Cu(i) and Zn(ii) complexes of 7-azaindole-containing scorpionates: Structures, luminescence and fluxionality
SongCurrent address: Department of, Datong; Jia, Wen Li; Wu, Gang; Wang, Suning; SongCurrent address: Department of Chemistry, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139-4307, USA. Datong; Department of Chemistry, Queen's University; Jia Wen Li; Department of Chemistry, Queen's University; Wu Gang; Department of Chemistry, Queen's University; Wang Suning; Department of Chemistry, Queen's University
Журнал:
Dalton Transactions
Дата:
2005
Аннотация:
A new scorpionate borate ligand K[HB(7-azain)3] (1, 7-azain = 7-azaindolyl) has been obtained from the reaction of KBH4 with excess 7-azaindole. The scorpionate ligand 1 was found to be able to form complexes with Zn<sup>II</sup> and Cu<sup>I</sup> ions. Complex 2 with the formula [BH(7-azain)3](ZnCl) has been obtained from the reaction of ZnCl2 with 1. Complex 3 with the formula [BH(7-azain)3][Cu(PPh3)] has been obtained from the reaction of [Cu(PPh3)2(CH3CN)2][BF4] with 1. The crystal structures of 1â 3 have been determined by single-crystal X-ray diffraction analyses which revealed that 1 has a dimeric structure linked together by two K<sup>+</sup> ions, 2 has a symmetric tripodal structure with all three 7-azaindolyl groups being coordinated to the Zn<sup>II</sup> center, and 3 has an asymmetric structure with two of the 7-azaindolyl groups being coordinated to the Cu<sup>I</sup> center and the third 7-azaindolyl group uncoordinated. Variable temperature <sup>1</sup>H NMR experiments established that 3 is highly dynamic in solution involving a rapid exchange between the coordinated and the non-coordinated 7-azaindolyl groups. All three compounds display blue emission in the solid state at ambient temperature. However, in solution at ambient temperature, compounds 1 and 2 display bright blue emission while compound 3 has no emission at all. At 77 K, solutions of all three compounds display blue-green phosphorescent emission with a long decay lifetime (> 2 ms).
384.2Кб