Low-dimensional compounds containing cyanido groups. XXVIII. Crystal structure, spectroscopic and magnetic properties of two copper(II) tetracyanidoplatinate complexes with 1,2-diaminopropane

Violet crystals of {[Cu(pn)₂]₂[Pt(CN)₄]}[Pt(CN)₄]·2H₂O (1, pn=1,2-diaminopropane) and blue crystals of [Cu(pn)Pt(CN)₄]_n·nH₂O (2) were prepared under hydrothermal conditions and characterized using elemental analysis, IR and UV–vis spectroscopy and by X-ray crystal structure analysis. Different number of ν(C≡N) absorption bands of these two compounds reflects their different structures. An X-ray crystal structure analysis has shown that complex 1 is of ionic character and is formed from trinuclear [Cu(pn)₂–Pt(CN)₄–Cu(pn)₂]²⁺ complex cation and discrete [Pt(CN)₄]^2– anion together with two molecules of crystal water. On the other hand, complex 2 is of polymeric character and is formed by 2D networks of [Cu(pn)Pt(CN)₄]_n composition and completed by n molecules of crystal water. Magnetic measurements show the presence of a weak antiferromagnetic exchange interaction in complex 1 (Θ = –0.2 K), while the magnetic susceptibility of complex 2 is well described by the model of uniform S = 1/2 spin chain with exchange interaction J/k_B = –1.64 K.