- Photochemistry of BrNCO and INCO
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The absorption spectra of BrNCO and INCO in the region 160-400 nm are continuous in nature,and photolysis of these molecules with pulsed excimer lasers leads to dissociation.Photolysis of BrNCO and INCO at 308 and 351 nm, respectively, produces vibrationally cold ground state NCO radicals.Weak NCO A 2Σ+ X 2Π emission results from two-photon absorption processes at these wavelengths.Photolysis of BrNCO and INCO at 193 and 222 nm, respectively, produces intense NCO A 2Σ+ X 2Π emission.The NCO(A) is a direct one-photon photofragment in each case, and has considerable vibrational excitation.The yield of NCO(A) from BrNCO photolysis at 193 nm is approximately 16percent; the yield of NCO(A) from INCO photolysis at 222 nm is near 13percent.From the production of NCO(a) at these wavelengths and the short wavelength limit of the NCO A 2Σ+ X 2Π emission, limits on the heats of formation of these molecules are found to be ΔHf(BrNCO) -1.7 kcal mol-1 and ΔHf(INCO) 10.9 kcal mol-1.These results demonstrate the preference of the halogen isocyanates for dissociation to double fragments by scission of the nitrogen-halogen bond, in contrast to the analogous halogen azides which photodissociate to singlet or triplet fragments.
- Liu, X.,Gilbert, J. V.,Coombe, R. D.
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- Preparations of Pure ISeCN, ISCN, and INCO
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Pure INCO, ISCN, and the hitherto unknown molecule ISeCN have been prepared in the HeI photoelectron spectrometer (PES) by the heterogeneous reactions of ICI gas with AgNCO, AgSCN at room temperature, and AgSeCN at -9 (±1) °C, respectively. They were characterized on line by PES experiments and OVGF calculations. The well-matched results between the PES experiments and OVGF calculations not only show that the new reaction is a good reaction to prepare pure INCO and pure ISCN, but also that the new compound prepared by passing the ICI gas over the freshly AgSeCN powder at -9(±1) °C is the hitherto unknown ISeCN.
- Yimin, Li,Zhimin, Qiao,Qiao, Sun,Jincai, Zhao,Haiyang, Li,Dianxun, Wang
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p. 8446 - 8448
(2008/10/09)
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- THE INFRARED SPECTRA OF THE HALOGEN ISOCYANATE AND THIOCYANATE VAPOR MOLECULES
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Fourier transform infrared spectroscopy has been used to investigate the IR spectra of the XNCO (X = Cl, Br, I, CN), the XSCN (X = Cl, Br, I) and the NCNCS vapor molecules from 4800 to 400 cm-1.Vibrational frequencies have been determined for e
- Devore, T. C.
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p. 287 - 304
(2007/10/02)
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