Luminescent and magnetic bifunctional coordination complex based on a chiral tartaric acid derivative and europium

摘要

A new mononuclear europium complex incorporating the (+)‐di‐ p ‐toluoyl‐ d ‐tartaric acid ( d ‐H 2 DTTA) ligand, namely, catena ‐poly[tris{μ 2 ‐3‐carboxy‐2,3‐bis[(4‐methylphenyl)carbonyloxy]propanoato}tris(methanol)europium(III)], [Eu(C 20 H 17 O 8 ) 3 (CH 3 OH) 3 ] n , (I), has been synthesized and characterized by IR spectroscopy, elemental analysis, powder X‐ray diffraction and single‐crystal X‐ray diffraction analysis. The structure analysis indicates that complex (I) crystallizes in the trigonal space group R 3 and exhibits an infinite one‐dimensional chain structure, in which the Eu 3+ ion is surrounded by six O atoms from six d ‐HDTTA ? ligands and three O atoms from three coordinated methanol molecules, thus forming a tricapped trigonal prism geometry. The d ‐H 2 DTTA ligand is partially deprotonated and adopts a μ 1,6 ‐coordination mode via two carboxylate groups to link adjacent Eu 3+ ions, affording an infinite one‐dimensional propeller‐shaped coordination polymer chain along the c axis, with an Eu…Eu distance of 7.622?(1)??. Moreover, C—H…π interactions lead to the formation of helical chains running along the c axis and the whole structure displays a snowflake pattern in the ab plane. The circular dichroism spectrum confirms the chirality of complex (I). The solid‐state photoluminescence properties were also investigated at room temperature and (I) exhibits characteristic red emission bands derived from the Eu 3+ ion (CIE 0.63, 0.32), with a reasonably long lifetime of 0.394?ms, indicating effective energy transfer from the ligand to the metal centre. In addition, a magnetic investigation reveals single‐ion magnetic behaviour. The spin‐orbit coupling parameter (λ) between the ground and excited states is fitted to be 360?(2)?cm ?1 through Zeeman perturbation. Therefore, complex (I) may be regarded as a chiral optical‐magneto bifunctional material.