Mechanistic information on reactions proceeding via photoredox catalysis has enabled rational optimizations of existing reactions and revealed new synthetic pathways. One essential step in any photoredox reaction is catalyst quenching via photoinduced electron transfer or energy transfer with either a substrate, additive, or cocatalyst. Identification of the correct quencher using Stern–Volmer studies is a necessary step for mechanistic understanding; however, such studies are often cumbersome, low throughput and require specialized luminescence instruments. This report describes a high-throughput method to rapidly acquire a series of Stern–Volmer constants, employing readily available fluorescence plate readers and 96-well plates. By leveraging multichannel pipettors or liquid dispensing robots in combination with fast plate readers, the sampling frequency for quenching studies can be improved by several orders of magnitude. This new high-throughput method enabled the rapid collection of 220 quenching constants for a library of 20 common photocatalysts with 11 common quenchers. The extensive Stern–Volmer constant table generated greatly facilitates the systematic comparison between quenchers and can provide guidance to the synthetic community interested in designing and understanding catalytic photoredox reactions.

Recent advances in biotechnology, protein engineering, and enzymatic immobilization have made it possible to carry out biocatalytic transformations through alternative non-conventional activation strategies. In particular, mechanoenzymology (i.e., the use of the mechanical force produced by milling or grinding to activate a biotransformation) has become a new area in so-called “green chemistry”, reshaping key fundaments of biocatalysis and leading to the exploration of enzymatic transformations under more sustainable conditions. Significantly, numerous chiral active pharmaceutical ingredients have been synthesized via mechanoenzymatic methods, boosting the use of biocatalysis in the synthesis of chiral drugs. In this regard and aiming to widen the scope of the young field of mechanoenzymology, a dual kinetic resolution of propranolol precursors was explored. The biocatalytic methodology mediated by Candida antarctica Lipase B (CALB) and activated by mechanical force allowed the isolation of both enantiomeric precursors of propranolol with high enantiomeric excess (up to 99% ee), complete conversion (c = 50%), and excellent enantiodifferentiation (E > 300). Moreover, the enantiomerically pure products were used to synthesize both enantiomers of the β-blocker propranolol with high enantiopurity.

A synthetically beneficial visible-light-mediated protocol has been disclosed to achieve C–H amination of readily available feedstocks cyclic and acyclic ethers. A rarely identified N-bromosuccinamide–tetrahydrofuran electron donor–acceptor complex served as an initiator to functionalize both α-diazoketones and dialkyl azodicarboxylates. This developed methodology gives an alternative and milder way to construct the C–N bond and can be explored for the formation of C–C bond to perform arylation and allylation reactions.

We present here new synthetic strategies for the isolation of a series of Ru(II) complexes with pyridyl-mesoionic carbene ligands (MIC) of the 1,2,3-triazole-5-ylidene type, in which the bpy ligands (bpy = 2,2′-bipyridine) of the archetypical [Ru(bpy)3]2+ have been successively replaced by one, two, or three pyridyl-MIC ligands. Three new complexes have been isolated and investigated via NMR spectroscopy and single-crystal X-ray diffraction analysis. The incorporation of one MIC unit shifts the potential of the metal-centered oxidation about 160 mV to more cathodic potential in cyclic voltammetry, demonstrating the extraordinary σ-donor ability of the pyridyl-MIC ligand, while the π-acceptor capacities are dominated by the bpy ligand, as indicated by electron paramagnetic resonance spectroelectrochemistry (EPR-SEC). The replacement of all bpy ligands by the pyridyl-MIC ligand results in an anoidic shift of the ligand-centered reduction by 390 mV compared to the well-established [Ru(bpy)3]2+ complex. In addition, UV/vis/NIR-SEC in combination with theoretical calculations provided detailed insights into the electronic structures of the respective redox states, taking into account the total number of pyridyl-MIC ligands incorporated in the Ru(II) complexes. The luminescence quantum yield and lifetimes were determined by time-resolved absorption and emission spectroscopy. An estimation of the excited state redox potentials conclusively showed that the pyridyl-MIC ligand can tune the photoredox activity of the isolated complexes to stronger photoreductants. These observations can provide new strategies for the design of photocatalysts and photosensitizers based on MICs.

Optically pure epoxides are recognized as highly valuable products and key intermediates, useful in different areas from pharmaceutical and agrochemical industries to natural product synthesis and materials science. The predictable fate of the ring-opening process, in terms of stereoselectivity and often of regioselectivity, enables useful functional groups to be installed at vicinal carbon atoms in a desired manner. In this way, products of widespread utility either for synthetic applications or as final products can be obtained. The advent of asymmetric organocatalysis provided a new convenient tool, not only for their preparation but also for the elaboration of this class of heterocycles. In this review, we focus on recent developments of stereoselective organocatalytic ring-opening reactions of meso-epoxides, kinetic resolution of racemic epoxides, and Meinwald-type rearrangement. Examples of asymmetric organocatalytic processes toward specific synthetic targets, which include ring opening of an epoxide intermediate, are also illustrated.

Amalgams have played an important role in fundamental and applied solid-state chemistry and physics because of the diversity of crystallographic features and properties that they have to offer. Moreover, their peculiar chemical properties can sometimes give rise to unconventional superconducting or magnetic ground states. In the current work, we present an in-depth analysis of single crystals of YHg3 and LuHg3 (Mg3Cd structure type, space group P63/mmc). Both compounds show superconductivity below Tc = 1 ± 0.1 K (YHg3) and Tc = 1.2 ± 0.1 K (LuHg3). Given the high air-sensitivity and toxicity of these compounds, this study was only possible using a number of dedicated experimental techniques.

The manufacture of high-value products from biomass derived platform chemicals is becoming an integral part of the biorefinery industry. In this study, we demonstrate a green catalytic process using solvent free conditions for the synthesis of hydroxymethylfurfural (HMF) levulinate from HMF and levulinic acid (LA) over tin exchanged tungstophosphoric acid (DTP) supported on K-10 (montmorillonite K-10 clay) as the catalyst. The structural properties of solid acid catalysts were characterized by using XRD, FT-IR, UV–vis, titration, and SEM techniques. Partial exchange of the H+ of DTP with Sn (x = 1) resulted in enhanced acidity of the catalyst and showed an increase in the catalytic activity as compared to the unsubstituted DTP/K-10 as the catalyst. The effects of different reaction parameters were studied and optimized to get high yields of HMF levulinate. The kinetic model was developed by considering the Langmuir–Hinshelwood–Hougen–Watson (LHHW) mechanism, and the activation energy was calculated to be 41.2 kJ mol–1. The prepared catalysts were easily recycled up to four times without any noticeable loss of activity, and hot filtration test indicated the heterogeneous nature of the catalytic activity. The overall process is environmentally benign and suitable for easy scale up.

A pathway for the synthesis of 3-sulfonylindoles has been devised. Upon blue LED irradiation, in the presence of a gold(I) or a silver(I) salt, ortho-alkynyl N-sulfonyl precursors readily undergo a 5-endo-dig cyclization concomitant with a 1,3-sulfonyl migration. While the gold-catalyzed reaction takes place in photocatalyst-free conditions, an iridium photocatalyst (Ir[dF(CF3)ppy]2(dtbbpy)PF6) is necessary with silver catalysis. Mechanistic studies featuring the generation of a sulfonyl radical support this dichotomy.

Selenium-containing organic molecules have recently found a plethora of applications, ranging from organic synthesis to pharmacology and material sciences. In view of these concepts, the development of mild, efficient, and general protocols for the formation of C–Se bonds is desirable, and light induced approaches are appealing ways. The aim of this Review is to provide the reader with the most recent examples of light promoted selenylation processes.

We report the isolation and study of dimers stemming from popular thiazol-2-ylidene organocatalysts. The model featuring 2,6-di(isopropyl)phenyl (Dipp) N-substituents was found to be a stronger reducing agent (Eox = −0.8 V vs SCE) than bis(thiazol-2-ylidenes) previously studied in the literature. In addition, a remarkable potential gap between the first and second oxidation of the dimer also allows for the isolation of the corresponding air-persistent radical cation. The latter is an unexpected efficient promoter of the radical transformation of α-bromoamides into oxindoles.

We report the facile synthesis of a rare niobium(V) imido NHC complex with a dianionic OCO-pincer benzimidazolylidene ligand (L1) with the general formula [NbL1(NtBu)PyCl] 1-Py. We achieved this by in situ deprotonation of the corresponding azolium salt [H3L1][Cl] and subsequent reaction with [Nb(NtBu)Py2Cl3]. The pyridine ligand in 1-Py can be removed by the addition of B(C6F5)3 as a strong Lewis acid leading to the formation of the pyridine-free complex 1. In contrast to similar vanadium(V) complexes, complex 1-Py was found to be a good precursor for various salt metathesis reactions, yielding a series of chalcogenido and pnictogenido complexes with the general formula [NbL1(NtBu)Py(EMes)] (E = O (2), S (3), NH (4), and PH (5)). Furthermore, complex 1-Py can be converted to alkyl complex (6) with 1 equiv of neosilyl lithium as a transmetallation agent. Addition of a second equivalent yields a new trianionic supporting ligand on the niobium center (7) in which the benzimidazolylidene ligand is alkylated at the former carbene carbon atom. The latter is an interesting chemically “noninnocent” feature of the benzimidazolylidene ligand potentially useful in catalysis and atom transfer reactions. Addition of mesityl lithium to 1-Py gives the pyridine-free aryl complex 8, which is stable toward “overarylation” by an additional equivalent of mesityl lithium. Electrochemical investigation revealed that complexes 1-Py and 1 are inert toward reduction in dichloromethane but show two irreversible reduction processes in tetrahydrofuran as a solvent. However, using standard reduction agents, e.g., KC8, K-mirror, and Na/Napht, no reduced products could be isolated. All complexes have been thoroughly studied by various techniques, including 1H-, 13C{1H}-, and 1H-15N HMBC NMR spectroscopy, IR spectroscopy, and X-ray diffraction analysis.

The stereoselective synthesis of geometrical iron(II) complexes bearing azine-NHC ligands is described. Facial and meridional selectivity is achieved as a function of the steric demand of the azine unit, with no remarkable influence of the carbene nature. More specifically, meridional complexes are obtained upon selecting bulky 5-mesityl-substituted pyridyl coordinating units. Unexpectedly, increase of the steric hindrance in the α position with respect to the N coordinating atom results in an exclusive facial configuration, which is in stark contrast to the meridional selectivity induced by other reported α-substituted bidentate ligands. Investigation of the structure and the optical and electrochemical properties of the here-described complexes has revealed the non-negligible effect of the fac/mer ligand configuration around the metal center.

Data are shaping the future of humanity. We want the data published in and associated with ACS journals to be high-quality, robust, and, where it is ethically and legally feasible, accessible. We strongly endorse the FAIR Data Principles (1) and ACS Organic & Inorganic Au will be involved in spearheading ACS’ move to be a leader in data standards. ACS Organic & Inorganic Au encourages all researchers to submit data alongside their manuscripts. We encourage authors to submit free induction decay (FID) data alongside publications and include a note in published work to say when “FAIR” data is available. (2) We also encourage the deposition of data in open repositories. Authors may refer to re3data.org and FAIRsharing.org for information on available repositories, their certification status, and services offered. Last Fall, the ACS Research Data Policy was launched on the ACS Publishing Center to provide best practice recommendations for data citation, Data Availability Statements, and the use of appropriate data repositories. In addition, the ACS Publishing Center also features a section dedicated to ACS Research Data Guidelines. These guidelines are a living reference source to support researchers to include data as a prioritized publication component. Current guidelines include Biological data, Simulations, Machine Learning, Computational Data, and Organic chemistry data, and coming soon in 2022, Nanoscience, Materials science, and Energy. In March 2022, ACS Organic & Inorganic Au rolled out our new data check. This process is analogous to the process at our sister journals, The Journal of Organic Chemistry and Organic Letters. It ensures that the data presented in Articles, Letters, Reviews, and Perspectives are robust and reliable. In doing this, we are also keen to ensure that the organic chemistry community experience consistent processes across all our organic chemistry journals. A member of our Data Team will check the data in the manuscript, and feedback will be included in the decision letter. When the revised manuscript is submitted, the data team reviews the revision to ensure the data meets journal requirements prior to acceptance. This is the first important step that ACS Organic & Inorganic Au is taking to embrace data as a prioritized publication component. Do keep an eye out for future developments from the journal─we have some exciting data initiatives on the horizon! We hope our authors and readers share our passion for the future of open data and open science. This article references 2 other publications. This article has not yet been cited by other publications. This article references 2 other publications.

Ethylene copolymerizations with 2-methyl-1-pentene, 1-dodecene (DD), vinylcyclohexane (VCH), [Me2Si(C5Me4)(NtBu)]TiCl2 (1), Cp*TiMe2(O-2,6-iPr2-4-RC6H2) [R = H (2), SiEt3 (3)]–borate, and [A(H)]+[BAr4]− [Ar = C6F5; A(H)+ = N+(H)Me(n-C18H37)2, N+(H)(CH2CF3)(n-C18H37)2, HO+(n-C14H29)2·O(n-C14H29)2, HO+(n-C16H33)2·O(n-C16H33)2; Ar = C10F7, A(H)+ = HO+(n-C14H29)2·O(n-C14H29)2 (B5), N+(H)(CH2CF3)(n-C18H37)2] catalyst systems conducted in methylcyclohexane (MCH) exhibited better comonomer incorporation than those conducted in toluene (in the presence of methylaluminoxane (MAO) or borate cocatalysts). The activity was affected by the borate cocatalyst and 1,3–B5 catalyst systems in MCH and showed the highest activity in the ethylene copolymerizations with VCH and DD.

The use of a readily accessible polyazahelicene as a strongly reducing metal-free alternative to the commonly used precious metal based photoredox catalysts is demonstrated. An improved two-step synthesis of the catalyst is described, and its photophysical properties with respect to its use as a photoredox catalyst are evaluated. Its activity under visible light irradiation is proven by application in two double radical light-driven multicomponent reactions. The azahelicene gave comparable results to an iridium-based catalyst originally used for the same transformations.

Visible light is perceived as an ideal source of energy to activate organic and inorganic compounds and mediate photophysical and photochemical transformations. In the early 20th century, Ciamician reported his vision to exploit the renewable energy potential of visible-light irradiation as a strategy for sustainable chemical development. (1) However, the lack of color for most organic and inorganic molecules and their transparency to visible light has impeded progress toward this goal. Although the UV irradiation of organic and/or inorganic compounds has allowed the development of efficient organic (2) and inorganic photochemical reactions, (3) this approach suffers from poor functional group tolerance and harnesses less than 10% of the solar power potential. (4) Over the past 20 years, a great deal of research has been devoted to triggering chemical transformations with abundant and chemically inert visible light. Inorganic materials such as TiO2 were initially reported to be potent photocatalysts, (5) and in the 1970s, Fujishima and Honda reported an important contribution on solar water-splitting and carbon dioxide reduction, which stimulated the field of research on semiconductor photocatalysts. (6) During the same period, the selected activation of small organic molecules by visible-light-absorbing organometallic photocatalysts was also demonstrated by several researchers, thereby establishing the foundations for visible-light homogeneous photocatalysis. (7) However, while research on semiconductor photocatalysts progressively increased, (8) the concept of photocatalysis in the field of organic chemistry remained undiscussed until 2008/2009, when MacMillan, Yoon, and Stephenson demonstrated significant advances, illustrating its significant potential for the research community. (9) Since then, photoredox catalysis has been extensively developed in organic and inorganic chemistry, and even in other fields of science. We are pleased to launch this issue of ACS Organic & Inorganic Chemistry Au, which includes selected Reviews and Articles covering key topics and advances in organic and inorganic photoredox catalysis. Several Articles and Reviews in this issue are dedicated to the preparation of new photocatalysts. Chiral-at-metal Lewis acid catalysts, in which the chiral information comes from the metal center, have been shown to be useful in a wide range of enantioselective metal-catalyzed reactions, as discussed in the in-depth and insightful Review from Biplab Maji et al. (10) Chiral-at-metal photocatalysts have been successfully employed in several important enantioselective transformations, and their huge contribution to the recent progress of asymmetric photoredox catalysis is presented. The Review also provides a critical analysis of the topic and outlines future directions for the field. This issue contains reports on novel metal or organo-photocatalysts and their applications (mainly in organic chemistry). Designing photoredox catalysts that absorb in the red-light region has recently stimulated intensive research toward broad biological applications. Katarzyna Rybicka-Jasińska and Dorota Gryko et al. disclose the opportunities offered by free-base porphyrin photocatalysts to functionalize biomolecules under red light irradiation. (11) They demonstrate that free-base porphyrin can serve both as a photo-oxidant and reductant in various organic reactions. Moreover, the development of phosphorescent organometallic compounds emitting in the deep red to near-infrared has been the subject of intensive reserch in recent years. In this context, new heteroleptic bis-cyclometalated iridium complexes have been synthesized and studied by Thomas S. Teets et al. (12) In addition, several efforts have been made to develop metal-free photocatalysts with similar redox properties to metal-based ones. In this vein, Till Opatz et al. report a two-step synthesis of polyazahelicene, which displays high reductive ability. Its efficiency as a photoreductant has been demonstrated in two multicomponent reactions and shows similar activity to Ir(ppy)3 photocatalysts. (13) The immobilization of metal-based photocatalysts is also a complementary approach to develop more eco-friendly transformations and has been the subject of intensive research in organic and inorganic chemistry. In this issue, Kelly Materna and Carl-Johan Wallentin et al. present the application of heterogeneous iridium-on-alumina as a photoredox catalyst in a set of five model reactions (reductive dehalogenation, atom-transfer radical addition, aerobic oxidative hydroxylation of boronic acids, oxidative fragmentation of ethers and acetals, and the E–Z isomerization of cinnamates). (14) The results show that this supported photoredox catalyst displays excellent activity, higher than that of the homogeneous catalyst, with good recyclability properties. Molybdenum disulfide (MoS2) quantum dots (QDs) have attracted significant attention for application in photocatalytic water splitting for H2 generation. However, recently they have found application in photoredox transformations of organic compounds. De et al. disclose in their Article that MoS2 QDs are an efficient photocatalyst for the C–H functionalization of tetrahydroisoquinolines with indoles (or phosphites). Detailed mechanistic studies suggest that after irradiating MoS2 QDs, the excited electron in the conduction band can trigger the oxidation of amines in the presence of O2. (15) DFT calculations are useful for designing high-performance catalysts and better understanding catalytic activity. In that regard, Theresa McCormick et al. demonstrate the value of computational studies as a tool for fine-tuning photoredox catalysts, namely tuning Ni(II) tris-pyridinethiolate for water splitting. (16) This study provides insight into the structure of the catalyst with the formation of various isomers after the protonation of different possible sites on the Ni(II) complex. The development of new synthetic reactions using known organic or inorganic photocatalysts is also included in this issue. Gary Molander et al. present recent advances in photoinduced chemical reactions involving 1,2-radical shifts. (17) This Review provides an excellent overview of the recent synthetic applications of this radical process, with special emphasis on understanding the mechanism and its utility for the synthesis of organic molecules. Then, Maurizio Fagnoni et al. describe recent progress in visible-light-promoted selenylation, presenting useful radical methodologies for C(sp2)–Se bond and C(sp3)–Se bond formation. (17) The authors also highlight the need to develop new photocatalytic synthetic procedures to form (sp3)–Se bonds. Two Articles dealing with a related subject, the formation of C(sp2)–S and C(sp3)–S bonds, discuss the use of diazonium salts as precursors of aryl radicals. Yevheniia Markushyna and Aleksandr Savateev et al. report the efficient synthesis of sulfonyl chlorides using potassium poly(heptazine imide) as a photocatalyst. (18) Using this cheap and available heterogeneous organocatalyst, they describe a novel Sandmeyer-type transformation between thiols and arenediazonium salts with good functional group tolerance on the aromatic rings. Samir Messaoudi et al. have developed a photoredox-catalyzed Stadler–Ziegler arylation of thiosugars with in situ-generated diazonium salts from anilines. This protocol affords direct access to various S-aryl thioglycosides, which are valuable building synthons for drug discovery and chemical biology. (19) The visible-light photocatalytic functionalization of alkenes is a useful procedure for preparing high-value organic compounds. Zhu et al. present an efficient method for synthesizing allylic and homoallylic azides through the visible-light-promoted photoredox-mediated difluoroalkylation of trisubstituted alkenes with ethyl bromodifluoroacetate. The reaction allows the functionalization of internal alkenes, leading to the formation of allylic or homoallylic products according to the substitution of alkenes. (20) Visible-light mediated [2 + 2] cycloaddition via energy transfer mechanism is a valuable method for the synthesis of highly strained cyclobutanes. Here, Olga García Mancheño et al. disclose intermolecular [2 + 2] photocycloaddition reactions between enamides and styrenes for the direct synthesis of unnatural 2-substituted cyclobutane α-amino acids. (21) The method employs [[Ir(dFCF3ppy2)dtbpy]PF6 as a photoredox catalyst, and a variety of cyclobutanes were prepared in good yields. In addition, Christoforos Kokotos et al. report the synthesis of cyclobutanes via [2 + 2] cycloaddition between N-aryl maleimides and styrenes, catalyzed by thioxanthone as an organic sensitizer. Interestingly, no catalyst was needed to promote the reaction when N-alkyl maleimides were used as a partner. A range of cyclobutanes were prepared (with or without photocatalyst) in good yields with moderate diastereoselectivity. (22) The combination of photoredox catalysis with other catalysis modes offers exciting opportunities for the development of new transformations. For instance, Alfonso Carotenuto, Diego Brancaccio, and Mariateresa Giustiniano et al. develop a photoredox-catalyzed amide formation between N-methyl-N-alkyl aromatic amines and isocyanides in an aqueous micellar medium. (23) Based on intensive NMR studies, the formation of photoactive micelles was proposed due to an interaction between photocatalyst and surfactant, which opens new exciting perspectives in the photoredox catalysis field. Cyril Ollivier, Virginie Mouriès-Mansuy, and Louis Fensterbank et al. present a dual catalytic system combining a visible-light photoredox catalyst and a silver(I) salt for the synthesis of 3-sulfonylindoles. (24) The process relies on the 5-endo-dig cyclization of ortho-alkynyl N-sulfonyl precursors with a concomitant 1,3-sulfonyl migration. During optimization, when gold(I) salt was used instead of silver(I) salt, they observed that no photocatalyst was needed for this transformation. Nowadays, photocatalyst-free strategies have attracted extensive attention, and here, three Articles illustrate the potential of these strategies in photochemical synthesis. Takahiko Akiyama et al. accomplished C(sp2)–S bond formation by exploiting the C–H functionalization of alkanes via electron donor–acceptor EDA complex photoexcitation. (25) Several experiments establish the formation of an EDA complex between the electron-rich thiolates and a sacrificial acceptor (electron-poor arene). This EDA-complex-initiated free-radical reaction allows access to structurally diverse thioethers in good yields. Indranil Chatterjee et al. also report EDA complex formation through N-bromosuccinimide additives to promote the visible-light-driven C–H functionalization of tetrahydrofuran derivatives. (26) A broad range of radical acceptors, including α-diazoketones, azodicarboxylates, and aryl and allyl sulfones, were well tolerated affording efficient access to α-functionalized tetrahydrofurans. An alternative photocatalyst-free strategy involved introducing photoactivable functional groups into organic molecules to trigger radical transformations. An additional example of a photocatalyst-free strategy is presented by Stefano Protti et al., who describe the use of arylazo sulfones as visible-light photoactivable substrates to photochemically arylate various enol silyl ethers and ketene silyl acetals. (27) This report provides a novel and general approach for the synthesis of α-arylated ketones and esters under mild conditions. The contributions in this issue outline some recent exciting developments in photoredox catalysis, encompassing organic, organometallic, and inorganic chemistry, reporting new compounds, insight, and transformations. We wish to thank each of the researchers who contributed their exciting work to this collection and thank the reviewers for their valuable insight. We hope you enjoy reading this issue! This article references 27 other publications. Review on the leading-edge work of Kellogg, Sakurai, Willner, Fukuzumi, Tanaka, Deronzier, Tomioka, Pandey and Okada, This article has not yet been cited by other publications. This article references 27 other publications. Review on the leading-edge work of Kellogg, Sakurai, Willner, Fukuzumi, Tanaka, Deronzier, Tomioka, Pandey and Okada,

Organophosphorus nerve agents (OPAs) are a toxic class of synthetic compounds that cause adverse effects with many biological systems. Development of methods for environmental remediation and passivation has been ongoing for years. However, little progress has been made in therapeutic development for exposure victims. Given the postexposure behavior of OPA materials in enzymes such as acetylcholinesterase (AChE), development of electrophilic compounds as therapeutics may be more beneficial than the currently employed nucleophilic countermeasures. In this report, we present our studies with an electrophilic, 16-electron manganese complex (iPrPNP)Mn(CO)2 (1) and the nucleophilic hydroxide derivative (iPrPNHP)Mn(CO)2(OH) (2). The reactivity of 1 with phosphorus acids and the reactivity of 2 with the P–F bond of diisopropylfluorophosphate (DIPF) were studied. The role of water in both nucleophilic and electrophilic reactivity was investigated with the use of 17O-labeled water. Promising results arising from reactions of both 1 and 2 with organophosphorus substrates are reported.

We have revisited the electrochemistry of metallocorrole dimers with low-temperature cyclic voltammetry and UV–visible–NIR spectroelectrochemistry, with the aim of determining the sites of the redox processes undergone by these compounds. The systems studied include the metal–metal triple-bonded complexes {Ru[TpOMePC]}2 and {Os[TpOMePC]}2 and the metal–metal quadruple-bonded complex {Re[TPC]}2, where TpOMePC and TPC refer to trianionic meso-tris(p-methoxyphenyl)corrole and meso-triphenylcorrole ligands. For all three compounds, the first oxidation potentials are found at 0.52 ± 0.04 V vs SCE in CH2Cl2/0.1 M TBAP and are accompanied by major changes in the optical spectra, especially the appearance of broad, low-energy bands, suggesting macrocycle-centered oxidation in each case. In contrast, the reduction potentials span an 800 mV range, occurring at E1/2 = −0.52 V for {Re[TPC]}2, −0.81 V for {Ru[TpOMePC]}2, and −1.32 V for {Os[TpOMePC]}2, with more modest changes in the optical spectra, implying a significant metal-centered character in the reduction process. Density functional theory (DFT) calculations largely (but not entirely) bear out these expectations. The combined experimental and theoretical data indicate that one-electron addition to the Re dimer involves the Re–Re δ* LUMO, while one-electron addition to the Ru dimer largely involves the Ru–Ru π* LUMO. In contrast, the calculations suggest that one-electron reduction of the Os dimer occurs largely on the corrole ligands, a phenomenon attributed to the relativistic destabilization of the Os–Os π* MOs.

Quantification is essential to fairly compare between synthetic reactions in chemistry. Here we propose two new parameters called “adapted sensitivity constant” (ρadap) and “substrate electronics adaptability” (SEA), easily obtainable from Hammett plots, to assess the ability of a (catalytic) reaction to transform substrates with opposing electronics. These new parameters allow one to list reactions, catalyzed or not, as a function of substrate scope.

In this work, we report the first selective, photocatalyzed [2+2]-cycloaddition of dehydroamino acids with styrene-type olefins. This simple, mild, and scalable approach relies on the use of the triplet energy transfer catalyst [Ir(dFCF3ppy2)dtbpy]PF6 under visible light irradiation and provides fast access to value-added substituted strained cyclobutane α-amino acid derivatives.