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

Abstract

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-NO(2))(C[triple bond]C-C(6)H(5))](PF(6))(3) (1), where ptpy-ph-p-NO(2) = 4'-{4-(4-nitrophenyl)-phenyl}-[2,2';6',2'']terpyridine, and C[triple bond]C-C(6)H(5) = phenylacetylide and [Pt(ptpy-ph-m-NO(2))(C[triple bond]C-C(6)H(5))](PF(6))(2) (2), where ptpy-ph-m-NO(2) = 4'-(4-m-nitrophenyl-phenyl)-2,2';6',2''-terpyridine, as well as the related donor-chromophore-acceptor (D-C-A) triads [Pt(ptpy-ph-p-NO(2))(C[triple bond]C-C(6)H(4)CH(2)-PTZ)]PF(6) (3), where C[triple bond]C-C(6)H(4)CH(2)-PTZ = 4-ethynylbenzyl-N-phenothiazine, and [Pt(ptpy-ph-m-NO(2))(C[triple bond]C-C(6)H(4)CH(2)-PTZ)]PF(6) (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[triple bond]C-C(6)H(5))]PF(6) (5), where ttpy = 4'-p-tolyl-[2,2';6',2'']terpyridine.