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Inorg Chem

Title:		"Trinuclear copper(I) and silver(I) adducts of 4-chloro-3,5-bis(trifluoromethyl)pyrazolate and 4-bromo-3,5-bis(trifluoromethyl)pyrazolate"
Author(s):		Hettiarachchi CV; Rawashdeh-Omary MA; Korir D; Kohistani J; Yousufuddin M; Dias HV;
Address:		"Department of Chemistry, Faculty of Science, University of Peradeniya , Peradeniya 20400, Sri Lanka"
Journal Title:		Inorg Chem
Year:		2013
Volume:		20131108
Issue:		23
Page Number:		13576 - 13583
DOI:		10.1021/ic402080y
ISSN/ISBN:		1520-510X (Electronic) 0020-1669 (Linking)
Abstract:		"Syntheses, structural, and photoluminescence properties of [4-X-3,5-(CF3)2Pz]M3 (X = Cl or Br, M = Cu or Ag) containing a heavier halide at the pyrazolyl ring 4-positions are reported. The Cu2O and Ag2O react with [4-Cl-3,5-(CF3)2Pz]H or [4-Br-3,5-(CF3)2Pz]H to form the corresponding metal pyrazolates, which are trinuclear adducts of the type [4-X-3,5-(CF3)2Pz]M3 with a nine-membered M3N6 metallacyclic core. They also feature relatively short M...Cl or M...Br intertrimer separations ( approximately 3.6 A) leading to supramolecular aggregates in the solid state. Distinct from the 4-H analogues [3,5-(CF3)2Pz]M3, none of the four complexes described herein exhibits short intertrimer metal-metal interactions (as closest such M...M separations are at a distance greater than 5.0 A). The [4-X-3,5-(CF3)2Pz]M3 adducts exhibit bright photoluminescence even at room temperature. The photophysical data suggest that the [4-X-3,5-(CF3)2Pz]Cu3 complexes emit from an associative excited state, and the drastic Stokes shift suggests a significant change to the ground state structure of the trinuclear moiety and/or intermolecular interactions upon photoexcitation. The [4-X-3,5-(CF3)2Pz]Ag3 complexes emit from a ligand-centered excited state affected by silver and the heavier halogens. Thin films of [4-X-3,5-(CF3)2Pz]Cu3 trimers are promising for volatile organic compound (VOC) sensor applications as they exhibit luminescence color change upon exposure to vapors of benzene and its alkylated derivatives"
Keywords:
Notes:		"PubMed-not-MEDLINEHettiarachchi, Champika V Rawashdeh-Omary, Manal A Korir, Daniel Kohistani, Jehan Yousufuddin, Muhammed Dias, H V Rasika eng 2013/11/12 Inorg Chem. 2013 Dec 2; 52(23):13576-83. doi: 10.1021/ic402080y. Epub 2013 Nov 8"