Pyrididine-Carboxylate Ligands as Double-Bridge Spacers in CuI Metallacycles

Abstract

Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.The addition of pyridine-3-carboxylic acid (3-PyCOOH), (E)-3-(pyridin-3-yl)acrylic acid (3-PyCH=CHCOOH), or 3-(pyridin-4-yl)benzoic acid (3-PyPhCOOH) to the Lewis acidic [Cu(dppf)(NCMe)2][BF4]·2MeCN·2H2O [1·2MeCN·2H2O, dppf = 1,1′-bis(diphenylphosphanyl)ferrocene] in the presence of NEt3 afforded the complexes [Cu2(dppf)2(3-PyCOO)2]·3CHCl3 (2·3CHCl3), [Cu2(dppf)2(3-PyCH=CHCOO)2]·CH2Cl2·C6H14 (3·CH2Cl2·C6H14), and [Cu2(dppf)2(3-PyPhCOO)2]·CH2Cl2 (4·CH2Cl2) with a common metallomacrocycle core and doubly bridging pyridine-carboxylate ligands as spacers. These dinuclear complexes have been structurally characterized by single-crystal X-ray crystallography, and their emission activities have been studied. Pyridine-carboxylate-bridged dinuclear CuI complexes capped by 1,1′-bis(diphenylphosphanyl)ferrocene (dppf) exhibit macrocycles with diagonal distances of 6.586, 9.159, and 10.006 Å. Such cavity sizes are formed by the introduction of CH=CH or phenyl units into the original pyridine-3-carboxylic acid (3-PyCOOH) spacer.