Unconventional hydrogen bonds: Intermolecular B-H center dot center dot center dot H-N interactions
Unconventional hydrogen bonds: Intermolecular B-H center dot center dot center dot H-N interactions
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DOI：
10.1021/ja00156a032
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发表时间：
1995-12-27
影响因子：
15
通讯作者：
Siegbahn, PEM
中科院分区：
文献类型：
--
作者：
Richardson, TB;deGala, S;Siegbahn, PEM
典型的氢键受体1具有O或N孤对电子，但最近，过渡金属氢化物的α-电子对被证明2，3产生非常规类型的分子内N-H *“H-M和O-H”* H-M氢键，我们将其命名为“二氢键”。这些相互作用的键强度为4-6 kcal/mol，H*-H距离（μ hh）约为1.5。1.7-1.9 A，似乎在质子转移、流动过程和其他反应中起作用。[2，3] H_3CCH_3（mp-181 C）和等电子H_3BNH_3（1，mp+ 104 C dec）之间的熔点差异表明，在胺硼烷中可能存在分子间氢键。当然，H3 BNH 3是极性的，但极性的、基本上不成氢键的分子CH 3F也与乙烷等电子，其熔点为-141 ℃，仅比乙烷稍高。
Typical hydrogen bond acceptors1 possess an O or N lone pair, but more recently, the a-electron pair of a transition metal hydride has been shown2, 3 togive intramolecularN—H*“H—M and O—H"* H—M hydrogenbonds of an unconventional type, for which we suggest4 theterm dihydrogen bonds. These interactions have bond strengths of 4—6 kcal/mol and H*” H distances (^ hh) of ca. 1.7—1.9 A and seem to play a role in proton transfer, fluxional processes, and other reactions. 2, 3 The striking melting point difference between H3CCH3 (mp—181 C) and the isoelectronic H3BNH3 (1, mp+ 104 C dec) suggested that intermolecular dihydrogen bonds might be present in amineboranes. Of course, H3BNH3 is polar, but the polar and essentially non-H-bonding moleculeCH3F, also isoelec-tronic with ethane, has a melting point of—141 C, only slightly elevated from that of ethane.