Hydration and 'inverse hydration' of platinum(II) complexes: an analysis using the density functionals PW91 and BLYP

The interaction between two platinum complexes and water was investigated u sing the DFT functionals PW91 and BLYP. Previous MP2 and HF calculations ha ve shown that when a H2O molecule approaches Pt with its O atom, the intera ction is governed by electrostatics and the MP2 and HF interaction energy c urves nearly coincide, whereas for the approach with H pointing towards Pt, there is a significant dispersion component portrayed only by MP2 calculat ions. Here we show that both PW91 and BLYP satisfactorily reproduce the MP2 curves, PW91 slightly exaggerating and BLYP slightly underestimating the d ispersion-induced energy minima. This result is discussed in view of the di fferent behavior of the two exchange functionals at large density gradients . (C) 2001 Elsevier Science B.V. All rights reserved.