Synthesis, optical and magnetic properties of homo- and heteronuclear systems and glasses containing them

Abstract

To study the effect of ion pairs (f and d–f) coupled in a polymeric system on their optical and magnetic properties, syntheses of homo- and heteronuclear systems were undertaken. Single crystals of the polynuclear Nd glutarate of formula [Nd(Glut)(H₂O)₄]Cl·2H₂O (1) were obtained. The X-ray diffraction analysis shows the triclinic system and the P1 space group. The structure consists of polynuclear two-dimensional chains built of dimeric units with two nonequivalent Nd³⁺ centres. The two Nd³⁺ ions are coordinated by carboxyl groups of the glutarate anion and water molecules. Two different coordination modes of the carboxylate group occur in the structure: simple bridging (bidentate) and chelating bridging (tridentate). There are five oxygen atoms of four carboxylate groups in the direct environment of each Nd ion and four water molecules complete the coordination number at nine. The network of hydrogen bonds stabilises the crystal structure. The above structural characteristics are well manifested in the spectroscopic properties of crystalline 1. Using the sol–gel technique, neodymium (2) and Nd³⁺:Cu²⁺ glutarate (3) were incorporated in glass. Glasses of good optical quality were obtained, enabling an analysis of the spectroscopic properties of the investigated systems and consideration of the heteronuclear forms in the glass. The optical and magnetic behaviour of these systems were analysed down to 1.8 K. The effect of the dimensionality of the systems on their optical and magnetic properties is also discussed.