Red-, blue-, or no-shift in hydrogen bonds: A unified explanation

被引:832
作者
Joseph, Jorly
Jemmis, Eluvathingal D.
机构
[1] Univ Hyderabad, Sch Chem, Hyderabad 500046, Andhra Pradesh, India
[2] Indian Inst Sci, Dept Inorgan & Phys Chem, Bangalore 560012, Karnataka, India
关键词
D O I
10.1021/ja067545z
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
We provide a simple explanation for X-H bond contraction and the associated blue shift and decrease of intensity in IR spectrum of the so-called improper hydrogen bonds. This explanation organizes hydrogen bonds (HBs) with a seemingly random relationship between the X-H bond length (and IR frequency and its intensity) to its interaction energy. The factors which affect the X-H bond in all X-H center dot center dot center dot Y HBs can be divided into two parts: (a) The electron affinity of X causes a net gain of electron density at the X-H bond region in the presence of Y and encourages an X-H bond contraction. (b) The well understood attractive interaction between the positive H and electron rich Y forces an X-H bond elongation. For electron rich, highly polar X-H bonds (proper HB donors) the latter almost always dominates and results in X-H bond elongation, whereas for less polar, electron poor X-H bonds (pro-improper HB donors) the effect of the former is noticeable if Y is not a very strong HB acceptor. Although both the above factors increase with increasing HB acceptor ability of Y, the shortening effect dominates over a range of Ys for suitable pro-improper X-Hs resulting in a surprising trend of decreasing X-H bond length with increasing HB acceptor ability. The observed frequency and intensity variations follow naturally. The possibility of HBs which do not show any IR frequency change in the X-H stretching mode also directly follows from this explanation.
引用
收藏
页码:4620 / 4632
页数:13
相关论文
共 69 条
[1]   Electronic basis of improper hydrogen bonding: A subtle balance of hyperconjugation and rehybridization [J].
Alabugin, IV ;
Manoharan, M ;
Peabody, S ;
Weinhold, F .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2003, 125 (19) :5973-5987
[2]  
Alabugin IV, 2004, J PHYS CHEM A, V108, P4720, DOI [10.1021/jp049723l, 10.1021/jp0497231]
[3]  
Alkorta I, 2002, INT J QUANTUM CHEM, V86, P122, DOI 10.1002/qua..1613
[4]   Weak C-H•••O and C-H•••F-C hydrogen bonds in the oxirane-trifluoromethane dimer [J].
Alonso, JL ;
Antolínez, S ;
Blanco, S ;
Lesarri, A ;
López, JC ;
Caminati, W .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2004, 126 (10) :3244-3249
[5]   Blue-shifting hydrogen bonds - are they improper or proper? [J].
Barnes, AJ .
JOURNAL OF MOLECULAR STRUCTURE, 2004, 704 (1-3) :3-9
[7]  
Caminati W, 1999, ANGEW CHEM INT EDIT, V38, P2924, DOI 10.1002/(SICI)1521-3773(19991004)38:19<2924::AID-ANIE2924>3.0.CO
[8]  
2-N
[9]   Progress toward understanding the nature and function of C-H•••O interactions [J].
Castellano, RK .
CURRENT ORGANIC CHEMISTRY, 2004, 8 (10) :845-865
[10]  
CHEINER S, 1999, HYDROGEN BONDING