515125-29-8

Upstream product

• 1122-62-9 2-acetylpyridine 
• 100-52-7 benzaldehyde 

Downstream Products

• 515125-20-9 [Re(CO)3(CH₃CN)(4'-phenyl-2,2':6',2''-terpyridine)]CF₃SO₃ 

Relevant academic research and scientific papers

Experimental and computational exploration of photophysical and electroluminescent properties of modified 2,2′:6′,2″-terpyridine, 2,6-di(thiazol-2-yl)pyridine and 2,6-di(pyrazin-2-yl)pyridine ligands and their Re(I) complexes

The excited-state characteristics of a series of 2,2′:6′,2″-terpyridine (terpy), 2,6-di(thiazol-2-yl)pyridine (dtpy) and 2,6-di(pyrazin-2-yl)pyridine (dppy) derivatives as well as their corresponding Re(I) complexes [ReCl(CO)3(Ln-κ2N)] were investigated both experimentally and theoretically, and the crucial effect of pyrrolidine substituent and peripheral rings on the optical and electrochemical properties was found evident. For Re(I) complexes bearing the ligands with electron-rich pyrrolidine substituent, different emission profiles were found in polar and non-polar solvents, indicating a change in the character of the excited state. Dual-emission effect of [ReCl(CO)3(L4-κ2N)] and [ReCl(CO)3(L5-κ2N)] in chloroform was attributed to the presence of two emitting states, identified as an 1ILCT excited state deactivated at higher energies and a longer-lived red-shifted phosphorescence assigned to the 3MLCT excited state. The triplet excited state was confirmed by recording the nanosecond time-resolved transient absorption spectra for the compound [ReCl(CO)3(L4-κ2N)]. To verify the charge transfer problem of low-lying excited states of the free ligands, the Λ parameter was calculated. In addition, the compounds were applied as emitting layers for both non-doped and doped single-layer organic light-emitting diodes fabricated by solution processing.

Coordination Environment Prevents Access to Intraligand Charge-Transfer States through Remote Substitution in Rhenium(I) Terpyridinedicarbonyl Complexes

Six rhenium(I) κ3N-dicarbonyl complexes with 4′-(4-substituted phenyl)terpyridine ligands were evaluated in their ground and excited states. These complexes, bearing substituents of different electron-donating strengths - from CN to NMe2 - were studied by a combination of transient IR (TRIR), electrochemistry, and IR spectroelectrochemistry, as well as time-dependent density functional theory (TD-DFT). They exhibit panchromatic absorption and can act as stronger photoreductants than their tricarbonyl counterparts. The ground- and excited-state potentials, absorption maxima, and lifetimes (250-750 ps) of these complexes correlate well with the Hammett σp substituent constants, showing the systematic effect of remote substitution in the ligand framework. TRIR spectroscopy allowed us to assign the lowest singlet and triplet excited states to a metal-to-ligand charge-transfer (MLCT) character. This result contrasts our previous report on analogous κ2N-tricarbonyl complexes, where remote substitution switched the character from MLCT to intraligand charge transfer. With the help of TD-DFT calculations, we dissect the geometric and electronic effects of coordination of the third pyridine, local symmetries, and increasing conjugation length. These results give valuable insights for the design of complexes with long-lived triplet excited states and enhanced absorption throughout the visible spectrum, while showcasing the boundaries of the excited-state switching strategy via remote substitution.