Burling F T, Goldstein B M
Department of Biophysics, University of Rochester Medical Center, New York 14642.
Acta Crystallogr B. 1993 Aug 1;49 ( Pt 4):738-44. doi: 10.1107/s0108768193000709.
A search of the Cambridge Structural Database (1991, version 4.5) was performed to investigate nonbonded intramolecular 1,4 S...O close contacts of the kind seen in the thiazole nucleoside tiazofurin and other classes of compounds. The search yielded 362 structures with 1,4 S...O connectivity. S...O distances in 70% of these structures were less than the sum of the sulfur and oxygen van der Waals radii. Findings indicate that 1,4 S...O close contacts are common and so probably result from intramolecular interactions rather than from external crystal packing forces. A structure containing a sulfur atom in a conjugated ring system is more likely to exhibit 1,4 S...O close contacts than a structure containing a sulfur atom in an unconjugated and/or acyclic environment. Sulfur-nitrogen contacts were also investigated and were found to show similar properties. These results are consistent with findings from previous quantum-chemical-based studies performed on model fragments [Burling & Goldstein (1992). J. Am. Chem. Soc. 114, 2313-2320].
对剑桥结构数据库（1991年，版本4.5）进行了检索，以研究噻唑核苷替加氟及其他类化合物中所见的非键合分子内1,4 S...O紧密接触。检索得到362个具有1,4 S...O连接性的结构。这些结构中70%的S...O距离小于硫和氧的范德华半径之和。研究结果表明，1,4 S...O紧密接触很常见，因此可能是由分子内相互作用而非外部晶体堆积力导致的。与在非共轭和/或无环环境中含有硫原子的结构相比，在共轭环系统中含有硫原子的结构更有可能表现出1,4 S...O紧密接触。还研究了硫-氮接触，发现其具有相似的性质。这些结果与之前对模型片段进行的基于量子化学的研究结果一致[Burling & Goldstein (1992). J. Am. Chem. Soc. 114, 2313 - 2320]。
