Syntheses, properties and crystal structures of several new bis(polypyrazolylborato)lanthanoid(III) complexes

Abstract

Lanthanoid(III) chlorides MCl 3·6H 2O (M  Lu, Nd, Yb) in THF were treated with potassium tris(1-pyrazolyl)hydroborate K(BHpz 3) (pz = 1-pyrazolyl) in a (1/1) molar ratio at −78°C, and the complexes [MCl(BHpz 3) 2(L)] (L  Hpz for M  Lu and Nd; L  H 2O for M  Yb) were isolated. In the presence of N-methylpyrazole ( N-CH 3pz), similar reaction procedures gave the complexes [MCl(BHpz 3) 2( N-CH 3pz)], of which further treatment with sodium 8-quinolinolate Na(quin) afforded the stable complexes [M(BHpz 3) 2(quin)] quantitatively. From single crystal X-ray structural analyses, distorted square-antiprismatic geometry was determined for [NdCl(BHpz 3) 2(L)] (L  Hpz and H 2O). Compared with N-CH 3pz adduct formation, Hpz coordination to Lu and Nd was fairly strong, owing to the hydrogen bonding formed between the chlorine atom on neodymium and the acidic 1-N proton in the coordinated Hpz.