Abstract
Motivated by the Haldane conjecture, the powder susceptibilities of two nickel complexes (1: NiCl2L2, with LP(CH2CH2CN)3; 2: bis(propiolato)tetraaquonickel(II)) have been investigated as part of a search for new S=1 antiferromagnetic linear chains. The effective moments of both complexes correspond to high-spin S=1 Ni(II) ions at room temperature but decrease rapidly below 20 K. Analysis of the data showed the decreases to correspond to the effects of single-ion anisotropy and not magnetic exchange. The susceptibilities of 1 and 2 can be described as resulting from single-ion anisotropy parameters D/k=7 and 8.5 K, respectively, with the ms=0 single state low for both complexes. Neither 1 nor 2 can be considered a magnetic linear chain.