Nonlinear Absorbing Cationic Iridium(III) Complexes Bearing Benzothiazolylfluorene Motif on the Bipyridine (N∧N) Ligand: Synthesis, Photophysics and Reverse Saturable Absorption

被引:52
作者
Li, Yuhao [1 ]
Dandu, Naveen [1 ]
Liu, Rui [1 ]
Hu, Lei [1 ]
Kilina, Svetlana [1 ]
Sun, Wenfang [1 ]
机构
[1] N Dakota State Univ, Dept Chem & Biochem, Fargo, ND 58108 USA
关键词
iridium complex; synthesis; photophysics; luminescence; nonlinear optics; EXCITED-STATE ABSORPTION; DENSITY-FUNCTIONAL METHODS; MOLECULAR-ORBITAL METHODS; TURN-ON TIMES; CYCLOMETALATED IRIDIUM(III); CHARGE-TRANSFER; BASIS-SET; SUBSTITUTED 1,10-PHENANTHROLINES; PLATINUM(II) COMPLEX; DIIMINE COMPLEXES;
D O I
10.1021/am401133p
中图分类号
TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
Four new heteroleptic cationic Ir(III) complexes bearing benzothiazolylfluorene motif on the bipyridine (N boolean AND N) (1 and 2) and phenylpyridine (C boolean AND N) (3 and 4) ligands are synthesized and characterized. The influence of the position of the substituent and the extent of pi-conjugation on the photophysics of these complexes is systematically investigated by spectroscopic methods and simulated by time-dependent density functional theory (TDDFT). The complexes exhibit ligand-centered (1)pi,pi* transitions with admixtures of (ILCT)-I-1 (pi(benzothiazolylfluorene) -> pi*(bpy)) and (MLCT)-M-1 (metal-to-ligand charge transfer) characters below 475 nm, and very weak (MLCT)-M-1,3 and (LLCT)-L-1,3 (ligand-to-ligand charge transfer) transitions above 475 nm. The emission of these complexes at room temperature in CH2Cl2 solutions is ascribed to be predominantly from the (MLCT)-M-3/(LLCT)-L-3 states for 1 and from the (3)pi,pi* state for 2, while the emitting state of 3 and 4 are assigned to be an admixture of (MLCT)-M-3, (LLCT)-L-3, and (3)pi,pi* characters. The variations of the photophysical properties of 1-4 are attributed to different degrees of pi-conjugation in the bipyridine and phenylpyridine ligands induced by different positions of the benzothiazolylfluorenyl substituents on the bipyridine ligand and different extents of pi-conjugation in the phenylpyridine ligands, which alters the energy and lifetime of the lowest singlet and triplet excited states. 1-4 all possess broadband transient absorption (TA) upon nanosecond laser excitation, which extends from the visible to the NIR region. Therefore, 1-4 all exhibit strong reverse saturable absorption (RSA) at 532 nm for ns laser pulses. However, the TA of complexes 1, 2, and 3 are much stronger than that of 4. This feature, combined with the difference in ground-state absorption and triplet excited-state quantum yield, result in the difference in RSA strength, which follows this trend: 1 approximate to 2 approximate to 3 > 4. Therefore, complexes 1-3 are strong reverse saturable absorbers at 532 nm and could potentially be used as broadband nonlinear absorbing materials.
引用
收藏
页码:6556 / 6570
页数:15
相关论文
共 106 条
[1]   Toward reliable density functional methods without adjustable parameters: The PBE0 model [J].
Adamo, C ;
Barone, V .
JOURNAL OF CHEMICAL PHYSICS, 1999, 110 (13) :6158-6170
[2]  
[Anonymous], 2007, GAUSS VIEW
[3]   Effect of deprotonation on absorption and emission spectra of Ru(II)-bpy complexes functionalized with carboxyl groups [J].
Badaeva, Ekaterina ;
Albert, Victor V. ;
Kilina, Svetlana ;
Koposov, Alexey ;
Sykora, Milan ;
Tretiak, Sergei .
PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 2010, 12 (31) :8902-8913
[4]  
Barone V, 1998, J COMPUT CHEM, V19, P404, DOI 10.1002/(SICI)1096-987X(199803)19:4<404::AID-JCC3>3.0.CO
[5]  
2-W
[6]   Exciton localization in a Pt-acetylide complex [J].
Batista, ER ;
Martin, RL .
JOURNAL OF PHYSICAL CHEMISTRY A, 2005, 109 (43) :9856-9859
[7]   Metal-Induced Phosphorescence in (Pentafluorophenyl)gold(III) Complexes [J].
Bojan, Vilma R. ;
Lopez-de-Luzuriaga, Jose M. ;
Manso, Elena ;
Monge, Miguel ;
Elena Olmos, M. .
ORGANOMETALLICS, 2011, 30 (17) :4486-4489
[8]   Stable single-layer light-emitting electrochemical cell using 4,7-diphenyl-1,10-phenanthroline-bis(2-phenylpyridine) iridium(III) hexafluorophosphate [J].
Bolink, Henk J. ;
Cappelli, Luca ;
Coronado, Eugenio ;
Graetzel, Michael ;
Orti, Enrique ;
Costa, Ruben D. ;
Viruela, Pedro M. ;
Nazeeruddin, Md. K. .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2006, 128 (46) :14786-14787
[9]   TRIPLET-TRIPLET ABSORPTION-SPECTRA OF ORGANIC-MOLECULES IN CONDENSED PHASES [J].
CARMICHAEL, I ;
HUG, GL .
JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA, 1986, 15 (01) :1-250
[10]   Photoinduced intramolecular electron transfer in ruthenium and osmium polyads:: Insights from theory [J].
Ciofini, I ;
Lainé, PP ;
Bedioui, F ;
Adamo, C .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2004, 126 (34) :10763-10777