Attila Kovács and Zoltán
Varga
Halogen
acceptors in hydrogen bonding
Coordination Chemistry Reviews, 250 (2006) 710-727
In the present review we performed a comparative
assessment of hydrogen bonding (HB) interactions with halogen (X) acceptors.
Based on the available data in the literature we selected various inter- and
intramolecular systems, for which (possibly) all the four halogen derivatives
have been studied either by experimental or theoretical methods. Four main
acceptor types have been considered in our assessment, viz., free X-
anions, halogens involved in M–X (M = transition metal), H–X and
C–X bonds. The hydrogen donors in the HB systems (DH) included the simple
H2O, NH3, HX, H2 molecules, various alcohols,
amines as well as aliphatic and aromatic CH groups. Among the molecular
properties we focussed on the HB energy and structural characteristics (at the
first place on the H…X distance), which are particularly
informative on the HB propensities of the halogens. Where available, the shift
of the DH stretching frequency (nDH) upon the HB interaction was also
discussed.
2.1. Experimental methods for gas-phase
studies
2.2. X-ray and neutron diffraction
2.3. Quantum chemical computations
3.1. Anionic (X-) acceptors
3.1.1. Hydrogen bihalides
3.1.2. Small halide complexes
3.1.3. Halide complexes observed in the
condensed phase
3.2. M–X acceptors
3.3. H–X acceptors
3.3. C–X acceptors
4.1. 2-Halophenols
4.2. 2-Haloethanols
5. Conclusions
Acknowledgements
References