title: Synthesis and properties of [Pt(4-CO(2)CH(3)-py)(2)(mnt)]: comparison of pyridyl and bipyridyl-based dyes for solar cells.
abstract: The dye complexes [Pt(4-CO(2)R-py)(2)(mnt)] (R = H (3a), CH(3) (3b)) and the precursor complexes [Pt(4-CO(2)R-py)(2)Cl(2)] (2a, 2b) (py = pyridyl) were synthesised, characterised by electrochemical, spectroscopic, spectroelectrochemical (UV-vis-nIR and in situ EPR) and hybrid DFT computational methods and attached to a TiO(2) substrate to determine charge recombination kinetics. The results were compared to the bipyridyl analogues [Pt{X,X'-(CO(2)R)-2,2'-bipyridyl}(mnt)], (X = 3 or 4). The electronic characteristics of the bis-pyridyl complex were found to be different to the bipyridyl complexes making the former harder to reduce, shifting the lowest-energy absorption band to higher energy and showing separate degenerate LUMO orbitals on the two pyridine rings. The latter point determines that the di-reduced pyridyl complex remains EPR active, unlike the bipyridyl analogue. Complex 3a attached to nanocrystalline TiO(2) shows a long charge recombination lifetime in comparison with the analogous complex with the ubiquitous 4,4'-(CO(2)H)(2)-bipyridyl ligand, suggesting that pyridyl complexes may possess some advantage over bipyridyl complexes in dye-sensitised solar cells.
authors.affiliation: School of Chemistry, Joseph Black Building, King's Buildings, West Mains Road, Edinburgh, UK.
authors.forename: Lucy P
authors.initials: LP
authors.lastname: Moorcraft
authors.forename: Ana
authors.initials: A
authors.lastname: Morandeira
authors.forename: James R
authors.initials: JR
authors.lastname: Durrant
authors.forename: James R
authors.initials: JR
authors.lastname: Jennings
authors.forename: Laurence M
authors.initials: LM
authors.lastname: Peter
authors.forename: Simon
authors.initials: S
authors.lastname: Parsons
authors.forename: Andrew
authors.initials: A
authors.lastname: Turner
authors.forename: Lesley J
authors.initials: LJ
authors.lastname: Yellowlees
authors.forename: Neil
authors.initials: N
authors.lastname: Robertson
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D004396:Coloring Agents / Q000138:chemical synthesis* / Q000737:chemistry; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D007700:Kinetics; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010984:Platinum / Q000737:chemistry*; D011789:Quantum Theory; D012993:Solar Energy; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004396:Coloring Agents; D009942:Organometallic Compounds; D010984:Platinum; D015082:2,2'-Dipyridyl