title: Syntheses, structures, and sensitized lanthanide luminescence by Pt --> Ln (Ln = Eu, Nd, Yb) energy transfer for heteronuclear PtLn2 and Pt2Ln4 complexes with a terpyridyl-functionalized alkynyl ligand.
abstract: Reaction of Pt(dppm-P,P')Cl2 (dppm = 1,2-bis(diphenylphosphino)methane) with HCCPhtpy (HCCPhtpy = 4'-(4-ethynylphenyl)-2,2':6',2"-terpyridine) in the presence of copper(I) iodide and diisopropylamine induced isolation of mononuclear complex cis-Pt(dppm-P,P')(C[triple bond]CPhtpy)2 (1), which can be converted into face-to-face diplatinum(II) species Pt2(mu-dppm)2(C[triple bond]CPhtpy)4 (5) when equivalent dppm is added. Incorporating 1 or 5 to Ln(hfac)3(H2O)2 (Hhfac = hexafluoroacetylacetone) gave PtLn2 (Ln = Nd (2), Eu (3), Yb (4)) or Pt2Ln4 (Ln = Nd (6), Eu (7), Gd (8), Yb (9)) adducts with the lanthanide centers chelated by terdentate terpyridyl in the bridging C[triple bond]CPhtpy. The structures of 1, 6, 7, and 9 were determined by X-ray crystallography. Upon excitation at lambdaex = 360-450 nm (2-4) or 360-500 nm (6-9), where the PtII alkynyl antenna chromophores absorb strongly but the model complexes Ln(hfac)3(HC[triple bond]CPhtpy) lack obvious absorption in this region, these PtLn2 and Pt2Ln4 (Ln = Nd, Eu, Yb) species exhibit band-like lanthanide luminescence that is typical of the corresponding Ln3+ ions, demonstrating unambiguously that efficient Pt --> Ln energy transfer occurs indeed from the PtII alkynyl antenna chromophores to the lanthanide centers across the bridging CCPhtpy with intramolecular Pt...Ln distances being ca. 14.2 A. The Pt --> Ln energy transfer rate (kET) is 6.07 x 10(7) s(-1) for Pt2Nd4 (6) and 2.12 x 10(5) s(-1) for Pt2Yb4 (9) species.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
authors.forename: Xiu-Ling
authors.initials: XL
authors.lastname: Li
authors.forename: Lin-Xi
authors.initials: LX
authors.lastname: Shi
authors.forename: Li-Yi
authors.initials: LY
authors.lastname: Zhang
authors.forename: Hui-Min
authors.initials: HM
authors.lastname: Wen
authors.forename: Zhong-Ning
authors.initials: ZN
authors.lastname: Chen
mesh_terms: D000478:Alkylation; D018360:Crystallography, X-Ray; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D008958:Models, Molecular; D015394:Molecular Structure; D010984:Platinum / Q000737:chemistry*; D017671:Platinum Compounds / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D013053:Spectrophotometry
chemical_list: D028581:Lanthanoid Series Elements; D008024:Ligands; D017671:Platinum Compounds; D011725:Pyridines; D010984:Platinum; C023666:pyridine