or terdentate ligand being the anionic complex [(eta(5)-C(5)Me(5)) IrCl{PO(OMe)(2)}(2)](-) has been studied. It reacts with metal ions and with some organometallic fragments to yield trinuclear or binuclear complexes Spectroscopy data for the isolated complexes are discussed.
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    Chiral sulfur diphosphazanes derived from S-(Ph2P)2N(CHMePh) and its rhodium(I), (III) and iridium(III) complexes. Crystal structures of Ph2P(S)N(CHMePh)PPh2, {Ph2P(S)}2N(CHMePh) and [(Cp*)MCl{η2-P,S-Ph2PNHP(S)Ph2}]BF4, Cp* = η5-C5Me5; M = Rh, Ir
    (2002) Simón-Manso, E; Valderrama, M; Gantzel, P; Kubiak, CP
    The reaction of S-(Ph2P)(2)N(CHMePh) with sulfur (1:1 molar ratio) in diethyl ether solution leads to S-Ph2P(S)N(CHMePh)PPh2 (1). The disulphide S-{Ph2P(S)}(2)N(CHMePh) (2), was obtained when the reaction was carried out in tetrahydrofuran with an excess of sulfur (1:5 molar ratio). 1 reacts with the solvated rhodium. (I) complex [Rh(cod)S-x]BF4 to afford the cationic complex [Rh(cod){eta(2)-S,P-Ph2P(S)N(CHMePh)PPh2}]BF4 (3). However, when the above reaction was carried out with 2, cleavage of the C-N bond of the ligand occurred, to yield the complex [Ph(cod)(eta(2)-S,S-{Ph2P(S)}(2)NH)]BF4 (4). Reactions of I with the fragments of Rh (III) and Ir (III) [Cp*MClSx]BF4 lead to cleavage of the C-N bond of the ligand yielding cationic complexes, [(Cp*)MCl{eta(2)- P,S-Ph2PNHP(S)Ph-2}]BF4 (M = Rh, 5; Ir, 6]. Crystal structures of 1, 2, 5 and 6 have beet determined by X-ray diffraction methods. Compounds 1 and 1 crystallize in the same space group P2(1)2(1)2(1). The molecular structure of 1 shows a nearly trigonal planar nitrogen atom bound to two different phosphorus atoms and to the chiral carbon atom. Compound 2 acquires a twisted conformation with the two sulfur atoms adopting mutually trans positions with respect to the PNP backbone. (C) 2002 Elsevier Science B.V. All rights reserved.
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    Diphenylphosphino(phenylthio)methane as a monodentate or bidentate chelate ligand in rhodium, iridium and ruthenium complexes, crystal structure of [(eta(5)-C(5)Me(5)) IrCl(eta(2)-Ph(2)PCH(2)SPh-P,S)]BF4 center dot Me(2)CO
    (1997) Valderrama, M; Contreras, R; Boys, D
    Reactions of complexes [{(eta(5)-C(5)Me(5))MCl(2)}(2)] (M = Rh, Ir) and [{(eta(6)-MeC(6)H(4)Pr(i))RuCl2}(2)] with the ligand Ph(2)PCH(2)SPh in acetone solution led to neutral complexes with the general formula [(ring)MCl(2)(eta(1)-Ph(2)PCH(2)SPh-P)] (1-3). These compounds react with thallium tetrafluoroborate in acetone solution to yield new cationic complexes in which the ligand is acting in its chelate P,S-donor fashion, [(ring)MCl(eta(2)Ph(2)PCH(2)SPh-P,S)]BF4 (4-6). When the removal of the chloride ligand in complexes 1-3 was carried out in the presence of a stoichiometric amount of Ph(2)PCH(2)SPh, cationic compounds containing two P-donor monodentate ligands of the type [(eta(5)-C(5)Me(5))MCl(eta(1)-Ph(2)PCH(2)SPh-P)(2)]BF4 (7 and 8) were obtained. The structure of the iridium derivative [(eta(5)-C(5)Me(5))IrCl(eta(2)-Ph(2)PCH(2)SPh-P,S)]BF4 . Me(2)CO has been determined by single-crystal X-ray diffraction methods. The complex cation contains a C(5)Me(5) group occupying three coordination positions of a distorted octahedral iridium centre, a bidentate chelate P,S-bonded ligand and a chloride atom completing the coordination sphere. (C) 1997 Elsevier Science Ltd.
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    Group VIII transition metal complexes with the chiral diphosphazane ligand (S)-alpha-(Ph2P)(2)N(CHMePh): Synthesis and structural characterization
    (ELSEVIER SCIENCE SA, 2006) Simon Manso, E; Valderrama, M
    The chiral ligand S-(Ph2P)(2)N(CHMePh) reacts with Ni(CO)(4) in benzene solution to yield the mononuclear complex [Ni(CO)(2)]{kappa(2)-(PPh2)2N(CHMePh))] (1). The reactions of the chiral ligand with the solvated complexes [(eta(5)-C5Me5)MCl(solvent)(2)]BF4 (M = Rh, Ir) or with the binuclear complex [{(eta(6)-C6Me6)RuCl}(2)(mu-Cl)] in the presence of a chloride scavenger, give cationic complexes of the type [(eta(5)-ring)MCl(kappa(2)-(PPh2)(2)N(CHMePh)]BF4 [eta(5)-ring = -C5Me5; M = Rh (2), Ir (3). eta(6)-C6Me6; M = Ru (4)]. The P-31 NMR spectra of compounds 2-4 show two signals corresponding of two phosphorus nuclei with different chemical environments. The related complex [(eta(5)-C5H5)Fe(CO)(kappa(2)-(PPh2)(2)N(CHMePh))]BF4 (5) was prepared by reaction of the ligand with the complex [(eta(5)-C5H5)Fe(CO)(2)I) in toluene following by a metathesis with AgBF4. This compound exhibits only one signal in the 31P NMR spectra at room temperature, which splits into two signals at low temperature (213 K). The crystal structures of complexes 2, 3 and 5 have been determined by X-ray diffraction studies. All complexes show the presence of an intramolecular n-stacking interaction. The separation between least-squares planes defined by the two intramolecularly stacked phenyl rings are in the range 3.318-3.649 (c) 2005 Elsevier B.V. All rights reserved.
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    Heterodinuclear PtRh and PtIr complexes with phosphinite groups as bridging ligands
    (1998) Contreras, R; Valderrama, M; Moscoso, R
    Compounds of the general formula [Pt(eta(2)-L) {P(O)Ph-2}{P(OH)Ph-2}], where eta(2)-L = {eta(2)-S2P(OEt)(2)}(-) (I) and {eta(2)-(SCNEt2)-C-2}(-) (2), react in THF solution with the dinuclear complex [{(cod)M(mu-OMe)}(2)] (M = Rh-I or Ir-I) to give new heterodinuclear compounds of the type [(eta(2)-L)Pt{mu-P(O)Ph-2}(2)M(cod)], where eta(2)-L = {eta(2)-S2P(OEt)(2)}(-); M = Rh-I (3), Ir-I (4) and eta(2)-L = {eta(2)-S2C-NEt2}(-); M = Rh-I (5) and Ir-I (6). Compounds (3) and (4) react with an excess of CO, leading to displacement of the coordinated pi-diolefin (cod) and the formation of the dicarbonyl derivatives [{eta(2)-S2P(OEt)(2)}Pt{mu-P(O)-Ph-2}(2)M(CO)(2)] [M = Rh-I (7), Ir-I (8)].
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    Pentamethylcyclopentadienyliridium(III) complexes containing tertiary phosphorus chalcogenide ligands: Crystal structure of [(eta(5)C(5)Me(5))Ir{PO(OMe)(2)}{eta(2)(SPPh(2))(2)CH2-S,S'}]BF4 center dot 0.5Me(2)CO
    (1996) Valderrama, M; Contreras, R
    Neutral iridium(III) complexes of the unidentate P-donor ligands dppm, dppmS and dppmSe, and cationic complexes with these ligands acting in their bidentate form have been prepared and characterized. Similar cationic complexes with the symmetrical bidentate dichalcogenide ligands dppmS, and dppmSe, have been described. These compounds react with sodium hydride in tetrahydrofuran or with thallium pyrazolate in dichloromethane to yield the new cationic complexes [(eta(5)C(5)Me(5))Ir{eta(3)(EPPh(2))(2)CH-C,E,E'}](+) (E = S, Se) in which the anionic methanide dichalcogenide ligand is acting as a tripod ligand with a C,E,E'-donor set. However, the complexes [(eta(5)C(5)Me(5))IrCl(eta(2)dppmE(2))]BF4 react with P(OMe)(3) in the presence of TIBF4, to give the dicationic compounds [(eta(5)C(5)Me(5))Ir{P(OMe>(3)}(eta(2)dppmE(2))(BF4)(2). In these complexes, the P(OMe)(3) ligand is transformed into a coordinated PO(OMe)(2) group by reaction with sodium iodide in acetone. The structure of the complex [(eta(5)C(5)Me(5))Ir{PO(OMe)(2)}(eta(2)dppmS(2)-S,S')]BF4 . 0.5Me(2)CO have been determined by single crystal X-ray diffraction methods.
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    Platinum(II) complexes with dithiolates and phosphinites as ligands: Crystal structure of [Pt{S2CO}{P(OMe)Ph(2)}(2)]
    (PERGAMON-ELSEVIER SCIENCE LTD, 1996) Contreras, R; Valderrama, M; Riveros, O; Moscoso, R; Boys, D
    Reaction of the complex [PtCl{P(O)Ph(2)} {P(OH)Ph(2)}(2)] with silver or thallium derivatives of dithiolate ligands led to neutral complexes of general formula [Pt{S-S} {P(O)Ph(2)} {P(OH)Ph(2)}], where {S-S}(-) ={S(2)CNEt(2)}(-) (1), {S2P(OEt)2}(-) (2) and {S(2)COEt}(-) (3). Complexes 2 and 3 reacted with an excess of NaI in acetone solution by dealkylation of the coordinated dithiolate ligand and formation of the compounds [Pt{S2P(O) (OEt)} {P(O)Ph(2)} {P(OH)Ph(2)}] Na (4) and [Pt{S2CO}{P(O)Ph(2)}{P(OH)Ph(2)}] Na (5), respectively. The corresponding tetraphenylphosphonium derivatives (6, 7) were prepared by a metathetical reaction of these complexes with Ph(4)PBr in acetone solution. Related dithiolate complexes were obtained by reaction of the complex [Pt{S-S}(2)] with P(OMe)Ph(2) in molar ratio 1:2. Thus, the reaction of [Pt{S(2)COEt}(2)] in dichloromethane solution at room temperature gave [Pt{S(2)COEt} {P(OMe)Ph(2)}(2)] Cl (8). This complex reacted with NaI in acetone to form the neutral compound [Pt{S2CO} {P(OMe)Ph(2)}(2)] (9). When the reaction was carried out in dichloromethane at reflux temperature using [Pt{S2P(OEt)(2)}(2)] as starting material, the neutral compound [Pt{S2P(O)(OEt)} {P(OMe)Ph(2)}(2)] (10) was obtained. The crystal structure of the complex 9 has been determined by X-ray diffraction. The neutral complex shows a nearly square-planar coordination of the metal and a planar dithiocarbonate ligand.
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    Rhodium(III) and ruthenium(II) complexes with the chiral phosphine-alcohol PH2PCH2CHMeCH2OH. Synthesis and characterisation
    (SOC CHILENA QUIMICA, 2002) Sanhueza, J; Contreras, R; Valderrama, M
    Reaction of the dinuclear complex [{(eta(5)-C5Me5)RhCl}(2)(mu-Cl)(2)] with the chiral phosphine (R)-Ph2PCH2CHMeCH2OH leads to the complex [{(eta(5)-C5Me5)RhCl2(eta(1)-Ph2PCH2CHMeCH2OH-P)}](1). This reaction, in the presence of AgBF4, yields the cationic compound [{(eta(5)-C5Me5)RhCl(eta(2)-Ph2PCH2CHMeCH2OH-P,O)}]BF4 (2). Variable-temperature H-1 NMR and circular dichroism experiments support the stereoselective eta(2)-chelate coordination of the ligand and the proposed configuration for the metal centre. In a similar way, the reaction of the dimer [{(eta(6)-C6Me6)RuCl}(2)(mu-Cl)(2)] with the ligands (R)- and (S)-Ph2PCH2CHMeCH2OH afford the neutral complexes [(eta(6)-C6Me6)RuCl2{eta(1)-PPh2CH2CHMeCH2OH-P}] [R-ligand (3), S-ligand (4)], which in turn react with AgBF4 to give the cationic compounds [(eta(6)-C6Me6)RuCl{eta(2)-PPh2CH2CHMeCH2OH-P,O}]BF4 [R-ligand (5), S-ligand (6)]. All complexes have been characterised by elemental analysis, IR and multinuclear NMR spectroscopies.
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    Syntheses and characterization of binuclear Rh-2, Ir-2 and RhIr complexes containing dimethyl phosphonate and pyrazolate bridging ligands
    (ROYAL SOC CHEMISTRY, 1996) Valderrama, M; Cuevas, J; Boys, D; Carmona, D; Lamata, MP; Viguri, F; Atencio, R; Lahoz, FJ; Oro, LA
    The reaction of [Ir(eta(5)-C(5)Me(5))I{PO(OMe)(2)}{P(OH)OMe)(2)}] with pyrazole (Hpz) in the presence of AgPF6 gave [Ir(eta(5)-C(5)Me(5)){PO(OMe)(2)}{P(OH)(OMe)(2)}(Hpz)]PF6 1. Deprotonation of 1 with sodium carbonate afforded the neutral compound [Ir(eta(5)-C(5)Me(5)){PO(OMe)(2)}(2)(Hpz)] 2 which, in turn, can be deprotonated to [(eta(5)-C(5)Me(5))Ir{PO(OMe)(2)}(2)(pz)M'] (M' = Tl 3 or Na 4) by Tl(acac) (acac = acetylacetonate) or NaH, respectively. The complex [Ir(eta(5)-C(5)Me(5))I-2{P(OH)(OMe)(2)}] 5, prepared by cleaving the iodide bridges in [{Ir(eta(5)-C(5)Me(5))I}(2)(mu-I)(2)] with HPO(OMe)(2), reacted with Hpz in the presence of AgPF6 to give [Ir(eta(5)-C(5)Me(5)){PO(OMe)(2)}(Hpz)(2)]PF6 6. Complexes of formulae [(eta(5)-C(5)Me(5))Ir{PO(OMe)(2)(pz)M '' L(2)][M '' L(2) = Rh(CO)(2) 7, Rh(cod) 8 or Ir(cod) 9] were prepared from 2 [Rh(acac)(CO)(2)] or from 3 and the appropriate [{M ''(cod)}(2)(mu-Cl)(2) dimer (cod = cycloocta-1,5-diene). Complex 6 reacted with [{Rh(cod)}(2)(mu-Cl)(2)] in basic medium to give [(eta(5)-C(5)Me(5))Ir{PO(OMe)(2)}(pz)(2)Rh(cod)] 10. The rhodium-thallium compound [(eta(5)-C(5)Me(5))Rh{PO(OMe)(2)}(2)(pz)Tl] or the in situ prepared sodium derivative [(eta(5)-C(5)Me(5))Rh{PO(OMe)(2)}(pz)(2)Na] reacted with the dimers [{M ''(diolefin)}(2)(mu-Cl)(2)] affording [(eta(5)-C(5)Me(5))Rh{PO(OMe)(2)}(2)(pz)M ''(diolefin) = [M ''(diolefin) = Ir(cod) 11 or Rh(nbd) 12] or [(eta(5)-C(5)Me(5)){PO(OMe)(2)}Rh(pz)(2)}Rh(pz)(2)M ''(diolefin)][M ''(diolefin) = Rh(cod) 13, Ir(cod) 14 or Rh(nbd) 15], respectively (nbd = bicyclo[2.2.1]hepta-2,5-diene). Related heterovalent complexes of general formula [I(eta(5)-C(5)Me(5))M{PO(OMe(2)}(2)M ''(diolefin)][M = Ir, M'(diolefin) = Rh(cod) 16 or Ir(cod) 17; M = Rh, M ''(diolefin) = Rh(cod) 18, Ir(cod) 19, or Rh(nbd) 20] have been prepared starting from the mononuclear complexes [M(eta(5)-C(5)Me(5))I{PO(OMe)(2)}{P(OH)(OMe)(2)}] (M = Ir or Rh). All the complexes have been characterized by spectroscopic of 8 by toluene-p-sulfonic acid is reported. The structures of 8 and 16 have been determined by X-ray diffraction methods. Both complexes consist of doubly bridged binuclear (C(5)Me(5))Ir-Rh(cod) species, where the Ir atoms exhibit pseudo-octahedral co-ordination and the rhodium square planar. The bridging system in 16 is formed by two identical P,O-bonded phosphonate groups, while in 8 a pyrazolate and a phosphonate ligand are bridging the metals. The intermetallic separations are 4.0445(9) (8) and 4.0928(9) Angstrom (16).
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    Synthesis and characterization of heterodinuclear RuPt and IrPt complexes containing pyrazolate bridging ligands.: Crystal structure of [(η5-C5Me5)Ir(μ-pz)3PtMe3] (pz = pyrazolate)
    (2000) Contreras, R; Valderrama, M; Orellana, EM; Boys, D; Carmona, D; Oro, LA; Lamata, MP; Ferrer, J
    The reaction of the metallo-ligand [Ru(eta(6)-p-cymene)(pz)(2)(Hpz)] with the platinum complex [{PtIMe3}(4)] affords mixtures of the heterodinuclear complexes [(eta(6)-p-cymene)Ru(mu-pz)(3)PtMe3] (1) and [(eta(6)-p-cymene)Ru(mu-pz)(2)(mu-I)PtMe3] (2). The reaction of the iridium derivative [Ir(eta(5)-C5Me5)(pz)(2)(Hpz)] with [{PtIMe3}(4)] gives [(eta(5)-C5Me5)Ir(mu-pz)(2)(mu-I)PtMe3] (3). Both [Ru(eta(6)-p-cymene)(pz)(2)(Hpz)] and [Ir(eta(5)-C5Me5)(pz)(2)(Hpz)] react with [{PtIMe3}(4)] in the presence of NaOH yielding 1 and [(eta(5)-C5Me5)Ir(eta-pz)(3)PtMe3] (4), respectively. While [Ru(eta(6)-p-cymene)(pz)(2)(Hpz)] reacts with [PtBr2Me2Sx] to give mixtures of [(eta(6)-p-cymene)Ru(mu-pz)(3)PtBrMe2] (5) and [(eta(6)-p-cymene)Ru(mu-pz)(2)(mu-Br)PtBrMe2] (6), the reaction of [Ir(eta(5)-C5Me5)(pz)(2)(Hpz)] with [PtBr2Me2Sx] gives [(eta(5)-C5Me5)Ir(mu-pz)(2)(mu-Br)PtBrMe2] (7) as the sole product. All species were characterized in solution by H-1-NMR spectroscopy. The crystal structure of complex 4 has been determined by single-crystal X-ray diffraction. (C) 2000 Elsevier Science S.A. All rights reserved.
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    Synthesis and characterization of new dimethylplatinum(IV) complexes with O-(diphenylphosphino)thioanisole and its chalcogenide derivatives as ligands.: Crystal structure of trans-[Me2PtBr2{O-Ph2P(S)C6H4SMe-S,S'}]
    (2001) Contreras, R; Valderrama, M; Beroggi, C; Boys, D
    The compound o-(diphenylphosphino)thioanisole can be oxidized by S or Se in benzene leading to the derivatives Ph2P(E)C6H4SMe [EPSMe: E = S (1), Se (2)]. These compounds act as bidentate chelate ligands in reactions with the platinum(IV) complex [Me2PtBr2](n) to form trans and cis isomers of the general formula [Me2PtBr2(L-2)] [L-2 = SPSMe (3, 4); SePSMe (5, 6)]. The reaction of the complex [Me2PtBr2](n) with the starting ligand Ph2PC6H4SMe (PSMe) led to a reductive elimination affording the neutral complex [PtBr2(PSMe)] (7). The structure of the complex [Me2PtBr2{o-Ph2P(S)C6H4SMe}] was established by X-ray crystallography. The platinum atom has a distorted octahedral coordination and it is bonded to two methyl carbons, two bromide atoms and two sulfur atoms of the (o-diphenylphosphinesulfide)thioanisole bidentate ligand. (C) 2001 Elsevier Science Ltd. Ail rights reserved.
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    Synthesis and characterization of new homo-heterobinuclear platinum(II) complexes with dimethylphosphonate as bridging ligands. Crystal structure of [(eta(2)dppm)Pt{mu-P(O)(OMe)(2)}(2)(mu-I)PtMe(3)]
    (1997) Contreras, R; Valderrama, M; Nettle, A; Boys, D
    The preparation of the new neutral complex [(eta(2)-dppm)Pt{P(O)(OMe)(2)}(2)] (1) (dppm = 1,1-bis(diphenylphosphino) methane) and its behaviour as a chelate (O,O)-donor ligand is described. This ligand reacts with [Me(3)PtI](4) to give the homobimetallic complex [(eta(2)dppm)Pt{mu-P(O)(OMe)(2)}(2)(mu-I)PtMe(3)] (2), which in turn reacts with AgPF6 in the presence of PPh(3) to yield the new cationic complex [(eta(2)dppm)Pt{mu-P(O)(OMe)(2)}(2){PtMe(3)(PPh(3))}]PF6 (3). In contrast, the treatment of binuclear complexes [{Pd(mu-Cl)(2-MeC(3)H(4))}(2)] and [{Rh(mu-Cl)(cod)}(2)] with silver perchlorate in the presence of the bidentate ligand 1 yields the heterobinuclear compounds [(eta(2)dppm)Pt{mu-P(O)(OMe)(2)}Pd-2(eta(3)MeC(3)H(4))]ClO4 (4) and [(eta(2)dppm)Pt{mu-P(O)(OMe)(2)}Rh-2(cod)]ClO4 (5). Complex 5 reacts with an atmosphere of CO at room temperature yielding the cis-dicarbonyl complex [(eta(2)dppm)Pt{mu-P(O)(OMe)(2)}Rh-2(CO)(2)]ClO4 (6). The structure of complex [(eta(2)dppm)Pt{mu-P(O)(OMe)(2)}(2)(mu-I)PtMe(3)] has been determined by single crystal X-ray diffraction methods.
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    Synthesis and reactivity of new trimethylplatinum(IV) complexes containing chiral Schiff bases as ligands: Crystal structure of (OC-6-44-C)-[PtIMe3{kappa(2)-(R)-Ph2P(C6H4)CH=NC*H(Ph)Me-P,N}]
    (ELSEVIER SCIENCE SA, 2006) Ramirez, P; Contreras, R; Valderrama, M; Boys, D
    Reaction of the tetranuclear complex [PtIMe3](4) with the ligand (S)- and (R)-Ph2P(C6H4)CH=NC*H(Ph)Me in a 1:4 molar ratio yields the mononuclear neutral complexes in diastereoisomeric mixtures [PtIMe3{K-2-Ph2P(C6H4)CH=NC*H(Ph)Me-P,N}]. Iodide abstraction from mixture with AgBF4 in the presence of pyridine (Py) induces a reductive elimination reaction with loss of ethane, leading to the cationic complex [PtMe(Py) {kappa(2) -Ph2P(C6H4)CH=NC*H(Ph)Me-P,N}[BF4] [C* = (S)-, 3; (R)-, 4]. When this reaction was carried out in the presence of PPh3 a consecutive orthometallation reaction with loss of methane is produced, forming the cationic complex [Pt(PPh3){kappa(3)-Ph2P(C6H4)CH=NC*H(C6H4)Me-C,P,N][BF4], [(S)-, 5; (R)-, 6]. All species were characterised in solution by H-1 and P-31{H-1} NMR spectroscopy, elemental analysis and mass spectrometry.
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    Synthesis and single-crystal characterization of the square planar complex [Ni{(SPPh2)2 N-S,S′}2]•2THF
    (2001) Simón-Manso, E; Valderrama, M; Boys, D
    Reaction of Ni(CO)(4) with HN(SPPh2)(2) in tetrahydrofuran yielded the nickel(II) neutral complex [Ni-{(SPPh2)(2)}(2)N-S,S'].2THF. X-ray crystallography shows a square planar NiS4 core, with a center of inversion at Ni atom. It crystallized in the space group P(1)over-bar. This compound easily isomerizes in organic solvents at room temperature or by heating a solid-state sample to form the corresponding tetrahedral isomer.
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    Synthesis of rhodium(III) complexes with the chiral phosphine (S)-Ph2PCH2CHMeCH2OH.: Crystal structure of (SRhSC)-[(η5-C5Me5)RhCl(η2-PPh2CH2CHMeCH2OH-P,O)]BF4
    (2001) Valderrama, M; Contreras, R; Araos, G; Boys, D
    Reaction of dinuclear complex [{(eta (5)-C5Me5)RhCl}(2)(mu -Cl)(2)] with the chiral phosphine (S)-Ph2PCH2CHMeCH2OH leads to the complex [{eta (3)-C5Me5)RhCl2(eta (1)-PPh2CH2CHMeCH2OH-P)] (1). Complex 1 reacts with NaH and T1BF(4) affording the chiral-at-metal rhodium compounds [(eta (5)-C5Me5)RhCl(eta (2)-PPh2CH2CHMeCH2O-P,O)] (2) and [(eta (5)-C5Me5)RhCl(eta (2)-PPh2CH2CHMeCH2OH-P,O)]BF4(3), respectively. Complex 2 has been alternatively prepared by reaction of [{(eta (5)-C5Me5)RhCl}(2)(mu -Cl)(2)] with the sodium salt Ph2PCH2CHMeCH2ONa. Complex 2 reacts with HBF, to give 3. The reaction of 3 with an excess of NaI affords the neutral complex [(eta (5)-C5Me5)RhI2(eta (1)-PPh2CH2CHMeCH2OH-P)] (4). All the complexes have been characterised by elemental analyses and multinuclear NMR spectroscopy. The crystal structure of complex 3 has been determined by X-ray diffraction. (C) 2001 Elsevier Science B.V. All rights reserved.
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    Synthesis of transition-metal complexes with heterodifunctional ligands derived of NH(PPh2)2.: Crystal structure of [(η5-C5Me5)RhCl{η2-P, Se-Ph2PNP(Se)Ph2}]•CH2Cl2
    (2001) Valderrama, M; Contreras, R; Muñoz, P; Lamata, MP; Carmona, D; Lahoz, FJ; Elipe, S; Oro, LA
    The uncoordinated P atom of the bis(diphenylphosphine)amine (dppa) ligand in complexes [(ring)MCl2(eta (1)-P-PPh2NHPPh2)] (M = Rh, Ir. Ru) reacts with sulphur or selenium to form [(ring)MCl2(eta (1)-P-PPh2-NHP(E)Ph-2)] (E = S (1-3), Se (4-6)) containing the P-coordinated monosulphide or monoselenide ligands. The selenium derivatives have also been directly prepared from the corresponding [{(ring)MCl2)(2)] dimer and dppaSe. Chloride abstraction from rhodium and ruthenium complexes gives the neutral compounds [(ring)MCl(eta (2)-P,E-PPh2NP(E)Ph-2)] (7-10) whilst the iridium derivatives yield cationic complexes of the general formula [{eta (5)-C5Me5)IrCl(eta (2)-P,E-PPh2NHP(E)Ph-2)](+) (11 and 12). The crystal structure of complex [(eta (5)-C5Me5)RhCl{eta (2)-P,SePPh2NP(Se)Ph-2}] has been established by X-ray crystallography. The rhodium atom exhibits a distorted octahedral coordination with a eta (5)-C5Me5 group occupying the centre of three octahedral sites, a bidentate chelate P,Se-bonded ligand and a chloride atom complete the metal coordination sphere. (C) 2001 Elsevier Science B.V. All rights reserved.
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    Trimethylsilylcyclopentadienylchromium(III) complexes with diphenyl-2-pyridylphosphine
    (2004) Rojas, R; Valderrama, M
    Reaction of CrCl with LiCpSiMe3 in THF leads to the formation of a solvated intermediate, [(n(5)-Me3SiCp)CrCl2(THF)], which in turn reacts with diphenyl-2-pyridylphosphine to yield the complex [(C6H5)(2)PC5H4NH][(eta(5) -Me3SiCp)CrCl3] (1) in 66% yield. As a secondary product was isolated the neutral complex [(eta(5)-Me3SiCp)CrCl2{(C6H5)(2)PC5H4N}] (2) in 5% yield. The structure of complex 1 has been determined by single crystal X-ray diffraction. In the anion the metal centre shows a pseudo-octahedral geometry with the centroid of the trimethylsilylcyclopentadienyl ligand occupying the centre of three octahedral sites, and three chloride atoms completing the co-ordination sphere. Complex 1 in the presence of MAO leads to the formation of an active catalyst for the polymerization of ethylene. (C) 2004 Elsevier B.V. All rights reserved.