Effects of Organic Templates on Directing the Structures of Nickel(II)−1-Hydroxyethylidenediphosphonate Compounds:  A Structural and Magnetic Study

Abstract

Hydrothermal reactions of NiSO 4 and 1-hydroxyethylidenediphosphonic acid (hedpH 4 ) in the presence of different organic templates resulted in the formation of three new compounds: (enH 2 )Ni(hedpH 2 ) 2 ·2H 2 O 1, (pnH 2 )Ni(hedpH 2 ) 2 (H 2 O), 2 and (bnH 2 )Ni(hedpH 2 ) 2 (H 2 O) 2, 3, (hedp = 1-hydroxyethylidenediphosphonate, en = ethylenediamine, pn = 1,3-propanediamine, bn = 1,4-butylenediamine). Crystal data: 1, monoclinic, C 2/ c, a = 24.7864(5), b = 5.2565(1), c = 16.0468(2) Å, β = 117.903(1)°, V = 1847.67(6) Å 3, Z = 4; 2, triclinic, P 1̄, a = 10.0926(4), b = 10.5621(4), c = 10.9212(4) Å, α = 111.520(1), β = 110.833(1), γ = 93.630(1)°, V = 986.77(7) Å 3, Z = 2; 3, monoclinic, C 2/ c, a = 16.230(2), b = 12.430(13), c = 12.657(13) Å, β = 121.997(10)°, V = 2165(4) Å 3, Z = 4. The compound 1 has a one-dimensional chain structure which is composed of corner-sharing {NiO 6 } octahedra and {O 3 PC} tetrahedra with the ethylenediammonium cations and water molecules stabilized between the chains. By replacing ethylenediamine with 1,3-propanediamine or 1,4-butylenediamine, molecular species have been obtained. The compound 2 contains dimers of [Ni(hedpH 2 ) 2 (H 2 O)] 2 2 - whereas 3 is a mononuclear compound. The thermal stabilities, spectroscopic and magnetic properties of all three compounds have been investigated.