1,720,973 research outputs found
Intermolecular versus intramolecular C–H activation reaction in the thermolysis of [Ru(Me)Cp*(PMe2Ph)2] (Cp* = η5-C5Me5): formation and crystallographic characterisation of [Ru(Ph)Cp*(PMe2Ph)2]
No full textThermolysis of the ruthenium complex [Ru(Me)Cp*(PMe 2Ph)2] (1) (Cp* = η5-C 5Me5) in benzene gives methane and [Ru(Ph) Cp*(PMe2Ph)2] (2), which is converted slowly to [Ru(C6H4PMe2)Cp*(PMe2Ph)] (3) through the loss of benzene. 2 was structurally characterised by single-crystal X-ray diffraction experiments. DFT calculations were performed in order to understand the behaviour of the ruthenium complex 1 towards inter- or intra-molecular C-H bond activation reactions
Catalytic and stoichiometric reactions of tertiary silanes with [Ir(Me)2Cp*L] (Cp*=h5-C5Me5; L= PMe3, PMe2Ph, PMePh2, PPh3) in the presence of one-electron oxidants. A unique case of Si-H, Si-C, Ir-C and P-F bonds one-step activation: crystal structure of [Ir(Ph)(SiPh2F)Cp*(PMe3)]
No full textThe iridium(III) dimethyl derivatives [Ir(Me)(2)Cp*L] (Cp* = eta(5)-C5Me5; L = PMe3 1a, PPh3 1d) catalyze the dehydrogenative coupling of dimethylphenylsilane in the presence of one-electron oxidants to yield Me2PhSiSiPhMe2. Compounds 1a-d react with triphenylsilane in the presence of [FeCp2]PF6 to give methane and [Ir(Ph)(SiFPh2)Cp*L] (L = PMe3 (2a), PMe2Ph (2b), PMePh2 (2c), PPh3 (2d)). 2a was structurally characterized by single-crystal X-ray diffraction experiments. The 'three-legged piano stool' coordination polyhedron is slightly deformed
Cyclometallation Reactions in Neopentyl and Trimethylsilyl methyl Systems of Rhodium(III) and Iridium(III). Formation and X-Ray Crystal Structures of the Four-membered Metallacycles [Rh(CH2CMe2CH2)(eta-5-C5Me5)(PPh3)] and [Ir(CH2SiMe2CH2)(eta-5-C5Me5) (PPh3)]
No full textfull title:Cyclometallation reactions in neopentyl and trimethylsilylmethyl systems of rhodium(III) and iridium(III). Formation and X-ray crystal structures of the four-membered metallacycles [Rh(CH2CMe2CH2)(η5-C 5Me5)(PPh3)] and [Ir(CH2SiMe2CH2)(η5-C 5Me5)(PPh3)] The interaction of [RhCl2(η5-C5Me5) (PPh3)] with Mg(CH2CMe3)Cl in pentane gives the rhodacyclo butane [Rh(CH2)(η5-C5Me5)(PPh 3)] (2). The analogous reaction of [MCl2(η5-C5Me5)(PPh 3)] (M = Rh or Ir) with Mg(CH2SiMe3)Cl allows the isolation of the dialkyl derivatives [M(CH2SiMe3)2(η5-C 5Me5)(PPh3)]. Thermolysis of [Ir(CH2SiMe3)2(η5-C 5Me5)(PPh3)] in cyclohexane leads to the iridasilacyclobutane derivative [Ir(CH2SiMe3CH2) (η5-C5Me5) (PPh3)] (6). The mechanism of formation of the metallacyclobutane derivatives is discussed. The X-ray crystal structures of (2) and (6) have been determined. The two metallacycle compounds give isostructural crystals belonging to the P21/n space group with four molecules in the unit cell of dimensions for (2): a = 17.199(6), b = 10.987(4), c = 16.064(5) Å,β = 109.54(2)°; (6): a = 17.098(7), b = 11.294(5), c = 15.977(7) Å,β = 108.17(2)°. Their crystal structures, refined to R = 0.0441 and 0.0389 for (2) and (6) respectively, are built up of deformed 'three-legged piano stools', one leg being the M-P bond [Rh-P = 2.230(2), Ir-P = 2.236(2) Å], the other two being the M-C a bonds [Rh-C = 2.1 00(5) (av.), Ir-C = 2.1 59(7) Å (av.)] of the metallacyclobutane ring with C-Rh-C = 66.8(2) and C-Ir-C = 77.3(4)°. These rings are puckered: angle between M-C ⋯ C and E-C ⋯ C = 16.5(4) and 18.9(6)° for (2) (E = C) and (6) (E = Si), respectively
Neopentyl and Trimethylsilylmethyl Compounds of Rhodium(III) and Iridium(III) with ortho-Metallated Triphenylphosphine. X-Ray Crystal Structure of [Ir(C6H4PPh2)(CH2SiMe3)(eta-5-C5Me5)]
No full textThe compound [RhCl2(η5-C5Me5) (PPh3)] reacts with Li(CH2SiMe3) to give the ortho-metallated complex [R[graphic omitted]Ph2)(CH2SiMe3)(η5-C 5Me5)] (2), and with Mg(CH2SiMe3)Cl in CH2Cl2 (molar ratio 1:1) to yield [RhCl(CH2SiMe3) (η5-C5Me5) (PPh3)], (3). Complex (3) is converted by the action of Li(CH2SiMe3) into the ortho-metallated compound (2). The reaction of [IrCl2(η5-C5Me5)-(PPh 3)] with Mg(CH2SiMe3)Cl in CH2Cl2 gives [I[graphic omitted]Ph2)(CH2SiMe3)(η5-C 5Me5)], (6), and [lrCl(Me)(η5-C5Me5)(PPh3)]. Reaction of [RhCl2(η5-C5Me5)(PPh 3)] with Mg(CH2CMe3)Cl or Li(CH2CMe3) in diethyl ether affords a mixture of [R[graphic omitted]H2)(η5 -C5Me5)(PPh3)], [R[graphic omitted]Ph2)(CH2CMe3)(η5-C 5Me5)], and [Rh(η5-C5Me5)(C2H 4)(PPh3)], while reaction in CH2Cl2 in equimolar amounts gives [RhCl(CH2CMe3)(η5-C5Me 5)(PPh3)]. Reaction of [lrCl2(η5-C5Me5) (PPh3)] with Mg(CH2CMe3)Cl gives [I[graphic omitted]Ph2)(CH2CMe3)(η5 -C5Me5)]. The X-ray crystal structure analysis of compound (6) has been carried out: a = 17.537(7), b = 11.304(4), c = 15.410(7) Å, β = 94.49(1)°, space group P21/n, Z = 4, R = 0.0361 for 4114 observed reflections. The 'piano-stool' metal co-ordination polyhedron is deformed by ortho-metallation which imposes a 67.0(2)° angle at iridium in the metallacycle, while the other angles, P-Ir-C(17) 89.0(2) and C(17)-Ir-C(36) 89.2(2)°, between the 'legs' of the 'stool' are near to 90°. The bulky C5Me5 ligand (effective cone angle 146°), in approaching the metal, produces large widenings of the other co-ordination polyhedron angles: Cp-Ir-P 137.0(3), Cp-Ir-C(36) (benzene)133.4(3)°, and Cp-Ir-C(17) (silyl)122.6(3)° (Cp = centroid of C5Me5). The ortho-metallated ring is nearly planar, (P-Ir-C) ∧ (P-C-C) 5.3(3)°, and bent by only 6.6(2)° with respect to the metal-bound benzene ring which maintains its planarity; the only deformation this ring suffers involves the endocyclic angles at the carbon bound to phosphorus which widen to 124.5(5)° and at the ortho carbons which narrow to 115.9(6) and 116.7(5)°
Alumina/Chloroform-promoted conversion of the ruthenacycles [Ru(CH2CMe2CH2)(eta-6-C6Me6)(PRPh2)] (R = Me or Ph) into the Chloro orthometallated derivatives [Ru(C6H4PRPh)Cl(eta-6-C6Me6)]
No full textInteraction of the ruthenacyclobutanes [Ru(CH2CMe2CH2)(eta6-C6Me6)(PRPh2)] (R = Me 1 or Ph 3) with neutral alumina causes the decomposition of the metallacyclic moiety, with the formation of 1,1-dimethylcyclopropane, neopentane and alumina-adsorbed metal complexes which lead to the corresponding chloro orthometallated compounds [Ru(C6H4PRPh)CI(eta6-C6Me6)] (R - Me 2 or Ph 4) by reaction with CHCl3. The X-ray crystal structure of complex 2 reveals the presence of clathrated benzene. Crystal data: space group P2(1)/c, a = 14.068(14), b = 15.392(13), c = 13.064(14) angstrom, beta = 116.38(6)-degrees, Z = 4, R = 0.0510
Synthesis and Thermal Decomposition of Palladacyclopentane Derivatives of the type [Pd(CH2CHRCHRCH2)L2] (R=H or Me). X-Ray Crystal Structure of [Pd(CH2CH2CH2CH2)(bipy)]
No full textA series of new palladacyclopentane derivatives of formula [Pd(CH2)CHRCHRCH2L2] [L2 = (C6H11)2PCH2CH2P(C 6H11)2 (dcpe) or Ph2P(CH2)4PPh2 (dppb), R = H; L2 = Ph2PCH2CH2PPh2 (dppe), 2,2′-bipyridyl (bipy), or Me2NCH2CH2NMe2 (tmen), R = Me] has been prepared. The first X-ray crystal structure determination of a palladacyclopentane derivative is reported: the compound [Pd(CH2CH2CH2CH2)(bipy)] gives crystals belonging to the C2/c space group: a = 16.643(9), b = 11.174(4), c = 7.451(3) Å, β = 116.05(9)°, and Z = 4; R = 0.0340 for 826 observed reflections. The metal co-ordination is square planar and the molecules lie on a two-fold axis. The palladacyclopentane ring shows a half-chair conformation with the two-fold axis running through Pd and the middle of the C(β)-C(β′) bond. A study of the thermal decomposition of the palladacyclopentanes has been carried out: [Pd(CH2CH2CH2CH2)L2] (L = PPh3; L2 = dppe, tmen, bipy, dcpe, or dppb) gives butenes as the major products; cyclobutane (L = PPh3) and ethylene (L2 = dppe or dcpe) are also formed as minor products. By comparing these results with those for the decomposition of some methyl-substituted palladacyclopentanes, it is shown that the presence of ethylene is not attributable to fragmentation of the metallacyclic skeleton, but rather to the rupture of the P-C bonds of the diphosphine ligands. The decomposition of palladacyclopentanes is also induced by Bun 2O·BF3: linear C4 hydrocarbons are formed
Cyclometallation of Phenyl Phosphine and Neopentyl Ligands in Ruthenium(II) Complexes: Synthesis and Crystal Structure of the Orthometallated Complexes [Ru(C6H4PR1R2)(CH2CMe3)(eta-6-C6Me6)] (R1 = R2 = Ph; R1 = Me, R2 = Ph; R1 =R2 = Me) and of the Metalla-cyclobutanes [Ru(CH2CMe2CH2)(eta-6-C6Me6)(PPhR1R2)] (R1 = R2 = Ph; R1 = Me, R2 = Ph)
No full textThe compounds [RuCl2(eta-6-C6Me6)L] (L = PPh3 1, or PMePh2 2) react with an excess of Mg(CH2CMe3)Cl to give the corresponding orthometallated complexes activated [Ru(C6H4PR1R2)(CH2CMe3)-(eta-6-C6Me6)] [R1 = R2 = Ph, 4; R1 = Me, R2 = Ph, 5, only the diastereomer (RS:SR)], and the metallacyclobutanes activated [Ru(CH2CMe2CH2)(eta-6-C6Me6) (PPhR1R2)] (R1 = R2 = Ph, 7; R1 = Me, R2 = Ph, 8). In contrast [(RuCl2(eta-6-C6Me6)(PMe2Ph)] 3 reacts to give only the orthometallated complex activated [Ru(C6H4PMe2)(CH2CMe3)(eta-6-C6Me6)] 6. The X-ray crystal structures of complexes 4-8 have been determined and their conformations are discussed. Crystal data are: 4, a = 10.483(2), b = 16.050(10), c = 18.451(9) angstrom, beta = 103.65(4)-degrees, Z = 4, space group P2(1)/c, R = 0.0548; 5, a = 11.926(3), b = 17.810(5), c = 12.780(3) angstrom, beta = 99.37(1)-degrees, Z = 4, space group P2(1)/c, R = 0.0480; 6, a = 16.762(21), b = 10.116(10), c = 14.874(15) angstrom, beta = 108.08(5)-degrees, Z = 4, space group P2(1)/n, R = 0.0441; 7, a = 10.720(20), b = 11.670(20), c = 12.050(10) angstrom, alpha = 80.32(4), beta = 78.60(10), gamma = 87.88(3)-degrees, Z = 2, space group P1BAR, R = 0.0232; 8, a = 8.842(10), b = 8.898(20), c = 17.840(70) angstrom, alpha = 92.91(6), beta = 102.48(50), 102.48(50), gamma = 103.12(9)-degrees, Z = 2, space group P1BAR, and R = 0.0529
Reduction of the NO+ ligand in half-sandwich ruthenium derivatives
No full textThe reduction of the tetrafluoroborate salts of the ruthenium nitrosyl dicationic [Ru(η5-C5R5) (NO)(L)2]2+ (R=Me, L=PMe3, 1a; PMe2Ph, 1b; R=H, L=PPh3, 2d) and monocationic complexes [Ru(Me)Cp*(NO)L]+ (L=PMe3, 3a; PMe2Ph, 3b (Cpz.ast;=η5- C5Me5) has been studied by electrochemical and spectroscopic (IR, NMR, EPR) techniques. The nitrosyl complexes 1a, 1b and 2d exhibit two successive one-electron cathodic processes due to the sequential reduction of coordinated NO+ to NO and NO-, respectively. Chemical reduction yields products of rearrangement of the intermediates which have been spectroscopically characterized. EPR studies and theoretical calculations show that in the first one-electron reduction product the electron interacts with the NO nitrogen atom and that the RuNO moiety presents significant distortion from linearity. The X-ray structure of the related [Ir(Me)2Cpz.ast;(NO)]BF4 has been determined
Sulphonation of Palladium-Carbon Bonds: Synthesis and X-Ray Crystal Structures of the Disulphinato Derivatives [Pd{S(O)2CH2CH2CH2CH2S(O)2}(tmen)](tmen=Me2NCH2CH2NMe2) and [Pd{S(O)2Me}2(tmen)]
No full textThe sulphonation of [Pd(CH2CH2CH2CH2M)(tmen)] (1a) and [PdMe2(tmen)] (1b) (tmen = Me2NCH2CH2NMe2) in CH2Cl2 leads to the corresponding disulphinato compounds [Pd{S(O)2CH2CH2CH2CH 2S](O)2}(tmen)] (2a) and [Pd{S(O)2Me}2(tmen)] (2b), while the reaction of (1a) and (1b) with liquid SO2 gives the derivatives [Pd{S(O)2CH2CH2CH2CH 2S(O)2}(tmen)]·2SO2 (3a) and [Pd{S(O)2Me}2(tmen)]·2SO2 (3b) respectively. On heating under vacuum, (3a), and (3b) lose SO2 and revert to the disulphinates (2a) and (2b), respectively, which give (3a) and (3b) on reaction with liquid SO2. The X-ray crystal structures of complexes (2a) and (2b) have been determined: (2a), a = 9.259(8), b = 13.380(10), c = 6.213(5) Å, β = 92.96(2)°, space group P21, Z = 2, R = 0.0325 for 2 619 observed reflections; (2b), a = 9.377(2), c = 16.182(3) Å, space group P41212, Z = 4, R = 0.0396 for 1 249 observed reflections. The absolute configurations of the two structures have been determined, and the conformations of the two molecules compared. The metal co-ordination in both compounds is square planar with a very small tetrahedral deformation: av. Pd-S 2.288(1) and av. Pd-N 2.168(4) Å. Closure of the Pds(CH2)4S chelate ring in compound (2a) causes a small increase in the S-Pd-S angle which is 91.3(1)° in (2a) and 90.3(1)° in (2b), but does not significantly influence the co-ordination of the diamine [av. N-Pd-N 82.9(1)°]. The conformation of the palladadithiaheptane ring in (2a) is twisted-boat
- …
