@article {1062, title = {Distinctive properties of Cp {\textquoteright} M(NO)(alkyl)(2) (M = MO, W) complexes}, journal = {Organometallics}, volume = {24}, number = {17}, year = {2005}, note = {ISI Document Delivery No.: 953ZRTimes Cited: 16Cited Reference Count: 40}, month = {Aug}, pages = {4088-4098}, type = {Review}, abstract = {This account summarizes our work with the title complexes, which are rare examples of electronically and coordinatively unsaturated transition-metal alkyls that can be isolated under ambient conditions. It first outlines the synthetic methods employed for the preparation of these compounds and then presents their distinctive physical properties. It then classifies the characteristic chemical properties of these complexes in terms of the reactivity being either metal or ligand based, and specific examples of particular transformations are illustrated with reference to the most studied systems.}, keywords = {CARBON BONDS, CP{\textquoteright}M(NO)R2, INTERMOLECULAR ACTIVATION, MIGRATORY INSERTION, MOLYBDENUM, NITRIC-OXIDE, ORGANOMETALLIC NITROSYL CHEMISTRY, {C-H BONDS}, isbn = {0276-7333}, url = {://000231124400002}, author = {Blackmore, I. J. and Jin, X. and Legzdins,Peter} } @article {1169, title = {Intermolecular activation of hydrocarbon C-H bonds initiated by the tungsten hydrocarbyl hydrido complexes Cp*W(NO)(R)(H)(PMe3) (R = alkyl, aryl)}, journal = {Organometallics}, volume = {24}, number = {4}, year = {2005}, note = {ISI Document Delivery No.: 896HITimes Cited: 5Cited Reference Count: 32}, month = {Feb}, pages = {638-649}, type = {Article}, abstract = {trans-CP*W(NO)(CH2EMe3)(H)(PMe3) (E = C, Si) complexes can be prepared by the hydrogenation at 1 atm of the appropriate Cp*W(NO)(CH2EMe3)(2) precursor in the presence of a slight excess of PMe3. (Our designation of a particular geometrical isomer as cis or trans in this family of complexes indicates the relative positions of the hydrocarbyl and the hydrido ligands in the base of a four-legged piano-stool molecular structure.) The use of D-2 in place of H-2 during these syntheses affords the corresponding trans-Cp*W(NO)(CH2EMe3)(D)(PMe3) (E = C, Si) complexes. The cis-Cp*W(NO)(CH2EMe3)(H)(PMe3) isomers are obtainable by C-H bond-activation reactions of the trans precursors. Thus, activation of SiMe4 by trans-Cp*W(NO)(CH2CMe3)(H)(PMe3) under ambient conditions produces cis-Cp*W(NO)(CH2SiMe3)(H)(PMe3). Similarly, activations of C6H6 and C6D6 at 20-27 degreesC by the trans-Cp*W(NO)(CH2EMe3)(H)(PMe3) complexes produce cis-Cp*W(NO)(C6H5)(H)(PMe3) and cisCp*W(NO)(C6D5)(D)(PMe3), respectively, and the solid-state molecular structure of the latter complex has been established by a single-crystal X-ray crystallographic analysis. Kinetic, mechanistic, and theoretical investigations of these benzene C-H activation processes are consistent with initial trans to cis isomerization of the reactants followed by intramolecular reductive elimination of EMe4 to form the 16-electron Cp*W(NO)(PMe3) intermediate. Subsequent oxidative addition of the incoming benzene substrate to this coordinatively unsaturated intermediate produces the final cis hydrido phenyl complex. These single C-H activation processes are the requisite first steps in the development of these organometallic complexes as catalysts for the selective functionalization of hydrocarbons. All new complexes have been characterized by conventional spectroscopic methods.}, keywords = {CALCULATIONS, density, EFFECTIVE CORE POTENTIALS, MOLECULAR, MOLYBDENUM, ORGANOMETALLIC NITROSYL CHEMISTRY, REACTIVITY}, isbn = {0276-7333}, url = {://000226924800024}, author = {Lee, K. and Legzdins,Peter and Pamplin, C. B. and Patrick, B. O. and Wada, K.} } @article {1140, title = {Parallel transformations of cyclohexene mediated by the Cp*W(NO) fragment}, journal = {Journal of the American Chemical Society}, volume = {127}, number = {19}, year = {2005}, note = {ISI Document Delivery No.: 925WWTimes Cited: 6Cited Reference Count: 10}, month = {May}, pages = {6928-6929}, type = {Article}, keywords = {C-H BONDS, COMPLEXES, ORGANOMETALLIC NITROSYL CHEMISTRY, THERMAL-ACTIVATION, TUNGSTEN}, isbn = {0002-7863}, url = {://000229085200008}, author = {Jin, X. and Legzdins,Peter and Buschhaus, M. S. A.} } @article {699, title = {Thermal activation of hydrocarbon C-H bonds initiated by a tungsten allyl complex}, journal = {Journal of the American Chemical Society}, volume = {125}, number = {49}, year = {2003}, note = {ISI Document Delivery No.: 750QETimes Cited: 12Cited Reference Count: 62}, month = {Dec}, pages = {15210-15223}, type = {Article}, abstract = {Gentle thermolysis of the allyl complex, (CpW)-W-*(NO)(CH2CMe3)(eta(3)-H2CCHCMe2) (1), at 50 degreesC in neat hydrocarbon solutions results in the loss of neopentane and the generation of transient intermediates that subsequently activate solvent C-H bonds. Thus, thermal reactions of 1 with tetramethylsilane, mesitylene, and benzene effect single C-H activations and lead to the exclusive formation of (CpW)-W-*(NO)(CH2SiMe3)(eta(3)-H2CCHCMe2) (2), (CpW)-W-*(NO)(CH2C6H3-3,5-Me-2)(eta(3)-H2CCHCMe2) (3), and (CpW)-W-*(NO)(C6H5)(eta(3)-H2CCHCMe2) (4), respectively. The products of reactions of 1 with other methyl-substituted arenes indicate an inherent preference of the system for the activation of stronger arene sp(2) C-H bonds. For example, C-H bond activation of p-xylene leads to the formation of (CpW)-W-*(NO)(CH2C6H4-4-Me)(eta(3)-H2CCHCMe2) (5) (26\%) and (CpW)-W-*(NO)(C6H3-2,5-Me-2)(eta(3)-H2CCHCMe2) (6) (74\%). Mechanistic and labeling studies indicate that the transient C-H-activating intermediates are the allene complex, (CpW)-W-*(NO)(eta(2)-H2C=C=CMe2) (A), and the eta(2)-diene complex, (CpW)-W-*(NO)(eta(2)-H2C=CHC(Me)=CH2) (B). Intermediates A and B react with cyclohexene to form (CpW)-W-*(NO)(eta(3)-CH2C(2-cyclohexenyl)CMe2)(H) (18) and (CpW)-W-*(NO)(eta(3)-CH2CHC)(Me)CH2CbetaH(C4H8)CalphaH (19), respectively, and intermediate A can be isolated as its PMe3 adduct, (CpW)-W-*(NO)(PMe3)(eta(2)-H2C=C=CMe2) (20). Interestingly, thermal reaction of 1 with 2,3-dimethylbut-2-ene results in the formation of a species that undergoes eta(3) {\textendash}> eta(1) isomerization of the dimethylallyl ligand following the initial C-H bond-activating step to yield (CpW)-W-*(NO)(eta(3)-CMe2CMeCH2)(eta(1)-CH2CHCMe2) (21). Thermolyses of 1 in alkane solvents afford allyl hydride complexes resulting from three successive C-H bond-activation reactions. For instance, 1 in cyclohexane converts to (CpW)-W-*(NO)(eta(3)-C6H9)(H) (22) with dimethylpropylcyclohexane being formed as a byproduct, and in methylcyclohexane it forms the two isomeric complexes, (CpW)-W-*(NO)(eta(3)-C7H11)(H) (23a,b). All new complexes have been characterized by conventional spectroscopic methods, and the solid-state molecular structures of 2, 3, 4, 18, 19, 20, and 21 have been established by X-ray crystallographic analyses.}, keywords = {ALKYLIDENE COMPLEXES, ALLENE, CHEMICAL-PROPERTIES, COMPLEXES, CRYSTAL-STRUCTURE, ETA-3-ALLYL COMPLEXES, MOLECULAR-STRUCTURE, ORGANOMETALLIC NITROSYL CHEMISTRY, SOLID-STATE, STRUCTURAL CHARACTERIZATION, TRANSITION-METAL COMPLEXES}, isbn = {0002-7863}, url = {://000187007400050}, author = {Ng, S. H. K. and Adams, C. S. and Hayton, T. W. and Legzdins,Peter and Patrick, B. O.} } @article {328, title = {C-H activation of substituted arenes by tungsten alkylidene complexes: Products, selectivity, and mechanism}, journal = {Organometallics}, volume = {21}, number = {7}, year = {2002}, note = {ISI Document Delivery No.: 534QZTimes Cited: 18Cited Reference Count: 35}, month = {Apr}, pages = {1474-1486}, type = {Article}, abstract = {Thermolyses (70 degreesC, 40 h) of Cp*W(NO)(CH2CMe3)(2) (1) and Cp*W(NO)(CH2CMe3)(CH2C6H5) (2) in xylenes, mesitylene, and a,a,(x-trifluorotoluene generate mixtures of the corresponding aryl and/or benzyl products derived from aromatic sp(2) and benzylic sp(3) C-H bond activations of the solvent molecules by the intermediate alkylidene complexes Cp*W(NO)(=CHCMe3)(sigma-CMe4) (sigma-A) and Cp*W(NO)(=CHC6H5)(sigma-CMe4) (sigma-B), respectively. For instance, the thermolysis of 1 in p-xylene affords products resulting from the activation of one and two molecules of p-xylene. The two products derived from the activation of one solvent molecule are Cp*W(NO)(CH2CMe3)(C6H3-2,5-Me-2) (10) and CP*W(NO)(CH2CMe3)(CH2C6H4-4-Me)(2) (11). The other two complexes derived from the activation of two solvent molecules are Cp*W(NO)(CH2C6H4-4-Me)(C6H4-2,5-Me-2) (12) and Cp*W(NO)(CH2C6H4-4Me)(2) (13). The ratio of the four products in the final reaction mixture is 10:11:12:13 = 1.81 +/- 0.09:0.44 +/- 0.05:1.0:0.15 +/- 0.02. All new complexes prepared have been characterized as fully as possible by conventional spectroscopic methods, and the solid-state molecular structures of Cp*W(NO)(CH2C6H5)(C6H3-3,5-Me-2) (7) and Cp*W(NO)(CH2C6H5)(CH2C6H3-3,5-Me-2) (9) have been established by X-ray diffraction methods. Analyses of the product distributions resulting from the various thermolyses indicate that the benzyl products are increasingly favored over the aryl products as the number of methyl substituents on the solvent molecule increases. Likewise, the movement of the methyl groups from the ortho to meta to para position in the xylenes shifts the aryl vs benzyl product distribution toward the benzyl products. With respect to the aryl product regioselectivities, only the least sterically congested aryl regioisomers are formed in the activations of o- and m-xylene, while the meta and para aryl products are formed preferentially for (x,(x,(x-trifluorotoluene. Finally, the distributions obtained from sigma-B are more abundant in the aryl products than are those obtained from a-A. However, despite these general trends, it is also apparent that the origin of the observed product selectivities is highly dependent on the nature of the substrate, the nature of the C-H activation products, and the intermediate alkylidene complex.}, keywords = {1, 2-RH-ELIMINATION, ARYL, BOND ACTIVATION, CARBON-HYDROGEN, FUNCTIONALIZATION, HYDROCARBON ACTIVATION, METHANE, MOLYBDENUM, ORGANOMETALLIC NITROSYL CHEMISTRY, REVERSIBLE, THERMOLYSIS}, isbn = {0276-7333}, url = {://000174599400020}, author = {Adams, C. S. and Legzdins,Peter and Tran, E.} } @article {5196, title = {The elusive 16-electron Cp*M(NO)Me-2 (M = Mo, W) complexes and their spontaneous conversions to Cp*M(NMe)(O)Me isomers}, journal = {Journal of the American Chemical Society}, volume = {123}, number = {26}, year = {2001}, note = {ISI Document Delivery No.: 447QPTimes Cited: 17Cited Reference Count: 115}, month = {Jul}, pages = {6272-6282}, type = {Review}, abstract = {Treatment of [Cp*Mo(NO)Cl mu(-Cl)](2) with magnesium (Me2Mg.dioxane, MeMgCl) or aluminum (Me3Al) methylating reagents affords the known compound [Cp*Mo(NO)Me(mu 0Cl)](2) (1). Similar treatment of the dicbloro precursor with MeLi in ethereal solvents generates an equimolar mixture of 1 and the trimethyl "ate" complex, Cp*MoMe3(NO-Li(OEt2)(n)). (2-Et2O). Reaction of 2-Et2O with a source of [Me](+) forms Cp*MoMe3(dropN-OMe) (3), a rare terminal alkoxylimido complex. Metathesis of the chloro ligands of [Cp*Mo-(NO)Cl(mu -Cl)](2) by MeLi in toluene at low temperatures produces the target dimethyl complex. Cp*Mo(NO)-Me-2 (4). in 75\% isolated yield. In solution, 4 is predominantly a monomeric species, whereas in the solid state it adopts a dimeric or oligomeric structure containing isonitrosyl bridges as indicated by IR and N-15/C-13 NMR spectroscopies. Hydrolysis of 4 affords meso- and rac-[Cp*Mo(NO)Me](2)(mu -O)(5), and the reactions of 4 with a range of Lewis bases. L, to form the 18e adducts Cp*Mo(NO)(L)Me-2 (e.g., Cp*Mo(NO)(PMe3)Me-2 (7)), have established it to be the most electrophilic complex of its family. Acidolysis of the methyl groups of 4 is also facile. Most notably, 4 is thermally unstable in solution and undergoes isomerization via nitrosyl N-O bond cleavage to its oxo(imido) form, Cp*Mo(NMe)(O)Me (11), which is isolable from the final reaction mixture as the mu -oxo-bridged adduct formed by 4 and 11, i.e., Cp*Mo(NO)Me2(mu -O)Cp*Mo(NMe)Me (4 <{\textendash} 11). The rate of this isomerization is significantly faster for the tungsten dimethyl complex; hence, Cp*W(NO)- (NO)Me-2 (12) is not isolable free of a supporting donor interaction and can only be isolated as Cp*W(NO)-Me-2(mu -O)Cp*W(NMe)Me (12 <{\textendash} 13) or Cp*W(NO)Me-2(PMe3) (14) adducts.}, keywords = {ALPHA-OLEFINS, COORDINATED NITRIC-OXIDE, CRYSTAL-STRUCTURE, EFFECTIVE CORE POTENTIALS, INSERTION, LIGAND REDISTRIBUTION REACTIONS, MIGRATORY, MOLECULAR CALCULATIONS, OLEFIN POLYMERIZATION, ORGANOMETALLIC NITROSYL CHEMISTRY, POLYMERIZATION CATALYSTS}, isbn = {0002-7863}, url = {://000169584200009}, author = {Sharp, W. B. and Daff, P. J. and McNeil, W. S. and Legzdins,Peter} } @article {4995, title = {Intermolecular C-H activation of hydrocarbons by tungsten alkylidene complexes: An experimental and computational mechanistic study}, journal = {Organometallics}, volume = {20}, number = {23}, year = {2001}, note = {ISI Document Delivery No.: 493VBTimes Cited: 17Cited Reference Count: 65}, month = {Nov}, pages = {4939-4955}, type = {Article}, abstract = {Cp*W(NO)(CH2CMe3)(2) (1) and Cp*W(NO)(CH2CMe3)(CH2C6H5) (2) under moderate conditions (70 degreesC, 40 h) generate the reactive complexes Cp*W(NO)(=CHCMe3) (A) and Cp*W(NO)(=CHC6H5) (B), respectively, which activate hydrocarbon solvents via the addition of C-H across the M=C bond. The alpha -deuterated derivative Cp*W(NO)(CD2CMe3)(2) (1-d(4)) undergoes intramolecular H/D exchange within the neopentyl ligands, consistent with the formation of a-neopentane complexes prior to neopentane elimination. The thermolysis of 1 in a 1:1 molar mixture of tetramethylsilane-h(12) and tetramethylsilane-d(12) (70 degreesC, 40 h) yields an intermolecular KIE of 1.07(4):1. Thermolysis of I and 2 in 1:1 benzene/benzene-d(6) yields intermolecular KIEs of 1.03(5):1 and 1.17(19):1, respectively. The KIE values are inconsistent with rate-determining C-H bond addition to the M=C linkage and indicate that coordination of the substrate to the metal center is the discriminating factor in alkane and arene intermolecular competitions. The complexes Cp*W(NO)(CH2CMe3)(C6D5) (5-d(5)) and CP*W(NO)(CH2C6H5)(C6D5) (6-d(5)) convert to the respective H/D scrambled products Cp*W(NO)(CHDsynCMe3)(C6D4H1) (5{\textquoteright}-d(5)) and Cp*W(NO)(CHDsynC6H5)(C6D4H1) (6{\textquoteright}-d(5)) under thermolytic conditions, consistent with the occurrence of reversible aromatic sp(2) C-H bond cleavage. The results suggest that the previously reported discrimination between the aryl and benzyl products of toluene activation by A and B originates from coordination of toluene to the metal center in two distinct modes. Supporting DFT calculations on the activation of toluene by CpW(NO)(=CH2) (C) indicate that aromatic sp(2) C-H bond activation proceeds through a pi -arene complex, while benzylic sp(3) C-H bond activation proceeds through a eta (2)(C,H),sigma -phenylmethane complex. The principal factor behind the preferential formation of the aryl products appears to be the relative energies of formation of these intermediates.}, keywords = {BOND ACTIVATION, EFFECTIVE CORE POTENTIALS, EXCHANGE, METAL-ALKANE COMPLEXES, METHANE, METHYL-HYDRIDE, MOLECULAR CALCULATIONS, MOLYBDENUM, ORGANOMETALLIC NITROSYL CHEMISTRY, REDUCTIVE ELIMINATION}, isbn = {0276-7333}, url = {://000172243200026}, author = {Adams, C. S. and Legzdins,Peter and McNeil, W. S.} } @article {4669, title = {A computational study of two-state conformational changes in 16-electron [CpW(NO)(L)] complexes (L = PH3, CO, CH2, HCCH, H2CCH2)}, journal = {Chemistry-a European Journal}, volume = {5}, number = {5}, year = {1999}, note = {ISI Document Delivery No.: 194UQTimes Cited: 20Cited Reference Count: 52}, month = {May}, pages = {1598-1608}, type = {Article}, abstract = {Electronically and coordinatively unsaturated [Cp*W(NO)(L)] complexes have been postulated as intermediates in several related systems. Model [CpW(NO)(L)] compounds (L= PH3, CO, CH2, H2CCH2, HCCH) have been investigated theoretically by means of density functional theory computational techniques. The structural parameters calculated for saturated [CpW(NO)(PH,)(L)] complexes are in good agreement with the solid-state molecular structures determined crystallographically for the corresponding [Cp*W(NO)(PMe3)(L)] compounds. The 16-electron, singlet [CpW(NO)(L)] species have geometries comparable to those of the same fragment in the phosphine adducts and include a highly pyramidal conformation at W. The energy of the triplet spin state is calculated to be close to or even lower than that of the singlet state for these unsaturated compounds, and depends largely on the pi-bonding capabilities of L (Delta Es-t=Delta E-t-Delta E-s = - 3.3 kcalmol(-1) (PH3), + 2.8 (CO), + 2.4 (CH2), +6.3 (H2CCH2), -2.3 (HCCH)). The optimization of partially constrained structures in both spin states allows for a conformational analysis of the [CpW(NO)(L)] species. The inversion of the conformation of the pyramidal singlet [CpW(NO)(L)] complexes via the planar-at-W triplet species (two-state pathway) is calculated to be competitive with the equivalent process solely along the singlet spin hypersurface. Rotation of the W-CH, bond in the singlet carbene species is also found to proceed more readily via a two-state pathway. The preferred alkyne conformation, the unusually stable triplet states, and the strong W-to-L sc-donation observed in these systems may all be rationalized by the relatively high energies of the occupied orbitals of the formally WO compounds.}, keywords = {ACTIVATION, CROSSOVER, density functional calculations, H BOND, LIGAND, ligand effects, MOLECULAR CALCULATIONS, ORGANOMETALLIC NITROSYL CHEMISTRY, OXIDATIVE ADDITION, pi interactions, PIANO-STOOL COMPLEXES, REACTIVITY, REDUCTIVE ELIMINATION, SPIN, SPIN-STATE, TUNGSTEN}, isbn = {0947-6539}, url = {://000080212600026}, author = {Smith, K. M. and Poli, R. and Legzdins,Peter} } @article {4517, title = {Hydrocarbon C-H bond activation by a tungsten acetylene complex}, journal = {Organometallics}, volume = {18}, number = {17}, year = {1999}, note = {ISI Document Delivery No.: 230KBTimes Cited: 13Cited Reference Count: 60}, month = {Aug}, pages = {3414-3428}, type = {Article}, abstract = {Thermal activation of Cp*W(NO)(eta(2)-CPhCH2)(CH2SiMe3) (1) in neat hydrocarbon solutions transiently generates Cp*W(NO)(eta(2)-PhC=CH) (A), which subsequently activates solvent C-H bonds. For example, the thermolysis of 1 in benzene solution generates quantitatively Cp*W(NO)(eta(2)-CPhCH2)(Ph) (2) The thermolysis of 1 in solutions of methyl-substituted arenes such as toluene or p-, m-, or o-xylene provides mixtures of aryl and benzyl vinyl complexes of the general formulas Cp*W(NO)(eta(2)-CPhCH2)(aryl), Cp*W(NO)(eta(2)-CPhCH2)(eta(1)-benzyl), or Cp*W(NO)(eta(2)-benzyl)(eta(1)-CPh=CH2). Similarly, the thermolysis of 1 in (Me3Si)(2)O affords Cp*W(NO)(eta(2)-CPhCH2)(CH2SiMe2OSiMe3) (10). Mechanistic and kinetic studies support the proposal that the formation of A from 1 by elimination of silane is the rate-controlling process in these reactions. Intra- and intermolecular selectivity studies reveal that the strongest C-H bond (yielding the stronger M-C bond) is the preferred site of reactivity, as expected. Dual C-H bond activation of aliphatic hydrocarbons occurs during the thermal activation ;of I in solutions of these substrates. Consequently, metallacycles of the form Cp*W(NO)(eta(2)-CH(eta(2)-Ph)CH2CH(R)CH2) [(11)R = Pr-n; (12)R = Bu-n; (13)R = Bu-t; and (14)R = OEt] result from the dehydrogenation of n-pentane, n-hexane, 2,2-dimethylbutane, and diethyl ether, respectively. This dual C-H activation process displays a selectivity for substrates that contain an ethyl substituent. Dual C-H bond activation of 2,3-dimethyl-2-butene in the presence of 1 under thermolysis conditions regioselectively affords Cp*W(NO)(eta(3)-endo-CH2C(Me)C(Me)CH2(eta(1)-CPhMe)) (15), Attempts to trap acetylene complex A with PNMe3 result in the formation of the metallacyclopropane complex Cp*W(NO)(CH2SiMe3)(eta(2)-CH2CPh(PMe3)) (16). All new complexes have been characterized by conventional spectroscopic methods, and the solid-state molecular structures of compounds 11, 15, and 16 have been established by X-ray diffraction methods.}, keywords = {ELIMINATION, HYDROGEN-TRANSFER, ISOMERIZATION, LIGAND, METAL-COMPLEXES, MOLECULAR-STRUCTURE, ORGANIC-SYNTHESIS, ORGANOMETALLIC NITROSYL CHEMISTRY, OXIDATIVE ADDITION, REDUCTIVE, R{\textquoteright} =}, isbn = {0276-7333}, url = {://000082249400023}, author = {Debad, D. and Legzdins,Peter and Lumb, S. A. and Rettig, S. J. and Batchelor, R. J. and Einstein, F. W. B.} } @article {4325, title = {Ligand elaboration mediated by a Cp*W(NO) template: Stepwise incorporation of small molecules into a tungsten vinyl fragment}, journal = {Organometallics}, volume = {17}, number = {5}, year = {1998}, note = {ISI Document Delivery No.: ZC012Times Cited: 21Cited Reference Count: 81}, month = {Mar}, pages = {854-871}, type = {Article}, abstract = {{Thermolysis of the alkyl vinyl complex Cp*W(NO)(CH2SiMe3)(CPh=CH2) (1) in the presence of unsaturated, heteroatom-containing compounds such as esters and nitriles quantitatively affords metallacyclic products of reductive coupling. These are trapped as 18e complexes via either intramolecular rearrangement or intermolecular reaction with added trapping reagents. The nature of these metallacycles is consistent with the intermediacy of the acetylene complex Cp*W(NO)(eta(2)-CPh=CH) (A) derived in situ from the reductive elimination of SiMe4 from 1. With esters ROAc (R = Me, Et), reductive coupling and C-O bond cleavage yields the alkoxide-containing oxametallacyclopentadiene complexes Cp*W-(No)(eta(2)-O=C(Me)CH=CPh)(OR) (2}, keywords = {ACTIVATION, ALKYNE COMPLEXES, BOND-CLEAVAGE, C-H, INSERTION, KETONE COMPLEXES, METAL-COMPLEXES, ORGANIC-SYNTHESIS, ORGANOMETALLIC NITROSYL CHEMISTRY, RAY CRYSTAL-STRUCTURE, SEQUENTIAL, ZIRCONOCENE COMPLEXES}, isbn = {0276-7333}, url = {://000072530700014}, author = {Legzdins,Peter and Lumb, S. A. and Young, V. G.} } @article {3420, title = {SPONTANEOUS ISOMERIZATION OF SYMMETRICAL M(MU-NO)(2)M LINKAGES TO (ON)M=N=M=O GROUPINGS}, journal = {Journal of the American Chemical Society}, volume = {117}, number = {34}, year = {1995}, note = {ISI Document Delivery No.: RR735Times Cited: 13Cited Reference Count: 50}, month = {Aug}, pages = {8798-8806}, type = {Article}, abstract = {{Treatment of Cp*Mo(NO)R(2) complexes (Cp* = eta(5)-C(5)Me(5); R = CH(2)CMe(3), CH(2)CMe(2)Ph) in C6H6 at 5 degrees C with H-2 results in the formation of [Cp*MoR](2)(mu-NO)(2) products (R = CH(2)CMe(3) (1), CH(2)CMe(2)Ph (2)) which are isolable in 25-30\% yields. Similar treatment of an equimolar mixture of Cp*Mo(NO)(CH(2)SiMe(3))(2) and Cp*W(NO)(CH(2)SiMe(3))(2) with H-2 results in the formation of a heterobimetallic species, [Cp*Mo(CH(2)SiMe(3))](mu-NO)(2)[Cp*W(CH(2)SiMe(3))] (3). Complexes 1, 2, and 3 isomerize in solution at ambient temperatures To form [Cp*Mo-(NO)R](mu-N)[Cp*Mo(O)R] (R = CH(2)CMe(3) (4), CH(2)CMe(2)Ph (5)) and a 60:40 (M(1) = W:M(1) = Mo) mixture of [Cp*M(1)(NO)(CH(2)SiMe(3))](mu-N)[Cp*M(2)(O)(CH(2)SiM(3))] (6), respectively. The solid-state molecular structures of 1 and 6 have been established by single-crystal X-ray crystallographic analyses. Crystals of [Cp*Mo(CH(2)CMe(3))](2)-(mu-NO)(2) (1) are orthorhombic of space group Pbcn: a = 12.570(3) Angstrom}, keywords = {(ETA-5-C5ME5)RU(NO), BOND, COMPLEXES, GAS-PHASE, LIGANDS, MOLYBDENUM, NITRIC-OXIDE, ORGANOMETALLIC NITROSYL CHEMISTRY, OXIDATIVE ADDITION-REACTIONS, TUNGSTEN}, isbn = {0002-7863}, url = {://A1995RR73500013}, author = {Legzdins,Peter and Young, M. A. and Batchelor, R. J. and Einstein, F. W. B.} } @article {3102, title = {ALKYL-FOR-IODIDE METATHESIS INITIATED BY DISSOCIATION OF THE PHOSPHINE LIGAND FROM CPCR(NO)(PPH3)I}, journal = {Journal of the American Chemical Society}, volume = {116}, number = {17}, year = {1994}, note = {ISI Document Delivery No.: PD697Times Cited: 6Cited Reference Count: 20}, month = {Aug}, pages = {7700-7705}, type = {Article}, abstract = {{The alkyl-for-iodide metathesis reaction that occurs when CpCr(NO)(PPh(3))I (1) is treated with 2 equiv of Me(3)SiCH(2)MgCl in THF to form CpCr(NO)(PPh(3))(CH(2)SiMe(3)) (6) has been investigated in some detail. The conversion is initiated by loss of the phosphine ligand from the chromium atom{\textquoteright}s coordination sphere, the most compelling evidence for this step being that addition of excess phosphine (e.g. 4 equiv) to the initial reaction mixture completely inhibits the reaction. Four intermediate complexes which are formed sequentially on the reaction path from 1 to 6 have been detected by IR and ESR spectroscopy. These complexes have been identified as CpCr(NO)(THF)I (2), CpCr-(NO{\textendash}>Mg{CH(2)SiMe(3)})Cl)(THF)I (3), CpCr(NO{\textendash}>Mg{CH(2)SiMe(3)}Cl)(THF)(CH(2)SiMe(3)) (4), and CpCr(NO) (THF)(CH(2)SiMe(3)) (5). Complexes 3 and 4 have also been detected spectroscopically during the reaction of CpCr(NO)(THF)I (2) with Me(3)SiCH(2)MgCl which produces CpCr(NO)(THF)(CH(2)SiMe(3)) (5). This understanding of the mechanistic pathway has resulted in the development of a general synthetic route to previously inaccessible 17-valence-electron CpCr(NO)(L)R complexes (L = C5H11N Or NH(2)CMe(3)}, keywords = {COMPLEXES, MECHANISM, MO, MOLYBDENUM, ORGANOMETALLIC NITROSYL CHEMISTRY, TUNGSTEN}, isbn = {0002-7863}, url = {://A1994PD69700029}, author = {Legzdins,Peter and Shaw, M. J.} } @article {3099, title = {SYNTHESIS, CHARACTERIZATION, AND REDOX PROPERTIES OF THE 17-VALENCE-ELECTRON COMPLEXES CP{\textquoteright}CR(NO)(L)X}, journal = {Organometallics}, volume = {13}, number = {2}, year = {1994}, note = {ISI Document Delivery No.: MX338Times Cited: 8Cited Reference Count: 35}, month = {Feb}, pages = {562-568}, type = {Article}, abstract = {Treatment of CH2Cl2 solutions of [Cp{\textquoteright}Cr(NO)I]2 [CP{\textquoteright}= Cp (eta5-C5H5) or Cp* (eta5-C5Me5)] with various P- and N-containing Lewis bases, L, affords good yields of Cp{\textquoteright}Cr(NO)(L)I complexes [L = PPh3, P(OMe)3, P(OPh)3, py, or C5H11N (pip)]. Photolysis of toluene solutions of CpCr(NO)(CO)2 in the presence of PPh3 and a source of halogen such as CH2Cl2 results in a 63\% isolated yield of CpCr(NO)(PPh3)Cl. In donor solvents, S, the ESR-active CpCr(NO)(L)X (X = Cl, I) compounds undergo either L or X substitution to form the 17-valence-electron CpCr-(NO)(S)X and [CpCr(NO)(L)(S)+ species, respectively. A kinetic analysis of the reaction of CpCr(NO)(THF)I with PPh3 shows the process to be second-order overall (first-order in each reactant) and associative in nature. The reduction potentials for the various CpCr(NO)(L)X complexes in THF vary from -1.05 to -1.65 V. These reductions are irreversible and are followed by loss of X-. Consistently, reduction of CpCr(NO)(PPh3)I in THF by Zn in the presence of P(OPh)3 affords the 18-valence-electron mixed phosphine-phosphite complex, CpCr(NO)(PPh3)[P(OPh)3]. The redox chemistry of the CpCr(NO)(L)X complexes is thus unusual in that the odd-electron species are substitutionally less labile than are, their 18-electron reduction products.}, keywords = {19-ELECTRON, carbonyl ligands, COMPLEXES, COMPOUNDS, ME, METAL-CENTERED RADICALS, ORGANOMETALLIC NITROSYL CHEMISTRY, phosphine, {17-ELECTRON}, isbn = {0276-7333}, url = {://A1994MX33800030}, author = {Legzdins,Peter and McNeil, W. S. and Shaw, M. J.} } @article {2857, title = {CP{\textquoteright}M(NO)R2 - 16-ELECTRON PIANO-STOOL MOLECULES OF MOLYBDENUM AND TUNGSTEN}, journal = {Accounts of Chemical Research}, volume = {26}, number = {2}, year = {1993}, note = {ISI Document Delivery No.: KM450Times Cited: 48Cited Reference Count: 37}, month = {Feb}, pages = {41-48}, type = {Review}, keywords = {ALKYL, COMPLEXES, CRYSTAL-STRUCTURES, LIGANDS, ORGANOMETALLIC NITROSYL CHEMISTRY}, isbn = {0001-4842}, url = {://A1993KM45000002}, author = {Legzdins,Peter and Veltheer, J. E.} } @article {2730, title = {INSERTIONS OF HETEROCUMULENES INTO THE M-C SIGMA-BONDS OF CP-ASTERISK-M(NO)(ARYL)2 (M=MO, W) COMPLEXES}, journal = {Organometallics}, volume = {12}, number = {10}, year = {1993}, note = {ISI Document Delivery No.: MC322Times Cited: 14Cited Reference Count: 32}, month = {Oct}, pages = {4234-4240}, type = {Note}, abstract = {{Treatment of the 16-valence-electron complexes Cp*M(NO)(aryl)2 (Cp* = eta5-C5Me5; M = Mo, W; aryl = phenyl (Ph), p-tolyl) with the heterocumulenes carbon disulfide, p-tolyl isocyanate, and carbon dioxide leads to the eta2-thiocarboxylate, eta2-amide-, and eta2-carboxylate-containing complexes, respectively, in 10-65\% isolated yields. Furthermore, Cp* W(NO) (eta2-S2C-Ph)(Ph) (1) reacts with trimethylphosphine to form Cp*W(NO)(eta2-S2C(PMe3)Ph)(Ph) (10), which contains a zwitterionic phosphonium betaine ligand. The solid-state molecular structure of 10-CH2Cl2 has been established by a single-crystal X-ray crystallographic analysis. Crystal data for Cp*W(NO)(eta2-S2C(PMe3)Ph)(Ph). CH2Cl2: monoclinic}, keywords = {ALKYL, CARBON BONDS, CO2, H-BONDS, ORGANOMETALLIC NITROSYL CHEMISTRY, REACTIVITY, TUNGSTEN, WATER, X-ray structure}, isbn = {0276-7333}, url = {://A1993MC32200074}, author = {Brouwer, E. B. and Legzdins,Peter and Rettig, S. J. and Ross, K. J.} } @article {2779, title = {METAL-MEDIATED DIMERIZATION OF 1,3-CYCLOOCTADIENE TO 2-CYCLOOCT-2-EN-1-YL-1,3-CYCLOOCTADIENE - A NOVEL BICYCLIC TRIENE}, journal = {Journal of the American Chemical Society}, volume = {115}, number = {5}, year = {1993}, note = {ISI Document Delivery No.: KR825Times Cited: 17Cited Reference Count: 8}, month = {Mar}, pages = {2051-2052}, type = {Note}, keywords = {COMPLEXES, ORGANOMETALLIC NITROSYL CHEMISTRY, REACTIVITIES}, isbn = {0002-7863}, url = {://A1993KR82500069}, author = {Debad, J. D. and Legzdins,Peter and Young, M. A. and Batchelor, R. J. and Einstein, F. W. B.} } @article {2731, title = {NOVEL ROUTE TO THE UNSYMMETRICAL DIALKYL COMPLEX CPW(NO)(CH2SIME3)(CH2CPH3) AND FORMATION OF METALLACYCLES BY THERMOLYSIS OF CPW(NO)(CH2SIME3)(CH2CR2PH) (R=ME, PH)}, journal = {Organometallics}, volume = {12}, number = {11}, year = {1993}, note = {ISI Document Delivery No.: MH645Times Cited: 7Cited Reference Count: 33}, month = {Nov}, pages = {4572-4579}, type = {Article}, abstract = {{Treatment of CpW(NO)(CH2SiMe3)2 (CP =eta5-C5H5) with [Ph3C]PF6 results in cleavage of the Si-C bond and formation of the unsymmetrical dialkyl complex CpW(NO) (CH2SiMe3)(CH2CPh3) (1). Crystal data for 1: a = 10.930(2) angstrom}, keywords = {MO, ORGANOMETALLIC NITROSYL CHEMISTRY, TUNGSTEN}, isbn = {0276-7333}, url = {://A1993MH64500048}, author = {Brunet, N. and Debad, J. D. and Legzdins,Peter and Trotter, J. and Veltheer, J. E. and Yee, V. C.} } @article {2731, title = {NOVEL ROUTE TO THE UNSYMMETRICAL DIALKYL COMPLEX CPW(NO)(CH2SIME3)(CH2CPH3) AND FORMATION OF METALLACYCLES BY THERMOLYSIS OF CPW(NO)(CH2SIME3)(CH2CR2PH) (R=ME, PH)}, journal = {Organometallics}, volume = {12}, number = {11}, year = {1993}, note = {ISI Document Delivery No.: MH645Times Cited: 7Cited Reference Count: 33}, month = {Nov}, pages = {4572-4579}, type = {Article}, abstract = {{Treatment of CpW(NO)(CH2SiMe3)2 (CP =eta5-C5H5) with [Ph3C]PF6 results in cleavage of the Si-C bond and formation of the unsymmetrical dialkyl complex CpW(NO) (CH2SiMe3)(CH2CPh3) (1). Crystal data for 1: a = 10.930(2) angstrom}, keywords = {MO, ORGANOMETALLIC NITROSYL CHEMISTRY, TUNGSTEN}, isbn = {0276-7333}, url = {://A1993MH64500048}, author = {Brunet, N. and Debad, J. D. and Legzdins,Peter and Trotter, J. and Veltheer, J. E. and Yee, V. C.} } @article {2785, title = {REACTIONS OF 16-ELECTRON CP{\textquoteright}M(NO)R2 COMPOUNDS [M = MO, W R = ALKYL, ARYL] WITH CARBON-MONOXIDE}, journal = {Organometallics}, volume = {12}, number = {6}, year = {1993}, note = {ISI Document Delivery No.: LG158Times Cited: 14Cited Reference Count: 28}, month = {Jun}, pages = {2085-2093}, type = {Article}, abstract = {{This paper reports the reactions of 16-electron Cp{\textquoteright}M(NO)R2 complexes [Cp{\textquoteright} = CP (eta5-C5H5), Cp* (eta5-C5Me5); M = Mo, W; R = alkyl, aryl] with carbon monoxide. The reactions proceed in a stepwise fashion, and their outcomes are dependent on both the natures of Cp{\textquoteright} and R and the experimental conditions employed. Thus, treatment of solutions of Cp{\textquoteright}W(NO)R2 with CO under ambient conditions affords the corresponding 18-electron monoacyl species Cp{\textquoteright}W(NO)-(eta2-C{O}R) (R) (Cp{\textquoteright} = Cp*}, keywords = {COORDINATION, CRYSTAL, ETA-2-ACYL COMPLEXES, MOLYBDENUM, ORGANOMETALLIC NITROSYL CHEMISTRY, TUNGSTEN}, isbn = {0276-7333}, url = {://A1993LG15800019}, author = {Dryden, N. H. and Legzdins,Peter and Lundmark, P. J. and Riesen, A. and Einstein, F. W. B.} } @article {2778, title = {REACTIVITY OF THE LEWIS-ACIDS CP-ASTERISK-M(NO)(CH2CME3)CL [M = MO, W] AND RELATED COMPLEXES}, journal = {Organometallics}, volume = {12}, number = {7}, year = {1993}, note = {ISI Document Delivery No.: LU682Times Cited: 26Cited Reference Count: 43}, month = {Jul}, pages = {2714-2725}, type = {Article}, abstract = {{Treatments of Cp*M(NO)Cl2 [Cp* = eta5-C5Me5; M = Mo, W] with 0.5 equiv of (Me3CCH2)2Mg.X(dioxane) in THF at low temperatures affords the monoalkylated complexes, Cp*M(NO)(CH2CMe3)Cl (1, 1{\textquoteright}). Exposure to a second 0.5 equiv of (Me3CCH2)2Mg.X(dioxane) at higher temperatures produces the dialkyl complexes, Cp*M(NO)(CH2CMe3)2 (2,2{\textquoteright}). Utilizing the two series of Cp*M(NO)Cl2, Cp*M(NO)(CH2CMe3)Cl and Cp*M(NO)(CH2CMe3)2 complexes, the relative electron deficiencies in these 16-electron complexes can be assessed spectroscopically and electrochemically. Without exception, the Mo complexes are the stronger Lewis acids. Also, the mononeopentyl derivatives for both metals are more reactive toward a variety of substrates than are their bis(neopentyl) analogues. Complexes 1 and 1{\textquoteright} serve as precursors to mixed alkyl and alkyl aryl complexes (3, 3{\textquoteright}, 4, 4{\textquoteright}) and yield metal-centered adducts with PMe3 and pyridine (5, 5{\textquoteright}, 6, 6{\textquoteright}). CO and CNCMe3 readily insert into the M-C bonds of 1 and 1{\textquoteright}. The insertion products, Cp*M(NO)(C{E}CH2CMe3)Cl (7, 7{\textquoteright}}, keywords = {ALKYL, C-H, CARBONYLATION, CONVERSION, DERIVATIVES, H ACTIVATION REACTIONS, MIGRATORY INSERTION, MOLYBDENUM, ORGANOMETALLIC NITROSYL CHEMISTRY, TUNGSTEN}, isbn = {0276-7333}, url = {://A1993LU68200046}, author = {Debad, J. D. and Legzdins,Peter and Rettig, S. J. and Veltheer, J. E.} } @article {2853, title = {SYNTHESIS, CHARACTERIZATION, AND REACTIVITY OF ALKOXO COMPLEXES CONTAINING CP-ASTERISK-M(NO) GROUPS (M=MO, W)}, journal = {Organometallics}, volume = {12}, number = {9}, year = {1993}, note = {ISI Document Delivery No.: LX172Times Cited: 11Cited Reference Count: 29}, month = {Sep}, pages = {3545-3552}, type = {Article}, abstract = {{Stepwise treatment of Cp*M(NO)Cl2 [CP* = eta5-C5Me5;M = Mo,W] in THF at low temperatures with 2 equiv of alkoxide anion affords first Cp*M(NO)(OR)CI complexes and then the bis(alkoxo) compounds Cp*M(NO)(OR)2 [M = Mo}, keywords = {ALKYL, MOLYBDENUM, ORGANOMETALLIC NITROSYL CHEMISTRY, PI-DONATION, TUNGSTEN}, isbn = {0276-7333}, url = {://A1993LX17200029}, author = {Legzdins,Peter and Lundmark, P. J. and Rettig, S. J.} } @article {2856, title = {THERMAL CHEMISTRY OF CPMO(NO)(CH2CME3)2 - LEWIS BASE ADDUCTS OF CPMO(NO)(=CHCME3) AND A NEW BONDING MODE FOR NITRIC-OXIDE}, journal = {Organometallics}, volume = {12}, number = {9}, year = {1993}, note = {ISI Document Delivery No.: LX172Times Cited: 28Cited Reference Count: 55}, month = {Sep}, pages = {3575-3585}, type = {Article}, abstract = {{Treatment of CpMo(NO)Cl2 with (Me3CCX2)2Mg-X(dioxane) [X = H, D] in THF at low temperatures provides moderate yields of the bis(neopentyl) complexes, CpMo(NO)(CH2CMe3)2 (1) and CpMo(NO)(CD2CMe3)2 (1-d4). The solid-state molecular structure of 1-d4 has been determined at 170 K. Crystals of 1-d4 are monoclinic of space group P2(1)/n; a = 5.9781(6) angstrom}, keywords = {METAL MULTIPLE BONDS, METATHESIS, MOLYBDENUM, NEOPENTYLIDENE COMPLEXES, ORGANOMETALLIC NITROSYL CHEMISTRY, {LIGANDS}, isbn = {0276-7333}, url = {://A1993LX17200033}, author = {Legzdins,Peter and Rettig, S. J. and Veltheer, J. E. and Batchelor, R. J. and Einstein, F. W. B.} }