Synthesis, Structures, and Electronic Spectroscopy of Luminescent Acetylene‐ and (Buta‐1,3‐diyne)platinum Complexes

Abstract

The electronic absorption and emission spectroscopy of a series of diphenylaceylene‐ and (buta‐1,3‐diyne)‐Pt0 complexes (L)Pt[(1,2‐η2)‐R–(C≡C)n–R] and [(dppp)Pt]2[μ‐(1,2‐η2):(3,4‐η2)‐R–(C≡C)2–R] {R = Ph or CH3, L = dppp or(PPh3)2, n = 1 or 2} was investigated. The structures of(dppp)Pt[(1,2‐η2)‐Ph–C≡C–Ph], (dppp)Pt[(1,2‐η2)‐PhC4Ph] and [(dppp)Pt]2[μ‐(1,2‐η2):(3,4‐η2)‐Ph–(C≡C)2–Ph] were characterized by X‐ray diffraction. The complexes all display intense absorptions that were attributed to Pt→P(dπ*) and Pt→acetylene(πx*) transitions. Except for the CH3C4CH3 complexes, the complexes all exhibit two emissions at 380–550 nm and 500–800 nm. The higher energy emission could arise from the 3[P(dπ*)→Pt] transition, and the lower energy emission, which has a longer lifetime than the higher energy one, was attributed to the 3[acetylene(πx*)→Pt] transition. The energy of the MLCT absorption and emission was affected by the electronic properties of the acetylenes and the ancillary phosphanes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

An Adaptable Chelating Diphosphine Ligand for the Stabilization of Palladium and Platinum Carbenes

“…The solid-state molecular structure shows a bent geometry around the metal center, as indicated by the P–Pt–P angle of 153.95° (Figure ). Although two-coordinate platinum(0) species are known, − four- or three-coordinate complexes are common when bidentate ligands are employed. − Additionally, it is interesting to note that the structurally related para- and meta-substituted terphenyl systems reported by Agapie and co-workers (2,2″-bis­(diisopropylphosphino)­terphenyl) commonly exhibit an interaction between the metal center and the central aryl moiety. − In contrast with these examples, the ortho-substituted analogue described here renders the ligand too rigid to allow such an interaction. The transformation from cis to trans diphosphine coordination of P ter P from platinum­(II) to platinum(0) demonstrates that the ligand is coordinatingly flexible, a characteristic that could be further exploited upon carbene formation.…”

Mono- and Diphosphine Platinum(0) Complexes of Methylenecyclopropane, Bicyclopropylidene, and Allylidenecyclopropane

“…Four of the 81 complexes were Pt(0) species, and of the four, three were trigonal-planar complexes. All four Pt(0) complexes had dppp in a chair conformation. − These complexes had P–Pt–P angles of 90.99–97.76°, with that of 1a falling at the top end of the range.…”

Mono‐ or Diplatinum Complexes Containing a π‐Conjugated Pentadiynyl Ligand

“…However, the fact that 5 was produced in the polar solvent [D 8 ]thf shows that such solvent effects may be related to the relative stability of the products in solution. [17] and dimetal coordination to alkynes has been reported. [18] In contrast, a similar reaction was carried out in 2 Cl unit, attached to the platinacyclobutene ring, could not be clearly established, because complex 8 is less stable in solution and detectable only in the early stage of the reaction, but the perceived coordination and the composition of 8 are also supported by comparison with protonation product 10 as shown below (Scheme 9).…”