Intramolecular versus Intermolecular Hydrogen Bonding of Coordinated Acetate to Organic Acids: A Neutron, X-ray, and Database Study

The effect of strong intra- and intermolecular hydrogen bonding on molecular geometry in carboxylate
coordination complexes is examined by means of a search of the Cambridge Crystallographic Database. Accurate
hydrogen-bonding parameters for two representative examples, [Cu2(μ-O2CCH3)4(CH3CO2H)2] (1; intramolecular) and [Cu2(μ-O2CCH3)4(H2O)2]·2CH3CO2H (2; intermolecular), are determined by single-crystal neutron diffraction. Electronic effects are probed by the synthesis and characterization of a further mixed carboxylate derivative,
[Cu2(μ-O2CCH3)2(μ-O2CCF3)2 (H2O)2]·2CH3CO2H (5).