New series of ruthenium(II) and osmium(II) complexes showing solid-state phosphorescence in far-visible and near-infrared.
A new Ru(II) complex, [Ru(fpbpymH)(2)]Cl(2) (1), in which fpbpymH = [5-(trifluoromethyl)pyrazol-3-yl](2,2'-bipyrid-6-yl)methane, was prepared by the treatment of [Ru(DMSO)(4)Cl(2)] with 2 equiv of the terdentate chelate fpbpymH in refluxing ethanol. A single-crystal X-ray diffraction study of 1 revealed a distorted octahedral Ru(II) framework, showing strong N-H...Cl hydrogen bonding between the fpbpymH ligand and Cl anions. In the presence of Na(2)CO(3), the methylene linkers of chelates in 1 underwent stepwise oxygenation, forming the charge-neutral complexes [Ru(fpbpym)(fpbpyk)] (2) and [Ru(fpbpyk)(2)] (3) [fpbpykH = [5-(trifluoromethyl)pyrazol-3-yl](2,2'-bipyrid-6-yl) ketone] in sequence. The respective charge-neutral Os(II) complex [Os(fpbpyk)(2)] (4) was also isolated by the treatment of OsCl(3).3H(2)O with 2 equiv of the terdentate chelate fpbpymH. Electrochemical analysis indicated that the introduction of the electron-withdrawing ketone group in 2-4 increased the metal-based oxidation potential in sequence. For the photophysical properties, complexes 1-4 are essentially nonluminescent in solution (e.g., CH(2)Cl(2) or MeOH) at room temperature, but all exhibit 600-1100 nm phosphorescence with moderate intensity for the powdery, solid sample at room temperature. The trend in terms of the emission peak wavelength of 1 (666 nm) < 3 (795 nm) < 2 (810 nm) < 4 (994 nm) among titled complexes is in agreement with the corresponding onset of absorption spectra as well as the time-dependent density functional theory calculation of 1 < 3 < 2 < 4.
Chen
Jing-Lin
JL
Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan.
Chi
Yun
Y
Chen
Kellen
K
Cheng
Yi-Ming
YM
Chung
Min-Wen
MW
Yu
Ya-Chien
YC
Lee
Gene-Hsiang
GH
Chou
Pi-Tai
PT
Shu
Ching-Fong
CF
D018360:Crystallography, X-Ray; D004563:Electrochemistry; D006860:Hydrogen Bonding; D008163:Luminescent Measurements; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D009992:Osmium / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D019265:Spectroscopy, Near-Infrared; D013237:Stereoisomerism
D009942:Organometallic Compounds; D009992:Osmium; D012428:Ruthenium