Platinum diimine bis(acetylide) complexes: Synthesis, characterization, and luminescence properties
A new set of luminescent platinum(II) diimine complexes has been synthesized and characterized. The anionic ligands in these complexes are arylacetylides. The complexes are brightly emissive in fluid solution with relative emission quantum yields {phi}{sub em} ranging from 3 x 10{sup {minus}3} to 10{sup {minus}1}. Two series of complexes have been investigated. The first has the formula Pt(Rphen)(C{equivalent{underscore}to}CC{sub 6}H{sub 5}){sub 2} where Rphen is 1,10-phenanthroline substituted in the 5-position with R = H, Me, Cl, Br, NO{sub 2}, or C{equivalent{underscore}to}CC{sub 6}H{sub 5}, while the second has the formula Pt(dbbpy)(C{equivalent{underscore}to}CC{sub 6}H{sub 4}X){sub 2} where dbbpy = 4,4{prime}-di(tert-butyl)bipyridine and X = H, Me, F, or NO{sub 2}. From NMR, IR, and electronic spectroscopies, all of the complexes are assigned a square planar coordination geometry with cis-alkynyl ligands. The crystal structure of Pt(phen)(C{equivalent{underscore}to}CC{sub 6}H{sub 4}CH{sub 3}){sub 2} confirms this assignment. All of the complexes exhibit an absorption band at ca. 400 nm that corresponds to a Pt d {r{underscore}arrow} {pi}{asterisk}{sub diimine} charge-transfer transition. The variation of {lambda}{sub max} for this band with substituent variation supports this assignment. From similar changes in the energy of the solution luminescence as a function of substituents R and X, the emissive excited state is also of MLCT origin, but with spin-forbidden character on the basis of excited-state lifetime measurements (0.01--5.6 {mu}s). The complexes undergo electron-transfer quenching, showing good Stern-Volmer behavior using 10-methylphenothiazine and N,N,N{prime},N{prime}-tetramethylbenzidine as reductive quenchers. Excited-state reduction potentials are estimated on the basis of a simple thermochemical analysis. Crystal data for Pt(phen)(C{equivalent{underscore}to}CC{sub 6}H{sub 4}CH{sub 3}){sub 2}: monoclinic, space group C2/c, a = 19.0961(1){angstrom}, b = 10,4498(1){angstrom}, c = 11.8124(2){angstrom}, {beta} = 108.413(1){degree}, V = 2236.49{angstrom}{sup 3}, number of reflections 1614, number of variables 150, R1 = 0.0163, wR2 (I > 2{sigma}) = 0.0410.
- Research Organization:
- Univ. of Rochester, NY (US)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 20017280
- Journal Information:
- Inorganic Chemistry, Vol. 39, Issue 3; Other Information: PBD: 7 Feb 2000; ISSN 0020-1669
- Country of Publication:
- United States
- Language:
- English
Similar Records
The unperturbed oxo-sulfido functional group cis-Mo{sup VI}OS related to that in the xanthine oxidase family of molybdoenzymes: Synthesis, structural characterization, and reactivity aspects
Luminescent platinum(II) complexes of quinoxaline-2,3-dithiolate