@article {2537, title = {Reactions of Tertiary Phosphines with Alcohols in Aqueous Media}, journal = {Inorganic Chemistry}, volume = {48}, number = {1}, year = {2009}, note = {ISI Document Delivery No.: 388HUTimes Cited: 4Cited Reference Count: 29Moiseev, Dmitry V. Patrick, Brian O. James, Brian R.}, month = {Jan}, pages = {239-245}, type = {Article}, abstract = {The phosphines R2R{\textquoteright}P [R = R{\textquoteright} = Me, Et, Pr-n, Pr-i, (CH2)(3)OH; Me2PhP and MePh2P] react with 2- or 4-hydroxybenzyl alcohols, including "lignin-type" vanillyl, syringyl, and alpha-methylvanillyl alcohols, in a 1:1 ratio in aqueous media, to give zwitterionic phosphobetaine products; these on treatment with aq HCl form the corresponding phosphonium chlorides in good to excellent yields. The syringyl derivative [3,5-(OMe)(2)-4-OH-C6H2CH2PEt3]Cl was structurally characterized by X-ray analysis. Kinetically, the reactivity of the benzyl alcohols, studied with the water-soluble [HO(CH2)(3)](3)P, decreases with substituents in the order 2-hydroxy > 4-hydroxy > vanillyl > syringyl > alpha-methylvanillyl, while 3-hydroxybenzyl alcohol is unreactive; the trend is consistent with reactivity requiring the presence of an ortho- or para-OH substituent in the aromatic ring of the alcohol, and that the reactions proceed via a carbocation species stabilized as a quinone methide. Triethylphosphine reacts with coniferyl alcohol at the C=C moiety to give a zwitterionic intermediate that is again converted by aq HCl to a phosphonium chloride; no reaction was observed with cinnamyl alcohol. The effect on a phenolic pK(a) by incorporation of a phosphonium substituent is also measured.}, keywords = {ALDEHYDES, BENZYL, FACILE SYNTHESIS, LIGNIN, PHOSPHONIUM SALTS, QUINONE METHIDE}, isbn = {0020-1669}, url = {://000262011700032}, author = {Moiseev, D. V. and Patrick, B. O. and James, Brian R.} } @article {5072, title = {Synthesis and structure of the hafnium alkylidene complex [P2Cp]Hf=CHPh(Cl) ([P2Cp] = (eta(5)-C5H3-1,3-(SiMe2CH2PPr2i)(2)))}, journal = {Organometallics}, volume = {20}, number = {8}, year = {2001}, note = {ISI Document Delivery No.: 427FWTimes Cited: 14Cited Reference Count: 16}, month = {Apr}, pages = {1608-1613}, type = {Article}, abstract = {The synthesis, structural characterization, and solution behavior of hafnium complexes stabilized by the potentially tridentate ancillary ligand [P2Cp] ([P2Cp] = (eta (5)-C5H3-1,3-(SiMe2CH2PPr2i)(2))) are described. The reaction of [P2Cp]Li with HfCl4(THT)(2) produces the hafnium trichloride complex [P2Cp]HfCl3 (1), the structure of which was determined by X-ray crystallography. Trichloride 1 is isostructural with the analogous zirconium complex [P2Cp]ZrCl3 (2) in the solid state, but in solution 1 exists as an equilibrium mixture of two isomers that interconvert by fluxional phosphine coordination. Treatment of 1 with 2 equiv of KCH2Ph, followed by thermolysis, yields the first structurally characterized hafnium alkylidene complex, [P2Cp]Hf=CHPh(Cl) (3). A crystal structure determination obtained for 3 shows this complex to be isostructural with the zirconium analogue [P2Cp]Zr=CHR(Cl) (4). The primary difference between the Hf systems presented here and the previously studied Zr analogues is that metal-ligand bonding is stronger in the former, which accounts for shorter bond distances, a greater degree of chemically inertness, and the divergent solution behaviors observed for the trichloride derivatives 1 and 2.}, keywords = {BENZYL, CRYSTAL-STRUCTURE, DERIVATIVES, MOLECULAR-STRUCTURE, PH, SIME3, trichloride, ZIRCONIUM}, isbn = {0276-7333}, url = {://000168395000016}, author = {Fryzuk,Michael D. and Duval, P. B. and Patrick, B. O. and Rettig, S. J.} } @article {5125, title = {Synthesis, characterization, and properties of some cyclopentadienyl molybdenum nitrosyl benzyl complexes}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {79}, number = {5-6}, year = {2001}, note = {ISI Document Delivery No.: 456EVTimes Cited: 2Cited Reference Count: 46}, month = {May}, pages = {502-509}, type = {Article}, abstract = {Reaction of CpMo(NO)(CH2Ph)Cl with Me2Mg, Ph2Mg, or PhCCLi reagents in THF affords the corresponding alkyl, aryl, or alkynyl CpMo(NO)(CH2Ph)R (R = hydrocarbyl) complexes as orange powders in good yields. Unlike related 16-electron CpMo(NO)R-2 complexes, these 18-electron species exhibit good thermal stability due to their eta (2)-benzyl-Mo interactions. Treatment of CpMo(NO)(CH2Ph)Cl with Na(DME)Cp provides dark green Cp2Mo(NO)(CH2Ph), whose solid-state molecular structure has been established by a single-crystal X-ray crystallographic analysis. The two Cp rings display different binding modes to the Mo atom, while the benzyl ligand is coordinated to the metal centre in an eta (1) fashion. The triflate complex, CpMo(NO)(CH2Ph)(OTf), is obtained by addition of AgOTf to the benzyl chloride precursor. The covalent Mo-OTf bond in this compound can be disrupted by the addition of Lewis bases (L) such as PPh3 or pyridine, leading to the corresponding [CpMo(NO)(CH2Ph)(L)][OTf] salts. Attempts to generate neutral benzylidene complexes by deprotonation of [CpMo(NO)(CH2Ph)(PPh3)][OTf] have not yet been successful.}, keywords = {BENZYL, CATIONS, CRYSTAL-STRUCTURES, GROUP-6 METALS, hydrocarbyl, LIGANDS, {ALKYLIDENE COMPLEX}, isbn = {0008-4042}, url = {://000170070900006}, author = {Legzdins,Peter and Smith, K. M. and Rettig, S. J.} } @article {3306, title = {SYNTHESIS, CHARACTERIZATION, AND PROPERTIES OF [CP-ASTERISK-M(NO)(ETA(2)-CH(2)PH)(NCME)]BF4 SALTS (M=MO, W) AND RELATED COMPLEXES - THE STABILIZING INFLUENCE OF BENZYL LIGANDS}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {73}, number = {7}, year = {1995}, note = {ISI Document Delivery No.: RT503Times Cited: 6Cited Reference Count: 29}, month = {Jul}, pages = {1035-1043}, type = {Article}, abstract = {Treatment of orange solutions of Cp*M(NO)(eta(2)-CH(2)Ph)Cl (M = Mo or W) with an equimolar amount of solid AgBF4 in MeCN affords the salts [Cp*M(NO)(eta(2)-CH(2)Ph)(NCMe)]BF4 as analytically pure crystals in good yields. Both orange complexes have been subjected to single-crystal X-ray crystallographic analyses in order to establish their molecular geometries and their intramolecular metrical parameters. Both salts consist of discrete organometallic cations and tetrahedral BF4- anions, the intramolecular dimensions of the two cationic complexes being essentially the same and resembling those found for related Cp*M(NO)-containing compounds. The isolated [Cp*M(NO)(eta(2)-CH(2)Ph)(NCMe)](+) cations are quite electrophilic, being able to abstract Cl- from a NaCl IR cell to revert to their chloro precursors. However, treatment of the [Cp*W(NO)(eta(2)-CH(2)Ph)(NCMe)]BF4 salt with various unsaturated substrates (e.g., diphenylacetylene, 2,3-dimethyl-1,3-butadiene, carbon monoxide, and acetone) in CDCl3 results in no detectable chemical reaction. Lewis bases weaker than Cl- evidently cannot displace the acetonitrile ligand from the coordination sphere of the metal or induce the benzyl ligand to diminish its hapticity. Such a diminution does occur for the CH(2)Ph ligand when the MeCN group in the cationic complexes is replaced by a carboxylate anion to produce neutral Cp{\textquoteright}M(NO)(eta(1)-CH(2)Ph)(eta(2)-O(2)CR) complexes. The latter complexes are obtainable by treatment of Cp*M(NO)(eta(2)-CH(2)Ph)Cl with AgO(2)CR (R = CH(Et)(Ph)) in CH2Cl2 and have been fully characterized by conventional spectroscopic methods.}, keywords = {ARYL, ASYMMETRIC COMPLEXES, BENZYL, CARBON-MONOXIDE, CATIONS, CP{\textquoteright}M(NO)R2, {ALKYL}, isbn = {0008-4042}, url = {://A1995RT50300017}, author = {Dryden, N. H. and Legzdins,Peter and Sayers, S. F. and Trotter, J. and Yee, V. C.} } @article {3306, title = {SYNTHESIS, CHARACTERIZATION, AND PROPERTIES OF [CP-ASTERISK-M(NO)(ETA(2)-CH(2)PH)(NCME)]BF4 SALTS (M=MO, W) AND RELATED COMPLEXES - THE STABILIZING INFLUENCE OF BENZYL LIGANDS}, journal = {Canadian Journal of Chemistry-Revue Canadienne De Chimie}, volume = {73}, number = {7}, year = {1995}, note = {ISI Document Delivery No.: RT503Times Cited: 6Cited Reference Count: 29}, month = {Jul}, pages = {1035-1043}, type = {Article}, abstract = {Treatment of orange solutions of Cp*M(NO)(eta(2)-CH(2)Ph)Cl (M = Mo or W) with an equimolar amount of solid AgBF4 in MeCN affords the salts [Cp*M(NO)(eta(2)-CH(2)Ph)(NCMe)]BF4 as analytically pure crystals in good yields. Both orange complexes have been subjected to single-crystal X-ray crystallographic analyses in order to establish their molecular geometries and their intramolecular metrical parameters. Both salts consist of discrete organometallic cations and tetrahedral BF4- anions, the intramolecular dimensions of the two cationic complexes being essentially the same and resembling those found for related Cp*M(NO)-containing compounds. The isolated [Cp*M(NO)(eta(2)-CH(2)Ph)(NCMe)](+) cations are quite electrophilic, being able to abstract Cl- from a NaCl IR cell to revert to their chloro precursors. However, treatment of the [Cp*W(NO)(eta(2)-CH(2)Ph)(NCMe)]BF4 salt with various unsaturated substrates (e.g., diphenylacetylene, 2,3-dimethyl-1,3-butadiene, carbon monoxide, and acetone) in CDCl3 results in no detectable chemical reaction. Lewis bases weaker than Cl- evidently cannot displace the acetonitrile ligand from the coordination sphere of the metal or induce the benzyl ligand to diminish its hapticity. Such a diminution does occur for the CH(2)Ph ligand when the MeCN group in the cationic complexes is replaced by a carboxylate anion to produce neutral Cp{\textquoteright}M(NO)(eta(1)-CH(2)Ph)(eta(2)-O(2)CR) complexes. The latter complexes are obtainable by treatment of Cp*M(NO)(eta(2)-CH(2)Ph)Cl with AgO(2)CR (R = CH(Et)(Ph)) in CH2Cl2 and have been fully characterized by conventional spectroscopic methods.}, keywords = {ARYL, ASYMMETRIC COMPLEXES, BENZYL, CARBON-MONOXIDE, CATIONS, CP{\textquoteright}M(NO)R2, {ALKYL}, isbn = {0008-4042}, url = {://A1995RT50300017}, author = {Dryden, N. H. and Legzdins,Peter and Sayers, S. F. and Trotter, J. and Yee, V. C.} }