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Lo WJ, Chen HF, Chou PH, Lee YP: Isomers of OCS2: IR absorption spectra of OSCS and O (CS2) in solid Ar. J Chem Phys. 2004 Dec 22;121(24):12371-8.
Irradiation of an Ar matrix sample containing O (3) and CS (2) with a KrF excimer laser at 248 nm yielded new lines at 1402.1 (1404.7), 1056.2 (1052.7), and 622.3 (620.5) cm (-1); numbers in parentheses correspond to species in a minor matrix site. Secondary photolysis at 308 nm diminished these lines and produced mainly OCS and SO (2). Annealing of this matrix to 30 K yielded a second set of new lines at 1824.7 and 617.8 cm (-1). The first set of lines are assigned to C=S stretching, O-S stretching, and S-C stretching modes of carbon disulfide S-oxide, OSCS; and the second set of lines are assigned to C=O stretching and OCS bending modes of dithiiranone, O (CS (2)), respectively, based on results of (34) S- and (18) O-isotopic experiments and quantum-chemical calculations. These calculations using density-functional theory (B3LYP/aug-cc-pVTZ) predict four stable isomers of OCS (2): O (CS (2)), SSCO, OSCS, and SOCS, listed in order of increasing energy. According to calculations, O (CS (2)) has a cyclic CS (2) moiety and is the most stable isomer of OCS (2). OSCS is planar, with bond angles angle OSC congruent with 111.9 degrees and angle SCS congruent with 177.3 degrees ; it is less stable than SSCO and O (CS (2)) by approximately 102 and 154 kJ mol (-1), respectively, and more stable than SOCS by approximately 26 kJ mol (-1). Calculated vibrational wave numbers, IR intensities, (34) S- and (18) O-isotopic shifts for OSCS and O (CS (2)) fit satisfactorily with experimental results. |
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