CO2 Compounds Research Articles

Synthesis of a mixed cluster/binuclear compound. Electrochemical properties and X-ray diffraction structure of Co3(CO)9[μ3-CCO2CH2CCH{Co2(CO)6}

The tetrahedrane cluster Co3(Co)9(μ3-CCO2CH2C≡CH) reacts with Co2(CO)6 to furnish the pentacobalt compound Co3(CO)9[μ3-CCO2CH2CCH{Co2(CO)6}] in high yield. Functionalization of the pendant alkyne group by Co2(CO)6 was ascertained by IR and NMR spectroscopies (1H and 13C), and the solid-state structure of Co3(CO)9[μ3-CCO2CH2CCH{Co2(CO)6}] was unequivocally established by X-ray diffraction analysis. Co3(CO)9[μ3-CCO2CH2CCH{Co2(CO)6}] crystallizes in the triclinic space group $${P\bar 1}$$ , a = 7.9674(5), b = 13.208(1), c = 13.3094(9) A, α = 76.257(6), β = 79.123(6), γ = 86.403(6)°, V = 1335.8(2) A3, Z = 2, and d calc = 2.016 g/cm3. The electrochemical properties of Co3(CO)9[μ3-CCO2CH2CCH{Co2(CO)6}] were examined by cyclic voltammetry and the first reduction wave was found to be a reversible, one-electron reduction associated with the tricobalt moiety. No evidence for electronic communication between the Co3 and Co2 portions of the complex was observed. The results of extended Huckel MO calculations on Co3(CO)9[μ3-CCO2CH2CCH{Co2(CO)6}] establish the nature of the LUMO in Co3(CO)9[μ3-CCO2CH2CCH{Co2(CO)6}].

Diyne and Phosphorus−Carbon Bond Reactivity in the Reaction between [Co2(CO)6]2(PhC4Ph) and 2,3-Bis(diphenylphosphino)maleic Anhydride (bma). Syntheses, Molecular Orbital Properties, and X-ray Diffraction Structures of Co2(CO)4[μ-η2:η2:η1:η1-(Z)-Ph2P(Ph)CC(PhC2)- CC(Ph2P)C(O)OC(O)], Co2(CO)2(bma)2·CH2Cl2, and Co2(CO)2(bma)[μ-CC(Ph2P)C(O)OC(O)](μ2-Ph2P)·C6H14

Thermolysis (>80 °C) of the diyne complex [Co2(CO)6]2(PhC4Ph) (1) with 2,3-bis(diphenylphosphino)maleic anhydride (bma) affords the new compounds Co2(CO)4[μ-η2:η2:η1:η1-(Z)-Ph2P(Ph)CC(PhC2)CC(Ph2P)C(O)OC(O)] (3), Co2(CO)2(bma)2 (4), and Co2(CO)2(bma)[μ-CC(Ph2P)C(O)OC(O)](μ2-Ph2P) (5) in low yields, while [Co2(CO)6]2(PhC4Ph) reacts with added bma in either refluxing CH2Cl2 or in the presence of Me3NO to give the thermally sensitive complex [Co2(CO)4(bma)(PhC4Ph)Co2(CO)6] (2). Independent experiments reveal that 3 arises from 2 by loss of the Co2(CO)6 group, coupled with PC bond cleavage and diyne functionalization by the transient phosphido and maleic anhydride moieties, and the reaction between 2 and excess bma leads to both 4 and 5, with 5 originating from 4. The kinetics for the reaction of 4 to 5 have been measured by UV−vis spectroscopy, and on the basis of the first-order rate constants and the activation parameters (ΔH⧧ = 27.0 ± 0.6 kcal mol-1 and ΔS⧧ = 1.0 ± 0.3 eu), a mechanism involving dissociative CO loss as the rate-determining step is presented. Binuclear 4 is extremely photosensitive and is converted cleanly to 5 by 366 nm light with a quantum efficiency of 0.0043. Compounds 2−5 have been isolated and characterized in solution by IR and 31P NMR spectroscopy. The solid-state structures of 3−5 have been established by X-ray crystallography. The X-ray structure of 4 reveals the presence of two bma ligands that are attached to the Co2(CO)2 unit in a head-to-tail fashion via the PPh2 groups and maleic anhydride π bond, and the X-ray structure of 5 supports the existence of a μ2-PPh2 moiety and a noncomplexed maleic anhydride π bond, the result of PC(maleic anhydride) bond activation. The redox properties of 2−5 were explored by cyclic voltammetry in CH2Cl2, and the oxidation/reduction behavior is discussed with respect to redox stabilization that each complex experiences, as modulated by the bma ligand(s). The orbital composition of the HOMO and LUMO levels in 3−5 has been studied by extended Hückel calculations, and the data are discussed relative to the observed electrochemistry. A plausible mechanism for the activation of Co2(CO)2(bma)2 and the formation of Co2(CO)2(bma)[μ-CC(Ph2P)C(O)OC(O)](μ2-Ph2P) is presented.

Über die Reaktion von C(NMe2)4 mit zweikernigen Übergangsmetallcarbonylen; Kristallstrukturen von [C(NMe2)3][Mn(CO)5] und [C(NMe2)3][Co(CO)4] / On the Reaction of C(NMe2)4 with Binuclear Transition Metal Carbonyls: Crystal Structures of [C(NMe2)3][Mn(CO)5] and [C(NMe2)3][Co(CO)4

The reactions of C(NMe2)4 (1) with Mn2(CO)10 or Co2(CO)8 in THF yield [C(NMe2)3][Co(CO)4] (3) and [C(NMe2)3][Mn(CO)5] (4), respectively. The compounds Co(CO)4NMe2 (5) and Mn(CO)5NMe2 (6) could not be found. With CH2Cl2 4 is quantitatively converted into [C(NMe2)3][Mn(CO)4Cl2] (7) as shown by IR and 13C NMR investigations. 3 and 4 were characterized by an X-ray structure determination. 3: Space group Pnma, Z = 4, a = 7.435(2), b = 10.79(2), c = 20.299(5)Å. 4: Space group C2/c, Z = 4, a = 11.378(2), b = 10.165(1), c = 14.533(1) Å; β = 103.37(1)°. The compounds form independent ions with no bonding interactions between cation and anion; the central CN3 unit of the [C(NMe2)3]+ cation in 3 and 4 is disordered.

Ethylidyne formation on Pt(111), studied by FT-RAIRS

Adsorption of ethene at 94 K followed by heating to 370 K and subsequent cooling to 94 K produced a RAIR spectrum in which three bands, at 2884, 1341 and 1124 cm-1, were observed. These bands may be assigned by reference to the EEL spectrum of ethylidyne on Pt(111) and the infrared spectrum of the ethylidyne ligand in the cluster compound Co3(CO)9CCH3. The resulting excellent agreement, particularly with the IR spectrum of the cluster compound, leads to an unambiguous assignment of the three bands to the symmetric methyl stretch, symmetric methyl deformation and carbon-carbon stretch respectively of the ethylidyne species.

Ethylidyne formation on Pt(111), studied by FT-rairs

Adsorption of ethene at 94 K followed by heating to 370 K and subsequent cooling to 94 K produced a RAIR spectrum in which three bands, at 2884, 1341 and 1124 cm−1, were observed. These bands may be assigned by reference to the EEL spectrum of ethylidyne on Pt(111) and the infrared spectrum of the ethylidyne ligand in the cluster compound Co3(CO)9CCH3. The resulting excellent agreement, particularly with the IR spectrum of the cluster compound, leads to an unambiguous assignment of the three bands to the symmetric methyl stretch, symmetric methyl deformation and carbon-carbon stretch respectively of the ethylidyne species.

ChemInform Abstract: Radiation Synthesis of Organometallic Compounds. Radiolysis of Benzene Solutions of Co2(CO)8.

AbstractAfter repeated separation, the novel complexes (I) and (II) were isolated from the title reaction, besides two well‐known compounds Co2(CO)6(C2H2) and Co4(CO)12.

ChemInform Abstract: EFFECT OF THE BRIDGING LIGANDS ON THE C‐O STRETCHING FORCE CONSTANTS OF THE COMPOUNDS CO2(CO)6(MU‐Y)2 AND FE2(CO)6(MU‐X)2 (WHERE Y=CO, P, AS, CR AND X=S, SR, SE, PRR′, BR, J)

Chemischer InformationsdienstVolume 6, Issue 46 Physical Organic Chemistry ChemInform Abstract: EFFECT OF THE BRIDGING LIGANDS ON THE C-O STRETCHING FORCE CONSTANTS OF THE COMPOUNDS CO2(CO)6(MU-Y)2 AND FE2(CO)6(MU-X)2 (WHERE Y=CO, P, AS, CR AND X=S, SR, SE, PRR′, BR, J) G. BOR, G. BORSearch for more papers by this author G. BOR, G. BORSearch for more papers by this author First published: November 18, 1975 https://doi.org/10.1002/chin.197546062AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume6, Issue46November 18, 1975 RelatedInformation

Zur kenntnis der chemie der metallcarbonyle und der cyano-komplexe in flüssigem ammoniak: XXIX.Über neue carbamoyl-carbonyl-komplexe des kobalts

The reaction between the cationic complex [Co(CO)4(PPh3)]Cl·HCl and NHMe2 (MeCH3) leads to the very stable compound N,N-dimethylcarbamoyltriphenylphosphinetricarbonylcobalt(I), Co(CO)3(PPh3(CONMe2). If liquid NH3 is used the products HCo(CO)3(PPH3), NH4NCO and NH4Cl are formed. The carbamoyl compound Co(CO)3(PPh3)(CONH2) is discussed as a possible intermediate, but could not be isolated even at low temperature. The non-ionic Co(CO)3)PPh3)I, however, reacts with liquid NH3 to form the moderately stable complex Co(CO)2(PPh3)(NH3)(CONH2).The properties of the new compounds are described and their structures are discussed on the basis of IR-spectral data.

Zusammensetzung und strukturelle Eigenschaften des „zweiwertigen”︁ Kobaltcyanids

AbstractThe products obtained by mixing aqueous solutions of cobalt (II) chloride and potassium or hydrogen cyanide are nonstoichiometric compounds Co(CN)x, yH2O whith x between 2.2 and 2.4 and y between 1.75 and 2.15. They have a cubic face‐centered unit cell with a = 10.20 ± 0.02 Å and Z between 6.8 and 7.1 (Z = number of units Co (CN)x yH2O per cell). Infrared spectra show that there is zeolitic as well as coordinated water present. The coordination units derived from reflectance spectra in the ultraviolet and visible region are (CoIII)C6 and CoIIN6‐xOx. There exists a close structural relationship between Co(CN)x, yH2O and the stoichiometric compound Co3[Co(CN)6]2, zH2O. Comparison of calculated with experimental density shows that there must be holes in the threedimensional CoCNCo‐framework, which can be occupied by water molecules.

Vibrational and electronic spectra of transition-metal carbonyl complexes. Part V. Solvent effects on the infrared spectra of the complexes (π-C5H5)Mn(CO)3and (π-C6Me6)Cr(Co)3

Precise measurements of the i.r. spectra in the C–O stretching region of the compounds (π-C5H5)Mn(CO)3 and (π-C6Me6)Cr(CO)3 have been made in a range of solvents. The general behaviour is similar to that of the compound Co(CO)3NO and no evidence for a breakdown of the C3v selection rules could be observed.