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Wiring terpyridine: approaches to alkynylthienyl 2,2':6',2''-terpyridines
Edwin C Constable1, Egbert Figgemeier, Catherine E Housecroft
1Department of Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland.
Abstract:
The reaction of triisopropylsilylethyne or trimethylsilylethyne with 4'-(5-bromo-2-thienyl)-2,2':6',2''-terpyridine () leads to 4'-(5-triisopropylsilylethynyl-2-thienyl)-2,2':6',2''-terpyridine () or 4'-(5-trimethylsilylethynyl-2-thienyl)-2,2':6',2''-terpyridine (). The latter compound may be deprotected to give 4'-(5-ethynyl-2-thienyl)-2,2':6',2''-terpyridine (). Treatment of the complexes [Ru()(2)][PF(6)](2), [Ru(tpy)()][PF(6)](2) and [Ru()(2)][PF(6)](2) ( = 4'-(4-bromo-2-thienyl)-2,2':6',2''-terpyridine) with triisopropylsilylethyne yields the corresponding homoleptic and heteroleptic alkynylthienyl-terminated ruthenium(ii) complexes, for which spectroscopic and electrochemical data are presented. The reaction of [RuCl(2)(DMSO)(4)] with leads to [Ru()(2)][PF(6)](2), in which the tpy ligands bear conjugated thienyl and alkynyl groups; the latter can also be accessed by deprotection of [Ru()(2)][PF(6)](2). The single-crystal structures of ligands and , and of [Ru()(tpy)][BPh(4)](2).1.3MeCN, [Ru()(2)][PF(6)](2).2MeNO(2), 2{[Ru()(2)][PF(6)](2)}.5MeCN, [Ru()(2)][PF(6)](2) and [Ru()(2)][PF(6)](2).MeCN are presented, and among the homoleptic complexes, pi-stacking interactions between thiophene and pyridine rings leading to pairs of associated cations provide a common structural motif.
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