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首页> 外文期刊>Acta Crystallographica, Section B. Structural Science >The Hydrogen-Bond C-H Donor and π-Acceptor Characteristics of Three-Membered Rings
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The Hydrogen-Bond C-H Donor and π-Acceptor Characteristics of Three-Membered Rings

机译：三元环的氢键C-H供体和π受体特性

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摘要

Crystallographic results, retrieved from the Cambridge Structural Database, show that the C-H protons of cyclopropane, aziridine and oxirane form C-H- o o() (particularly C-H…πC) hydrogen bonds. The frequency of formation and geometrical characteristics of these bonds indicate a bond-strength ordering: Csp1- Ho…O > C(ring)- H…0 ~ Csp2-H- -O > Csp3-H- o -O, which is in excellent agreement with the well known ethylenic properties of C(ring)-H and with residual 8+ charges calculated for these systems. There is some evidence to suggest that C=C-H in cyclopropene, known to be a highly acidic H, forms stronger hydrogen bonds than C-H in saturated three-membered rings. Crystallograpbic data have also been used to provide geometrical evidence for the formation of O,N-H…π(ring) bonding to three-membered rings, proposed on the basis of spectroscopic data [Joris, Schleyer & Gleiter (1968). J. Am. Chem. Soc. 90, 327-336]. The two modes of H-O…π(ring) binding suggested there, viz. 'edge-on' approach of H to a ring C-C bond and 'face-on' approach towards the ring centroid, are found to be dominant in crystallographic observations of this novel hydrogen bond.
机译：从剑桥结构数据库中检索到的晶体学结果表明，环丙烷，氮丙啶和环氧乙烷的C-H质子形成C-H-o（）（特别是C-H…πC）氢键。这些键的形成频率和几何特征表明键强度顺序：Csp1-Ho…O> C（环）-H…0〜Csp2-H- -O> Csp3-H- o -O，在与众所周知的C（环）-H的烯键性质以及这些系统计算出的残留8+电荷极好的一致性。有证据表明，环丙烯中的C = C-H（已知为高酸性H）比饱和三元环中的C-H形成更强的氢键。基于光谱数据[Joris，Schleyer＆Gleiter（1968）。]，晶体对晶体的数据也已经被用来提供形成三元环的O，N-H…π（环）键的几何证据。 J.上午化学Soc。 90，327-336]。这里提出了H-O…π（环）结合的两种模式。在这种新型氢键的晶体学观察中，发现H对环C-C键的“边对边”方法和对环质心的“对面”方法占主导地位。

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