Platinum diimine bis(acetylide) complexes: Synthesis, characterization, and luminescence properties

Journal Article · Mon Feb 07 04:00:00 EST 2000 · Inorganic Chemistry

DOI:https://doi.org/10.1021/ic991250n· OSTI ID:20017280

Hissler, M; Connick, W B; Geiger, D K; McGarrah, J E; Lipa, D; Lachicotte, R J; Eisenberg, R

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: US Department of Energy
• OSTI ID: 20017280
• Journal Information: Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 3 Vol. 39; ISSN 0020-1669; ISSN INOCAJ
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BIPYRIDINES
CRYSTAL STRUCTURE
IMINES
LUMINESCENCE
PHENANTHROLINES
PLATINUM COMPLEXES
SPECTRA
SYNTHESIS