15444-65-2Relevant articles and documents
Electrochemistry and [60]fullerene displacement reactions of (dihapto-[60]fullerene) pentacarbonyl metal(0) (M = Cr, Mo, W)
Igartua-Nieves, Elvin,Ocasio-Delgado, Yessenia,Torres-Castillo, Maria D. L. A.,Rivera-Betancourt, Omar,Rivera-Pagan, Jose A.,Rodriguez, Diana,Lopez, Gustavo E.,Cortes-Figueroa, Jose E.
, p. 1293 - 1299 (2007)
Cyclic voltammetry (CV) measurements on (η2-C 60)M(CO)5 complexes (M = Cr, Mo, W) in dichloromethane show three [60]fullerene-centered and reversible reduction/oxidation waves. The E1/2 values of these waves are shifted to positive values relative to the corresponding values of the uncoordinated [60]fullerene in the same solvent. A Jahn-Teller type distortion of the spherical surface of [60]fullerene promoted by [60]fullerene-metal π-backbonding may explain the observed positive shifts. Lewis bases (L = piperidine and triphenyl phosphine) displace [60]fullerene from (η2-C60)M(CO)5 complexes. Analysis of the activation parameters for the metal-[60]fullerene dissociation, the metal-[60]fullerene bond enthalpies (from DFT computations), and metal-solvent (benzene) bond enthalpies (from DFT computations) suggests appreciable solvent contribution to the transition state leading to formation of the intermediate species solvent-M(CO)5. Appreciable transition state stabilization due to solvation of the intermediate species is inferred for M = Mo and W. For M = Cr, stabilization of the intermediate species due to solvation is not accompanied by the corresponding transition state stabilization. The Royal Society of Chemistry 2007.
The selective complexation of adamantane nitriles by tungsten pentacarbonyl
Jefford, Valerie J.,Schriver, Melbourne J.,Zaworotko, Michael J.
, p. 107 - 113 (1996)
Adamantyl-1,3,4-oxathiazol-2-one is usually prepared as a mixture with 1-adamantanecarbonitrile. To separate these two compounds the mixture is reacted with thf·W(CO)5, which selectively forms a complex with the nitrile. The resulting mixture can then be readily separated into pure compounds by sublimation. Characterization data are presented, including the X-ray crystal structure of the nitrile complex, which can be prepared directly from the reaction of the adamantyl nitrile and thf·W(CO)5. (Crystal data for C16H15NO5W: orthorhombic, space group Pmcn, a = 10.5869(19) A, b = 14.0622(22) A, c = 23.342(4) A, V = 3475.0(11) A3, Z = 8, R = 0.042.) The nitrile can be recovered from the complex by reaction with P(C6H5)3 followed with separation by sublimation. The reaction of the related 1-cyano-3-(1,3,4-oxathiazol-2-on-5-yl)-adamantane with thf·W(CO)5 yields a complex in which the site of coordination is shown spectroscopically to be the nitrile moiety. Semi-empirical calculations at the PM3 level indicate that the oxathiazolone heterocycle may be a poor ligand due to the influence of the exo- and endo-cyclic oxygen atoms.
Photophysical and photochemical properties of W(0) and Re(I) carbonyl complexes incorporating ferrocenyl-substituted pyridine ligands
Sun, Shih-Sheng,Tran, Dat T.,Odongo, Onduru S.,Lees, Alistair J.
, p. 132 - 135 (2002)
The photophysical and photochemical properties of a series of W(O) and Re(I) carbonyl complexes incorporating ferrocenyl-substituted pyridine ligands were investigated.
Unprecedented allenylidene transfer from chromium to tungsten
Szesni, Normen,Drexler, Matthias,Fischer, Helmut
, p. 3989 - 3995 (2008/10/09)
Pyrimidylallenylidene complexes 1 ([(CO)5M=C=C=C(NC 3H3NEt)]; M = Cr (a), W (b)) were prepared in a one-pot procedure from readily available 2-ethynylpyrimidine, butyllithium, [(CO) 5M-(THF)], and triethyloxonium tetrafluoroborate. In addition to 1a,b, the homobinuclear allenylidene complexes 2a,b ([(CO)5M=C=C= C(NC3H3NEt)M(CO)5]; M = Cr, W) were formed. In 2a,b the second (CO)5M moiety is attached to the nonalkylated nitrogen atom of the pyrimidyl ring. Treatment of the chromium complex la with an excess of [(CO)5W(THF)] afforded the tungsten allenylidene complex 2b by transmetalation of the allenylidene ligand and addition of (CO) 5W. The allenylidene ligands of other chromium allenylidene complexes [(CO)5Cr=C=C=C(R1)R2] could likewise be transferred to tungsten. In contrast, the reverse transmetalation from tungsten to chromium could not be achieved. DFT calculations indicate that the reaction proceeds by an associative rather than a dissociative pathway. The initiating reaction step is coordination of a (CO)5W fragment to the C α-Cβ bond of the allenylidene ligand.
Photoinduced coupling of CO and vinylidene ligands-formation of cyclobutane-1,3-diones
Abd-Elzaher, Mokhles M.,Weibert, Bernhard,Fischer, Helmut
, p. 1050 - 1052 (2008/10/09)
Photolysis of pentacarbonyl vinylidene complexes of chromium and tungsten affords cyclobutane-1,3-dione derivatives, whereas thermolysis yields binuclear vinylidene nonacarbonyl complexes. In contrast to vinylidene complexes, photolysis of the diphenylall
The oxidative addition of SnCl4 to [W(CO)4(NCMe)(PPh3)]. The X-ray crystal structure of [WH(CO)3(NCMe)(PPh3)2]- [SnCl5·MeOH]
Szymańska-Buzar, Teresa,G?owiak, Tadeusz,Czelu?niak, Izabela
, p. 1817 - 1823 (2008/10/08)
The oxidative addition reaction of SnCl4 with [W(CO)4(NCMe)(PPh3)] in acetonitrile gives a mixture of seven-]coordinate tungsten(II) compounds: [WCl(SnCl3)(CO)3(NCMe)(PPh3)] (1), [WCl2(CO)3(NCMe)(PPh3)] (2), [WCl(SnCl3)(CO)2(NC-Me)2(PPh3)] (3), and [WCl2(CO)2(NCMe)2(PPh3)] (4) identified by IR and NMR (1H, 13C{1H}, and 31P{1H}) studies. Treatment of [W(CO)4(NCMe)(PPh3)] with 1 equiv. of SnCl4 in CH2Cl2 solution besides compounds 1 and 2 also gives ionic species such as [HPPh3]+ and [SnCl6]2- and cationic tungsten(II) complexes. The crystal structure of one of these, [WH(CO)3(NCMe)(PPh3)2][SnCl5 ·MeOH] (5), has been established by single-crystal X-ray diffraction. The IR, 1H, 13C{1H} and 31P{1H} spectra of 5 are also described and can be correlated with the crystallographically observed geometry. A notable feature of 5 is the presence of an agostic interaction of the hydride ligand with one of the carbonyl ligands.
Electrophilic addition of Ph3PAu+ to anionic alkoxy Fischer-type carbene complexes: A novel approach to metal-stabilized bimetallic vinyl ether complexes
Raubenheimer, Helgard G.,Esterhuysen, Matthias W.,Timoshkin, Alexey,Chen, Yu,Frenking, Gernot
, p. 3173 - 3181 (2008/10/08)
The addition of the Ph3PAu+ electrophile to deprotonated Fischer-type alkoxy(methyl)-carbene complexes of pentacarbonyl group 6 metals leads to the formation of novel vinyl ether complexes of gold coordinated to the pentacarbonylmetal moiety. X-ray structures and DFT calculations show that the greatest bonding contribution in the vinyl coordination to the M(CO)5 fragment comes from the terminal, partially negatively charged, CH2 carbon atom via partial end-on η1-bonding rather than the usual η2-bonding of olefins. The corresponding positive charge from the asymmetric vinyl coordination is mainly delocalized onto the Ph3PAu fragment, stabilizing this coordination mode. The use of W instead of Cr in the M(CO)5 fragment, in otherwise isostructural compounds, results in somewhat greater asymmetry in the vinyl coordination, with the difference in the two M(CO)5-η2-vinyl carbon bond lengths increasing from 0.252(11) A? (M = Cr) to 0.307(5) A? (M = W) in the solid state.
Reactivity of electrophilic terminal phosphinidene complexes toward phosphorus ylides
Huy, Ngoc Hoa Tran,Compain, Carine,Ricard, Louis,Mathey, Francois
, p. 57 - 58 (2007/10/03)
Stabilised phosphorus ylides react with transient terminal phosphinidene complexes [RP-W(CO)5] (R=Ph, Me) to give products resulting from a formal insertion of P into a C-H bond via an initial nucleophilic attack of the ylidic carbon.
Synthesis and structure of heterobimetallic compounds with a single thiolato-bridged ligand
Hossain, Md. Munkir,Lin, Hsiu-Mei,Shyu, Shin-Guang
, p. 2655 - 2659 (2007/10/03)
Reactions between CpFe(CO)2SPh and M(CO)5THF (M = Cr, Mo, and W) in a mixture of benzene and THF at room temperature afforded compounds of the type CpFe(CO)2(μ-SPh)M(CO)5 (1) [M = Cr (1a), Mo (1b), and W (1c)] in high yield. However, migration of the thiolato ligand occurred during reactions between CpM(CO)xSPh (M = Fe, x = 2; M = Mo and W, x = 3) and Fe2(CO)9 forming compounds [Fe(μ-SPh)(CO)3]2 and [CpM(CO)x]2 (M = Fe, x = 2; M = Mo and W, x = 3). Single-crystal X-ray diffraction analyses reveal that 1c is a single thiolato-bridged hererobimetallic compound without a metal-metal bond. Metal-metal bond formation in compounds 1 by decarbonylation under thermal or photolytic condition was not observed. Reactions between compounds 1 and PPh3 produced CpFe(CO)2SPh and PPh3M(CO)5 (M = Cr, Mo, and W) by M-S bond cleavage in 1.
Compounds with unbridged dative metal-metal bonds of formula (R3P)2(OC)3OsW(CO)5 and related complexes
Jiang, Faming,Jenkins, Hilary A.,Biradha, Kumar,Davis, Harry B.,Pomeroy, Roland K.,Zaworotko, Michael J.
, p. 5049 - 5062 (2008/10/08)
Complexes of formula (R3P)2(OC)3OsW(CO)5 and similar complexes have been prepared from W(CO)5(THF) and Os(CO)3(PR3)2 in CH2Cl2/hexane at room temperature. The analogous Cr complexes could not be synthesized except for [MeC(CH2O)3P]2(OC)3OsCr(CO)5 and (Me2PCH2CH2PMe2)(OC)3OsCr(CO)5, that is, with sterically undemanding P substituents. Tungsten compounds with P ligands with cone angles greater than approx. 125° could also not be prepared. The crystal structures of (Me2PCH2CH2PMe2)(OC)3OsM(CO)5 (M = Cr, W), [MeC-(CH2O)3P]2(OC)3OsW(CO)5 (2), (OC)3(Me3P)2OsW(CO)5, (3), [MeC(CH2O)3P](OC)3(Me3P)OsW(CO)5, (4), and [(MeO)3P](OC)3(Me3P)OsW(CO)5 (5) reveal that all have unbridged OsM bonds that are considerably longer than the corresponding OsM bond in (Me3P)(OC)4OsM(CO)5. The P ligands have an axial, radial arrangement except in 3, where the PMe3 ligands have a trans, diradial orientation. In 4 and 5 the phosphite ligands are in the site trans to the OsW bond even though they have smaller cone angles than the PMe3 ligand. Solution NMR data indicates that for 2 and 3 both the ax,rad and dirad isomers are present; for 4 both ax,rad forms are present, whereas for 5 only the solid state form is found. There was no evidence in solution for the dirad forms of 4 and 5. (The 13C NMR spectra of the compounds also indicated that 2JPC becomes zero for PMC angles of about 103°). The unusual site preference of the P ligands in these molecules is interpreted in terms of steric effects and an electronic preference for a good π-acceptor ligand to adopt the position trans to the dative metal-metal bond. Complexes 2, 3, and 5 react with PPh3 in CH2Cl2 at room temperature over 2 days to give W(CO)5(PPh3) and Os(CO)3(PR3)(PR′3) in the order 3 > 5 > 2.
