CO absorption

Fig. 3. Attenuation of infrared as a function of normalized concentration caused by CO absorption in the 4.6 p.m band. = 6.6E3 ppm m,...

X-ray diffraction studies on [TpBut,Me]Zn 2(/i,-r)1,Tj1-C03) have identified that the bridging carbonate ligand is coordinated to each zinc center in a unidentate fashion (171,172), which thereby provides additional support for the presence of a unidentate, rather than bidentate, bicarbonate ligand in [TpBut,Me]Zn(0C02H). The carbonate complex [TpBut,Me]Zn 2(/iA-7)1,T)1-C03) is also characterized by v(CO) absorptions at 1587 and 1311 cm-1 in the IR spectrum (173), and a 13C NMR signal at 8 164 ppm (in C6D6). 

Microanalysis of the three PET-4,4 -SD copolymer yarns for sulfur yielded concentrations in agreement with the theoretical values. Since the 4,4 -SD comonomer was definitely incorporated into the three copolymer yarns, the absorption and luminescence characteristics of the copolymers point towards a co-absorption process between 4,4 -SD and PET rather than an electronic energy transfer process. 

The infrared (IR) spectrum of 7 exhibited an absorption band at 3413 cm-1 due to the NH and a strong absorption band corresponding to C=S at 1279 cm-1, respectively <1999IJB850>. In the case of compound 8, IR spectra were characterized by the presence of NH and CO absorption bands in the region 3301-3320 and 1660-1680cm, respectively <2004JCM399>. 

Experiments with CO adsorption on Ni-Cu/Si02 [19] and Pd-Au/Si02 catalysts [20] gave very similar results. In the latter, two CO absorption bands were also seen, one at around 1900 cm, assigned to bridge-bonded CO and another at 2070 cm1, characteristic of linear CO on single Pd atoms. Figure 8.6 shows the intensities of the two bands as a function of Pd content in the Pd-Au alloys. The almost quadratic... 

A tunable diode laser system and optics (Laser Photonics, L5736) was used to monitor the species release rates during an experiment. It consists of a liquid-nitrogen cooled diode emitter. For CO absorption measurements the laser emits a beam tuned to a wavenumber of 2082 cm4. This line is chosen as it exhibits strong absorption and is not subject to interference from other species likely to be present in the pyrolysate. 

Although Eq. (3) indicates that CO absorption is required for aldehyde formation, it has been shown by Karapinka and Orchin 18) that at 25° and with a moderate excess of olefin the rate of reaction and the yield of aldehyde are similar when either 1 atm of CO or 1 atm of Nj is present. Obviously CO is not essential for the reaction and a CO-deficient intermediate, probably an acylcobalt tricarbonyl, can be formed under these conditions. The relative rates of HCo(CO)4 cleavage of tricarbonyl and tetracarbonyl are not known, and thus the stage at which CO is absorbed in the stoichiometric hydroformylation of olefins under CO is not known with certainty. Heck (19) has shown conclusively that acylcobalt tetracarbonyls are in equilibrium with the acylcobalt tricarbonyl ... 

In the infant chemistry of iminoboranes only one example of insertion into a bridge position has been found [Eq. (56)] (86). That the structure of the product [Eq. (56)] corresponds to structure Xlla has been deduced from the CO absorption bands in the IR spectra, which... 

High pressure infrared (HP IR) spectroscopy has now been used for over 30 years for the study of homogeneous transition metal catalysed processes. The technique is particularly useful for reactions involving carbon monoxide, for which transition metal carbonyl complexes are key intermediates in the catalytic mechanisms. Such complexes have one or more strong r(CO) absorptions, the frequencies and relative intensities of which provide information about the geometry and electronic character of the metal center. As well as probing the metal species, HP IR spectroscopy can also be used to monitor the depletion and formation of organic reactants and products if they have appropriate IR absorptions. 

A subsequent study using neopentane as the alkane substrate gave evidence in support of the same mechanism, and also allowed resolution of near-coincident y(CO) absorptions due to [Cp Rh(CO)Kr] (1946 cm ) and [Cp Rh(CO)(di2-neopen-tane)] (1947 cm ) [18]. Further studies were able to quantify the reactivity of [Cp Rh(CO)Kr] towards a range of alkanes [20]. It was found that binding of the alkane to Rh becomes more favorable, thermodynamically, as the alkane size is increased, but that the rate of the C-H oxidative addition step shows less variation with linear alkane chain length. No reaction with methane was observed, which was explained by the ineffective binding of methane (relative to excess Kr) to Rh. 

Performing this reaction at 40°C in a closed system fitted with traps for COS and CO- absorption and passing nitrogen through it, 2-4% COS and 18 to 22% CO- were evolved after 16 hours. A two molar excess 01 glutathione released up to 40% of CO- and 5% of COS. The same experiments carried out with cysteine... 

The last ones isomerize on standing into N-alkyl derivatives. A mixture of both 0 and N ethyl isomers has been obtained by heating the silver salt of 3-methyl-5-hydroxy oxadiazole with ethyl iodide. The structure of both isomers has been established by comparing their IR spectra only N-ethyl oxadiazole shows a CO absorption band at 5-68 [jl. 

Although the infrared spectra of the polymers show the formation of oxadiazole rings, the presence of CO absorption bands indicates that... 

Studies by Crawford Rotenberg (Ref 4) who used a rapid-scan spectrometer in conjunction with a strand burning apparatus to examine NG-NC low temperature decomposition and flames. During the decomposition of commercial double-base propellants, the gas products were NO, N20, C02 CO. When these propellants were burned under 100-150 psi nitrogen pressure at a linear velocity of 100 cm/sec, C02 CO absorption bands appeared even at 2 cm away from the burning surface. Nitric oxide was barely detectable and N20 was completely absent... 

The hydroxypyrazolo[3,4-d]pyrimidine derivative 306 exists mainly as such based on the absence of a CO band in the IR (61JOC451). The IR spectrum of allopurinol, the C-6 thioxo derivative, and the C-6 0x0 derivative reveal strong CO absorption and an absence of any absorption for enol forms (76MI3). 

The tris(chloromethyldifluorophosphine)molybdenum tricarbonyl exhibited strong CO absorptions typical for terminal CO groups at 2038 and 1970 cm.-1. Strong P-F absorptions were found at 866 and 842 cm.-1, which in view of the above-mentioned observation in the case of tetrakis(trifluorophosphine)nickel-(0) may also be representative ef the uncoordinated fluorophosphine. Compared with molybdenum tricarbonyl derivatives with nitrogen compounds as donor mole-... 

The compound [PPN]2[Os6(CO)18] is insoluble in hydrocarbons, sparingly soluble in methanol, and very soluble in acetone, acetonitrile, dichlorometh-ane, and chloroform to give solutions that are stable indefinitely at room temperature. Its IR spectrum in CH2C12 exhibits an intense v(CO) absorption at 1991 and very weak absorptions at 1964, 1938, and 1910cm-1. The compound is easily oxidized back to Os6(CO)18 by treatment of a CH2C12 solution with iodine /2.n... 

Compound 4 is an air-stable, orange-red, crystalline solid. It is soluble in common organic solvents such as hexane, benzene and dichloromethane. Solutions of 4 in these solvents are stable in air for several days. The IR spectrum of the compound contains the following CO absorptions (hexane) 2090(s), 2065(s), 2028(vs), 2022(m), 1995(w), 1983(w), 1936 (w) cm-1. The crystal structure of 4 has been reported.9... 

The product [(j75-C5Me5)Mo(CO)n]2 is a mixture of the compounds with n = 2 and 3.13 It is not necessary to separate the mixture, since the oxidation described below proceeds with loss of CO. The mixture is moderately air sensitive, but may be stored in an inert atmosphere. The H NMR spectrum of the mixture (200 MHz, CDC13 solution) shows singlets at 1.92 and 1.89 ppm. The infrared spectrum (Nujol mull) shows v(CO) absorption bands at 1925, 1895, 1870, and 1827 cm 1. 

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