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(L1)3phen], where Ln = Nd, Eu, Er, Yb, HL1 = N,N′-dipyrrolidine-N′′-trichloracetylphosphortriamide, phen = 1,10-phenanthroline; [Ln(L1)3bpm], where Ln = La, Nd, Eu, Gd, Er, Y, bpm = 2,2′-bipyrimidine and [{Ln(L2)3}2(μ-bpm)], where Ln = La, Nd, Eu, Gd, Er, Y, HL2 = dimethyl-N-trichloracetylamidophosphate have been synthesized and characterized by means of IR and UV–Vis spectroscopy. Crystal structures of [Nd(L1)3phen] (1), [Nd(L1)3bpm] (2) and [{Nd(L2)3}2(μ-bpm)] (3) have been determined. It was found, that in the deprotonated form the phosphoryl ligands (L1)− and (L2)− 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(L2)3}2(μ-bpm)] (4) reveal a weak antiferromagnetic interaction between the two magnetic centres, whereas in the case of [{Eu(L2)3}2(μ-bpm)] (5) the presence of spin–orbit coupling leads to a deviation from the Curie and Curie–Weiss laws.

Graphical abstractCoordination compounds with general formula [Ln(L1)3phen], where Ln = Nd, Eu, Er, Yb, HL1 = Cl3CC(O)NHP(O)(NC4H8)2, phen = -phenanthroline and [Ln(L1)3bpm], where Ln = La, Nd, Eu, Gd, Er, Y, bpm = 2,2′-bipyrimidine and [{Ln(L2)3}2(μ-bpm)], where Ln = La, Nd, Eu, Gd, Er, Y, HL2 = Cl3CC(O)NHP(O)(OCH3)2 have been synthesized. The structural features, as well as spectroscopic and magnetic properties are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide