Preparation of imido pentamethylcyclopentadienyl molybdenum(IV) complexes. X-ray molecular structure of cis-[MoCp*CI(η-NtBu)]2·C6H6

The reduction of [MoCp * Cl2(NtBu)] 1 with 1 equiv. of 10% sodium amalgam in the presence of CN(2,6-Me2C6H3) yields the green crystalline compound [MoCp * Cl(NtBuCN(2,6-Me2C6H3)] 2 which can be alkylated by MgClMe to give [MoCp * Me(NtBu)CN(2,6-Me2C6H3)] 3. The same reduction in the absence of ligands leads to an almost equimolar mixture of compounds identified as cis- and trans-[MoCp* (μ-Cl)(NtBu)]24 which are slowly and irreversibly transformed into cis-[MoCp * Cl(μ-NtBu)]25 by heating a toluene solution at 90°C. Compounds (cis + trans)-4 and cis-5 are alkylated by MgClMe leading to the same final methyl derivative [MoCp * Me(μ-NtBu)]26, and react with ethylene to yield the adduct [MoCp * Cl(NtBu)(C2H4)] 7. All new complexes were characterized by their analytical composition, IR and NMR spectroscopy and mass spectrometry, and the structure of the benzene solvate of cis-[MoCp * Cl(μ-NtBu)]25 was determined by X-ray diffraction methods.Italian Consiglio Nazionale delle Ricerch

Alkyl and alkylidene imido cyclopentadienyl tungsten complexes

This paper reports the alkylation of the cyclopentadienyl imido tungsten complexes [WCp′(NtBu)Cl3] (Cp′=η5-C5H5, η5-C5Me5) with β-hydrogen containing alkyl groups to render halo alkyl and trialkyl complexes [WCp′(NtBu)Cl3−nRn] (R=Et, n-Pr). Thermal decomposition of the trialkyl compounds gives the alkylidene derivatives [WCp′(NtBu)(CHR)(CH2R)] (R=Me, Et) by α-hydrogen elimination. All of the compounds were characterized by NMR spectroscopy and the molecular structure of [W(η5-C5Me5)(NtBu)Et3] was determined by X-ray diffraction methods.The authors acknowledge DGICYT (project PB97-0677) for financial support

Cyclopentadienyl dithiocarbamate and dithiophosphate molybdenum and tungsten complexes

Reactions of [MCp*Cl4] (M=Mo, W; Cp*=η5-C5Me5) with salts of the N,N-diethyldithiocarbamate [Et2dtc]− and O,O′-diethyldithiophosphate [Et2dtp]− anions yield the paramagnetic metal(V) complexes [MCp*Cl3(Et2dtc)] (M=Mo, W) and [MCp*Cl3(Et2dtp)] (M=Mo, W), respectively. Hydrolytic oxidation of both dithiocarbamate–molybdenum complexes with aqueous hydrogen peroxide leads to η2-coordinated peroxo compounds [MoCp*Cl(O–O)O], which were also obtained from [MoCp*Cl4]. The related complexes [MCp′Cl(O–O)O] (M=Mo, Cp′=η5-C5H5; M=W, Cp′=η5-C5Me5) were isolated in a similar way. Reduction of a THF solution of [MoCp*Cl4] with one equivalent of 10% Na/Hg followed by the addition of one equivalent of ammonium dithiophosphate gives [MoCp*Cl2(Et2dtp)] which was also obtained via the reaction of [MoCp*Cl3(Et2dtp)] with MeMgCl, whereas reduction with three equivalents of Na/Hg in the presence of CNtBu leads to the molybdenum(II) complex [MoCp*(Et2dtp)(CNtBu)2] in high yield. All these compounds were characterized by elemental analysis, IR, 1H- and 13C-NMR spectroscopy, magnetic susceptibility measurements and the molecular structures of [Mo(η5-C5H5)Cl(O–O)O] and [Mo(η5–C5Me5)Cl3{η2-S2P(OEt)2}] were determined by X-ray diffraction studies.Consiglio Nazionale delle Ricerche (Rome

Stereoselective synthesis and reactivity of cis- and trans- dimolybdenum nitrosyl derivatives with the bridging bis(dimethylsilanediyl)di(η5-cyclopentadienyl) ligand. X-ray molecular structures of cis-[{Mo(CO)2(NO)}2(μ-(η5-C5H3)2(SiMe2)2}], trans-[(Mo(CO)(NO)(CNtBu)}2(μ-(η5-C5H3)2(SiMe2)2}], cis-[{Mo2(CO)3(NO)2(PMe3)}{μ-(η5-C 5H3)2(SiMe2)2}] and trans-[{Mo(NO)(CNtBu)2}2(μ-(η5-C5H3)2(SiMe2)2}]

New dimolybdenum nitrosyl [Mo(CO)2(NO)2μ-(η5-C5H3)2(SiMe2)2] cis-3 and trans-3 complexes have been isolated from the reaction of the previously reported cis-[Mo(CO)3H2μ-(η5-C5H3)2(SiMe2)2] cis-1 and trans-K2[Mo(CO)32μ-(η5-C5H3)2(SiMe2)2] trans-2 respectively, with p-CH3C6H4SO2N(NO)(CH3) (diazald). The reaction of [Mo(CO)2(NO)2μ-(η5-C5H3)2(SiMe2)2] cis-3 and trans-3 with Lewis bases L (L = tert-butylisocyanide and trimethylphosphine) under appropriate conditions gave monosubstituted [Mo2(CO)3(NO)2Lμ-(η5-C5H3)2(SiMe2)2] complexes (L = CNtBu cis-4; PMe3cis-5 and trans-5), disubstituted [Mo(CO)(NO)L2μ-(η5-C5H3)2(SiMe2)2] (L = CNtBu, cis-6, trans-6; PMe3cis-7 and trans-7) and tetrasubstituted [Mo(NO)L22μ-(η5-C5H3)2(SiMe2)2] complexes (L = CNtBu, cis-8 and trans-8), which were isolated in moderate yields and fully characterized by conventional analytical and spectroscopic methods. Addition of PCl5 under appropriate conditions to a diethyl ether solution of cis-3 or trans-3 afforded the dichloronitrosyl derivatives cis- and trans-[MoCl2(NO)2μ-(η5-C5H3)2(SiMe2)2] cis-9 and trans-9. The 13C and variable temperature 1H NMR spectra of complex cis-9 are consistent with the formation of 18 electron metal centres bridged by two chlorine atoms, providing two cis- and trans-nitrosyl isomers, which interchange rapidly in solution at room temperature through a postulated 16 electron intermediate. Treatment of cis-8 and trans-8 with stoichiometric amounts of PCl5 gave the tetrahalo derivatives [Mo(NO)(CNtBu)Cl22μ-(η5-C5H3)2(SiMe2)2] cis-10 and trans-10 respectively, whereas the oxidation of trans-6 with PCl5 under similar conditions gave a mixture of trans-10 and trans-[Mo2(CO)(NO)2(CNtBu)Cl4μ-(η5-C5H3)2(SiMe2)2] (trans-11). In addition, single crystal X-ray crystallographic analyses were performed for cis-3, cis-5, trans-6 and trans-8. All the complexes show two metal fragments bridged by the μ-(η5-C5H3)2(SiMe2)2 ligand, with different dispositions of the metal fragments. Stereoselective synthesis and reactivity of cis- and trans- dimolybdenum nitrosyl derivatives with the bridging bis(dimethylsilanediyl)di(η5-cyclopentadienyl) ligand. X-ray molecular structures of cis-[Mo(CO)2(NO)2μ-(η5-C5H3)2(SiMe2)2], trans-[Mo(CO)(NO)(CNtBu)2μ-(η5-C5H3)2(SiMe2)2], cis-[Mo2(CO)3(NO)2(PMe3)μ-(η5-C5H3)2(SiMe2)2] and trans-[Mo(NO)(CNtBu)22μ-(η5-C5H3)2(SiMe2)2]. Available from: http://www.researchgate.net/publication/256790936_Stereoselective_synthesis_and_reactivity_of_cis-_and_trans-_dimolybdenum_nitrosyl_derivatives_with_the_bridging_bis(dimethylsilanediyl)di(5-cyclopentadienyl)_ligand._X-ray_molecular_structures_of_cis-Mo(CO)2(NO)2-(5-C5H3)2(SiMe2)2_trans-Mo(CO)(NO)(CNtBu)2-(5-C5H3)2(SiMe2)2_cis-Mo2(CO)3(NO)2(PMe3)-(5-C5H3)2(SiMe2)2_and_trans-Mo(NO)(CNtBu)22-(5-C5H3)2(SiMe2)2 [accessed Nov 23, 2015].We acknowledge financial support from DGICYT (Project 92-0178-C). R.G-G acknowledges CAM for a fellowship

Synthesis of chloro and methyl imido cyclopentadienyl molybdenum and tungsten complexes. X-ray molecular structures of [WCp*C13(NtBu)], [MoCp*C1Me2(NtBu) ] and [WCp*C1Me2(NtBu) ]

Alternative methods to prepare [MCp'C14], [MCp'CL(N'Bu)] and [MCp'CI~(N'Bu)] [M=Mo, Cp'="qs-C~Me~ (Cp*); M=W,\ud Cp' = r/5-CsH5 (Cp), r/5-CsMe5 (Cp*) ] in high yields are reported. Alkylation of [MCp'CI3(N'Bu) ] with stoichiometric amounts of LiMe\ud or MeMgC1 under appropriate conditions leads to the dimethyl [MCp'CIMe2(N'Bu)] and trimethyl [MCp'Me~(N'Bu)], (M=Mo,\ud Cp' = Cp*; M = W, Cp' = Cp, Cp* ) complexes. The 18-electron trimethyltungsten complex [WCp*Me~(N'Bu) ] reacts very slowly with\ud CN(2,6-Me2C~,H3) to give the insertion product [WCp*{C(Me)= N(2,6-Me2C6H3)}Me2(N'Bu)]. All of the new compounds reported\ud were characterized by elemental analyses, IR and NMR spectroscopy and the X-ray molecular structures of [WCp*CI~(N'Bu)],\ud [ MoCp*CIMe2( N'Bu ) ] and [ WCp*C1Me_,.(NtBu ) ] have been determined by diffraction methods. O 1998 Elsevier Science S.A. All rights\ud reserved.The authors acknowledge DGICYT (Project PB92-0178-C) and CAM (I + D 0033/94) for financial support

Organocomplejos de cobalto (I) y (II) con el radical pentafluorofenilo / Amelio Vázquez de Miguel ; director Pascual Royo Gracia.

Tesis-Universidad de Murcia.Consulte la tesis en: BCA. GENERAL. ARCHIVO UNIVERSITARIO. T.M.-183.CRAI CIENCIAS. DEPOSITO. T.D. 78

Pentafluorophenylcobalt(II) complexes

Complexes (C6F5)2CoL2 (L2 = 2 PEt3, 2 P-Bu3, 2 PPh3, Ph2PCH2CH2PPh2) have been obtained by adding the relevant ligands to solutions of (C6F5)2Co(dioxane)2. The cis and trans isomers have been separated and identified for the complexes having L = PEt3 or PnBu3. Structural and chemical behaviour for all the complexes is described.We greatly appreciate the award of a Research Fellowship (to A.V.) by the Ministerio de Educación y Ciencia (Spain)

Carbonyl-organocobalt(I) and carbonyl-organocobalt(II) complexes

Passage of CO through solutions of complexes (C6F5)2CoL2 gives carbonyl derivatives (C6F5)2CoL2(CO) (L2 = 2PEt3, 2P-n-Bu3, 2PPh3, Ph2PCH2CH3PPh2). The properties of these compounds are described.\ud The compounds are also produced by treating solutions of (C6F5)2Co-(dioxane)2 with CO, but a simultaneous reduction to (C6F5)Co(CO)4 takes place. Treatment of the latter complex with monodentate ligands gives substitution products (C6F5)Co(CO)3L (L = PEt3, P-n-Bu3, PPh3) all of which are monomeric, whereas the addition of Ph2PCH2CH2PPh2 gives the dimer (C6F5)(CO)2CoL-LCo(CO)2(C6F5). The properties of these compounds are discussed.Ministerio de Educación y Cienci

Synthesis and P-31 NMR caracterization of substituted carbonylcobalt(I) complexes

Reactions of (C6 F5 )Co(C0) 4 (I) with equimolar amounts of different phosphorus donors give \ud monosubstituted complexes (C6 F5 )Co(C0) 3 L being L = PEt 3-(II), P-n­ But3 (III), PPh 3 (IV), \ud PMe2 Ph (V), PMePh 2 (VI), P(OMe), (VII), P(OEt), (VIII),\ud and P(OPh) 3 (IX). Complexes II-IV as well as the dimer (C6 F5 )Co(C0) 3PPh 2-\ud (CH2 )2PPhi(C0)3Co(C6 F5 ) (X) have been previously described.\ud When the same reactions are made using an excess of the ligand, the disubstituted species (C6 F5 \ud )Co(CO),L 2 are isolated, being L = PEt 3 (XI), P-n-But 3 (XII), PPh 3 (XIII), PMe2 Ph (XIV), PMePh \ud 2 (XV), P(OMe) 3 (XVI), P(OEt) 3 (XVII) and P(OPh 3 )\ud (XVIII). The mononuclear compound XIX with the bidentate ligand\ud PPh 2 (CH 2 ) 2 PPh 2 only could be obtained by reducing (C6F5 ) 2Co(PPh 2 (CH2 ) 2 PPh 2 )\ud with NaBH 4 under CO.\ud The IR and 31 P NMR spectra of all these compounds permit to make a structural\ud assignment.The authors greatly appreciate the financial support received from Comisión\ud Asesora de lnvestigación Científica y Técnica (Spain)