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The Wittig reaction is renowned as exceptionally versatile method for converting a diversity of aldehydes and ketones into alkenes. Recently, strategies for chiral phosphine catalysis under PIII/PV=O redox cycling emerged to render this venerable transformation stereoselective. Herein, we describe that phosphine redox catalysis enables the enantioselective synthesis of pertinent biaryl atropisomers by means of a stereocontrolled arene‐forming Wittig reaction. Key to the process is the release of an endogenous base from readily accessible tert‐butyloxycarbonylated Morita–Baylis–Hillman adducts triggered by catalyst intramolecularization, permitting mild phosphine redox catalysis for atroposelective Wittig reactions. By this strategy, a broad diversity of biaryl atropisomers is obtained with up to 94 : 6 enantioselectivity. [ABSTRACT FROM AUTHOR]

Polysubstituted acrylamides are ubiquitous in bioactive molecules and natural products. However, synthetic methods for the assembly of these important motifs remain underdeveloped. Herein, we report the expedient synthesis of structurally diverse and synthetically challenging polysubstituted acrylamides from readily available aromatic amines, cyclopropenones (CpOs), and aryl halides via the synergistic merging of nucleophilic phosphine-mediated amidation and palladium-catalyzed C–H arylation. The reaction is scalable, and some obtained acrylamides proved to be solid state luminogens with obvious aggregation-induced emission (AIE) properties, demonstrating the synthetic potential in drug discovery and material development. [ABSTRACT FROM AUTHOR]

We have found that amines significantly accelerate iodide substitution in CpFe(CO)2I (1) (Cp = η5-cyclopentadienyl) with phosphines and allow the synthesis of new complexes that are not available through reactions carried out without an amine. The reaction of equimolar amounts of 1 and triphenylphosphine in toluene containing DIPA afforded [CpFe(CO)2PPh3]+I− within 5 min at room temperature in 72% yield (90% after 24 h). DIPA and pyrrolidine gave the highest yields of the tested amines. We performed a similar reaction using model bisphosphines 1,3-bis(diphenylphosphino)ethane (dppe) and 1,1′-bis(diphenylphosphino)ferrocene (dppf). The products depended on the reagent ratio and bore the CpFe(CO)2 moiety coordinated to one or two phosphine phosphorus atoms. Chelates [CpFe(CO)(dppe)]+I− (4) and [Cp2Fe2(CO)4(dppe)]2+2I− (5) were formed in 72% and 98% yield, respectively. We also performed the DIPA-catalyzed reaction of 1 with triethyl phosphite and obtained the product of an Michaelis–Arbuzov-like rearrangement, CpFe(CO)2[P(O)(OCH2CH3)2] (11). All complexes were characterized with spectroscopic analysis by NMR, FT-IR, and ESI-MS, and by XRD for three complexes. To clarify the reaction mechanism, we performed theoretical calculations of the intermolecular interactions between 1 and amine molecules. We propose two possible reaction mechanisms to explain the formation of products. [ABSTRACT FROM AUTHOR]

Herein, we present a CuI-dimer, [CuI{Ph2PC6H4C(O)NC6H4PPh2-o}]2, which catalyzed direct C(sp3)–H homocoupling of benzyl and cycloalkane derivatives with excellent yields and regio-selectivity. The method is very simple and tolerates various functionalities. Synergistic metal–ligand cooperativity was observed in Cu–N bond cleavage and protonation of nitrogen, and facilitates a bifunctional pathway, minimising the free energy corrugation for catalytic intermediates. [ABSTRACT FROM AUTHOR]

A series of new pyrazole‐alkyl phosphine ligands with varying cycloalkyl ring sizes that enable additive‐free regio‐ and chemoselective C─H arylation of heterocycles are reported. Excellent α/β selectivity of various heterocycles such as benzo[b]thiophene, thiophene, furan, benzofuran, and thiazole can be achieved using these ligands, along with excellent chemoselectivity of C─Cl over C─OTf of chloroaryl triflates. Mechanistic studies supported by both experimental findings and density functional theory calculations indicate that the pyrazole phosphine ligands with optimal ring sizes allow the reaction to proceed with a lower energy barrier via a concerted metalation–deprotonation pathway. [ABSTRACT FROM AUTHOR]

α-Chiral alkyl phosphines are privileged structural motifs with a wide application in organic and medical synthesis. It is highly desirable to develop stereoselective methods to prepare these enantioenriched molecules. The incorporation of C(sp³)-H functionalization and chiral phosphine chemistry is much less explored, probably because of the weak reactivity of C(sp³)-H bonds and/or the challenging site-and stereoselectivity issues. Herein, we disclose a synergistic catalysis system to enable an enantioselective radical addition process of α-substituted vinylphosphine oxides. An array of diverse α-chiral alkyl phosphors compounds is smoothly accessed by using the readily available chemicals as the inert C(sp³)-H bond reagent, such as sulfides, amines, alkenes, and toluene derivatives, exerting remarkable chemo-, site-, and enantioselectivity. On the basis of the mechanistic studies, both the C(sp³)-H bond activation and the stereochemistry-determining step are proposed to involve a single-electron transfer/proton transfer process. [ABSTRACT FROM AUTHOR]

This document provides experimental results for the synthesis of various compounds using a general procedure. The compounds include 5-Pivalamidooctyl Benzoate, N-(1-(2-Methoxyphenoxy)heptan-4-yl)pivalamide, N-(1-(3-(Trifluoromethyl)phenyl)heptan-4-yl)pivalamide, 4-Pivalamidoheptyl 2-Bromobenzoate, N-(8-(2,6-Dichlorophenoxy)octan-4-yl)pivalamide, 6-Pivalamidononyl 2-(2-Fluoro-[1,1′-biphenyl]-4-yl)propanoate, 7-Pivalamidodecyl Thiophene-2-carboxylate, and 4-Pivalamidoheptyl 1-Methyl-1H-pyrrole-2-carboxylate. The compounds' yields, physical properties, and spectroscopic data, including NMR and HRMS, are reported. The document does not provide any additional information or context beyond the experimental results. [Extracted from the article]

Homogenous catalysis is an essential tool within the commercial manufacture of bulk and fine chemicals. Within this, phosphine ligands, such as tricyclohexylphosphine, otherwise known as CYTOP® 366, are a crucial component. When designing a pathway to your ligand of choice, some key considerations include safety, yield and quality, but at commercial volumes we must also balance cost and consider the technologies readily available. Herein, we report the synthetic route that was chosen to manufacture tricyclohexylphosphine at commercial scale. We also consider, with the use of computational calculations, why traditional hydrophosphination methods failed, where the selected pathway succeeded. [ABSTRACT FROM AUTHOR]

Described herein is the successful crystallization‐induced dynamic resolution (CIDR) of an α‐lithiated phosphine borane utilizing the easily accessible and inexpensive ligand (R,R)‐TMCDA. Starting from the essential P‐prochiral building block dimethyl phenyl phosphine borane we were able to obtain phosphine boranes in yields up to 80 % and e.r. up to 98 : 2 by crystallization of the lithiated intermediate prior to the trapping reaction. NMR‐based deuterium labeling experiments indicate that the epimerization in solution is based on the intermolecular proton transfer between nonlithiated phosphine borane and the corresponding lithiated intermediate, rendering the presence of the remaining starting compound in an optimized solvent mixture the main factor for successful enantioselective synthesis. Quantum chemical calculations using different model systems based on solid state structures confirm these experimental results. By gaining insights into the epimerization mechanism, essential principles for CIDR of lithiated phosphine boranes are elucidated that may be expanded to other important P‐stereogenic compounds and simple chiral amines. [ABSTRACT FROM AUTHOR]

The electronic properties, coordination chemistry and reactivity of metal complexes of a planar (C2v symmetric) acridane‐derived geometrically constrained phosphine, P(NNN), are described. On complexation to metal centers, the phosphine was found to adopt a distorted trigonal pyramidal structure with a high barrier to pyramidal inversion (22.3 kcal/mol at 298 K for Au[P(NNN)]Cl). Spectroscopic data and theoretical calculations carried out at the density functional level of theory indicate that P(NNN) is a moderate σ‐donor, with significant π‐acceptor properties. Despite the distortion undergone by the phosphorus atom on coordination to metal centers, the P(NNN) ligand retains its ability to react with small molecule substrates with polar E−H bonds (MeOH, NH2Ph, NH3). It does so in a concerted fashion across one of the P−N bonds, and reversibly in the case of amine substrates. This cooperative bond activation chemistry may ultimately prove beneficial in catalysis. [ABSTRACT FROM AUTHOR]

Phosphine ligands are widely used in the manufacture of small molecule active pharmaceutical ingredients, for they play a key role in transition-metal-catalyzed cross-coupling. However, chromatographic analysis of phosphine ligands can be challenging because of the easily oxidizable nature of this class of compounds. This manuscript describes an out-of-specification (OOS) investigation study of XPhos raw material analysis by high performance liquid chromatography (LC). It is concluded that on-column degradation/oxidation is the culprit behind this OOS result. In addition, a slightly modified yet much improved new LC method is developed by adding a trace amount of tris(2-carboxyethyl)phosphine (TCEP) into the aqueous mobile phase. TCEP is also a phosphine compound and is commonly used as a reducing reagent in molecular biology. The trace amount of TCEP serves as a surrogate reagent to passivate the LC column and eliminate the on-column degradation/oxidation. As a result, a much more robust performance is achieved with greatly improved method precision and sensitivity. This is a general approach and can be applied to the LC analysis of many other phosphine ligands in the same manner. [ABSTRACT FROM AUTHOR]

The addition of Na[BArF24] (BArF24 = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) to [Pd(PP)Cl2] (PP = 1,1′-bis(phosphino)ferrocene ligands) compounds results in the loss of a chloride ligand and the formation of the dimeric species [Pd2(PP)2(μ-Cl)2][BArF24]2. In most cases, the addition of a monodentate phosphine, PR3, to these dimeric species leads to cleaving of the dimer and formation of [Pd(PP)(PR3)Cl][BArF24]. While these reactions are readily observed via a significant color change, the 31P{1H} NMR spectra offer more significant support, as the singlet for the dimer is replaced with three doublets of doublets. The reaction seems to take place for a wide range of PR3 ligands, although there do appear to be steric limitations to the reaction. The compounds were thoroughly characterized by NMR, and X-ray crystal structures of several of the compounds were obtained. In addition, the ferrocenyl backbone of the 1,1′-bis(phosphino)ferrocene ligands provides an opportunity to examine the oxidative electrochemistry of these compounds. In general, the potential at which oxidations of these compounds occurs shows a dependence on the phosphine substituents. [ABSTRACT FROM AUTHOR]

Phosphine ligands play a crucial role in homogeneous catalysis, allowing fine-tuning of the catalytic activity of various metals by modifying their structure. An ultimate challenge in this field is to reach controlled modulation of catalysis in situ, for which the development of phosphines capable of photoswitching between states with differential electronic properties has been proposed. To magnify this lightinduced behavior, in this work we describe a novel phosphine ligand incorporating two dithienylethene photoswitchable moieties tethered to the same phosphorus atom. Double photoisomerization was observed for this ligand, which remains unhindered upon gold(I) complexation. As a result, the preparation of a fully ring-closed phosphine isomer was accomplished, for which amplified variation of phosphorus electron density was verified both experimentally and by computational calculations. Accordingly, the presented molecular design based on multiphotochromic phosphines could open new ways for preparing enhanced photoswitchable catalytic systems. [ABSTRACT FROM AUTHOR]

Alkylation of N‐substituted imidazoles ImR' (R'=2,4,6‐trimethylphenyl, 2,6‐diisopropylphenyl, 1‐adamantyl) with Mn(I) methylenephosphonium complexes [Cp(CO)2Mn(η2‐P,C‐R2P=C(H)Ph)](BF4) (PR2=PPh2, PCy2, trans‐PC(H)PhCH2CH2C (H)Ph) followed by photochemical demetallation afforded a series of bidentate NHC‐phosphine ligand precursors [R2PC(H)PhImR'](BF4) in moderate to good yield. The same strategy was successfully applied to N‐functionalized imidazoles ImL (L=2‐pyridyl, CH2SMe, CH2ImMe) to afford selectively NHC core pincer pre‐ligands featuring phosphine/thioether, phosphine/NHC and phosphine/pyridine side arms. For PCy2 derivatives, free NHCs in both bidentate and pincer series generated by deprotonation of the corresponding cationic precursors were shown to be persistent at room temperature. [ABSTRACT FROM AUTHOR]

Two different alkynyl-substituted C3-symmetric cyclotribenzylenes (CTB) were synthesized in racemic and enantiomerically pure forms, and six gold(I) phosphine complexes differing by the nature of the CTB and the phosphine were prepared and characterized, in particular by NMR spectroscopy, DOSY, electronic circular dichroism (ECD), and electrospray ionization mass spectrometry (ESI-MS). Their ECD patterns depended on the substitution of the starting CTBs and were shifted bathochromically by comparison with the latter. ESI-MS in the presence of HCO2H allowed us to detect the complexes as proton adducts. The intensities of the signals were stronger when the phosphine was more electron-rich. This technique was also used to investigate the exchange of phosphine betweeen pairs of CTB complexes. The scrambling reaction was demonstrated by the higher intensity of the signals of the complexes subjected to the exchange of a single phosphine ligand by comparison with the intensity of the signals of the starting complexes. [ABSTRACT FROM AUTHOR]

Phosphine‐functionalized metal‐organic frameworks (P‐MOFs) as an emerging class of coordination polymers, have provided novel opportunities for the development of heterogeneous catalysts. Yet, compared with the ubiquitous phosphine systems in homogeneous catalysis, heterogenization of phosphines in MOFs is still at its early stage. In this Minireview, we summarize the synthetic strategies, characterization and catalytic reactions based on the P‐MOFs reported in literature. In particular, various catalytic reactions are discussed in detail in terms of phosphine ligand structure‐function relationship, including the potential obstacles for future development. Finally, we discuss the possible solutions, including new types of reactions and techniques as the perspectives for the development of P‐MOF catalysts, highlighting the opportunities and challenges. [ABSTRACT FROM AUTHOR]

A convenient protocol for the synthesis of 25,26,27-tribenzoyl-28-[((S)-1-diphenylphos- phanyl-propan-2-yl)oxy]-calix[4]arene via stereospecific methylation on Evans' oxazolidinone moiety was reported. According to the 13C NMR analysis of this phosphine, the calix[4]arene skeleton adopted a 1,3-alternate conformation. The latter conformation of the macrocycle and the (S)-chirality of the carbon atom bearing the methyl substituent were confirmed by a single-crystal X-ray diffraction study. After coordination of the phosphinated ligand to the dimeric [RuCl2(p-cymene)]2 organometallic precursor, the resulting arene–ruthenium complex was tested in the asymmetric reduction of acetophenone and alcohol was obtained with modest enantiomeric excess. [ABSTRACT FROM AUTHOR]

Atropisomeric phosphines hold considerable significance in asymmetric catalysis, yet their synthesis presents a formidable challenge owing to intricate multistep procedures. In this context, a groundbreaking methodology has been presented for their preparation. This innovative approach entails an atroposelective rhodium‐catalyzed C−H activation employing aryl and heteroaryl halides, chelated by a P(III) center. The essence of this strategy lies in its ability to directly construct chiral phosphine ligands in a single step, thereby exhibiting exceptional efficiency in terms of atom and redox economy. Illustrative examples serve to demonstrate the immense potential of in situ‐formed ligands in asymmetric catalysis. Mechanistic experiments have further provided invaluable insights into this transformation. [ABSTRACT FROM AUTHOR]

Trifluoromethylphosphines (TFMPhos) represent a rare kind of phosphine with unique electronic properties that result in unusual reactivities, such as the ability to promote a reductive elimination step or as a trifluoromethylation reagent. This concept article summarizes current developments in methods for synthesizing this tertiary phosphine, as well as their practical applications. [ABSTRACT FROM AUTHOR]

Catalysis of O‐atom transfer (OAT) reactions is a characteristic of both natural (enzymatic) and synthetic molybdenum‐oxo and ‐peroxo complexes. These reactions can employ a variety of terminal oxidants, e. g. DMSO, N‐oxides, and peroxides, etc. but rarely molecular oxygen. Here we demonstrate the ability of a set of Schiff‐base‐MoO2 complexes (cy‐salen)MoO2 (cy‐salen=N,N'‐cyclohexyl‐1,2‐bis‐salicylimine) to catalyze the aerobic oxidation of PPh3. We also report the results of a DFT computational investigation of the catalytic pathway, including the identification of energetically accessible intermediates and transition states, for the aerobic oxidation of PMe3. Starting from the dioxo species, (cy‐salen)Mo(VI)O2 (1), key reaction steps include: 1) associative addition of PMe3 to an oxo‐O to give LMo(IV)(O)(OPMe3) (2); 2) OPMe3 dissociation from 2 to produce mono‐oxo complex (cy‐salen)Mo(IV)O (3); 3) stepwise O2 association with 3 via superoxo species (cy‐salen)Mo(V)(O)(η1‐O2) (4) to form the oxo‐peroxo intermediate (cy‐salen)Mo(VI)(O)(η2‐O2) (5); 4) the O‐transfer reaction of PMe3 with oxo‐peroxo species 5 at the oxo‐group, rather than the peroxo unit leading, after OPMe3 dissociation, to a monoperoxo species, (cy‐salen)Mo(IV)(η2‐O2) (7); and 5) regeneration of the dioxo complex (cy‐salen)Mo(VI)O2 (1) from the monoperoxo triplet 37 or singlet 17 by a concerted, asynchronous electronic isomerization. An alternative pathway for recycling of the oxo‐peroxo species 5 to the dioxo‐Mo 1 via a bimetallic peroxo complex LMo(O)‐O−O‐Mo(O)L 8 is determined to be energetically viable, but is unlikely to be competitive with the primary pathway for aerobic phosphine oxidation catalyzed by 1. [ABSTRACT FROM AUTHOR]

The reaction of (ortho-acetalaryl)arylmethanols with various phosphines PR1R2R3 (R1 = R2 = R3 = Ph; R1 = R2 = Ph, R3 = Me and R1 = R2 = Me, R3 = Ph) under acidic conditions (e.g., HCl, HBF4, TsOH) unexpectedly led to the formation of (10-hydroxy-9,10-dihydroanthr-9-yl)phosphonium salts instead of the corresponding anthryl phosphonium salts. The cyclization occurred according to the Friedel–Crafts mechanism but without the usually observed Bradsher dehydration, giving cyclic products in the form of cis/trans isomers and their conformers. In case of electron-rich and less-hindered dimethylphenylphosphine, all four stereoisomers were recorded in 31P{1H} NMR spectra, while for the other phosphines, only the two most stable cis/trans stereoisomers were detected. This study was supported by DFT and NCI calculations in combination with FT-IR analysis. [ABSTRACT FROM AUTHOR]

The reaction of arylidene-α-amino esters with electrophilic alkenes to yield Michael-type addition compounds is optimized using several phosphines as organocatalysts. The transformation is very complicated due to the generation of several final compounds, including those derived from the 1,3-dipolar cycloadditions. For this reason, the selection of the reaction conditions is a very complex task and the slow addition of the acrylic system is very important to complete the process. The study of the variation in the structural components of the starting imino ester is performed as well as the expansion of other electron-poor alkenes. The crude products have a purity higher than 90% in most cases without any purification. A plausible mechanism is detailed based on the bibliography and the experimental results. The synthesis of pyroglutamate entities, after the reduction of the imino group and cyclization, is performed in high yields. In addition, the hydrolysis of the imino group, under acidic media, represents a direct access to glutamate surrogates. [ABSTRACT FROM AUTHOR]

In an attempt to understand the findings presented in the Comment by Greaves et al. (2023, https://doi.org/10.1029/2023GL103539), we followed their data analysis methodology, omitting the hot and cold‐load calibrations that are an important part of the standard SOFIA GREAT instrument calibration procedure. This process requires scaling of the Venus off‐source spectra by an arbitrary factor, which in turn introduces residuals of the intrinsic receiver bandpass shape as spurious components in the resulting line/continuum spectra. Although these additional artifacts can be reduced via Fourier‐domain spectral filtering, their removal depends on an ill‐constrained interpolation of the Venus continuum across the PH3 spectral line positions, resulting in an unreliable final spectrum. We therefore conclude that the PH3 lines claimed to be detected in the Comment by Greaves et al. (2023, https://doi.org/10.1029/2023GL103539) originate from data/analysis artifacts, and confirm our original result that there is no evidence for phosphine in the SOFIA Venus data. Plain Language Summary: We performed observations using a unique, flying telescope—the Stratospheric Observatory for Infrared Astronomy (SOFIA)—to search for a gas called phosphine in the atmosphere of Venus, which has been suggested to be an indicator for life. The observations, published by Cordiner et al. (2022, https://doi.org/10.1029/2022gl101055), were analyzed carefully but showed no evidence of phosphine. Our findings were called into question in the Comment by Greaves et al. (2023, https://doi.org/10.1029/2023GL103539), who claimed to find phosphine lines in the SOFIA observations after following an unconventional data analysis method. We have investigated their method, and conclude that it is likely to introduce spurious signals into the data, so the claimed phosphine detection is therefore not significant. Key Points: The revised calibration procedure adopted by Greaves et al. (2023, https://doi.org/10.1029/2023GL103539) introduces additional receiver artifacts into the SOFIA 4G2 Venus spectraThe claimed PH3 detection is likely a result of this, combined with interpolation artifacts that occur during subsequent Fourier filteringWe confirm our original conclusion that there is no evidence for phosphine in the SOFIA GREAT Venus data [ABSTRACT FROM AUTHOR]

Searches for phosphine in Venus' atmosphere have sparked a debate. Cordiner et al. (2022, https://doi.org/10.1029/2022gl101055) analyze spectra from the Stratospheric Observatory For Infrared Astronomy (SOFIA) and infer <0.8 ppb of PH3. We noticed that some spectral artifacts arose from non‐essential calibration‐load signals. By‐passing these signals allows simpler post‐processing and a 5.7σ candidate detection, suggesting ∼3 ppb of PH3 above the clouds. Compiling six phosphine results hints at an inverted abundance trend: decreasing above the clouds but rising again in the mesosphere from some unexplained source. However, no such extra source is needed if phosphine is undergoing destruction by sunlight (photolysis), to a similar degree as on Earth. Low phosphine values/limits are found where the viewed part of the super‐rotating Venusian atmosphere had passed through sunlight, while high values are from views moving into sunlight. We suggest Venusian phosphine is indeed present, and so merits further work on models of its origins. Plain Language Summary: Cordiner et al. (2022, https://doi.org/10.1029/2022gl101055) find no phosphine in Venus' atmosphere, using the airborne SOFIA telescope. By‐passing some instrumental effects, we extract a detection with 5.7σ‐confidence from the same data. We can resolve the tension between high and low PH3 abundance values by noticing that the former are from "mornings" in Venus' atmosphere and the latter from "evenings." Sunlight reduces the amount of phosphine in Earth's atmosphere by an order of magnitude, so similarly on Venus, we might expect lower abundances in data taken when the part of the atmosphere observed has passed through sunlight. If the six available data sets can be reconciled in this way, further modeling of possible sources of PH3 (e.g., volcanic, disequilibrium chemistry, extant life) seem worthwhile. Key Points: We recover Venusian phosphine in SOFIA spectra by reducing contaminating signals; the PH3 abundance is ∼3 part‐per billion (ppb)Six recoveries/limits show PH3 depleting between clouds and mesosphere, which would require an unknown re‐formation process or extra sourceRecoveries and upper limits can instead be reconciled by PH3 photolysis, as high/low abundances correspond to Venusian mornings/evenings [ABSTRACT FROM AUTHOR]

Under phosphine catalysis facilitated through desilylation, intramolecular annulation/nucleophilic addition of trimethylsilylethynyl benzoxazinanones with electron‐deficient imines or alkenes was achieved to afford a series of indole derivatives in moderate to high yields. The trimethylsilylethynyl benzoxazinanones without electron‐withdrawing group on the alkyne moiety functioned as phosphine acceptors. Notably, the distinctive desilylation activation played a key role in catalytic process. Particularly, those indole derivatives could be readily transformed into various biologically significant γ‐carboline compounds. The use of chiral phosphine achieved asymmetric reaction, leading to a 95% ee of product. [ABSTRACT FROM AUTHOR]

This work reports on ligand exchange reactions between a [FeFe] hydrogenase model containing the higher homologue (PhosDT) and phosphines selected to cover a variety of electronic properties and possible coordination modes. Additionally, the amount of the phosphines and the reaction temperature were varied to study the formation of complexes with multiple phosphines or altered binding modes. Due to steric effects caused by the position of the bridgehead, the phosphines bind preferentially at the more accessible iron centre on the phosphinate averted side. While all ligand exchanges resulted in a ligand‐specific main product at room temperature, reflux conditions induced decomposition in case of PhosDT‐(κ2‐dppe) and PhosDT‐(κ2‐dppv) and a change in the binding mode for the dppm containing complex. Moreover, we highlight two novel iron complexes obtained as side products of the reactions with dppe and dppv, while in case of dppm an additional model with two bridging phosphine ligands was generated. Finally, the six novel phosphine substituted PhosDT models were electrochemically investigated, revealing a cathodic shift compared to the starting material due to the increased electron density at the iron atoms. Moreover, the models with monodentate ligands exhibit a different CV pattern for the FeIFeI/FeIFe0 process than complexes with bidentate phosphines. [ABSTRACT FROM AUTHOR]

A series of coinage metal complexes bearing rarely explored ortho-silylated phosphine is reported. The treatment of diphenyl(2-(trimethylsilyl)phenyl)phosphine (1) with CuCl and [Cu(CH3CN)4]BF4 furnished the corresponding neutral [(1)CuCl]2 (2) and mono-cationic [(1)2Cu(CH3CN)]BF4 (3) complexes, respectively. The reactions of 1 with AgX (X = BF4−, NO3−) in 2 : 1 ratio furnished the corresponding mono cationic dicoordinate silver(I) complexes of the type [(1)2Ag]X (X = BF4− (4a), NO3− (4b)). The ortho-silylated phosphine ligand (1) was conveniently converted into the corresponding sulfide (5a) and selenide (5b) species, and their reactions with [Cu(CH3CN)4]BF4 yielded mono-cationic, homoleptic tris(silylphosphinochalcogenide)copper(I) complexes of the type [(5a/5b)3Cu]BF4 (6a/6b). The molecular structures of 2–4 and 6 were established by single-crystal X-ray diffraction analysis. The copper complexes 2, 3, and 6a were employed as catalysts in azide–alkyne cycloaddition reactions. Among these complexes, 3 was extensively used in the preparation of various mono- and bis-triazoles consisting of tolyl, benzyl, carbazolyl, and propargylic ether groups. Three sets of substituted triazole derivatives were achieved under mild conditions by employing copper(I) catalytic systems. The mechanistic studies indicated the formation of a heteroleptic copper(I) triazolide intermediate which was detected by high-resolution mass spectral analysis. [ABSTRACT FROM AUTHOR]

The rice weevil, Sitophilus oryzae (Linnaeus, Coleoptera: Curculionidae), is a serious cosmopolitan pest that affects grain in storage and has developed high levels of resistance toward phosphine. In this study, RNA-seq data was used to study the phosphine resistance mechanisms in S. oryzae. Resistant and susceptible populations of S. oryzae were identified based on phosphine bioassays conducted in 32 populations collected across Tamil Nadu, India. Differential expression of mitochondrial (COX1, COX2, COX3, ND2, ND3, ATP6 , and ATP8) and detoxification genes (Cyps , Gsts , and Cbe) were observed in the resistant and susceptible populations of S. oryzae. The previously characterized phosphine resistant gene, dld (dihydrolipoamide dehydrogenase) linked to the rph2 locus, was found to be up-regulated in resistant S. oryzae population (ISO-TNAU-RT) treated with phosphine. Also, the genes involved in Tricarboxylic acid (TCA) cycle were significantly down-regulated. In addition, a significant up-regulation in the expression of the antioxidant enzymes superoxide dismutase (2.5×) and catalase (2.1×) in ISO-TNAU-RT populations was recorded. Furthermore, a distinct amino acid substitution, Lysine > Glutamic acid (K141E) was identified in resistant phenotypes. In silico docking studies of both resistant and susceptible DLD protein with phosphine molecule revealed that the amino acid residues involved in the interaction were different. This suggested that the amino acid substitution might lead to structural modifications which reduces the affinity of the target (phosphine). This study provides insight on the various genes, pathways, and functional mechanisms having a significant role in phosphine resistance in S. oryzae. [ABSTRACT FROM AUTHOR]

The phosphino‐phosphonium cations of the form [R3PPR′2]+ are labile and provide access to the constituent Lewis acidic and Lewis basic fragments. This permits frustrated Lewis pair‐type addition reactions to alkynes, affording unprecedented phosphino‐phosphination reactions and giving cations of the form [cis‐R3PCHC(R′′)PR′2]+. This reactivity is further adapted to prepare several examples of a rare class of dissymmetric cis‐olefin‐linked bidentate phosphines. [ABSTRACT FROM AUTHOR]

For the heterogeneous reaction of asymmetric hydroformylation (AHF), a highly decentralized active Rh site played a key role in enhancing the yield of chiral isomeric aldehydes. Herein, the mesoporous Rh-loaded catalyst (Rh@MOF-5) was prepared using a zinc-based metal--organic framework (MOF-5) to serve as a carrier. During the AHF reaction, the HRh(BINAP)(CO)2 component was formed by the combination of active Rh in Rh@MOF-5 and (R)-BINAP under a syngas atmosphere (H2/CO = 1). The Rh@MOF-5 showed a higher yield of iso-aldehydes (Yiso = 86.71%) and enantioselectivity (ee = 25.01%) of S-iso-aldehydes, which was attributed to the synergy of BINAP and the highly dispersed active Rh sites. Furthermore, density functional theory (DFT) calculation results show the feasible mechanism of HRh(BINAP)(CO)2 catalyzed with 6 steps, and the Rh--H insertion step determined the type of product. The higher enantioselectivity and regioselectivity of S-iso-aldehydes using this catalyst were due to the lower barrier of the S-iso-aldehyde precursor than other product precursors in the step of Rh--H insertion. [ABSTRACT FROM AUTHOR]

1,8‐Naphthalimides (NIs) represent a class of organic dyes with interesting optical properties that has been extensively explored in the last decades in lighting devices, chemosensors, optical probes or medicinal chemistry. However, despite their remarkable potential, reports on organometallic dyes bearing NIs are scarce and virtually inexistent regarding palladium(II) complexes. Herein, we report the synthesis of NIs bearing phosphine and amine chelating moieties and the characterization of their optical properties both as single molecules and when complexed on Pd(II) ions. It is shown that the introduction of phosphine moieties in the naphthalimide core results in a marked increase in non‐radiative processes, leading to a significant reduction of the emission efficiency and lifetime of these dyes, compared to amine‐bearing counterparts. The complexation to Pd(II) sequesters the electronic contribution of chelating moieties, with complexes assuming an optical behavior similar to that of unsubstituted 1,8‐naphthalimide. The complexation significantly increases the acidity of chelating secondary amines, giving rise to an unexpected intramolecular reaction that results in the formation of a novel 1,8‐naphthalimide dye bearing a cyclic phosphorylamide moiety. The new dye exhibits good emission quantum yield, long fluorescence lifetime and sensitivity to basic media, evidencing potential for application in optical imaging and sensing scenarios. [ABSTRACT FROM AUTHOR]

The asymmetric hydrophosphination of cyclopropenes with phosphines is of much interest and importance, but has remained hardly explored to date probably because of the lack of suitable catalysts. We report here the diastereo‐ and enantioselective hydrophosphination of 3,3‐disubstituted cyclopropenes with phosphines by a chiral lanthanocene catalyst bearing the C2‐symmetric 5,6‐dioxy‐4,7‐trans‐dialkyl‐substituted tetrahydroindenyl ligands. This protocol offers a selective and efficient route for the synthesis of a new family of chiral phosphinocyclopropane derivatives, featuring 100 % atom efficiency, good diastereo‐ and enantioselectivity, broad substrate scope, and no need for a directing group. [ABSTRACT FROM AUTHOR]

A general synthetic entryway into novel cationic Pd(II) indenyl complexes bearing one alkyl/aryl phosphine and one N‐heterocyclic carbene is reported. All metal complexes have been exhaustively characterized by spectroscopic and structural analyses, highlighting that the indenyl fragment has an hapticity intermediate between η3 and η5. Most of the target complexes are stable in solid state and in solution for a long time. Two different applications of these organopalladium compounds are proposed. Firstly, they have been tested as antiproliferative agents towards three different ovarian cancer cell lines, showing a cytotoxicity significantly higher than that of cisplatin, with a clear dependence on the nature of the coordinated phosphine. Moreover, the similar cytotoxicity towards cisplatin‐sensitive and cisplatin‐resistant cell lines suggests that these new palladium derivatives act with a different mechanism of action with respect to classical platinum‐based drugs. Finally, the water‐soluble palladium complexes bearing 1,3,5‐triaza‐7‐phosphaadamantane (PTA) have demonstrated interesting catalytic performances in Suzuki–Miyaura coupling in aqueous media, being, inter alia, readily and efficiently recyclable. [ABSTRACT FROM AUTHOR]

[Display omitted] A new efficient synthesis of racemic (R *, R *)-Pyrphos ligand based on aza-Michael addition reaction of 2,3-bis(di- phenylphosphoryl)buta-1,3-diene with ammonia followed by the reduction of resulting 3,4-bis(diphenylphosphoryl)- pyrrolidine is proposed. The starting reactants are available but-2-yne-1,4-diol and chloro(diphenyl)phosphine. [ABSTRACT FROM AUTHOR]

Despite the growing importance of fluorinated organic compounds in pharmaceuticals, agrochemicals, and materials science, the introduction of fluorine into organic molecules is still a challenge, and no catalytic fluorocarbonylation of aryl/alkyl boron compounds has been reported to date. Herein, we present the development of palladium and phosphine synergistic redox catalysis of fluorocarbonylation of potassium aryl/alkyl trifluoroborate. Trifluoromethyl arylsulfonate (TFMS), which was used as a trifluoromethoxylation reagent, an easily handled and bench-scale reagent, has been employed as an efficient source of COF2. The reaction operates under mild conditions with good to excellent yields and tolerates diverse complex scaffolds, which allows efficient late-stage fluorocarbonylation of marked small-molecule drugs. Mechanistically, the key intermediates of labile Brettphos-Pd(II)-OCF3 complex and difluoro-Brettphos were synthesized and spectroscopically characterized, including X-ray crystallography. A detailed reaction mechanism involving the synergistic redox catalytic cycles Pd(II)/(0) and P(III)/(V) was proposed, and multifunction of phosphine ligand was identified based on 19F NMR, isotope tracing, synthetic, and computational studies. Despite the growing importance of fluorinated organic compounds introduction of fluorine into organic molecules is still challenging. Here, the authors present the development of palladium and phosphine synergistic redox catalysis of fluorocarbonylation of potassium aryl/alkyl trifluoroborate. [ABSTRACT FROM AUTHOR]

A cavity‐shaped gold(I) complex derived from a bulky tri‐(ortho‐biaryl)‐phosphine ligand shows preferred selectivity towards terminal functionalities in the gold(I)‐catalysed hydration of alkynes under mild heating due to a well‐defined pocket as catalytic active site. The confinement‐induced size‐exclusion selectivity investigated for eight alkynes contrasts with other gold(I) complexes bearing bulky phosphine ligands that show reduced selectivity or even similar behaviour towards both internal and terminal alkynes. We also interrogate the potential of gold(III) derivatives for the same catalytic process. [ABSTRACT FROM AUTHOR]

The process of phosphine production by phosphate-reducing bacteria Pseudescherichia sp. SFM4 has been well studied. Phosphine originates from the biochemical stage of functional bacteria that synthesize pyruvate. Stirring the aggregated bacterial mass and supplying pure hydrogen could lead to an increase of 40 and 44% phosphine production, respectively. Phosphine was produced when bacterial cells agglomerated in the reactor. Extracellular polymeric substances secreted on microbial aggregates promoted the formation of phosphine due to the presence of groups containing phosphorus element. Phosphorus metabolism gene and phosphorus source analysis implied that functional bacteria used anabolic organic phosphorus, especially containing carbon-phosphorus bonds, as a source with [H] as electron donor to produce phosphine. [ABSTRACT FROM AUTHOR]

We present convenient syntheses of a range of PNP‐type phosphines which feature a pair of ortho‐functionalized ArPPh2 moieties linked via a central NMe unit, but which differ in the nature of the additional backbone 'tether' linking the aryl groups. These comprise the acyclic system bis(2‐diphenylphosphinophenyl)methylamine, together with related systems centred around 5‐, 6‐ and 7‐membered heterocycles. Structurally, contraction of the backbone tether causes the phosphine centres to be projected further apart, and to be more constrained torsionally to the plane containing the NMe unit. In terms of potential frustrated Lewis pair (FLP) reactivity, the conformationally more flexible systems based on an acyclic linker or a cyclic core featuring a 7‐membered ring, are capable of achieving P−B bond formation and generating a classical Lewis adduct with B(C6F5)3. The less flexible carbazole‐derived compound (featuring a five membered heterocyclic core) gives rise to an FLP at room temperature, and an equilibrium mixture of frustrated and classical Lewis pairs at lower temperatures. Most interestingly, the PNP system based on a central six‐membered acridine ring ‐ which gives rise to the shortest contacts in the solid state between phosphorus and the N‐bound methyl group – undergoes C−H activation in the presence of B(C6F5)3, resulting in the formation of B−H and P−C bonds. [ABSTRACT FROM AUTHOR]

Simple nucleophilic aliphatic substitution gives access to mono- and diphosphine ligands with a CpC group in the backbone. The monophosphine ligand coordinates to gold(I) via the phosphine site, to thallium(I) via the cyclopentadienyl site and to ruthenium(II) via a combination of both, resulting in an ansa-type structure. Coordination with the cyclopentadiene site is not possible for the diphosphine ligand. In this case, monodentate coordination to gold(I) and bidentate coordination to the [PdCl(μ2-Cl)]2, the [Rh(CO)(μ2-Cl)]2, and the Rh(CO)Cl fragment is observed, showing the variability in coordination modes possible for the long-chain diphosphine ligand. Ligands and complexes were characterized by means of NMR and IR spectroscopy, elemental analysis and X-ray structure analysis. [ABSTRACT FROM AUTHOR]

Dimethyl 2-vinylcyclopropane-1,1-dicarboxylate underwent a hydrophosphination reaction with either a primary or secondary phosphine under photolytic conditions. Notably, a free radical initiator was not required. The resulting tertiary phosphines were derivatized using S8 to afford moisture and air stable yellow or colorless oils in a 27%–73% isolated yield. A series of control reactions were performed, and we propose that this UV induced hydrophosphination reaction proceeds through a radical mechanism. [ABSTRACT FROM AUTHOR]

Transition metal coordination chemistry and catalysis are rife with phosphine ligands. One of the rather less studied members of the phosphine ligand family are phosphine aldehydes. We have synthesised 3-(diphenylphosphino)propanal (PCHO) with a slight modification of the known procedure and studied its complexation behaviour with palladium(II) and platinum(II). The catalytic activity of the palladium(II) phosphine aldehyde complexes was investigated in Cu-free Sonogashira and Suzuki–Miyaura cross-coupling reactions. Furthermore, the homogeneous nature of the catalytically active species was confirmed. [ABSTRACT FROM AUTHOR]

A palladium-catalysed aromative benzylic allylation and allenylation of benzyl chlorides with allyl and allenyl pinacolborates is described for the first time. The reactions proceed smoothly in the presence of a bidentate phosphine ligand to afford normal cross-coupling products in good yields. This novel synthetic procedure exhibits good tolerance for various electron-withdrawing and -donating functional groups linked to aromatic rings and is also well tolerant of sensitive functional groups such as NO2, CF3, CN, and COOMe. The utilisation of a bidentate ligand and heating are essential to transformation. The DFT calculation results reveal that wide-bite-angle bidentate ligands are beneficial to the formation of an η1-benzyl-η1-allylpalladium intermediate and that the normal coupling is thermodynamically favourable. [ABSTRACT FROM AUTHOR]

Bulky ylide‐substituted phosphines have recently found application as potent ligands in homogeneous catalysis. The attempted synthesis of the ylide‐substituted fluorenylphosphine YPhP(Cy)Flu [YPh=Cy3P(Ph)C; Flu=9‐methylfluorenyl] now resulted in the unexpected elimination of 9‐methylenefluorene during the deprotonation step of the intermediary α‐phosphino phosphonium salt to yield the secondary ylide‐substituted phosphine YPhP(Cy)H. This phosphine underwent formal H2 elimination under basic conditions to form a cyclic phosphonium ylide with a P−C−P−C four‐membered ring via deprotonation of one cyclohexyl group of the PCy3 moiety. Upon coordination to transition metals the secondary ylidylphosphine forms a neutral phosphide ligand by shift of the proton into the ylide‐backbone and formation of zwitterionic metal complexes. [ABSTRACT FROM AUTHOR]

Secondary phosphines are important building blocks in organic chemistry as their reactive P—H bond enables construction of more elaborate molecules. In particular, they can be used to construct tertiary phosphines that have widespread applications as organocatalysts, and as ligands in metal-complex catalysis. We report here a practical synthesis of the bulky secondary phosphine synthon 2,2,6,6-tetramethylphosphinane (TMPhos). Its nitrogen analogue tetramethylpiperidine, known for over a century, is used as a base in organic chemistry. We obtained TMPhos on a multigram scale from an inexpensive air-stable precursor, ammonium hypophosphite. TMPhos is also a close structural relative of di-tert-butylphosphine, a key component of many important catalysts. Herein we also describe the synthesis of key derivatives of TMPhos, with potential applications ranging from CO2 conversion to cross-coupling and beyond. The availability of a new core phosphine building block opens up a diverse array of opportunities in catalysis. Di-tert-butylphosphine is an important substituent in many phosphine ligands, however, its heterocyclic analogues have not yet been isolated. Here, the authors report the synthesis and isolation of 2,2,6,6-tetramethylphosphinane on a gram scale starting from ammonium hypophosphite, and its facile use as a building block in ligand construction. [ABSTRACT FROM AUTHOR]

Combination of a phosphinidene precursor, B(C6F5)3 and 4-ethynyltoluene afforded the FLP addition product, Et2N(C14H10)PC(Tol)＝CH (B(C6F5)3) 2. Compound 2 reacted with halides, pseudo-halides or Me3SiSPh to provide a facile route to the salts of anionic phosphines while reaction with PEt3 gave the zwitterion Et3PCH＝C(SiMe3)P(NEt2)C(Tol)＝CHB(C6F5)38. This latter species reacted with an alkyne to give a phosphine donor with both olefin-linked cationic and anionic substituents. [ABSTRACT FROM AUTHOR]

Thiourea‐based iminophosphorane (BIMP) organocatalysts featuring SPhos‐ or BIDIME phosphine units have been developed and successfully applied in the asymmetric addition of nitromethane to N‐Boc‐protected trifluoromethyl aryl ketimines. α‐Trifluoromethyl β‐nitroamines were obtained in 40–82% isolated yields and 80–95% enantioselectivities. A careful evaluation of the catalytic activity of BIMPs indicates that the catalysts derived from the combination via Staudinger reaction of a chiral 1,2‐amino alcohol‐derived thiourea‐organoazide with electron‐rich phosphines, promote the aza‐Henry reaction on fluorinated ketimines with the highest enantioselectivity, leading to the amine featuring a tetrasubstituted stereocenter in up to 95% ee. The reaction was performed also on gram scale, without loss of enantioselectivity. [ABSTRACT FROM AUTHOR]

In these studies, we designed and investigated cyto- and genotoxic potential of five ruthenium cyclopentadienyl complexes bearing different phosphine and phosphite ligands. All of the complexes were characterized with spectroscopic analysis (NMR, FT-IR, ESI-MS, UV-vis, fluorescence and XRD (for two compounds)). For biological studies, we used three types of cells – normal peripheral blood mononuclear (PBM) cells, leukemic HL-60 cells and doxorubicin-resistance HL-60 cells (HL-60/DR). We compared the results obtained with those obtained for the complex with maleimide ligand CpRu(CO)2(η1-N-maleimidato) 1, which we had previously reported. We observed that the complexes CpRu(CO)(PPh3)(η1-N-maleimidato) 2a and CpRu(CO)(P(OEt)3)(η1-N-maleimidato) 3a were the most cytotoxic for HL-60 cells and non-cytotoxic for normal PBM cells. However, complex 1 was more cytotoxic for HL-60 cells than complexes 2a and 3a (IC50 = 6.39 μM vs. IC50 = 21.48 μM and IC50 = 12.25 μM, respectively). The complex CpRu(CO)(P(OPh)3)(η1-N-maleimidato) 3b is the most cytotoxic for HL-60/DR cells (IC50 = 104.35 μM). We found the genotoxic potential of complexes 2a and 3a only in HL-60 cells. These complexes also induced apoptosis in HL-60 cells. Docking studies showed that complexes 2a and CpRu(CO)(P(Fu)3)(η1-N-maleimidato) 2b have a small ability to degrade DNA, but they may cause a defect in DNA damage repair mechanisms leading to cell death. This hypothesis is corroborated with the results obtained in the plasmid relaxation assay in which ruthenium complexes bearing phosphine and phosphite ligands induce DNA breaks. [ABSTRACT FROM AUTHOR]

Phosphines bearing guanidine substituents at the backbone are attractive hybrid ligands that have not yet received adequate attention. This paper describes group 11 metal complexes of a guanidine-substituted triphenylphosphine, viz., N′′-[2-(diphenylphosphino)phenyl]-N,N′-diisopropylguanidine (1). Reactions of 1 with Cu(I) and Ag(I) precursors yielded the P,N-chelate complexes [M(1-κ2P,N)2]X, where M/X = Cu/BF4, Cu/Br, Ag/SbF6 and Ag/Br. Conversely, reacting 1 and the hydrochloride 1·HCl with [AuCl(SMe2)] produced the corresponding phosphine complexes [AuCl(1-κP)] and [AuCl(1H-κP)]Cl, which were further converted into [{μ(P,N)-1}2Au2][SbF6]2 and [AuCl(1H-κP)][SbF6], respectively, by reacting with Ag[SbF6]. These compounds and the bis-phosphine complex [Au(1-κP)2][SbF6] were studied as precatalysts in the Au-mediated cyclisation of N-propargylbenzamide and the addition of benzoic acid across terminal alkynes. Of the Au(I)-1 complexes studied, the complex [{μ(P,N)-1}2Au2][SbF6]2 was particularly attractive as a stable and well-defined, silver-free precatalyst, which can be conveniently activated in situ by the addition of a protic acid (either as an additive or a substrate). [ABSTRACT FROM AUTHOR]

The synthesis of novel phosphine palladium PEPPSI and dimer complexes bearing RuPhos, SPhos and XPhos phosphines is reported. The crystal structures of XPhos Pd PEPPSI with pyridine, SPhos Pd PEPPSI with 3-chloropyridine as throw-away ligands and the RuPhos palladium dimer were obtained and compared with previously reported congeners. The catalytic activity of these novel complexes was examined via a C–N coupling reaction involving 4-chloroanisole and morpholine. RuPhos complex 2b proved most active, leading to 97% yield with a low (0.2 mol%) catalyst loading, while phosphine palladium dimers showed significantly lower catalytic activity. However, the addition of 3-pentanone as an activator/stabilizer significantly improved the yields of phosphine dimers and PEPPSI complexes when the reactions were performed in THF. [ABSTRACT FROM AUTHOR]

A new series of cationic heterodinuclear complexes, [M1M2Cl2(meso‐dpmppp)(RNC)2]PF6 (M1=Ni, M2=Rh, R=tBu (1 a); M1=Pd, M2=Rh, R=tBu (2 a), Xyl (2 b); M1=Pt, M2=Rh, R=tBu (3 a), Xyl (3 b); M1=Pd, M2=Ir, R=tBu (4 a)), supported by a tetradentate phosphine ligand, meso‐Ph2PCH2P(Ph)(CH2)3P(Ph)CH2PPh2 (meso‐dpmppp), were synthesized by stepwise reactions of meso‐dpmppp with NiCl2 ⋅ 6H2O or MCl2(cod) (M=Pd, Pt), forming mononuclear metalloligands of [M1Cl2(meso‐dpmppp)], and with [M2Cl(cod)]2 (M2=Rh, Ir) and RNC (R=tBu, Xyl) in the presence of [NH4][PF6]. The related neutral PdRh complex, [PdRhCl3(meso‐dpmppp)(XylNC)] (5), was also prepared. The structures of 1–5 were determined by X‐ray analyses to contain two square planar d8 metal centers with face‐to‐face arrangement, where meso‐dpmppp supports M1 and M2 metal ions in cis/trans‐P,P coordination mode, combining cis‐{M1P2Cl2} and trans‐{M2P2(CNR)2} units. Complexes 1–4 showed an intence characteristic absorption around 422–464 nm derived from RhI→RNC MLCT transition (HOMO→LUMO+1), which are influenced by changing M1 (NiII, PdII, PtII) metal ions since HOMO composed of dσ* orbitals appreciably destabilized by changing M1 from Ni to Pd, and Pt. The electronic structures of 1 a–4 a were investigated on the basis of DFT calculations and NBO analyses to show weak but noticeable d8–d8 metallophilic interaction as empirical dispersion energy of 0.9–1.5 kcal/mol without M1–M2 covalent bonding interaction. In addition, 1–5 were utilized as catalysts for hydrosilylation of styrene, and the NiRh complex 1 a was found to show higher activity and chemo‐ and regioselectivity compared with 2–5. [ABSTRACT FROM AUTHOR]