Coordination complexes of thiazyl rings - Synthesis, structure, and density functional theory (DFT) computational analysis of CpCr(CO)(x) (x=2, 3) complexes of fluorinated and nonfluorinated 1 lambda(3)-1,2,4,6-thiatriazinyls with differing Cr-S bond orders

摘要

The reaction of [3,5-Ph-2-C2N3S](2) with [CpCr(CO)(3)](2) in toluene at room temperature forms an adduct via a Cr-S bond, formulated as CpCr(CO)(3)SN3C2Ph2, which has fitting NMR, IR, and combustion analysis data. The structure was determined by a single-crystal X-ray structure diffraction study (P2(1), a = 8.4611(17) angstrom, b = 20.509(4) angstrom, c = 11.757(2) angstrom, beta = 104.453(7)degrees). The Cr-S bond length of 2.4908(11) angstrom corresponds to a bond order 1.0 from >90 values for CpCr(CO) x or Cp*Cr(CO)(x) moieties (x = 2, 3) bonded to S, which are used to establish a Pauling-type bond order scale specific to this class of compounds. Similar reactions of fluorinated thiatriazinyls derived from [3-Ph-5-CF3-C2N3S](2) or [4-MeOC6H4-5-CF3-C2N3S](2) are accompanied by the loss of CO to produce CpCr(CO)(2)SN3C2PhCF3 (P1, a = 8.0929(8) angstrom, b = 10.3160(10) angstrom, c = 11.2405(11) angstrom, alpha = 70.032(2)degrees, beta = 72.076(2)degrees, gamma = 82.375(2)degrees) and CpCr(CO)(2)SN3(CCF3)(C6H4OCH3) (P2(1)/c, a = 8.1311(7) angstrom, b = 24.284(2) angstrom, c = 9.1025(8) angstrom, beta = 97.218(2)degrees), also fully characterized by spectroscopy and crystallography. Their measured Cr-S bond lengths, 2.2987(14) and 2.2965(11) angstrom, correspond to bond orders of 1.5. (U/R)B3PW91/6-311+G(2df, 2p)//B3PW91/6-31G(2d, p) hybrid density functional theory (DFT) calculations show that the tricarbonyl complex has an unusual sigma bond. However, the dicarbonyl complexes of the fluorinated thiatriazinyls are pi bonded.