Osmium complexes with tridentate 6-pyrazol-3-yl 2,2-′bipyridine ligands:: Coarse tuning of phosphorescence from the red to the near-infrared region

被引:28
作者
Chen, Kellen
Cheng, Yi-Ming
Chi, Yun [1 ]
Ho, Mei-Lin
Lai, Chin-Hung
Chou, Pi-Tai
Peng, Shie-Ming
Lee, Gene-Hsiang
机构
[1] Natl Tsing Hua Univ, Dept Chem, Hsinchu 300, Taiwan
[2] Natl Taiwan Univ, Dept Chem, Taipei 106, Taiwan
[3] Natl Taiwan Univ, Instrumentat Ctr, Taipei 106, Taiwan
关键词
N ligands; near-infrared region; osmium; phosphorescence; pi interactions;
D O I
10.1002/asia.200600289
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
We have prepared and characterized a series of osmium complexes [Os-2(CO)(4)(fpbPY)(2)] (1), [OS(CO)(fpbpY)(2)] (2), and [Os(fpbpy)(2)] (3) with tridentate 6-pyrazol-3-yl 2,2'-bipyridine chelating ligands. Upon the transformation of complex 2 into 3 through the elimination of the CO ligand, an extremely large change in the phosphorescence wavelength from 655 to 935 nm was observed. The results are rationalized qualitatively by the strong pi-accepting character of CO, which lowers the energ of the osmium d(pi) orbital, in combination with the lower degree of T conjugation in 2 owing to the absence of one possible pyridine-binding site. As a result, the energy gap for both intraligand pi-pi* charge transfer (ILCT) and metal-to-ligand charge transfer (MLCT) is significantly greater in 2. Firm support for this explanation was also provided by the time-dependent DFT approach, the results of which led to the conclusion that the S-o -> T-1 transition mainly involves MLCT between the osmium center and bipyridine in combination with pyrazolate-to-bipyridine 3 pi-pi* ILCT. The relatively weak near-infrared emission can be rationalized tentatively by the energy-gap law, according to which the radiationless deactivation may be governed by certain low-frequency motions with a high density of states. The information provided should allow the successful design of other emissive tridentate metal complexes, the physical properties of which could be significantly different from those of complexes with only a bidentate chromophore.
引用
收藏
页码:155 / 163
页数:9
相关论文
共 68 条
[1]   New functional polymers and materials based on 2,2′:6′,2"-terpyridine metal complexes [J].
Andres, PR ;
Schubert, US .
ADVANCED MATERIALS, 2004, 16 (13) :1043-1068
[2]  
[Anonymous], 2002, ANGEW CHEM, V114, P3016, DOI DOI 10.1002/1521-3757(20020816)114:16<3016::AID-ANGE3016>3.0.CO
[3]  
2-5
[4]   Photophysics, photochemistry and electrochemistry of mixed-ligand platinum(II) complexes with 2-phenylpyridine and 2-(2'-thienyl) pyridine as cyclometalating ligands [J].
Balashev, KP ;
Puzyk, MV ;
Kotlyar, VS ;
Kulikova, MV .
COORDINATION CHEMISTRY REVIEWS, 1997, 159 :109-120
[5]   From ruthenium(II) to iridium(III): 15 years of triads based on bis-terpyridine complexes [J].
Baranoff, E ;
Collin, JP ;
Flamigni, L ;
Sauvage, JP .
CHEMICAL SOCIETY REVIEWS, 2004, 33 (03) :147-155
[6]   ABSORPTION AND FLUORESCENCE PROPERTIES OF CYANINE DYES [J].
BENSON, RC ;
KUES, HA .
JOURNAL OF CHEMICAL AND ENGINEERING DATA, 1977, 22 (04) :379-383
[7]   Eilatin complexes of ruthenium and osmium. synthesis, electrochemical behavior, and near-IR luminescence [J].
Bergman, SD ;
Gut, D ;
Kol, M ;
Sabatini, C ;
Barbieri, A ;
Barigelletti, F .
INORGANIC CHEMISTRY, 2005, 44 (22) :7943-7950
[8]   Synthesis of a novel rigid molecule family for the investigation of electron and energy transfer [J].
Beyeler, A ;
Belser, P .
COORDINATION CHEMISTRY REVIEWS, 2002, 230 (1-2) :29-39
[9]   Chiral 2,2′-bipyridines, 1,10-phenanthrolines, and 2,2′:6′,2"-terpyridines:: Syntheses and applications in asymmetric homogeneous catalysis [J].
Chelucci, G ;
Thummel, RP .
CHEMICAL REVIEWS, 2002, 102 (09) :3129-3170
[10]   Room-temperature NIR phosphorescence of new iridium (III) complexes with ligands derived from benzoquinoxaline [J].
Chen, HY ;
Yang, CH ;
Chi, Y ;
Cheng, YM ;
Yeh, YS ;
Chou, PT ;
Hsieh, HY ;
Liu, CS ;
Peng, SM ;
Lee, GH .
CANADIAN JOURNAL OF CHEMISTRY, 2006, 84 (02) :309-318