|
| ||
|
|
||
Carbonyl Complexes (carbonyl + complex)
Selected AbstractsChemInform Abstract: Inter- and Intramolecular Carbonylative Alkyne,Alkyne Coupling Reaction Mediated by Cobalt Carbonyl Complex.CHEMINFORM, Issue 13 2001Takanori Shibata Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Structural Studies of ,-Cyclodextrin and Permethylated ,-Cyclodextrin Inclusion Compounds of Cyclopentadienyl Metal Carbonyl ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 8 2006Susana S. Braga Abstract [CpM(CO)nCl] complexes with M = Fe (n = 2) and Mo (n = 3) have been immobilised in plain ,-cyclodextrin (,-CD) and permethylated ,-CD (TRIMEB) by methods tailored according to the stabilities and solubilities of the individual components. Four adducts were obtained with a 1:1 host/guest stoichiometry. The compounds were studied by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), 13C{1H} CP/MAS NMR and FTIR spectroscopy. A comparison of the experimental powder XRD data for the TRIMEB/[CpMo(CO)3Cl] inclusion compound with reference patterns revealed that the crystal packing is very similar to that reported previously for a TRIMEB/ethyl laurate inclusion compound. The unit-cell parameters refined to a = 14.731, b = 22.476, c = 27.714 Å (volume = 9176.3 Å3), and the space group was confirmed as P212121. A hypothetical structural model of the inclusion compound was subsequently obtained by global optimisation using simulated annealing. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Dinuclear Potassium-Chromium and Potassium-Tungsten Carbonyl ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 5 2004Vladimir Kirin Abstract The tetracarbonyl complexes [M(CO)4{,2 -(Ph2P)2NH}] [M = Cr (1a), W (1b)] have been synthesised by reaction of M(CO)6, Me3NO·2H2O, and (Ph2P)2NH. Subsequent treatment of complexes 1a,b with an excess of KH in THF at room temperature yields the potassium salts [Cr(CO)4{,2 -(Ph2P)2N}K(THF)3]n (2a) and [W(CO)4{,2 -(Ph2P)2N}K(THF)2]n (2b), respectively, in almost quantitative yields. The ionic compounds 2a,b are stable at room temperature. All four compounds 1a,b and 2a,b were characterised by single-crystal X-ray diffraction. Compounds 2a,b form infinite chains via isocarbonyl bridges in the solid state. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Stepwise Assembly of Mixed Metal Dinuclear Carbonyl ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2003Katja Heinze Abstract The one-pot/three-step solution synthesis of a library of nine directional, dinuclear mixed-metal complexes composed of different metal-carbonyl units (M = Cr, Mo, W) and a bifunctional bridging isocyanide Schiff-base ligand is described. The well-defined metal sequence in these complexes with Cr, Mo, and W in two positions can be determined post-synthesis by a combination of spectroscopic methods. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Grafting of Molecularly Ordered Mesoporous Phenylene-Silica with Molybdenum Carbonyl Complexes: Efficient Heterogeneous Catalysts for the Epoxidation of OlefinsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Abstract Arenetricarbonyl complexes, or the general formula C6H4Mo(CO)3, were incorporated into crystal-like mesoporous phenylene-silica by liquid-phase deposition of molybdenum hexacarbonyl [Mo(CO)6]. By adjusting the reaction conditions, different molybdenum loadings of 1.5 and 5.9,wt% were obtained, which correspond to 3% and 14% of the phenylene contents. The texture properties of the materials as well as the nature of the surface-fixed complexes were characterized by powder X-ray diffraction, transmission electron microscopy (TEM), N2 adsorption, FT-IR, UV-vis and MAS (13C, 29Si) NMR spectroscopy. The derivatized organosilicas were examined as catalyst precursors for the liquid-phase epoxidation of cis -cyclooctene, 1-octene, trans -2-octene and (R)-(+)-limonene at 55,°C, using tert -butyl hydroperoxide as the oxidant. For each olefin the corresponding epoxide was the only product detected. In the case of cyclooctene, the intrinsic reaction rates per surface molybdenum atom were similar for both Mo loadings (TOF,1150 mol,molMo,1,h,1), suggesting that the resultant materials act as single site epoxidation catalysts. Leaching tests and metal analyses of reaction solutions showed that the catalytic activity stemmed from the immobilized species and not from the leaching of active species into solution. The oxidation of limonene gave limonene oxide as the only product in 95% yield at 3,h, which reveals an outstanding regioselectivity to the epoxidation of the endocyclic double bond. [source] From Bis(N -Alkylimidazole) to Bis(NH,NHC) in Rhenium Carbonyl Complexes,ANGEWANDTE CHEMIE, Issue 36 2010Miguel Zwei Fliegen mit einer Klappe: Eine Abfolge aus Deprotonierung und Protonierung, bei der nur je ein Moläquivalent an Base und Säure zur Anwendung kommt, überführt zwei N -Alkylimidazol-Moleküle in einen N-heterocyclischen Carben-Liganden (siehe Schema; schwarz,C, grau,H, grün,F, blau,N, rot,O, cyan,Re, gelb,S). [source] Synthesis and Reactivity of Group 6 Metal Carbonyl Complexes with Bis(pyrazol-1-yl)methanes Modified by the Vinyltin GroupsCHINESE JOURNAL OF CHEMISTRY, Issue 5 2009Zhenkang WEN Abstract Diphenyl(vinyl)stannylbis(3,5-dimethylpyrazol-1-yl)methane and diphenyl(vinyl)stannylbis(3,4,5-trimethyl- pyrazol-1-yl)methane have been synthesized by the reaction of bis(3,5-dimethylpyrazol-1-yl)methyl or bis(3,4,5- trimethylpyrazol-1-yl)methyllithium with diphenyl(vinyl)tin iodide. Treatment of these bis(pyrazol-1-yl)methanes modified by the vinyltin groups with M(CO)5THF (M=Mo and W) in refluxing THF resulted in new heterobimetallic complexes R3SnCHPz2M(CO)3 (R3Sn represents trivinyltin or diphenyl(vinyl)tin, and Pz represents substituted pyrazol-1-yl), in which a vinyl group bonds to the molybdenum or tungsten atom in ,2 -fashion to lead to bis(pyrazol-1-yl)methanes acting as a tridentate ,3 -(,,N,N) ligand. Reaction of (CH2=CH)3SnCH(3,5-Me2Pz)2W(CO)3 and Ph2(CH2=CH)SnCH(3,5-Me2Pz)2W(CO)3 with I2 has been investigated. The former gave a complex CH2(3,5-Me2Pz)2W(CO)4, while the latter yielded a four-membered heterometallocyclic complex CH(3,5-Me2Pz)2W(CO)3I with the loss of the organotin group. Treatment of this four-membered heterometallocyclic complex with PhSNa led to the iodide anion replaced by the thiophenolate anion to give a complex CH(3,5-Me2Pz)2W(CO)3SPh. [source] Experimental and theoretical charge-density study of a tetranuclear cobalt carbonyl complexACTA CRYSTALLOGRAPHICA SECTION B, Issue 6 2009Jacob Overgaard Details of the complex bonding environment present in the molecular centre of an alkyne-bridged dicobalt complex have been examined using a combination of experimental and theoretical charge-density modelling for two compounds which share a central Co2C2 tetrahedral moiety as their common motif. Topological analysis of the experimental electron density illustrates the problem of separating the Co,C bond-critical points (b.c.p.s) from the intervening ring-critical point (r.c.p.), due largely to the flat nature of the electron density in the CoC2 triangles. Such a separation of critical points is immediately obtained from a topological analysis of the theoretical electron density as well as from the multipole-projected theoretical density; however, the addition of random noise to the theoretical structure factors prior to multipole modelling leads to a failure in consistently distinguishing two b.c.p.s and one r.c.p. in such close proximity within the particular environment of this Co2C2 centre. [source] Ring-Borylated 15-Electron and 17-Electron ansa -Chromocene Complexes, their Physical Properties and Molecular StructuresCHEMISTRY - A EUROPEAN JOURNAL, Issue 21 2007Pamela Abstract A detailed study of the thermal decomposition of the zwitterionic, ring-borylated ansa -chromocene hydrido carbonyl complex [Cr(CO)H{Me4C2(C5H4)[C5H3B(C6F5)3]}] (2) is described. This complex is formed in the reaction between [Cr(CO){Me4C2(C5H4)2}] (1) and B(C6F5)3 in toluene at ,78,°C. Above ,25,°C, 2 decomposes to a 50:50 mixture of the low-spin, 17,e CrIII complexes [Cr(CO){Me4C2(C5H4)[C5H3B(C6F5)3]}] (3,b) and [Cr(CO){Me4C2(C5H4)2}][HB(C6F5)3] (4). Carbon monoxide elimination from 3,b generates high-spin, 15,e [Cr{Me4C2(C5H4)[C5H3B(C6F5)3]}] (3,a), which coordinates two other electron-donating ligands, such as xylyl isocyanide, PMe3, and PPh2Me to form the low-spin, 17,e electron complexes 3,c, 3,d, and 3,e, respectively. High-spin, 15,e [Cr{Me4C2(C5H4)2}][HB(C6F5)3] (5) is generated by heating 3,b in toluene at 100,°C and periodically removing the evolved CO. Efforts to isolate more than a few X-ray quality crystals of 5 were thwarted by its tendency to form an insoluble precipitate (6) with the same molecular formula. Heating the solution of 5 at 120,°C results in its partial conversion (ca. 28,%) to 3,a, thereby allowing the formation of 3,a in yields as high as 74,% from the reaction between 1 and B(C6F5)3. The X-ray crystal structures of 3,b,e and 5 are described. Cyclic voltammetry measurements on 3,a,e reveal a dramatic reduction in the redox potentials of the complexes relative to their non-borylated analogues. DFT calculations show that this is due primarily to electrostatic stabilization of the oxidized species by the negatively charged borylate group. EPR and 19F,NMR spectroscopy allow 3,a to be distinguished from its Lewis base adducts 3,b,e and reveal the relative affinities of different Lewis bases for the chromium. [source] Dithiolate-Bridged Fe-Ni-Fe Trinuclear Complexes Consisting of Fe(CO)3,n(CN)n (n=0, 1) Components Relevant to the Active Site of [NiFe] HydrogenaseCHEMISTRY - AN ASIAN JOURNAL, Issue 6 2009Satyanarayan Pal Dr. Abstract Step-by-step: A trinuclear Fe-Ni-Fe complex 1 was synthesized from the reaction of [Fe(CO)4I2] with Li2[Ni(norbornane- exo -2,3-dithiolate)2]. The CO ligands in 1 were transformed into CN, upon treatment with ,N(SiMe3)2, and the monocyanide complex 3 and the dicyanide complex 4 were obtained. Complexes 3 and 4 were found to react with protonic acids, whereas 1 is robust. A dithiolate-bridged Fe-Ni-Fe trinuclear carbonyl complex [(CO)3Fe(,-ndt)Ni(,-ndt)Fe(CO)3] (1, ndt=norbornane- exo -2,3-dithiolate) has been synthesized from the reaction of [Fe(CO)4I2] and Li2[Ni(ndt)2]. This reaction was found to occur with concomitant formation of a tetranuclear cluster [Ni3(,-ndt)4FeI] (2). Treatment of 1 with Na[N(SiMe3)2] transforms some of the CO ligands into CN,, and the monocyanide complex (PPh4)[(CO)2(CN)Fe(,-ndt)Ni(,-ndt)Fe(CO)3] (3) and the dicyanide complex (PPh4)2[(CO)2(CN)Fe(,-ndt)Ni(,-ndt)Fe(CO)2(CN)] (4) were isolated. X-ray structural analyses of the trinuclear complexes revealed a Fe-Ni-Fe array in which the metal centers are connected by the ndt sulfur bridges and direct FeNi bonds. Hydrogen bonding between the CN ligand in 3 and cocrystallized ethanol was found in the solid-state structure. The monocyanide complex 3 and dicyanide complex 4 reacted with acids such as HOTf or HCl generating insoluble materials, whereas complex 1 did not react. [source] Synthesis of Enantiopure Ruthenium Tricarbonyl Complexes of a Bicyclic Cyclopentadienone DerivativeEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2008Min-soo Kim Abstract (,)-Menthone was converted stereoselectively into 3-menthylpropargyl alcohol 8 in several steps and subsequently converted into enantiopure cyclopentadienone ruthenium carbonyl complexes. In the malonate cases, ruthenacycle 15 was also formed during the cyclization reaction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Improved Protocols for Molybdenum- und Tungsten-Catalyzed HydrostannationsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009Alexander Abstract A series of (isonitrile)tungsten carbonyl complexes of type W(CO)m(CNR)n has been synthesized and evaluated as hydrostannation catalysts. The results are compared with those obtained by the previously reported tri(tert -butylisonitrile)molybdenum tricarbonyl catalyst, Mo(CO)3(CN- t- Bu)3 (=MoBI3). The yields and selectivities strongly depend on the isonitriles used, and with certain substrates better results are obtained compared to the molybdenum catalyst. No side products are observed in hydrostannations under microwave irradiation or when the reactions are carried out under an atmosphere of carbon monoxide. Based on these findings, a mechanistic rational is given, explaining the different pathways responsible for the formation of hydrostannation or distannation products. [source] Theoretical versus experimental geometries in S-bridged manganese carbonyl complexesJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 4 2003Juan F. Van der Maelen Uría The experimental geometry obtained from single-crystal X-ray diffraction for a number of binuclear S-bridged manganese complexes is compared with the results of theoretical calculations made at the ab initio level by using Hartree,Fock and density functional theory methods with medium-size and large basis sets. The optimized geometries obtained were somewhat relaxed when compared with the experimental ones, with very similar bond and torsion angles but longer bond lengths. The mean square deviation for bond lengths (angles) was found to be between 0.046,Å (1.1°) and 0.004,Å (0.7°) depending on the theoretical model used. [source] Synthesis, characterization and catalytic studies of ruthenium(II) chalconate complexesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 2 2009M. Muthukumar Abstract Stable ruthenium(II) carbonyl complexes of the type [RuCl(CO)(EPh3)(B)(L)] (E = P or As; B = PPh3, AsPh3 or Py; L = 2,-hydroxychalcones) were synthesized from the reaction of [RuHCl(CO)(EPh3)2(B)] (E = P or As; B = PPh3, AsPh3 or Py) with 2,-hydroxychalcones in benzene under reflux. The new complexes were characterized by analytical and spectroscopic (IR, electronic 1H, 31P and 13C NMR) data. They were assigned an octahedral structure. The complexes exhibited catalytic activity for the oxidation of primary and secondary alcohols into their corresponding aldehydes and ketones in the presence of N -methylmorpholine- N -oxide (NMO) as co-oxidant and were also found to be efficient transfer hydrogenation catalysts. Copyright © 2008 John Wiley & Sons, Ltd. [source] Oxidative addition of different electrophiles with rhodium(I) carbonyl complexes of unsymmetrical phosphine,phosphine monoselenide ligandsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2006Pratap Chutia Abstract Dimeric chlorobridge complex [Rh(CO)2Cl]2 reacts with two equivalents of a series of unsymmetrical phosphine,phosphine monoselenide ligands, Ph2P(CH2)nP(Se)Ph2 {n = 1(a), 2(b), 3(c), 4(d)}to form chelate complex [Rh(CO)Cl(P,Se)] (1a) {P,Se = ,2 -(P,Se) coordinated} and non-chelate complexes [Rh(CO)2Cl(P,Se)] (1b,d) {P,Se = ,1 -(P) coordinated}. The complexes 1 undergo oxidative addition reactions with different electrophiles such as CH3I, C2H5I, C6H5CH2Cl and I2 to produce Rh(III) complexes of the type [Rh(COR)ClX(P,Se)] {where R = C2H5 (2a), X = I; R = CH2C6H5 (3a), X = Cl}, [Rh(CO)ClI2(P,Se)] (4a), [Rh(CO)(COCH3)ClI(P,Se)] (5b,d), [Rh(CO)(COH5)ClI-(P,Se)] (6b,d), [Rh(CO)(COCH2C6H5)Cl2(P,Se)] (7b,d) and [Rh(CO)ClI2(P,Se)] (8b,d). The kinetic study of the oxidative addition (OA) reactions of the complexes 1 with CH3I and C2H5I reveals a single stage kinetics. The rate of OA of the complexes varies with the length of the ligand backbone and follows the order 1a > 1b > 1c > 1d. The CH3I reacts with the different complexes at a rate 10,100 times faster than the C2H5I. The catalytic activity of complexes 1b,d for carbonylation of methanol is evaluated and a higher turnover number (TON) is obtained compared with that of the well-known commercial species [Rh(CO)2I2],. Copyright © 2006 John Wiley & Sons, Ltd. [source] New polynuclear carbonyl ruthenium (II) complexes derived from 1,8-naphthyridineAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 4 2006Juana Gajardo Abstract This work shows the synthesis and characterization of new carbonyl complexes derived of 1,8-naphthyridine. Covalently bonded complex can be successfully employed in building of supramolecular structures. Copyright © 2005 John Wiley & Sons, Ltd. [source] Iridium Metal Thin Films and Patterned IrO2 Nanowires Deposited Using Iridium(I) Carbonyl PrecursorsCHEMICAL VAPOR DEPOSITION, Issue 7 2006Y.-L. Chen Abstract Highly volatile iridium(I) carbonyl complexes (1,5) with three anionic fluorinated chelates, namely ketoiminate, aminoalkoxide, or iminoalkoxide, have been synthesized and their physical properties relevant to CVD are evaluated. A single-crystal X-ray diffraction (XRD) study on Ir(CO)2(amakNMe2) (3) confirms a square-planar geometry with two cis-orientated carbonyl ligands. Metallic iridium, polycrystalline IrO2 thin films, or even patterned IrO2 nanowires are deposited using Ir(CO)2(hfdaNnPr) (5) as the CVD precursor. A systematic investigation of the deposition of IrO2 nanowires is conducted, showing a close correlation of observed crystallite morphology with applied system pressure, underlying growth surface, and deposition temperature. Of particular importance, tilted and vertically aligned IrO2 nanowires are obtained on LiTaO3(012) and LiNbO3(100) surfaces under a pressure of 30,Torr of oxygen at 425,°C. The morphology and structural composition of the IrO2 are confirmed by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and XRD analyses. [source] The Diversity of Difluoroacetylene Coordination Modes Obtained by Coupling Fluorocarbyne Ligands on Binuclear Manganese Carbonyl SitesCHEMISTRY - A EUROPEAN JOURNAL, Issue 22 2009Xian-mei Liu Abstract One Mn or two? The fluorocarbyne manganese carbonyl complexes [Mn(CF)(CO)n] (n=3,,4) and [Mn2(CF)2(CO)n] (n=4,7; see picture) have been investigated by density functional theory. In mononuclear complexes the CF ligand behaves very much like the NO ligand in terms of ,-acceptor strength. In binuclear complexes the two CF ligands couple in many of the low-energy structures to form a bridging C2F2 ligand derived from difluoroacetylene. Recent work has shown that the fluorocarbyne ligand CF, isoelectronic with the NO ligand, can be generated by the defluorination of CF3 metal complexes, as illustrated by the 2006 synthesis by Hughes et,al. of [C5H5Mo(CF)(CO)2] in good yield by the defluorination of [C5H5Mo(CF3)(CO)3]. The fluorocarbyne ligand has now been investigated as a ligand in the manganese carbonyl complexes [Mn(CF)(CO)n] (n=3,,4) and [Mn2(CF)2(CO)n] (n=4,7) by using density functional theory. In mononuclear complexes, such as [Mn(CF)(CO)4], the CF ligand behaves very much like the NO ligand in terms of ,-acceptor strength. However, in the binuclear complexes the two CF ligands couple in many of the low-energy structures to form a bridging C2F2 ligand derived, at least formally, from difluoroacetylene, FCCF. The geometries of such [Mn2(C2F2)(CO)n] complexes suggest several different bonding modes of the bridging C2F2 unit. These include bonding through the orthogonal ,,bonds of FCCF, similar to the well-known [R2C2Co2(CO)6] complexes, or bonding of the C2F2 unit as a symmetrical or unsymmetrical biscarbene. This research suggests that fluorocarbyne metal chemistry can serve as a means for obtaining a variety of difluoroacetylene metal complexes, thereby avoiding the need for synthesizing and handling the very unstable difluoroacetylene. [source] Switching Luminescent Properties in Osmium-Based ,-Diketonate Complexes,CHEMPHYSCHEM, Issue 10 2005Yao-Lun Chen Luminescent complexes: Through the design and synthesis of a series of new osmium-based ,-diketonate carbonyl complexes (see picture; MLCT=metal-to-ligand charge transfer, kisc=intersystem crossing constant), a remarkable aromatic tunable fluorescence/phosphorescence ratio was explored. The relative luminescent efficiencies and associated dynamics were evaluated. [source] Experimental and Theoretical Characterization of a Triplet Boron Carbonyl Compound: BBCOCHEMPHYSCHEM, Issue 7 2003Mingfei Zhou Prof. Unusually generous donation: Matrix isolation infrared spectroscopy and quantum chemical calculations characterize the new boron carbonyl compound BBCO (see graphic), which has a linear triplet ground state (3,,). The binding energy of CO and BB is quite large, due to the back bonding usually associated with transition metal carbonyl complexes. [source] | |||||||||||||||||||||||||