Platinum(II) 1,10-phenanthroline complexes of acetylides containing redox-active groups.
The new diimine ligand 3,8-di-n-pentyl-4,7-di(phenylethynyl)-1,10-phenanthroline (1) was used for the synthesis of a range of Pt(II) complexes, viz.[Pt(1)Cl2], [Pt(1)(C triple bond C-Ph)2], [Pt(1)(C triple bond C-Fc)2] and [Pt(1)(C triple bond C-p-C6H4-C triple bond C-Fc)2](Fc = ferrocenyl). Crystal structure analyses were performed for [Pt(1)Cl2] and [Pt(1)(C triple bond C-Ph)2] and revealed that the di(acetylide)pi-tweezer of the latter binds a molecule of chloroform through C-H...pi hydrogen bonds. The redox and optical properties of 1 and its complexes were investigated by (spectro-)electrochemistry, UV-Vis and luminescence spectroscopy, and an energy level diagram was derived for [Pt(1)(C triple bond C-Fc)2] and related compounds on the basis of the data collected. The ferrocenyl-substituted Pt(II) complexes are donor-sensitiser assemblies. Intramolecular quenching of the photoexcited Pt(II) diimine unit leads to very short luminescence lifetimes for [Pt(1)(C triple bond C-p-C(6)H(4)-C triple bond C-Fc)2](2 ns) and [Pt(1)(C triple bond C-Fc)2](0.3 ns), as opposed to [Pt(1)(C triple bond C-Ph)2](0.7 micros). Excimer formation has been observed for [Pt(1)(C triple bond C-Ph)(2)] at room temperature in dichloromethane and at low temperatures in frozen glassy dichloromethane and 2-methyltetrahydrofuran solution, but not in the solid state.
Institute of Chemistry and Centre for Interdisciplinary Nanostructure Science and Technology, University of Kassel, D-34109 Kassel, Germany. siemeling@uni-kassel.de
Ulrich
U
Siemeling
Kirstin
K
Bausch
Heinrich
H
Fink
Clemens
C
Bruhn
Marc
M
Baldus
Brigitta
B
Angerstein
Regina
R
Plessow
Andreas
A
Brockhinke
D000114:Acetylene / Q000737:chemistry*; D002413:Cations, Divalent; D005296:Ferrous Compounds / Q000737:chemistry; D005663:Furans / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007097:Imines / Q000737:chemistry; D008024:Ligands; D000075163:Metallocenes; D008752:Methylene Chloride / Q000737:chemistry; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D010084:Oxidation-Reduction; D010618:Phenanthrolines / Q000138:chemical synthesis*; D010984:Platinum / Q000737:chemistry*; D013057:Spectrum Analysis; D013696:Temperature
D002413:Cations, Divalent; D005296:Ferrous Compounds; D005663:Furans; D007097:Imines; D008024:Ligands; D000075163:Metallocenes; D009942:Organometallic Compounds; D010618:Phenanthrolines; C018674:tetrahydrofuran; D010984:Platinum; D008752:Methylene Chloride; D000114:Acetylene; C004998:ferrocene; C025205:1,10-phenanthroline