Apparent or real water exchange reactions on [Zn(H2O)(4)( L)](2+)center dot 2H(2)O ( L = sp-nitrogen donor ligands)? A quantum chemical investigation

作者：Alzoubi Basam M; Walther Markus; Puchta Ralph^*; van Eldik Rudi

来源：Dalton Transactions, 2012, 41(23): 6932-6941.

DOI：10.1039/c2dt30158j

The exchange of a second coordination sphere water molecule in [Zn(H2O)(4)(L)](2+)center dot 2H(2)O (L = HN3, HCN, FCN, ClCN, BrCN, CH3CN, (C4H3) CN, PhCN, (CH3)(3)CCN, CF3CN, CCl3CN, CHCl2CN, and CH2ClCN) against a coordinated water molecule was studied by quantum chemical calculations (RB3LYP/6-311+G**). The complete reaction consists of an associative binding of one H2O from the second coordination sphere leading to a six-coordinate intermediate [Zn(H2O)(5)(L)](2+)center dot H2O, followed by the dissociation of a water molecule to reach the product state [Zn(H2O)(4)(L)](2+)center dot 2H(2)O. For a real water exchange reaction to occur two different transition states have to be included, otherwise only an apparent water exchange reaction takes place. For the water exchange reaction in [Zn(H2O)(4)(L)](2+)center dot 2H(2)O, nearly iso-energetic cis- and trans-orientated transition states are crossed. The gas-phase proton affinity of L shows instructive correlations with structural parameters and energy gaps for the investigated reactions.

• 出版日期2012