The targeted choice of specific photocatalysts has been shown to play a critical role for the successful realization of challenging photoredox catalytic transformations. Herein, we demonstrate the successful implementation of a rational design strategy for a series of deliberate structural manipulations of cyanoarene-based, purely organic donor−acceptor photocatalysts, using 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) as a starting point. Systematic modifications of both the donor substituents as well as the acceptors' molecular core allowed us to identify strongly oxidizing as well as strongly reducing catalysts (e.g., for an unprecedented detriflation of unactivated naphthol triflate), which additionally offer remarkably balanced redox potentials with predictable trends. Especially halogen arene core substitutions are instrumental for our targeted alterations of the catalysts' redox properties. Based on their preeminent electrochemical and photophysical characteristics, all novel, purely organic photoredox catalysts were evaluated in three challenging, mechanistically distinct classes of benchmark reactions (either requiring balanced, highly oxidizing or strongly reducing properties) to demonstrate their enormous potential as customizable photocatalysts, that outperform and complement prevailing typical best photocatalysts.

Asymmetrically substituted tertiary phosphines and quaternary phosphonium salts are used extensively in applications throughout industry and academia. Despite their significance, classical methods to synthesize such compoundso ften demande ither harsh reaction conditions, prefunctionalization of startingm aterials, highly sensitive organometallic reagents, or expensive transition-metal catalysts. Mild, practical methodst husr emain elusive, despite being of great current interest. Herein, we describe av isible-light-drivenm ethod to form these products from secondary and primary phosphines. Using an inexpensive organic photocatalyst and blue-light irradiation, arylphosphines can be both alkylated anda rylatedu sing commercially available organohalides.I na ddition, the sameo rganocatalyst can be used to transform white phosphorus(P 4)d irectly into symmetrical aryl phosphines and phosphonium salts in as ingle reaction step, whichh as previously only been possibleu sing precious metalc atalysis.

We analyze internal transition rates and the singlet−triplet energy gap of the thermally activated delayed fluorescence (TADF) molecule 3CzClIPN, which recently was introduced as an efficient photocatalyst. The distribution and origin of the nonmonoexponential decays, which are commonly observed in TADF films, are revealed by an analysis of transient fluorescence with an inverse Laplace transform. A numerically robust global rate fit routine, which extracts all relevant TADF parameters by modeling the complete set of data, is introduced. To compare and verify the results, all methods are also applied to the well-known 4CzIPN. The influence of the molecular matrix is discussed by embedding low concentrations of TADF molecules in polystyrene films. Finally, quantum chemical calculations are compared to the experimental results to demonstrate that the chlorine atom increases the charge-transfer character of the relevant states, resulting in a reduction of the singlet−triplet energy gap.

The visible-light photocatalytic E/Z isomerization of olefins can be mediated by a wide spectrum of triplet sensitizers (photocatalysts). However, the search for the most efficient photocatalysts through screenings in photo batch reactors is material and time consuming. Capillary and microchip flow reactors can accelerate this screening process. Combined with a fast analytical technique for isomer differentiation, these reactors can enable high-throughput analyses. Ion mobility (IM) spectrometry is a cost-effective technique that allows simple isomer separation and detection on the millisecond timescale. This work introduces a hyphenation method consisting of a microchip reactor and an infrared matrix-assisted laser desorption ionization (IR-MALDI) ion mobility spectrometer that has the potential for high-throughput analysis. The photocatalyzed E/Z isomerization of ethyl-3-(pyridine-3-yl)but-2-enoate (E-1) as a model substrate was chosen to demonstrate the capability of this device. Classic organic triplet sensitizers as well as Ru-, Ir-, and Cu-based complexes were tested as catalysts. The ionization efficiency of the Z-isomer is much higher at atmospheric pressure which is due to a higher proton affinity. In order to suppress proton transfer reactions by limiting the number of collisions, an IM spectrometer working at reduced pressure (max. 100 mbar) was employed. This design reduced charge transfer reactions and allowed the quantitative determination of the reaction yield in real time. Among 14 catalysts tested, four catalysts could be determined as efficient sensitizers for the E/Z isomerization of ethyl cinnamate derivative E-1. Conversion rates of up to 80% were achieved in irradiation time sequences of 10 up to 180 s. With respect to current studies found in the literature, this reduces the acquisition times from several hours to only a few minutes per scan.

Research data is an essential part of research and almost every publication in chemistry. The data itself can be valuable for reuse if sustainably deposited, annotated and archived. Thus, it is important to publish data following the FAIR principles, to make it findable, accessible, interoperable and reusable not only for humans but also in machine-readable form. This also improves transparency and reproducibility of research findings and fosters analytical work with scientific data to generate new insights, being only accessible with manifold and diverse datasets. Research data requires complete and informative metadata and use of open data formats to obtain interoperable data. Generic data formats like AnIML and JCAMP-DX have been used for many applications. Special formats for some analytical methods are already accepted, like mzML for mass spectrometry or nmrML and NMReDATA for NMR spectroscopy data. Other methods still lack common standards for data. Only a joint effort of chemists, instrument and software vendors, publishers and infrastructure maintainers can make sure that the analytical data will be of value in the future. In this review, we describe existing data formats in analytical chemistry and introduce guidelines for the development and use of standardized and open data formats.