水-羰基硫络合物的微波傅里叶变换光谱

Microwave Fourier transform spectrum of the water-carbonyl sulfide complex.

作者信息

Tatamitani Yoshio, Ogata Teruhiko

机构信息

Department of Chemistry, Faculty of Science, Shizuoka University, Ohya, Shizuoka 422-5829, Japan.

出版信息

J Chem Phys. 2004 Nov 22;121(20):9885-90. doi: 10.1063/1.1809113.

DOI:10.1063/1.1809113

PMID:15549861

Abstract

The microwave spectrum of the water-carbonyl sulfide complex H(2)O-OCS was observed with a pulsed-beam, Fabry-Perot cavity Fourier-transform microwave spectrometer. In addition to the normal isotopic form, we also measured the spectra of H(2)O-S(13)CO, H(2)O-(34)SCO, H(2) (18)O-SCO, D(2)O-SCO, D(2)O-S(13)CO, D(2)O-(34)SCO, HDO-SCO, HDO-S(13)CO, and HDO-(34)SCO. The rotational constants are B = 1522.0115(2) MHz and C = 1514.3302(2) MHz for H(2)O-SCO; B = 1511.9153(5) MHz and C = 1504.3346(5) MHz for H(2)O-S(13)CO; B = 1522.0215(3) MHz and C = 1514.3409(3) MHz for H(2)O-(34)SCO; B = 1435.9571(3) MHz and C = 1429.1296(4) MHz for H(2) (18)O-SCO, B = 1409.6575(5) MHz and C = 1397.9555(5) MHz for D(2)O-SCO; B = 1399.8956(3) MHz and C = 1388.3543(3) MHz for D(2)O-S(13)CO; B = 1409.6741(24) MHz and C = 1397.9775(24) MHz for D(2)O-(34)SCO; (B+C)/2 = 1457.9101(2) MHz for HDO-SCO; (B + C)/2 = 1448.0564(4) MHz for HDO-S(13)CO; and (B+C)/2 = 1457.9418(15) MHz for HDO-(34)SCO, with uncertainties corresponding to one standard deviation. The observed rotational constants for the sulfur-34 complexes are generally higher than those for the corresponding sulfur-32 isotopomers. The heavier isotopomers have smaller effective moments of inertia due to the smaller vibrational amplitude of the (34)S-C vibration (zero point) as compared to the (32)S-C, making the effective O-(34)S bond slightly shorter. Stark effect measurements for H(2)O-SCO give a dipole moment of 8.875(9)x10(-30) C m [2.6679(28) D]. The most probable structure of H(2)O-SCO is near C(2v) planar with the oxygen of water bonded to the sulfur of carbonyl sulfide. The oxygen-sulfur van der Waals bond length is determined to be 3.138(17) A, which is very close to the ab initio value of 3.144 A. The structures of the isoelectronic complexes H(2)O-SCO, H(2)O-CS(2), H(2)O-CO(2), and H(2)O-N(2)O are compared. The first two are linear and the others are T shaped with an O-C/O-N van der Waals bond, i.e., the oxygen of water bonds to the carbon and nitrogen of CO(2) and N(2)O, respectively.

摘要

使用脉冲束法布里 - 珀罗腔傅里叶变换微波光谱仪观测了水 - 羰基硫络合物H₂O - OCS的微波光谱。除了正常同位素形式外，我们还测量了H₂O - S¹³CO、H₂O - ³⁴SCO、H₂¹⁸O - SCO、D₂O - SCO、D₂O - S¹³CO、D₂O - ³⁴SCO、HDO - SCO、HDO - S¹³CO和HDO - ³⁴SCO的光谱。对于H₂O - SCO，转动常数为B = 1522.0115(2) MHz，C = 1514.3302(2) MHz；对于H₂O - S¹³CO，B = 1511.9153(5) MHz，C = 1504.3346(5) MHz；对于H₂O - ³⁴SCO，B = 1522.0215(3) MHz，C = 1514.3409(3) MHz；对于H₂¹⁸O - SCO，B = 1435.9571(3) MHz，C = 1429.1296(4) MHz；对于D₂O - SCO，B = 1409.6575(5) MHz，C = 1397.9555(5) MHz；对于D₂O - S¹³CO，B = 1399.8956(3) MHz，C = 1388.3543(3) MHz；对于D₂O - ³⁴SCO，B = 1409.6741(24) MHz，C = 1397.9775(24) MHz；对于HDO - SCO，(B + C)/2 = 1457.9101(2) MHz；对于HDO - S¹³CO，(B + C)/2 = 1448.0564(4) MHz；对于HDO - ³⁴SCO，(B + C)/2 = 1457.9418(15) MHz，不确定性对应于一个标准偏差。观测到的含硫 - 34络合物的转动常数通常高于相应含硫 - 32同位素体的转动常数。与³²S - C相比，较重的同位素体由于³⁴S - C振动（零点）的振动幅度较小，有效转动惯量较小，使得有效O - ³⁴S键略短。对H₂O - SCO的斯塔克效应测量给出偶极矩为8.875(9)×10⁻³⁰ C·m [2.6679(28) D]。H₂O - SCO最可能的结构接近C₂v平面结构，其中水的氧与羰基硫的硫相连。氧 - 硫范德华键长确定为3.138(17) Å，非常接近从头算值3.144 Å。比较了等电子络合物H₂O - SCO、H₂O - CS₂、H₂O - CO₂和H₂O - N₂O的结构。前两者是线性的，其他的是具有O - C/O - N范德华键的T形结构，即水的氧分别与CO₂和N₂O的碳和氮相连。