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1.
Dheeraj K. SinghSunil K. Srivastava Prachi RaghuvanshRanjan K. Singh B.P. Asthana 《Vibrational Spectroscopy》2011,56(1):34-41
The Raman spectra of neat (C2H5)2CO (pentanone) and its binary mixtures with hydrogen donor solvent (CH3OH), [(C2H5)2CO + CH3OH] having different mole fractions of the reference system, (C2H5)2CO in the range 0.1-0.9 at a regular interval of 0.1 were recorded in the CO stretching region. In neat liquid, the Raman peak appears asymmetric. The asymmetric nature of the peak has been attributed to the CO stretching mode of the two conformers of (C2H5)2CO having C2 and C2v point groups and the corresponding bands at ∼1711 and ∼1718 cm−1, respectively. A careful analysis of the Iiso (isotropic component of the Raman scattered intensity) at different concentrations reveals that upon dilution with methanol, at mole fraction C = 0.6, an additional peak in the CO stretching region is observed at ∼1703 cm−1 which is attributed to the hydrogen bonding with methanol. A peculiar feature in this study is that upon dilution, the peak at ∼1718 cm−1 shows a minimum at C = 0.6, but on further dilution it shows a blue shift. However, the other peak at ∼1711 cm−1 shows a continuous red shift with dilution as well as a maximum at C = 0.7 in the linewidth vs. concentration plot, which is essentially due to competition between motional narrowing and diffusion phenomena. A significant amount of narrowing in the Raman band at ∼1718 cm−1 can be understood in terms of caging effect of the reference molecule by the solvent molecules at high dilution. A density functional theoretic (DFT) calculation on optimized geometries and vibrational frequencies of two conformers of neat (C2H5)2CO in C2 ad C2v forms and the complexes with one and two CH3OH molecules with both the conformers was performed. The experimental results and theoretical calculations together indicate a co-existence of two conformers as well as hydrogen bonded complex with methanol in the binary mixture, [(C2H5)2CO + CH3OH] at intermediate concentrations. 相似文献
2.
Marcin Konkol 《Journal of organometallic chemistry》2006,691(12):2839-2845
The iridium dinitrogen complex [IrCl(N2)(PPh3)2] (1) was found to react with alkynylsilanes to form the vinylidene iridium(I) complexes trans- (R/R′ = Ph/Me, 2; Me/Me, 3; Bn/Me, 4; SiMe3/Me, 5; SiEt3/Et, 6; iPr/Me, 7) and with Me3SiCCC(O)R to yield the iridium η2-alkyne complexes trans-[IrCl{η2-Me3SiCCC(O)R}(PPh3)2] (R = OEt, 9; Me, 11). Complex 9 was found to isomerize upon heating or upon UV irradiation yielding the vinylidene complex trans-[IrCl{CC(SiMe3)CO2Et}(PPh3)2] (10). The reaction of 1 with Me3SiCCCCSiMe3 yielded the complex trans-[IrCl{CC(SiMe3)CCSiMe3}(PPh3)2] (8), whereas with MeO2CCCCO2Me the iridacyclopentadiene complex [Ir{C4(CO2Me)4}Cl(PPh3)2] (13) was formed. The complexes were characterized by means of 1H, 13C and 31P NMR spectroscopy as well as by IR spectroscopy and microanalysis. 相似文献
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Jason M. Lynam Tracy D. Nixon Adrian C. Whitwood 《Journal of organometallic chemistry》2008,693(19):3103-3110
Reaction of cis-[RuCl2(dppm)2] (dppm = 1,2-bis(diphenylphosphino)methane) with PhCCH and NaPF6 utilising methanol as solvent results in the formation of the η3-butenynyl complex [Ru(η3-PhCCCCHPh)(dppm)2][PF6] in good yield. Similar reactions with ButCCH and PrnCCH resulted in the corresponding alkyl-substituted complexes and all three of these compounds have been characterised by NMR spectroscopy and X-ray crystallography. The mechanism of this reaction has been probed by employing labelling experiments with both PhCCD and PhC13CH allowing the identity of possible intermediates in the reaction to be determined. Furthermore, [Ru(η3-PhCCCCHPh)(dppm)2][PF6] has been shown to be an effective regio- and stereo-selective catalyst for the dimerisation of PhCCH to Z-PhCCCHCHPh in the absence of solvent. In contrast, no evidence for the formation of alkyne coupling was obtained from the reaction of cis-[RuCl2(dppe)2] (dppe = 1,2-bis(diphenylphosphino)ethane) with PhCCH and NaPF6. 相似文献
5.
Beatriz Alonso Esther Delgado Elisa Hernández Rubén A. Toscano 《Journal of organometallic chemistry》2007,692(23):5117-5124
The compounds [Os3(CO)10{μ,η3-(SCH2CH2SCCHC(O)CHCH(C5H4)Fe (C5H5)}] (2), [Os3(CO)9{μ,η3-(SCH2CH2SCCHC(O)CHCH(C5H4)Fe(C5H5)}] (3) and [Os3(CO)8{μ3,η2-{CCHC(O)CHCH(C5H4)Fe(C5H5)}(SCH2CH2S)}] (4) have been obtained by rupture of S-C bonds in the ketene dithioacetal [C5H5FeC5H4CHCHC(O)CHC(SCH2CH2S)], in their reaction with the activated cluster [Os3(CO)10(NCMe)2]. The presence of an oxametallacycle in these derivatives has been confirmed by an X-ray diffraction analysis. The electrochemical study has indicated the ability of these compounds to modify the electrode surfaces. 相似文献
6.
Manab Sharma Michael G. Gardiner Roderick C. Jones 《Journal of organometallic chemistry》2011,696(7):1441-1444
Trans-di(ortho-tolylethynyl)bis(dimethylphenylphosphine)palladium(II) reacts above −20 °C with the iodonium reagent IPhCl2 to give predominantly o-Tol-CC-Cl, above 15 °C with IPh2(OTf) (OTf = triflate) to give o-Tol-CC-Ph and (o-Tol-CC)2 in ca. 3:1 ratio, and above 10 °C with IPh(CCR)(OTf) (R = But, SiMe3) to give predominantly o-Tol-CC-CC-R and (o-Tol-CC)2. 31P NMR spectra provide evidence for detection of intermediates. The complexes trans-[Pd(CC-o-Tol)2(PMe2Ph)2] and trans-[PdCl(CC-o-Tol)(PMe2Ph)2] are obtained on reaction of trans-[PdCl2(PMe2Ph)2] with Li(CC-o-Tol) and o-Tol-CCH/Et3N, respectively, and have been characterised by X-ray crystallography. 相似文献
7.
The first luminescent rhenium(I)-gold(I) hetero organometallics, Re{phenAu(PPh3)}(CO)3Cl (3) and Re{(PPh3)AuphenAu(PPh3)}(CO)3Cl (4), have been prepared using the gold(I) complex AuCl(PPh3) (PPh3 = triphenylphosphine) and the novel rhenium(I) complexes Re(phenH)(CO)3Cl (5) (phenH = 3-ethynyl-1,10-phenanthroline) or Re(HphenH)(CO)3Cl (6) (HphenH = 3,8-bis(ethynyl)-1,10-phenanthroline). All the present rhenium(I) complexes 3-6 were revealed to possess a facial configuration (fac-isomer) with respect to the three carbonyl ligands. The main frameworks for these new gold(I) organometallics were constructed by the Au-C σ-bonding (with the η1-type coordination) between the ethynylphenanthrolines and the Au(I) phosphine unit. Re(I)-Au(I) heterometallics 3 and 4 have shown single phosphorescence from the 3MLCT excited state and this observation can be interpreted in terms of the efficient intramolecular energy transfer from the Au(I) unit to the Re(I) unit. 相似文献
8.
The mechanism of chloride substitution in CF2CFCl with [Re(CO)5]− and [CpFe(CO)2]− anions is investigated experimentally and theoretically. The substitution reaction begins with the nucleophile addition to CF2CFCl producing the carbenoid anion [MCF2CFCl]− (A) (M = Re(CO)5, CpFe(CO)2). This is shown by trapping the intermediate A with electrophiles - proton donor (t-BuOH) to give MCF2CFClH or with CF2CFRe(CO)5 to give acylmetallate III, and by the formation of the substitution products CF2CFM from the anion A, generated by the deprotonation of MCF2CFClH with t-BuOK. 1,2-Shift of metal carbonyl group concerted with the α-elimination of chloride anion is proposed as the transformation pathway of carbenoid A into CF2CFM. A competing process of carbene insertion into Fe-CO bond is proposed to explain the formation of (XI). The feasibility of these two pathways is confirmed by DFT (B3LYP/SDD and 6-31G∗) calculations of the carbenes [MCF2CF:] and carbenoid anions [MCF2CFCl]−. Transition states (TS) for 1,2-shift (+3.2 kcal/mol) and for nucleophilic addition at CO ligand (+5.4 kcal/mol) are located for [(CO)5ReCF2CFCl]−, but only one TS corresponding to carbene insertion into Fe-CO bond (+2.1 kcal/mol) is located for [(CO)2CpFeCF2CFCl]−. The formation of other newly observed products, F(CO)CHFRe(CO)5 (V) and Cp(CO)2FeCCFeCp(CO)2 (VIII) is also discussed. 相似文献
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Michael MillerFrank J. Owens 《Chemical physics》2012,394(1):52-55
Density functional theory is used to calculate the bond dissociation energy to cleave the C60C60 bond of the paramagnetic X-C60C60-X and X-C60C60 dimers where X is F, OH, O and H. The results show that these dimers would not be stable much above room temperature and therefore cannot constitute the paramagnetic phase needed to form the observed ferromagnetism which has been shown to be stable up to 800 K. The calculated bond dissociation energies to remove an F, OH or H from a single C60 are large suggesting that they could be the source of the unpaired spin needed for the high temperature ferromagnetism. 相似文献
11.
Two kinds of phenylacetylene-terminated poly(silyleneethynylene-4,4′-phenylethereneethynylene)s, {C6H5CC[Si(R)2CCC6H4OC6H4CC]nC6H5} wherein R represents methyl or phenyl, were synthesized by condensation reaction between dichlorosilanes and 4,4′-diethynyldiphenyl ether using organomagnesium reagents. The polymers were characterized by NMR, IR, gel permeation chromatography, thermogravimetric analysis, and differential scattering calorimetry. 相似文献
12.
Tushar S. Basu Baul Keisham Surjit Singh Michal Hol?apek 《Journal of organometallic chemistry》2005,690(6):1581-1587
The complex, [(PhCH2)2{O2CC6H4{N(H)N(C6H3-4(O)-5-O)}-o}Sn]2 (1), is obtained as the exclusive reaction product from the reaction of sodium 2-[(E)-2-(3-formyl-4-hydroxyphenyl)-1-diazenyl]benzoate and (PhCH2)3SnCl. The reaction possibly proceeds via Dakin type rearrangements where arylazosalicylaldehyde is oxidized to arylazocatechol, followed by facile Sn-C bond cleavage. Complete assignments were achieved by 1H, 13C, 2D 1H-119Sn HMQC (119Sn chemical shift), 1D gs 1H-15N HMQC (1J(15N, 1H) coupling constant) NMR and ESI-MS. The crystal structure of compound 1 as determined by X-ray diffraction analyses shows a cyclic centrosymmetric dinuclear moiety linked into extended chains by pairs of long Sn?O contacts of approximately 3.2 Å. Two polymorphs were identified and their structures differ primarily in the packing arrangement afforded by the benzyl groups. In one polymorph, when viewed along the Sn?Sn vector, the benzyl groups at each Sn-atom are oriented to form an S-shape, while they form a U-shape in the second polymorph. 相似文献
13.
Michael I. Bruce Marcus L. Cole Brian W. Skelton 《Journal of organometallic chemistry》2006,691(22):4601-4614
Complexes M(CCCSiMe3)(CO)2Tp′ (Tp′ = Tp [HB(pz)3], M = Mo 2, W 4; Tp′ = Tp∗ [HB(dmpz)3], M = Mo 3) are obtained from M(CCCSiMe3)(O2CCF3)(CO)2(tmeda) (1) and K[Tp′].Reactions of 2 or 4 with AuCl(PPh3)/K2CO3 in MeOH afforded M{CCCAu(PPh3)}(CO)2Tp′ (M = Mo 5, W 6) containing C3 chains linking the Group 6 metal and gold centres.In turn, the gold complexes react with Co3(μ3-CBr)(μ-dppm)(CO)7 to give the C4-bridged {Tp(OC)2M}CCCC{Co3(μ-dppm)(CO)7} (M = Mo 7, W 8), while Mo(CBr)(CO)2Tp∗ and Co3{μ3-C(CC)2Au(PPh3)}(μ-dppm)(CO)7 give {Tp∗(OC)2Mo}C(CC)2C{Co3(μ-dppm)(CO)7} (9) via a phosphine-gold(I) halide elimination reaction. The C3 complexes Tp′(OC)2MCCCRu(dppe)Cp∗ (Tp′ = Tp, M = Mo 10, W 11; Tp′ = Tp∗, M = Mo 12) were obtained from 2-4 and RuCl(dppe)Cp∗ via KF-induced metalla-desilylation reactions. Reactions between Mo(CBr)(CO)2Tp∗ and Ru{(CC)nAu(PPh3)}(dppe)Cp∗ (n = 2, 3) afforded {Tp∗(OC)2Mo}C(CC)n{Ru(dppe)Cp∗} (n = 2 13, 3 14), containing C5 and C7 chains, respectively. Single-crystal X-ray structure determinations of 1, 2, 7, 8, 9 and 12 are reported. 相似文献
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Mi S. Lim 《Journal of organometallic chemistry》2006,691(19):4100-4108
The cationic aniline complex [Cp∗Rh(η6-2,6-(Me2CH)2C6H3NH2)](OTf)2 (1) was prepared from either [Cp∗Rh(η2-NO3)(η1-OTf)] or [Cp∗Rh(OH2)3](OTf)2 and 2,6-diisopropylaniline. Complex 1 underwent substitution with phosphines or phosphites, indicating the labile character of the η6-aniline ligand. Complex 1 mediated cycloaddition reactions of several alkynes in refluxing ethanol: the [2 + 2] dimerization for PhCCPh and the [2 + 2 + 1] trimerization for PhCCH and CH3C6H4CCH. The unexpected cyclobutadiene complex [Cp∗Rh(η4-C4(C(O)CH3)2H(SiMe3))] was obtained from complex 1 and Me3SiCCCCSiMe3 and structurally characterized by X-ray diffraction. 相似文献
16.
Mei-Chun Lu 《Analytica chimica acta》2004,522(1):25-33
The electrochemical and electrogenerated chemiluminescence (ECL) properties of indium tin oxide (ITO) electrodes modified with poly(4-vinylpyridine) (PVP)-bound Ru(bpy)2Cl+ (where bpy = 2,2′-bipyridine) have been studied. In a sodium oxalate solution, two irreversible oxidation waves as well as two ECL emission waves were observed during the potential scan in the range 0.4-1.4 V (versus Ag/AgCl/saturated KCl reference). The first ECL wave appeared at ca. 0.8 V, which was caused by the excited-state Ru2+* generated through a bimolecular redox reaction between electrogenerated Ru3+ and the strong reducing agent, C−O2. The latter was formed via a Ru3+-mediated oxidation of oxalate. Direct oxidation of oxalate was not involved in the first ECL process. The second ECL wave started at ca. 1.1 V, which was also from the excited-state Ru2+* generated via the redox reaction between Ru3+ and C−O2. However, both direct and Ru3+-mediated oxidation of oxalate contributed to the formation of C−O2. The important role of the direct oxidation of oxalate in the ECL mechanism of PVP-bound Ru(bpy)2Cl+/oxalate system was demonstrated. The relative contribution of direct oxidation of oxalate to the observed ECL depended upon the surface concentration of PVP-bound Ru2+, the concentration of oxalate and the electrode potential applied. 相似文献
17.
In the thermolysis of the silaterazolines silatetrazoline tBu2SiNSiCltBu2 · tBu3SiN3 the silanimine tBu2SiNSiCltBu2 and the silyl azide tBu3SiN3 are formed quantitatively. The silanimine tBu2SiNSiCltBu2 has been trapped with Et3NHF, Me3NHCl, water, 1-butene, 2,3-dimethyl-1,3-butadiene, isobutene, methylvinyl ether, and tBu2SiClN3. The structure of the disiloxane (tBu2SiCl-NH-SitBu2)2O and of the bis(di-tert-butylchlorsilyl)-substituted silatetrazoline tBu2SiNSiCltBu2 · tBu2SiClN3 has been determined by X-ray structure analysis. 相似文献
18.
Séverine Roué 《Journal of organometallic chemistry》2005,690(3):594-604
The synthesis of the new complexes Cp*(dppe)FeCC2,5-C4H2SR (Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl; dppe = 1,2-bis(diphenylphosphino)ethane; 2a, R = CCH; 2b, R = CCSi(CH3)3; 2c, R = CCSi(CH(CH3)2)3; 3a, R = CC2,5-C4H2SCCH; 3c, R = CC2,5-C4H2SCCSi(CH(CH3)2)3) is described. The 13C NMR and FTIR spectroscopic data indicate that the π-back donation from the metal to the carbon rich ligand increases with the size of the organic π-electron systems. The new complexes were also analyzed by CV and the chemical oxidation of 2a and 3c was carried out using 1 equiv of [Cp2Fe][PF6]. The corresponding complexes 2a[PF6] and 3c[PF6] are thermally stable, but 2a[PF6] was too reactive to be isolated as a pure compound. The spectroscopic data revealed that the coordination of large organic π-electron systems to the iron nucleus produces only a weak increase of the carbon character of the SOMO for these new organoiron(III) derivatives. 相似文献
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Katsuhiko Takeuchi 《Journal of organometallic chemistry》2011,696(6):1156-12481
The reaction of 1,1,4,4-tetrakis[bis(trimethylsilyl)methyl]-1,4-diisopropyltetrasila-2-yne 1 with secondary or primary amines produced amino-substituted disilenes R(R2′N)SiSiHR 2a-d (R = SiiPr[CH(SiMe3)2]2, R2′NEt2N (2a), (CH2CH2)2N (2b), tBu(H)N (2c), and Ph2N (2d)). Spectroscopic and X-ray crystallographic analyses of 2 showed that 2a-c have a nearly coplanar arrangement of the SiSi double bond and the amino group, giving π-conjugation between the SiSi double bond and the lone pair on the nitrogen atom, whereas 2d has a nearly perpendicular arrangement precluding such conjugation. Theoretical calculations indicate that π-conjugation between the π-orbital of the SiSi double bond and the lone pair on the nitrogen atom is markedly influenced by the torsional angle between the SiSi double-bond plane and the amino-group plane. 相似文献