scholarly journals pH-Responsive N^C-Cyclometalated Iridium(III) Complexes: Synthesis, Photophysical Properties, Computational Results, and Bioimaging Application

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 232
Author(s):  
Anastasia Solomatina ◽  
Daria Kozina ◽  
Vitaly Porsev ◽  
Sergey Tunik

Herein we report four [Ir(N^C)2(L^L)]n+, n = 0,1 complexes (1–4) containing cyclometallated N^C ligand (N^CH = 1-phenyl-2-(4-(pyridin-2-yl)phenyl)-1H-phenanthro[9,10-d]imidazole) and various bidentate L^L ligands (picolinic acid (1), 2,2′-bipyridine (2), [2,2′-bipyridine]-4,4′-dicarboxylic acid (3), and sodium 4,4′,4″,4‴-(1,2-phenylenebis(phosphanetriyl))tetrabenzenesulfonate (4). The N^CH ligand precursor and iridium complexes 1–4 were synthesized in good yield and characterized using chemical analysis, ESI mass spectrometry, and NMR spectroscopy. The solid-state structure of 2 was also determined by XRD analysis. The complexes display moderate to strong phosphorescence in the 550–670 nm range with the quantum yields up to 30% and lifetimes of the excited state up to 60 µs in deoxygenated solution. Emission properties of 1–4 and N^CH are strongly pH-dependent to give considerable variations in excitation and emission profiles accompanied by changes in emission efficiency and dynamics of the excited state. Density functional theory (DFT) and time-dependent density functional theory (TD DFT) calculations made it possible to assign the nature of emissive excited states in both deprotonated and protonated forms of these molecules. The complexes 3 and 4 internalize into living CHO-K1 cells, localize in cytoplasmic vesicles, primarily in lysosomes and acidified endosomes, and demonstrate relatively low toxicity, showing more than 80% cells viability up to the concentration of 10 µM after 24 h incubation. Phosphorescence lifetime imaging microscopy (PLIM) experiments in these cells display lifetime distribution, the conversion of which into pH values using calibration curves gives the magnitudes of this parameter compatible with the physiologically relevant interval of the cell compartments pH.

2012 ◽  
Vol 388 (1) ◽  
pp. 012011 ◽  
Author(s):  
Manoj K Harbola ◽  
M Hemanadhan ◽  
Md Shamim ◽  
P Samal

2017 ◽  
Vol 31 (13) ◽  
pp. 1750149 ◽  
Author(s):  
Ling Ding ◽  
Wen-Hui Fan ◽  
Xu Chen ◽  
Ze-You Chen ◽  
Chao Song

We report, for the first time to our knowledge, the terahertz (THz) spectra of isonicotinic acid and 2-picolinic acid. The distinct THz spectral differences among these two isomers and nicotinic acid have also been observed, indicating that the THz vibrational modes are highly sensitive to the structural differences even in similar molecular crystals. Besides, solid-state density functional theory calculations reveal better qualitative agreement with the measured absorption features, which are related to the molecular vibrations of nicotinic acid and isonicotinic acid. As for 2-picolinic acid, the calculation based on the primitive cell reproduces the absorption features at 1.46, 1.82 and 2.46 THz originating from intermolecular vibrations. These results suggest that THz spectra can identify the complex intermolecular interactions even in similar molecular crystals, which shows potential applications in identifying isomers in food and pharmaceutical production.


2017 ◽  
Vol 05 (03) ◽  
pp. 1750009
Author(s):  
Teck Lip Dexter Tam ◽  
Ting Ting Lin ◽  
Steven Lukman

The ability to understand and predict excited state photophysics is vital for the development of photo- and electroluminescence materials, as well as light harvesting materials and photodynamic therapy. Herein, we demonstrate that single determinant time-dependent density functional theory can be computationally cost-effective and has the ability to explain both experimental singlet and triplet dynamics of pyrrolo[3,4-[Formula: see text]]pyrrole-1,4-dione and pyrrolo[3,2-b]pyrrole-2,5-dione isomers with intriguing photophysical properties. We also used the methodology to predict the photophysical properties of pyrrolo[3,4-c]pyrrole-1,3-dione and a hypothetical hybrid pyrrolo[3,4-b]pyrrole-2,4-dione isomers.


Computation ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 59
Author(s):  
Ágnes Nagy

A time-independent density functional theory for excited states of Coulomb systems has recently been proposed in a series of papers. It has been revealed that the Coulomb density determines not only its Hamiltonian, but the degree of excitation as well. A universal functional valid for any excited state has been constructed. The excited-state Kohn–Sham equations bear resemblance to those of the ground-state theory. In this paper, it is studied how the excited-state functionals behave under coordinate scaling. A few relations for the scaled exchange, correlation, exchange-correlation, and kinetic functionals are presented. These relations are expected to be advantageous for designing approximate functionals.


Sign in / Sign up

Export Citation Format

Share Document