[Criii(L)(CN)4]−: a new building block in designing cyanide-bridged 4,2-ribbon-like chains {[Criii(L)(CN)4]2Mn(H2O)2}·nH2O [L = 2-aminomethylpyridine (n = 6) and 1,10-phenanthroline (n = 4)]

Abstract

The preparation, X-ray crystallography and magnetic study of compounds PPh₄[Cr(ampy)(CN)₄]·H₂O (1), PPh₄[Cr(phen)(CN)₄]·H₂O·CH₃OH (2), {[Cr(ampy)(CN)₄]₂Mn(H₂O)₂}·6H₂O (3) and {[Cr(phen)(CN)₄]₂Mn(H₂O)₂}·4H₂O (4), with PPh₄⁺ = tetraphenylphosphonium cation, ampy = 2-aminomethylpyridine and phen = 1,10-phenanthroline, are reported here. 1 and 2 are mononuclear complexes whereas 3 and 4 are 4,2-ribbon-like bimetallic chains. The magnetic properties of 1–4 were investigated in the temperature range 1.9–300 K. A quasi Curie law behaviour for a magnetically isolated spin quartet is observed for 1 and 2. Compounds 3 and 4 are ferrimagnetic CrIII₂MnII chains, which exhibit a metamagnetic behaviour, the values of the critical field being H_c = 1 T (3) and 5000 G (4), which is due to the occurrence of weak interchain antiferromagnetic interactions. Below ca. 4.0 K, compound 4 shows a spin-canted structure with a narrow hysteresis loop, the value of the coercive field being 50 G.