Bis(tridentate) Iron(II) Complexes with a Cyclometalating Unit: Photophysical Property Enhancement with Combinatorial Strong Ligand Field Effect

Tang, Zhou1,2,3; Chang, Xiao-Yong1; Wan, Qingyun2,3; Wang, Jian1; Ma, Chensheng4; Law, Kwok-Chung2,3; Liu, Yungen1; Che, Chi-Ming1,2,3

2020-08-10

10.1021/acs.organomet.0c00149

ORGANOMETALLICS   影响因子和分区

0276-7333

1520-6041

A series of bis(tridentate) cyclometalated oligopyridine complexes [Fe-II(C<^> N<^>N)(L)](+) have been synthesized via the reactions of [Fe-II(C<^> N<^>N-py)Br(PMe3)(2)] (1, HC<^>N-py<^>N-py = 6-(phenyI)-2,2'-bipyridine) and [Fe-II(C<^>N-ppy<^>N-isoquin)Br(PMe3)(2)] (2, HC<^>N-ppy<^>N-isoquin = 3-(4,6-diphenylpyridin-2-yl)isoquinoline with tridentate ligands L, affording [Fe-II(C<^>N-ppy<^>N-py)(4'-R-tpy)](+) (3a-e, R = H, Cl, p-ClC6H4, p-MeOC6H4, p-tol, respectively; tpy 2,2':6',2 ''-terpyridine), [Fe-II(C<^>N-ppy<^>N-isoquin)(tpy)](+) (4), [Fe-II(C<^>N-ppy<^>N-py)(6-(Ph2PCH2)-bpy)](+) (5, bpy = 2,2'-bipyridine), and [Fe-II(C<^>N-py<^>N-py)(6-NHC-bpy)](+) (6, NHC = N-heterocyclic carbene). Complexes 3-6 exhibit bathochromically shifted absorption bands, markedly cathodically shifted E-1/2 (Fe-III/Fe-II) values, and narrowed electrochemical band gaps in comparison to those of [Fe-II(tpy)(2)](2+), as revealed by UV-vis absorption spectroscopy and cyclic voltammetry. DFT and TDDFT calculation studies revealed strong mixing of MLCT with LLCT transitions as origins to the major absorption bands. Complex 6 incorporating a cyclometalating unit and an NHC donor exhibits panchromic absorption, and 5 shows markedly enhanced molar absorptivity in the visible region. A femtosecond transient absorption spectroscopic study of 6, coupled with DFT and TDDFT calculations and spectroelectrochemical measurements, gave evidence for the possible involvement of a (MLCT)-M-3 state with a lifetime of 21.4 ps.

SCI ; EI

英语

第一 ; 通讯

Hong Kong Research Grants Council General Research Fund[17303815][17301817] ; National Natural Science Foundation of China[NSFC 91856203] ; Shenzhen Science and Technology Innovation Commission[JCYJ20170412140251576][JCYJ20180508162429786]

Chemistry

Chemistry, Inorganic & Nuclear ; Chemistry, Organic

WOS:000562124400002

AMER CHEMICAL SOC

20203108987963

Cyclic voltammetry ; Spectroscopic analysis ; Ultraviolet spectroscopy ; Absorption spectroscopy ; Organic compounds ; Synthesis (chemical) ; Energy gap ; Ligands

Chemistry:801 ; Physical Chemistry:801.4 ; Electrochemistry:801.4.1 ; Chemical Reactions:802.2 ; Organic Compounds:804.1

CHEMISTRY

Web of Science

1.Southern Univ Sci & Technol, Dept Chem, Shenzhen 518055, Guangdong, Peoples R China
2.Univ Hong Kong, Dept Chem, Hong Kong, Peoples R China
3.Univ Hong Kong, State Key Lab Synthet Chem, Hong Kong, Peoples R China
4.Shenzhen Univ, Coll Chem & Environm Engn, Shenzhen 518055, Guangdong, Peoples R China

Tang, Zhou,Chang, Xiao-Yong,Wan, Qingyun,et al. Bis(tridentate) Iron(II) Complexes with a Cyclometalating Unit: Photophysical Property Enhancement with Combinatorial Strong Ligand Field Effect[J]. ORGANOMETALLICS,2020,39(15):2791-2802.

Tang, Zhou.,Chang, Xiao-Yong.,Wan, Qingyun.,Wang, Jian.,Ma, Chensheng.,...&Che, Chi-Ming.(2020).Bis(tridentate) Iron(II) Complexes with a Cyclometalating Unit: Photophysical Property Enhancement with Combinatorial Strong Ligand Field Effect.ORGANOMETALLICS,39(15),2791-2802.

Tang, Zhou,et al."Bis(tridentate) Iron(II) Complexes with a Cyclometalating Unit: Photophysical Property Enhancement with Combinatorial Strong Ligand Field Effect".ORGANOMETALLICS 39.15(2020):2791-2802.