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Coordination Induction of Nonlinear Molecular Shape in Mesomorphic and Luminescent Zn II Complexes Based on Salen‐Like Frameworks
Author(s) -
Pucci Daniela,
Aiello Iolinda,
Bellusci Anna,
Crispini Alessandra,
Ghedini Mauro,
La Deda Massimo
Publication year - 2009
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200900536
Subject(s) - chemistry , mesophase , crystallography , molecule , dichloromethane , luminescence , stereochemistry , phase (matter) , organic chemistry , physics , optoelectronics , solvent
A series of tetradentate dimeric salicylaldimine ligands (H 2 L n R m ) with terminal chains of variable length (R m ) and a central flexible (CH 2 ) n spacer (L n = 10 and 12) was synthesized. For all ligands, according to their rod‐like molecular shape, mesomorphism characteristic of calamitic systems (nematic and smectic C phases) is observed. The reaction with Zn II acetate dihydrate afforded a series of ZnL n R m derivatives ( 1 – 6 ) that show mesomorphic behaviour only in the presence of the longest terminal tails (R 12 ). Interestingly, the flexibility of the very long spacer in the central core and the presence of the tetrahedral Zn II centre introduce nonlinearity in the central part of the molecule, responsible for the appearance of an intercalated smectic C mesophase. Moreover, the coordination of the Zn II ion to the salen‐like framework induces, in all the corresponding complexes, interesting blue‐light‐emitting properties at room temperature in dichloromethane solution (EQY in the 19–22 % range at about 450 nm), as well as in the solid (EQY: 9 % at about 450 nm) or, when present, in the mesophase (EQY 8 % at 440 nm).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)