title: Synthesis and photoluminescence properties of rhenium(I) complexes based on 2,2':6',2''-terpyridine derivatives with hole-transporting units.
abstract: Based on 2,2′:6′,2′′-terpyridine ligands (L1), five terpyridine derivatives, namely 4′-carbazol-9-yl-2,2′:6′,2′′-terpyridine (L2), 4′-diphenylamino-2,2′:6′,2′′-terpyridine (L3), 4′-bis(4-tert-butylphenyl)amino-2,2′:6′,2′′-terpyridine (L4), 4′-[naphthalen-1-yl-(phenyl)amino]-2,2′:6′,2′′-terpyridine (L5), 4′-[naphthalen-2-yl(phenyl)amino]-2,2′:6′,2′′-terpyridine (L6) and their corresponding Re(I) complexes ReL(n)(CO)3Cl (n = 1–6) have been synthesized and characterized by elemental analysis and 1H NMR spectroscopy. The X-ray crystal structure of ReL3(CO)3Cl has also been obtained. The luminescence spectra of ReL2(CO)3Cl–ReL5(CO)3Cl, obtained in CH2Cl2 solution at room temperature, show strong dπ (Re) → π* (diimine) MLCT character (λ(max) 600 nm) and a small red shift relative to ReL1(CO)3Cl. This, confirmed by the study of the triplet energy levels of the L1–L6 ligands at low temperature (77 K rigid matrix), indicates that the introduction of electron-donating moieties on the terpyridine unit decreases the triplet levels of the ligands, leading to a reduction of the energy gap between d and π* orbitals. In the solid state, upon MLCT excitation, all the complexes show an even stronger emission and a blue spectral shift (λ(max) ∼ 550 nm) compared to those obtained in solution.
authors.affiliation: State Key Laboratory of Coordination Chemistry, Center for Molecular Organic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Qiu-Lei
authors.initials: QL
authors.lastname: Xu
authors.forename: Song
authors.initials: S
authors.lastname: Zhang
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Li
authors.forename: Cheng-Cheng
authors.initials: CC
authors.lastname: Wang
authors.forename: Tian-Yi
authors.initials: TY
authors.lastname: Li
authors.forename: Yi-Ming
authors.initials: YM
authors.lastname: Jing
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.forename: You-Xuan
authors.initials: YX
authors.lastname: Zheng
authors.forename: Gianluca
authors.initials: G
authors.lastname: Accorsi
mesh_terms: D018360:Crystallography, X-Ray; D049449:Luminescence; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D012211:Rhenium / Q000737:chemistry*
chemical_list: C517923:(2,2'-6',2'')-terpyridine; D009942:Organometallic Compounds; D011725:Pyridines; D012211:Rhenium