As part of a program to create new low dimensional S=1/2 antiferromagnetic Heisenberg compounds with moderate exchange, we have prepared four new copper complexes with square magnetic lattices. The complexes L2[Cu&] have been prepared (L = 2-amino-5-methylpyridiniuq X = C1, Br; L = 2-amino-5chloropyriduq X = Br). The compounds are isomorphous, giving monoclinic crystals; space group C2/c. The tetrahalometallate ions lie in C-centered layers, forming a square magnetic lattice. The layers are separated by the organic cations. P r e l i i analysis of the magnetic data shows that the exchange constant, J, increases in the order Br > C1 and 2-amino-5-chloropyridinium > 2-amino-5-methylpyridinium. A new member of the pyrazine bridged family M(pyrazinehXz has also been prepared and studied. Cu(p+ (BF& also crystallizes in the space group C2/c. Analysis of the temperature dependence of the susceptibility yields and exchange value of -7.98 K., similar to that found for the known Cu(pzh(C10,h complex. 333 Downloaded by [Heriot-Watt University] at 00:57 27 December 2014 334 A.S. ALBRECHT el al.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.