We present an effective strategy to modulate the electron-rich capability in donor–acceptor (D-A) polymers for improving the performances of organic solar cell (OSC) devices. In order to confirm this strategy, based on a series of the reported D–A polymers ((PCPDTBT(Pa1), PCPDTFBT (Pa2), and PCPDTDFBT (Pa3)) which contain the electron-donating cyclopentadithiophene (CPDT) and differently electron-withdrawing units of benzo[c][1,2,5,]thiadiazole (BT), 5-fluorobenzo[c][1,2,5]thiadiazole (FBT), and 5,6-difluorobenzo[c] [1,2,5]thiadiazole (DFBT), we replace CPDT with electron-donating dithienogermolodithiophene (DTTG) in polymers Pa1–Pa3, respectively, and design a series of new D–A polymers Pb1–Pb3. Compared with the polymers Pa1–Pa3, the new designed polymers Pb1–Pb3 not only yield a greater red-shift of the absorption spectrum of the donor polymer and result in a larger absorption region within the solar emission spectrum and an improved light-absorbing efficiency but also exhibit much better electron transfer efficiency in active layer, larger hole transport rates and higher open circuit voltage. Moreover, the estimated power conversion efficiency of the designed polymers in OSC applications reaches up to ∼8.4%. Conclusively, the approach based on modulating the electron-donating capability in D–A polymer chain is a feasible way to enhance their intrinsic properties of donor polymers and thereby achieving the purpose that improves the performances of the OSC devices.

In this article, the radiative and nonradiative decay processes of four cyclometalated (C∧C*) platinum­(II) N-heterocyclic carbene (NHC) complexes were unveiled via density functional theory and time-dependent density functional theory. In order to explore the influence of π-conjugation on quantum yields of (NHC)­Pt­(acac) (NHCN-heterocyclic carbene, acac = acetylacetonate) complexes, the factors that determine the radiative process, including singlet–triplet splitting energies, transition dipole moments, and spin–orbit coupling (SOC) matrix elements between the lowest triplet states and singlet excited states were calculated. In addition, the SOC matrix elements between the lowest triplet state and the ground state as well as Huang–Rhys factors were also computed to describe the temperature-independent nonradiative decay processes. Also, the triplet potential energy surfaces were investigated to elucidate the temperature-dependent nonradiative decay processes. The results indicate that complex Pt-1 has higher radiative decay rate than complexes Pt-2–4 due to the larger SOC matrix elements between the lowest triplet states and singlet excited states. However, complexes Pt-2–4 have smaller Huang–Rhys factors, smaller SOC matrix elements between the lowest triplet and the ground states, and higher active energy barriers than complex Pt-1, indicating that complexes Pt-2–4 have smaller nonradiative decay rate constants. According to these results, one may discern why complex Pt-2 has higher phosphorescence quantum efficiency than complex Pt-1; meanwhile, it can be inferred that the nonradiative decay process plays an important role in the whole photodeactivation process. In addition, on the basis of complex Pt-2, Pt-5 was designed to investigate the influence of substitution group on the photodeactivation process of rigid (NHC)­Pt­(acac) complex.

For phosphorescent emitters, the rigidity of the geometry is a crucial indicator, which can directly determine the non-radiative decay rate. Small substituent groups as geometric controllers can effectively control the rigidities of tridentate platinum(ii) complexes.

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Carboranes have attracted increasing interest in the scientific community due to their remarkable structures and strong electron-withdrawing abilities. In this article, four platinum complexes [(C^N^N)PtC[triple bond, length as m-dash]CPh](1), [(C^N^N)PtC[triple bond, length as m-dash]C-TPA](2), [(C^N^N)PtC[triple bond, length as m-dash]C-TAB](3), [(C^N^N)PtC[triple bond, length as m-dash]C-CB](4) (where TPA = triphenylamine, TAB = triarylboryl, CB = o-carborane) have been calculated via density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods to mainly explore the influence of carborane substituents on electronic structures, photophysical properties and radiative decay processes. The calculated results reveal that 2 with electron-donating triphenylamine has a low radiative decay rate constant and a red-shifted emission band, but 3 and 4 containing electron-withdrawing triarylboryl and o-carborane exhibit the opposite properties, especially 4 is supposed to have the highest phosphorescence quantum yield with the smallest nonradiative decay rate constant. These findings successfully illustrated the structure-property relationship and the designed complex 4 with carborane can serve as a highly efficient phosphorescent material in the future.

A Michael addition-driven four-component reaction (4-CR) with four Ugi inputs was developed and utilized for the synthesis of chromone derivatives and tetrazole substituted chromones under mild reaction conditions.

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Mitochondria, as the powerhouse of most cells, are not only responsible for the generation of adenosine triphosphate (ATP) but also play a decisive role in the regulation of apoptotic cell death, especially of cancer cells. Safe potential delivery systems which can achieve organelle-targeted therapy are urgently required. In this study, for effective pancreatic cancer therapy, a novel mitochondria-targeted and ROS-triggered drug delivery nanoplatform was developed from the TPP-TK-CPI-613 (TTCI) prodrug, in which the ROS-cleave thioketal functions as a linker connecting mitochondrial targeting ligand TPP and anti-mitochondrial metabolism agent CPI-613. DSPE-PEG2000 was added as an assistant component to increase accumulation in the tumor via the EPR effect. This new nanoplatform showed effective mitochondrial targeting, ROS-cleaving capability, and robust therapeutic performances. With active mitochondrial targeting, the formulated nanoparticles (TTCI NPs) demonstrate much higher accumulation in mitochondria, facilitating the targeted delivery of CPI-613 to its acting site. The results of in vitro antitumor activity and cell apoptosis revealed that the IC50 values of TTCI NPs in three types of pancreatic cancer cells were around 20~30 µM, which was far lower than those of CPI-613 (200 µM); 50 µM TTCI NPs showed an increase in apoptosis of up to 97.3% in BxPC3 cells. Therefore, this mitochondria-targeted prodrug nanoparticle platform provides a potential strategy for developing safe, targeting and efficient drug delivery systems for pancreatic cancer therapy.