Preparation, characterisation and thermal behaviour of N-(3-aminopropyl)-1,3-propanediamine complexes of nickel (II) in the solid state

Abstract

The complexes [Ni(dpt)₂]X₂ • nH₂O (where dpt is N-(3-aminopropyl)-1,3-propanediamine; n = 0 when X is I, NCS or ClO₄; n = 1 when X is Cl, Br or NO₃; n ≫ 1 when X is 0.5SO₄ and 0.5SeO₄), Ni(dpt)X₂ • nH₂O (n = 0 when X is Cl or NO₃; n = 1 when X is Br or I; n = 2 when X is NO₃; n = 3 when X is 0.5SO₄ or 0.5SeO₄), [Ni(aepn) ₂)]I₂, Ni(aepn)I₂ (where aepn is N-(2-aminoethyl)-1,3-propanediamine, [Ni(dien) ₂]I₂ and Ni(-dien)I₂ (where dien is diethylenetriamine) have been synthesised from the solution and thermal investigations upon them have been carried out in the solid state. [Ni(dpt) ₂]X₂ (X is Br or NO₃) undergoes endothermic reversible phase transitions upon heating (198–212°C, ΔH = 3.5 kJ mol⁻¹ and 205–222°C for [Ni(dpt) ₂]Br₂ and [Ni(dpt) ₂](NO₃)₂ respectively). Ni(dpt)I₂ shows exothermic irreversible phase transition during heating (193–220°C; ΔH = 4.1 kJ mol⁻¹). The thermal stabilities of dpt complexes are compared with those of the corresponding aepn and dien complexes.