Tri-[Pt2Tl]3- and polynuclear chain [Pt−Tl]∞- Complexes based on nonbridged PtII−TlI bonds: Solid state and frozen solution photophysical properties

10 pages, 6 figures, 2 tables, 1 scheme.-- Supporting Information Available: http://pubs.acs.org.Treatment of (NBu4)2[PtR4] (R = C6F5) with 1 or 0.5 equiv of TlNO3 in EtOH/H2O produces colorless crystals of trinuclear complex (NBu4)3[Tl{PtR4}2], 1, in which the Tl+ center is complexed by two [PtR4]2- fragments (Pt−Tl = 2.9777(4) and 3.0434(4) Å). The expected mixed complex with a Pt/Tl composition of 1:1, 2, is generated as an orange microcrystalline solid by treating [PtR4]2- with a large excess of TlNO3 (8 equiv). Crystallographic analysis of 2 reveals the formation of a novel one-dimensional (1D) heterometallic linear chain (NBu4)∞[Tl{PtR4}]∞, 2, formed by alternating a [PtR4]2- fragment and a Tl+ center with a uniform Pt−Tl bond separation along the chain of 3.0321(2) Å. Surprisingly, treatment of (NBu4)2[PtR4] with 1 equiv of TlPF6 in EtOH yields pale greenish-yellow needles of an unusual adduct, 2·{(NBu4)(PF6)}∞ (3), which was found to form a similar extended linear chain, {TlPtR4}∞, constructed by two alternating Pt−Tl separations, a shorter (3.1028(6) Å) one and a longer (3.2306(6) Å) one. The solid state and solution photophysical properties have been examined. While complex 1 shows a high-energy MM‘CT blue phosphorescence (450 nm), the extended chain in 2 exhibits a lower-energy emission (582 nm) than that in adduct 3 (505 nm). For products 2 and 3, interesting luminescence thermochromism is observed in frozen solutions. The emissions are found to be strongly dependent on the solvent, concentration, and excitation wavelength.We thank the Dirección General de Investigación of Spain (Projects BQU2002-03997-C02-01, 02, CTQ2005-08606-C02-01, and CTQ2005-03141 and a grant for A.G.).Peer reviewe