Thermochemistry of adducts of manganese(II) and copper(II) pentane-2,4-dionate with heterocyclic amines

• Published in: Thermochimica acta 2000-08, Vol.356 (1), p.19-25
• Main Author: Dunstan, P.O
• Format: Article
• Language: English
• Subjects: Chemistry; Coordination compounds; Exact sciences and technology; Inorganic chemistry and origins of life; Manganese(II) and copper(II) pentane-2,4-dionate; Mn(II) and Cu(II) adducts; Mn–N and Cu–N bonds; Preparations and properties; Thermochemical parameters; Thermochemistry
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/S0040-6031(00)00496-2

The compounds [M(pd) 2(L)] (where M is manganese(II) or copper(II); pd is pentane-2,4-dionate; and L is piperazine (pipz), 4-cyanopyridine (4-cyanopy), quinoline (quin) or 2,2′-bipyridine (bipy)) were synthesized and characterized by elemental analysis, melting points, thermal studies and electronic and IR spectroscopy. The enthalpies of dissolution of adducts, metal pentane-2,4-dionate and ligands in a 1:3 (v/v) mixture of aqueous HCl 1.2 M and methanol were measured and by using thermochemical cycles the following thermochemical parameters for the adducts have been determined: the standard enthalpies for the Lewis acid/base reaction (Δ r H θ ), the standard enthalpies of formation (Δ f H θ ), the standard enthalpies of decomposition (Δ D H θ ), the lattice standard enthalpies (Δ M H θ )and the standard enthalpies of the Lewis acid/base reaction in the gaseous phase (Δ r H θ (g)). The mean standard bond dissociation enthalpies of the manganese–nitrogen and copper–nitrogen bonds have been determined.