Synthesis and investigations of mixed-ligand lanthanide complexes with N,N′-dipyrrolidine-N"-trichloracetylphosphortriamide, dimethyl-N-trichloracetylamidophosphate, 1,10-phenanthroline and 2,2′-bipyrimidine

Coordination compounds with general formula [Ln(L(1))(3)phen], where Ln = Nd, Eu, Er, Yb, HL(1) = N,N'-dipyrrolidine-N ''-trichloracetylphosphortriamide, phen=1,10-phenanthroline; [Ln(L(1))(3)bpm], where Ln = La, Nd, Eu, Gd, Er, Y, bpm = 2,2'-bipyrimidine and [{Ln(L(2))(3)}(2)(mu-bpm)], where Ln = La, Nd, Eu, Gd, Er, Y, HL(2) = dimethyl-N-trichloracetylamidophosphate have been synthesized and characterized by means of IR and UV-Vis spectroscopy. Crystal structures of [Nd(L(1))(3)phen] (1), [Nd(L(1))(3)bpm] (2) and [{Nd(L(2))(3)}(2)(mu-bpm)] (3) have been determined. It was found, that in the deprotonated form the phosphoryl ligands (L(1))- and (L(2))- are coordinated to the neodymium atoms in a bidentate manner via the oxygen atoms of the phosphoryl and the carbonyl groups with formation of six-membered metallocycles. In the case of compounds 1 and 2 the 1,10-phenanthroline (or 2,2'-bipyrimidine) molecules are coordinated to the metals in a bidentate manner via the nitrogen atoms. In contrast 2,2'-bipyrimidine acts in the bidentate-bridge mode forming binuclear complex 3. Variable-temperature magnetic susceptibility measurements of 3 and [{Gd(L(2))(3)}(2)(mu-bpm)] (4) reveal a weak antiferromagnetic interaction between the two magnetic centres, whereas in the case of [{Eu(L(2))(3)}(2)(mu-bpm)] (5) the presence of spin-orbit coupling leads to a deviation from the Curie and Curie-Weiss laws. (C) 2009 Elsevier Ltd. All rights reserved.