The H-Index Unambiguously Discriminates between Hydrogen Bonding and Improper Blue-Shifting Hydrogen Bonding.
Hobza, P.
,
Physical Chemistry Chemical Physics, 3 [13] 2555 - 2556 (2001)
X-H . . .Y contacts are characterised by a red shift of the X-H stretch frequency. We have shown recently (P. Hobza and Z. Havlas, Chem. Rev., 2000, 100, 4253) that these contacts can also be characterised by a blue shift of the X-H stretch frequency. An H-index, defined as the ratio of electron density transferred from the proton donor (Y) to the sigma* antibonding orbital of the X-H bond and the total electron density transferred between proton donor and proton acceptor unambiguously discriminates between both types of H-bonding. Its value for proper H-bonding lies between 1.0 and 0.7 while values between 0.3 and 0 are typical for improper (blue-shifting) H-bonding.
|
