Platinum(II) Terpyridyl-Acetylide Dyads and Triads with Nitrophenyl Acceptors via a Convenient Synthesis of a Boronated Phenylterpyridine

Four new Pt(II) terpyridyl acetylide complexes which possess a covalently linked nitrophenyl moiety were prepared and studied. Specifically, the chromophore-acceptor (C-A) dyads reported here include [Pt(ptpy-ph-p-NO2)(C C-C6H5)](PF6)(3) (1), where ptpy-ph-p-NO2 = 4'-{4-(4-nitrophenyl)-phenyl}-[2,2';6',2 '']terpyridine, and C C-C6H5 = phenylacetylide and [Pt(ptpy-ph-m-NO2)(C=C-C6H5)](PF6)(2) (2), where ptpy-ph-m-NO2 m-nitrophenyl-phenyl)-2,2';6',2-terpyridine, as well as the related donor-chromophore-acceptor (D-C-A) triads [Pt(ptpy-ph-p-NO2)(C C-C6H4CH2-PTZ)]PF6 (3), where C C-C6H4CH2-PTZ = 4-ethynylbenzyl-N-phenothiazine, and [Pt(ptpy-ph-m-NO2)(C C-C6H4CH2-PTZ)]PF6 (4). Transient absorption spectroscopy and electrochemical analyses were used to characterize these compounds. In contrast to previous observations for closely related multicomponent systems, it appears that, in the current systems, the nitrophenyl group is not an effective quencher of the excited state. The luminescence and transient absorption properties of the C-A dyads are virtually identical to those of the parent chromophore, [Pt(ttpy)(C C-C6H5)]PF6 (5), where ttpy = 4'-p-tolyl-[2,2';6',2 '']terpyridine.