15377-00-1Relevant academic research and scientific papers
Heterobinuclear and heterotrinuclear metal μ-allenyl complexes containing platinum and one or both of iron and ruthenium. Synthesis of higher nuclearity metal complexes from mononuclear metal η1-propargyls and η1-allenyls and from binuclear metal μ-η1:η2α,β-allenyls
Willis, Richard R.,Shuchart, Chris E.,Wojcicki, Andrew,Rheingold, Arnold L.,Haggerty, Brian S.
, p. 3179 - 3191 (2008/10/08)
The reactions of Cp(CO)2MCH2C≡CPh with Pt(PPh3)4 or Pt(PPh3)2C2H4 in THF at reflux and of Cp(CO)2MCH=C=CH2 with Pt(PPh3)2C2H4 in THF or hexane at -78 °C to ambient temperature afforded the heterobinuclear metal μ-allenyl complexes (PPh3)2Pt(μ-η1:η2 α,β-C(Ph)=C=CH2)M(CO)Cp (M = Ru, R = Ph (1a); M = Fe, R = Ph (2a); M = Ru, R = H (1b); M = Fe, R = H (2b)). The products reacted with Ru3(CO)12 or Fe2(CO)9 (Ru, Fe = M′) in THF at room temperature to yield open heterotrinuclear metal μ-allenyl complexes (PPh3)-(CO)Pt(μ3-η1:η 2:η2-C(R)=C=CH2)M′(CO) 3M(CO)Cp (M′ = M = Ru, R = H (4); M′ - Ru, M = Fe, R = H (5); M′ = Fe, M = Ru, R = Ph (6a); M′ = Fe, M = Ru, R = H (6b); M′ = M = Fe, R = H (7)), as well as M′(CO)4PPh3. The reaction of 1a with Fe2(CO)9 also afforded the CO-for-PPh3 substitution product (PPh3)(CO)Pt(μ-η1:η2 α,β-C(Ph)=C=CH2)Ru(CO)Cp (3). Treatment of the μ-allenylcarbonyl (CO)3Fe(μ-η1:η3-η 2-C(O)C(Ph)=C=CH2)Ru(CO)Cp with Pt(PPh3)2C2H4 in THF at 0 °C with warming to ambient temperature gave three heterometallic products: 6a, the PPh3-for-CO substituted (PPh3)(CO)2Fe(μ-η3:η 2-C(O)C(Ph)=C=CH2)Ru(CO)Cp, and (PPh3)2Pt(μ3-η1:η 1:η3-C(Ph)CCH2)Ru(CO)Cp(μ 2-CO)Fe(CO)2 (8). All new products were characterized by a combination of IR and NMR (1H, 13C{1H}, and 31P{1H}) spectroscopy, FAB mass spectrometry, and elemental analysis; the structures of 1b, 3, 6a, and 8 were elucidated by X-ray diffraction analysis. Complexes 1b and 3 each contain a Pt-Ru bond and a μ-allenyl group that is η1 ligated to Pt and η2 ligated, through the internal C=C bond, to Ru. 6a contains an open Pt-Fe-Ru metal framework, with the μ-C(Ph)=C=CH2 ligand being attached η1 to Pt, η2 through the C(Ph)=C to Fe, and η2 through the C=CH2 to Ru. 8 is also an open, Pt-Fe-Ru bonded cluster; however, it contains an η3-allyl group ligated to Fe and metalated at CPh (Ru) and Cβ (Pt). Possible mechanisms of formation of the new μ-allenylmetal complexes are presented. Complexes 1 and 2 underwent fragmentation of the binuclear framework to yield Cp(CO)2MCH=C=CH2 (M = Ru, Fe), Cp(CO)2RuC(Ph)=C=CH2, or Cp-(CO)2FeCH2C≡CPh, as appropriate, in addition to Pt(PPh3)2(CO)2, upon treatment with CO at room temperature. The reverse of these processes can be effected by sweeping the product solutions with Ar for the three η1-allenyl complexes, but not for Cp(CO)2FeCH2C=CPh.
Reactions with nucleophiles and cathodic electrochemical behaviour of some neutral and cationic diamino-, dioxy-, and aminooxycarbene complexes of palladium(II) and platinum(II)
Bertani, Roberta,Mozzon, Mirto,Michelin, Rino A.,Castilho, Tania J.,Pombeiro, Armando J. L.
, p. 117 - 128 (2007/10/02)
The bis-diaminocarbene complexes cis- (M = Pt or Pd) react with one mole of the diphosphine cis-Ph2PCH=CHPPh2 (diphoe) in tetrahydrofuran at room temperature or in 1,2-dichloroethane at reflux for 8h to form cationic derivatives cis- (M = Pt, 1; Pd, 2) with chloride displacement.The cationic hydridocarbene complex trans- reacts with one mole of diphoe in CH2Cl2 at room temperature to cleave the ring of the dioxycarbene, generate CO2 and C2H4, and form the cationic complex .The reaction of trans- with Cl- ions in CH2Cl2 gives the ring-opened alkoxycarbonyl complex trans->, trans-, ClCH2CH2OH and Pt0 species.The cathodic behaviour of the diaminocarbene complexes cis-(L)> (L = PPh3, R = C6H4OMe-p or tBu; L = CNtBu, R = tBu; L = PPhMe2, R = C6H4CH2Cl-o), as well as of the aminooxy- and dioxy-carbene compounds trans- (X = Cl or Br) and trans-, has been studied by cyclic voltammetry (CV) and controlled potential electrolysis (CPE) in aprotic media.They exhibit an irreversible reduction wave (Eredp in the range -1.50 to -2.0 V vs.SCE), corresponding to two-electron and single-electron cathodic processes for the dichloro-complexes and the other species, respectively.Evidence for the fromation of low-coordingation number zerovalent palladium species is presented, and, in the case of the electrochemical reduction of the dioxycarbenehydrido-complex, quantitative fragmentation of the cyclic carbene to CO2 and ethylene and liberation of dihydrogen were proved by gas chromatography.
CO labilization and hydrogen-transfer pathways in cationic phosphido-bridged Re-Pt heterobimetallic systems and the molecular structures of [η5-Cp(ON)Re(μ-PR2)(μ-H)Pt(PPh3) 2]X (R = Cy, X- = PF6-; R = Ph, X- = BF4-) and [η5-Cp(ON)HRe(μ-PCy ...
Powell, John,Sawyer, Jeffery F.,Stainer, Matthew V. R.
, p. 4461 - 4470 (2008/10/08)
Full title: CO labilization and hydrogen-transfer pathways in cationic phosphido-bridged Re-Pt heterobimetallic systems and the molecular structures of [η5-Cp(ON)Re(μ-PR2)(μ-H)Pt(PPh3) 2]X (R = Cy, X- = PF6-; R = Ph, X- = BF4-) and [η5-Cp(ON)HRe(μ-PCy2)Pt(PPh3) 2]BF4, a rare example of bridging- and terminal-hydrido geometric isomers. Oxidative addition of the cationic secondary phosphine complexes [η5-Cp(OC)(ON)Re(PR2H)]+ (6) (R = Ph, Cy, Pr) to Pt(C2H4)(PPh3)2 gives [η5-Cp(OC)(ON)Re(μ-PR2)PtH(PPh3) 2]+ (7). In contrast, reaction of 6 with Pt(PPh3)4 leads to CO loss and the formation of the terminal rhenium hydride derivative [η5-Cp(ON)HRe(μ-PR2)Pt(PPh3) 2]+ (8) as the kinetic product. On standing, 8 slowly transforms into the thermodynamically preferred bridging-hydrido isomer [η5-Cp(ON)Re(μ-PR2)(μ-H)-Pt(PPh 3)2]+ (9). The cations 7 will undergo slow CO loss to form 8 in the presence of base (e.g. F-, proton sponge), and the isomerization of 8 to 9 is promoted by added chloride ion with -d[8]/dt = k[8][Cl-]2. Complex 7 (R = Cy) reacts with added Cl- to give [η5-Cp(OC)(ON)Re(μ-PCy2)PtHCl(PPh3)] (10b), which reacts with Cl- abstractors (Ag+ or NaBPh4) to give an equilibrium mixture of [η5-Cp(ON)Re(μ-PCy2)(μ-H)Pt(PPh 3)(CO)]+ (11b) and [η5-Cp(ON)HRe(μ-PCy2)Pt(PPh3)(CO)] +, (12b) (PPh3 trans to μ-PCy2), which slowly transform to give [η5-Cp(ON)HRe(μ-PCy2)Pt(PPh3)(CO)] + (13b) (PPh3 cis to μ-PCy2). Cations 12b and 13b react rapidly with PPh3 to give 8 while 11b reacts with PPh3 to give 9b. The mechanism of formation of 7 and 8 from 6 and the mechanism of the base-promoted 7 to 8 rearrangement and the Cl--catalyzed 8 to 9 isomerization process are discussed. The molecular structures of [η5-Cp(ON)HRe(μ-PCy2)Pt(PPh3) 2]BF4 ((8b)BF4) and [η5-Cp(ON)Re(μ-PCy2)(μ-H)Pt(PPh 3)2]PF6 ((9b)PF6) (a rare example of terminal- and bridging-hydrido isomers) and [η5-Cp(ON)Re(μ-PPh2)(μ-H)Pt-(PPh 3)2]BF4 ((9a)BF4) have been determined. Crystal data for (8b)BF4: C53H58BF4NOP3PtRe·CH 2Cl2 crystallizes in space group P21/n with a = 11.031 (2) A?, b = 22.391 (5) A?, c = 21.603 (7) A?, β = 94.04 (2)°, V = 5322 A?3, and Z = 4. The structure was refined to R = 0.0407 and Rw = 0.0419. Crystal data for (9a)BF4: C53H46BF4NOP3PtRe, space group P1 with a = 12.563 (2) A?, b = 12.896 (1) A?, c = 15.024 (2) A?, α = 94.14 (1)°, β = 96.93 (2)°, γ = 92.01 (1)°, V = 2407 A°3, and Z = 2. The structure was refined to R = 0.0310 and Rw = 0.0325. Crystal data for (9b)PF6: C53H58F6NOP4PtRe·2.5CH 2Cl2, space group P1, a = 12.532 (2) A?, b = 13.077 (2) A?, c = 19.101 (2) A?, α = 94.85 (1)°, β = 105.40 (1)°, γ = 91.23 (1)°, V = 3004 A?3, and Z = 2. The structure was refined to R = 0.0471 and Rw = 0.0508. Cations 9a and 9b contain a planar "Re(μ-PR2)(μ-H)Pt" unit, the bridging hydrogen atom being located in both structures from difference Fourier maps, refined by least squares. The cation 8b contains a planar "HRe(μ-PCy2)Pt" unit. The position of the terminal hydride is inferred to be bonded to Re (confirmed by 1H NMR) in a position approximately trans to the Pt-Re bond by using (i) the approach of Orpen for the calculation of minimization of van der Waals repulsion energies and (ii) EHMO calculations. In contrast to previous studies a good correlation between 1J195Pt-31P and Pt-P bond lengths is observed for the complexes 8b, 9a, and 9b.
Hydrido-organometallic Complexes of Platinum(II). X-Ray Crystal Structure of trans-
Crespo, Margarita,Sales, Joaquim,Solans, Xavier,Altaba, Manuel Font
, p. 1617 - 1622 (2007/10/02)
A series of compounds trans- , cis-, and cis- (dppe=Ph2PCH2CH2PPh2) have been obtained by decarboxylation of formate complexes, or by the reaction of the halogeno complexes with NaBH4.The compounds have been characterized by i.r. and n.m.r. ((1)H, (31)P, and (195)Pt) spectroscopy.The molecular structure of trans- has been determined by a single-crystal X-ray structural analysis.The crystals are orthorhombic, space group Pcab, with a=25.304(5), b=23.963(5), c=11.530(3) Angstroem, and Z=8.Dimethyl acetylenedicarboxylate inserts into the Pt-H bond of trans- (R=C6H4Cl-p, C6H4Me-p, or C6H4Me-o) to give the corresponding ?-vinyl complexes, but other alkynes and olefins do not react.The thermal stability in solution has also been studied; decomposition takes place via reductive elimination to give RH.The results obtained are explained in terms of the electronegativity and the size of the ligands and the configuration of the complexes.
Some Reactions of Nitrosyl Complexes of Nickel, Palladium, and Platinum
Bhaduri, Sumit A.,Bratt, Ian,Johnson, Brian F. G.,Khair, Abul,Segal, John A.,et al.
, p. 234 - 239 (2007/10/02)
The reactions of n3, OPPh3, or NC5H5; X=Br, L=1/2 dppe or PPh3; X=NO2, L=1/2 dppe> and trans- (M=Pd, L=PEt2Ph or PEt2; M=Pt, L=PEt2Ph, PEt3, or P n-Bu3) with carbon monox
