Synthesis and Physical Properties of Two Chiral Terpyridyl Europium(III) Complexes with Distinct Crystal Polarity

By utilizing the chiral terpyridyl‐type ligand L(–) [L =“dipineno”‐(4,5:4″,5″)‐fused 2,2′:6′,2″‐terpyridine or 2,6‐bis(7,7‐dimethyl‐5,6,7,8‐tetrahydro‐6,8‐methanoisoquinolin‐3‐yl)pyridine], two novel Eu III complexes with the formula [Eu(tta) 3 L](C 3 H 6 O) · 0.5(H 2 O) ( 1 ) and [Eu(bta) 3 (L)](C 3 H 6 O)( 2 ) (tta = 2‐thenoyltrifluoroacetonate, bta = benzoyltrifluoroacetonate) were synthesized and characterized by X‐ray crystallography and spectroscopic methods. The Eu III atoms in 1 and 2 are nine‐coordinate in a geometrical environment of a distorted, monocapped square antiprism. Complex 1 crystallizes in the polar space group P 2 1 , while complex 2 crystallizes in the nonpolar space group P 2 1 2 1 2 1 . The chirality of both complexes is evidenced by the circular dichroism (CD) spectra. Both complexes show the characteristic photoluminescence of the Eu III ion. In contrast to complex 2 , complex 1 exhibits brilliant triboluminescence, an intense NLO property and ferroelectric behaviour at room temperature. The distinct chiral optical properties of complexes 1 and 2 originate from the differing crystal polarities.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)