The Cyanate and 2-Phosphaethynolate Anion Congeners ECO鈥?/sup> (E = N, P, As, Sb, Bi): Prelude to Experimental Characterization

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• 作者：Yunxiang Lu ; Hui Wang ; Yaoming Xie ; Honglai Liu ; Henry F. Schaefer
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：June 16, 2014
• 年：2014
• 卷：53
• 期：12
• 页码：6252-6256
• 全文大小：262K
• 年卷期：v.53,no.12(June 16, 2014)
• ISSN：1520-510X

文摘

Pioneering synthetic research by the groups of Grutzmacher and Goicoechea have made possible the preparation of 2-phosphaethynolates (PCO^{鈥?/sup>). The obvious question arises: can progress be made toward AsCO鈥?/sup>, SbCO鈥?/sup>, and BiCO鈥?/sup>? Here the properties of all five anion congeners ECO鈥?/sup> (E = N, P, As, Sb, Bi) were systematically investigated using ab initio coupled-cluster methods with correlation-consistent basis sets cc-pVXZ (X = D, T, Q). These anions exhibit linear structures with significant natural bond orbital negative charge on both the E and O atoms. These species should react with electrophiles via attack at either center. On going from nitrogen to bismuth, with the atomic radius increasing, the bond between E and C becomes weaker, while the C鈥揙 bond tends to be slightly stronger. By the time one gets to BiCO鈥?/sup>, the C鈥揙 bond distance is 1.181 脜, indicating a very strong double bond. Relative to the PCO鈥?/sup> anion, which is reactive toward several unsaturated compounds, the As/Sb/BiCO鈥?/sup> anions may undergo cycloaddition more readily with unsaturated substrates. The dissociation energy of the E鈥揅 bond, except for that of NCO鈥?/sup>, is predicted to be much less than that of the C鈥揙 bond. These dissociation energies are 76 kcal/mol (P鈥?/sup>鈥揅O), 58 kcal/mol (As鈥?/sup>鈥揅O), 37 kcal/mol (Sb鈥?/sup>鈥揅O), and 28 kcal/mol (Bi鈥?/sup>鈥揅O). Even the BiCO鈥?/sup> anion should be achievable in the laboratory. The vibrational frequencies for these anions are predicted, and our results should assist in the experimental characterization and exploration of the heavier congeners ECO鈥?/sup>.}