Markovnikov-Selective Cobalt-Catalyzed Wacker-Type Oxidation of Styrenes into Ketones under Ambient Conditions Enabled by Hydrogen Bonding

The replacement of palladium catalysts for Wacker-type oxidation of olefins into ketones by first-row transition metals is a relevant approach for searching more sustainable protocols. Besides highly sophisticated iron catalysts, all the other first-row transition metal complexes have only led to poor activities and selectivities. Herein, we show that the cobalt-tetraphenylporphyrin complex is a competent catalyst for the aerobic oxidation of styrenes into ketones with silanes as the hydrogen sources. Remarkably, under room temperature and air atmosphere, the reactions were exceedingly fast (up to 10 minutes) with a low catalyst loading (1 mol %) while keeping an excellent chemo- and Markovnikov-selectivity (up to 99 % of ketone). Unprecedently high TOF (864 h-1 ) and TON (5,800) were reached for the oxidation of aromatic olefins under these benign conditions. Mechanistic studies suggest a reaction mechanism similar to the Mukaiyama-type hydration of olefins with a change in the last fundamental step, which controls the chemoselectivity, thanks to a unique hydrogen bonding network between the ethanol solvent and the cobalt peroxo intermediate.

Iron-Catalyzed Intermolecular C-N Cross-Coupling Reactions via Radical Activation Mechanism

A concept for intermolecular C-N cross-coupling amination has been discovered using tetrazoles and aromatic and aliphatic azides with boronic acids under iron-catalyzed conditions. The amination follows an unprecedented metalloradical activation mechanism that is different from traditional metal-catalyzed C-N cross-coupling reactions. The scope of the reaction has been demonstrated by the employment of a large number of tetrazoles, azides, and boronic acids. Moreover, several late-stage aminations and a short synthesis of a drug candidate have been showcased for further synthetic utility. Collectively, this iron-catalyzed C-N cross-coupling should have wide applications in the context of medicinal chemistry, drug discovery, and pharmaceutical industries.

Reactivity of a Unique Si(I)-Si(I)-Based η2-Bis(silylene) Iron Complex

In this paper, we report the synthesis of a unique silicon(I)-based metalla-disilirane and report on its reactivity toward TMS-azide and benzophenone. Metal complexes containing disilylenes ((bis)silylenes with a Si–Si bond) are known, but direct ligation of the Si(I) centers to transition metals always generated dinuclear species. To overcome this problem, we targeted the formation of a mononuclear iron(0)–silicon(I)-based disilylene complex via templated synthesis, starting with ligation of two Si(II) centers to iron(II), followed by a two-step reduction. The DFT structure of the resulting η²-disilylene-iron complex reveals metal-to-silicon π-back donation and a delocalized three-center–two-electron (3c–2e) aromatic system. The Si(I)–Si(I) bond displays unusual but well-defined reactivity. With TMS-azide, both the initial azide adduct and the follow-up four-membered nitrene complex could be isolated. Reaction with benzophenone led to selective 1,4-addition into the Si–Si bond. This work reveals that selective reactions of Si(I)–Si(I) bonds are made possible by metal ligation.

The first selective ligation of a silicon(I)-based disilylene to a mononuclear metal center is achieved via templated synthesis. Computational analysis of the ensuing η²-disilylene-iron(0) complex supports a delocalized three-center−two-electron (3c−2e) aromatic system. The Si(I)−Si(I) bond displays well-defined reactivity toward trimethylsilyl azide and benzophenone. This work reveals that selective reactions of Si(I)−Si(I) bonds are made possible by metal ligation.

Atypical and Asymmetric 1,3-P,N Ligands: Synthesis, Coordination and Catalytic Performance of Cycloiminophosphanes

Novel seven-membered cyclic imine-based 1,3-P,N ligands were obtained by capturing a Beckmann nitrilium ion intermediate generated in situ from cyclohexanone with benzotriazole, and then displacing it by a secondary phosphane under triflic acid promotion. These "cycloiminophosphanes" possess flexible non-isomerizable tetrahydroazepine rings with a high basicity; this sets them apart from previously reported iminophophanes. The donor strength of the ligands was investigated by using their P-κ1 - and P,N-κ2 -tungsten(0) carbonyl complexes, by determining the IR frequency of the trans-CO ligands. Complexes with [RhCp*Cl2 ]2 demonstrated the hemilability of the ligands, giving a dynamic equilibrium of κ1 and κ2 species; treatment with AgOTf gives full conversion to the κ2 complex. The potential for catalysis was shown in the RuII -catalyzed, solvent-free hydration of benzonitrile and the RuII - and IrI -catalyzed transfer hydrogenation of cyclohexanone in isopropanol. Finally, to enable access to asymmetric catalysts, chiral cycloiminophosphanes were prepared from l-menthone, as well as their P,N-κ2 -RhIII and a P-κ1 -RuII complexes.

Effect-directed analysis and chemical identification of agonists of peroxisome proliferator-activated receptors in white button mushroom

Obesity has a serious effect on human health. It relates to metabolic syndrome, including the associated disorders such as type 2 diabetes, heart disease, stroke and hyperemia. The peroxisome proliferator-activated receptors (PPARs) are important receptors to control fat metabolism in the human body. Because of the safety concerns of synthetic drugs targeting PPARs, ligands from natural sources have drawn interest. Earlier, we have found high PPAR activities in extracts from Agaricus bisporus (white button mushroom, WBM). WBM contains a wide range of candidate compounds which could be agonists of PPARs. To identify which compounds are responsible for PPAR activation by WBM extracts, we used fractionation coupled to effect-directed analysis with reporter gene assays specific for all three PPARs for purification and LC/MS-TOF and NMR for compound identification in purified active fractions. Surprisingly, we identified the relatively common dietary fatty acid, linoleic acid, as the main ligand of PPARs in WBM. Possibly, the relatively low levels of linoleic acid in WBM are sufficient and instrumental in inducing its anti-obesogenic effects, avoiding high energy intake and negative health effects associated with high levels of linoleic acid consumption. However, it could not be excluded that a minor relatively potent compound contributes towards PPAR activation, while the anti-obesity effects of WBM may be further enhanced by receptor expression modulating compounds or compounds with completely PPAR unrelated modes of action.

Photoinduced and Thermal Single-Electron Transfer to Generate Radicals from Frustrated Lewis Pairs

Archetypal phosphine/borane frustrated Lewis pairs (FLPs) are famed for their ability to activate small molecules. The mechanism is generally believed to involve two-electron processes. However, the detection of radical intermediates indicates that single-electron transfer (SET) generating frustrated radical pairs could also play an important role. These highly reactive radical species typically have significantly higher energy than the FLP, which prompted this investigation into their formation. Herein, we provide evidence that the classical phosphine/borane combinations PMes3 /B(C6 F5 )3 and PtBu3 /B(C6 F5 )3 both form an electron donor-acceptor (charge-transfer) complex that undergoes visible-light-induced SET to form the corresponding highly reactive radical-ion pairs. Subsequently, we show that by tuning the properties of the Lewis acid/base pair, the energy required for SET can be reduced to become thermally accessible.

Performance of TDDFT Vertical Excitation Energies of Core-Substituted Naphthalene Diimides

We have evaluated the performance of various density functionals, covering generalized gradient approximation (GGA), global hybrid (GH) and range‐separated hybrid (RSH), using time dependent density functional theory (TDDFT) for computing vertical excitation energies against experimental absorption maximum (λ_max) for a set of 10 different core‐substituted naphthalene diimides (cNDI) recorded in dichloromethane. The computed excitation in case of GH PBE0 is most accurate while the trend is most systematic with RSH LCY‐BLYP compared to λ_max. We highlight the importance of including solvent effects for optimal agreement with the λ_max. Increasing the basis set size from TZ2P to QZ4P has a negligible influence on the computed excitation energies. Notably, RSH CAMY‐B3LYP gave the least error for charge‐transfer excitation. The poorest agreement with λ_max is obtained with semi‐local GGA functionals. Use of the optimally‐tuned RSH LCY‐BLYP* is not recommended because of the high computational cost and marginal improvement in results.

Distortion-Controlled Redshift of Organic Dye Molecules

It is shown, quantum chemically, how structural distortion of an aromatic dye molecule can be leveraged to rationally tune its optoelectronic properties. By using a quantitative Kohn-Sham molecular orbital (KS-MO) approach, in combination with time-dependent DFT (TD-DFT), the influence of various structural and electronic tuning parameters on the HOMO-LUMO gap of a benzenoid model dye have been investigated. These parameters include 1) out-of-plane bending of the aromatic core, 2) bending of the bridge with respect to the core, 3) the nature of the bridge itself, and 4) π-π stacking. The study reveals the coupling of multiple structural distortions as a function of bridge length and number of bridges in benzene to be chiefly responsible for a decreased HOMO-LUMO gap, and consequently, red-shifting of the absorption wavelength associated with the lowest singlet excitation (λ≈560 nm) in the model cyclophane systems. These physical insights together with a rational approach for tuning the oscillator strength were leveraged for the proof-of-concept design of an intense near-infrared (NIR) absorbing cyclophane dye at λ=785 nm. This design may contribute to a new class of distortion-controlled NIR absorbing organic dye molecules.

New Insights in Frustrated Lewis Pair Chemistry with Azides

The geminal frustrated Lewis pair (FLP) tBu2 PCH2 BPh2 (1) reacts with phenyl-, mesityl-, and tert-butyl azide affording, respectively, six, five, and four-membered rings as isolable products. DFT calculations revealed that the formation of all products proceeds via the six-membered ring structure, which is thermally stable with an N-phenyl group, but rearranges when sterically more encumbered Mes-N3 and tBu-N3 are used. The reaction of 1 with Me3 Si-N3 is believed to follow the same course, yet subsequent N2 elimination occurs to afford a four-membered heterocycle (5), which can be considered as a formal FLP-trimethylsilylnitrene adduct. Compound 5 reacts with hydrochloric acid or tetramethylammonium fluoride and showed frustrated Lewis pair reactivity towards phenylisocyanate.

Rational design of near-infrared absorbing organic dyes: Controlling the HOMO-LUMO gap using quantitative molecular orbital theory

Principles are presented for the design of functional near‐infrared (NIR) organic dye molecules composed of simple donor (D), spacer (π), and acceptor (A) building blocks in a D‐π‐A fashion. Quantitative Kohn–Sham molecular orbital analysis enables accurate fine‐tuning of the electronic properties of the π‐conjugated aromatic cores by effecting their size, including silaaromatics, adding donor and acceptor substituents, and manipulating the D‐π‐A torsional angle. The trends in HOMO–LUMO gaps of the model dyes correlate with the excitation energies computed with time‐dependent density functional theory at CAMY‐B3LYP. Design principles could be developed from these analyses, which led to a proof‐of‐concept linear D‐π‐A with a strong excited‐state intramolecular charge transfer and a NIR absorption at 879 nm. © 2018 The Authors. Journal of Computational Chemistry published by Wiley Periodicals, Inc.

A New Mode of Chemical Reactivity for Metal-Free Hydrogen Activation by Lewis Acidic Boranes

We herein explore whether tris(aryl)borane Lewis acids are capable of cleaving H2 outside of the usual Lewis acid/base chemistry described by the concept of frustrated Lewis pairs (FLPs). Instead of a Lewis base we use a chemical reductant to generate stable radical anions of two highly hindered boranes: tris(3,5-dinitromesityl)borane and tris(mesityl)borane. NMR spectroscopic characterization reveals that the corresponding borane radical anions activate (cleave) dihydrogen, whilst EPR spectroscopic characterization, supported by computational analysis, reveals the intermediates along the hydrogen activation pathway. This radical-based, redox pathway involves the homolytic cleavage of H2 , in contrast to conventional models of FLP chemistry, which invoke a heterolytic cleavage pathway. This represents a new mode of chemical reactivity for hydrogen activation by borane Lewis acids.

Parallels between Metal-Ligand Cooperativity and Frustrated Lewis Pairs

Metal ligand cooperativity (MLC) and frustrated Lewis pair (FLP) chemistry both feature the cooperative action of a Lewis acidic and a Lewis basic site on a substrate. A lot of work has been carried out in the field of FLPs to prevent Lewis adduct formation, which often reduces the FLP reactivity. Parallels are drawn between the two systems by looking at their reactivity with CO₂, and we explore the role of steric bulk in preventing dimer formation in MLC systems.

Construction of alkyl-substituted pentaphosphido ligands in the coordination sphere of cobalt

Rare mono- and diorganopentaphosphido cobalt complexes are accessible by P-P condensation using the unprecedented, reactive cobalt-gallium tetraphosphido complex [K(dme)₂{(^MesBIAN)Co(μ-η⁴:η²-P₄)Ga(nacnac)}] (2). Compound 2 was prepared in good yield by reaction of [K(Et₂O){(^MesBIAN)Co(η⁴-1,5-cod)}] [1, BIAN = bis(mesitylimino)acenaphthene diimine, cod = 1,5-cyclooctadiene] with [Ga(nacnac)(η²-P₄)] (nacnac = CH[CMeN(2,6-iPr₂C₆H₃)]₂). Reactions with R₂PCl (R = iPr, tBu, and Cy) selectively afford [(^MesBIAN)Co(cyclo-P₅R₂)] (3a-c), which feature η⁴-coordinated 1,1-diorganopentaphosphido ligands. The mechanism of formation of these species has been studied by ³¹P{¹H} NMR spectroscopy and DFT calculations. In the case of 3a (R = iPr), it was possible to identify the intermediate [(^MesBIAN)Co(μ-η⁴:η²-P₅iPr₂)Ga(nacnac)] (4) by single-crystal X-ray diffraction. A related, monosubstituted organopentaphosphido cobalt complex [(^MesBIAN)Co(μ-η⁴:η¹-P₅ tBu)GaCl(nacnac)] (5) was isolated by reacting dichloroalkylphosphane tBuPCl₂ with 2. Heterobimetallic complexes such as 2 thus may enable the targeted construction of a range of new metal-coordinated polyphosphorus frameworks by P-P condensation.

Synthesis of a Cyclic Co2Sn2 Cluster Using a Co- Synthon

[Ar'SnCo]2 (1, Ar' = C6H3-2,6{C6H3-2,6- iPr2}2), a rare metal-metal bonded cobalt-tin cluster with low-coordinate tin atoms, was prepared by the reaction of [K(thf)0.2][Co(1,5-cod)2] (cod = 1,5-cyclooctadiene) with [Ar'Sn(μ-Cl)]2. This reaction illustrates a promising synthetic strategy to access uncommon metal clusters. The structure of 1 features a rhomboidal Co2Sn2 core with strong metal-metal bonds between tin and cobalt and a weaker tin-tin interaction. Reaction of 1 with white phosphorus afforded [Ar'2Sn2Co2P4] (2), the first molecular cluster compound containing phosphorus, cobalt and tin.

Chiral Control in Pentacoordinate Systems: The Case of Organosilicates

Chirality at the central element of pentacoordinate systems can be controlled with two identical bidentate ligands. In such cases the topological Levi-Desargues graph for all the Berry pseudorotations (BPR, max. 20) reduces to interconnected inner and outer "circles" that represent the dynamic enantiomer pair. High enough barriers of the BPR crossovers between the two circles is all what is needed to ascertain chiral integrity. This is illustrated computationally and experimentally for the organosilicates 7 and 10 that carry besides a Me (a), Et (b), Ph (c), or F (d) group two bidentate 2-(phenyl)benzo[ b]-thiophene or 2-(phenyl)naphthyl ligands, respectively. The enantiomers of tetraorganosilane precursor 9 could be separated by column chromatography. Their chiral integrity persisted on forming the silicates. CD spectra are reported for 10c. Fluoro derivative 10d is shown to have its electronegative F substituent in an equatorial position, is stable toward hydrolysis, and its enantiomers do not racemize at ambient temperatures, while those of 10c racemize slowly.

Aryldiazonium Salts as Nitrogen-Based Lewis Acids: Facile Synthesis of Tuneable Azophosphonium Salts

Inspired by the commercially available azoimidazolium dyes (e.g., Basic Red 51) that can be obtained from aryldiazonium salts and N-heterocyclic carbenes, we developed the synthesis of a unique set of arylazophosphonium salts. A range of colours were obtained by applying readily tuneable phosphine donor ligands and para-substituted aryldiazonium salts as nitrogen-based Lewis acids. With cyclic voltammetry, a general procedure was designed to establish whether the reaction between a Lewis acid and a Lewis base occurs by single-electron transfer or electron-pair transfer.

Template-Directed Synthesis of an Inverted Spiro Architecture

The regular bicyclic spiro motif is highly abundant given its synthetic accessibility while the diastereomer-virtually obtained through inversion at the central atom-is almost unknown. We have developed methodology to access the elusive inverted spiro architecture by employing a covalent template-directed approach. Comparison with the regular spiro bicycle analog unequivocally established the diastereomeric relationship, providing insight into the fascinating stereochemical and structural properties.

Gold(I) Complexes of the Geminal Phosphinoborane tBu2PCH2BPh2

In this work, we explored the coordination properties of the geminal phosphinoborane tBu₂PCH₂BPh₂ (2) toward different gold(I) precursors. The reaction of 2 with an equimolar amount of the sulfur-based complex (Me₂S)AuCl resulted in displacement of the SMe₂ ligand and formation of linear phosphine gold(I) chloride 3. Using an excess of ligand 2, bisligated complex 4 was formed and showed dynamic behavior at room temperature. Changing the gold(I) metal precursor to the phosphorus-based complex, (Ph₃P)AuCl impacted the coordination behavior of ligand 2. Namely, the reaction of ligand 2 with (Ph₃P)AuCl led to the heterolytic cleavage of the gold-chloride bond, which is favored over PPh₃ ligand displacement. To the best of our knowledge, 2 is the first example of a P/B-ambiphilic ligand capable of cleaving the gold-chloride bond. The coordination chemistry of 2 was further analyzed by density functional theory calculations.

Synthesis and Reactivity of the Phosphorus Analogues of Cyclopentadienone, Tricyclopentanone, and Housene

The phosphorus analogues of cyclopentadienone, tricyclopentanone, and housene were accessed from bis(cyclopropenyl)diphosphetanedione 3, which was prepared by mixing 1,2,3-tris-tert-butylcyclopropenium tetrafluoroborate (1) and sodium phosphaethynolate [Na(OCP)(dioxane)_n ]. While photolysis of 3 results in decarbonylation, yielding bis(cyclopropenyl)diphosphene 4 and after rearrangement diphosphahousene 5, thermolysis of 3 leads to phosphatricyclo[2.1.0.0]pentanone 7. Metal-mediated valence isomerization of 7 and subsequent demetalation provides access to phosphacyclopentadienone 12.

Toward Asymmetric Synthesis of Pentaorganosilicates

Introducing chiral silicon centers was explored for the asymmetric Rh-catalyzed cyclization of dihydrosilanes to enantiomerically enriched spirosilanes as targets to enable access to enantiostable pentacoordinate silicates. The steric rigidity required in such systems demands the presence of two naphthyl or benzo[b]thiophene groups. The synthetic approach to the expanded spirosilanes extends Takai’s method (Kuninobu et al. in Angew Chem Int Ed 52(5):1520–1522, 2013) for the synthesis of spirosilabifluorenes in which both a Si–H and a C–H bond of a dihydrosilane are activated by a rhodium catalyst. The expanded dihydrosilanes were obtained from halogenated aromatic precursors. Their asymmetric cyclization to the spirosilanes were conducted with [Rh(cod)Cl]₂ in the presence of the chiral bidentate phosphane ligands (R)-BINAP, (R)-MeO-BIPHEP, and (R)-SEGPHOS, including derivatives with P-(3,5-t-Bu-4-MeO)-phenyl (DTBM) groups. The highest enantiomeric excess of 84% was obtained for 11,11′-spirobi[benzo[b]-naphtho[2,1-d]silole] with the DTBM-SEGPHOS ligand.

Functionalization of P4 through Direct P-C Bond Formation

Research on chlorine-free conversions of P4 into organophosphorus compounds (OPCs) has a long track record, but methods that allow desirable, direct P-C bond formations have only recently emerged. These include the use of metal organyls, carbenes, carboradicals, and photochemical approaches. The versatile product scope enables the preparation of both industrially relevant organophosphorus compounds, as well as a broad range of intriguing new compound classes. Herein we provide a concise overview of recent breakthroughs and outline the acquired fundamental insights to aid future developments.

A quantitative analysis of light-driven charge transfer processes using voronoi partitioning of time dependent DFT-derived electron densities

An analytical method is presented that provides quantitative insight into light-driven electron density rearrangement using the output of standard time-dependent density functional theory (TD-DFT) computations on molecular compounds. Using final and initial electron densities for photochemical processes, the subtraction of summed electron density in each atom-centered Voronoi polyhedron yields the electronic charge difference, QVECD . This subtractive method can also be used with Bader, Mulliken and Hirshfeld charges. A validation study shows QVECD to have the most consistent performance across basis sets and good conservation of charge between electronic states. Besides vertical transitions, relaxation processes can be investigated as well. Significant electron transfer is computed for isomerization on the excited state energy surface of azobenzene. A number of linear anilinepyridinium donor-bridge-acceptor chromophores was examined using QVECD to unravel the influence of its pi-conjugated bridge on charge separation. Finally, the usefulness of the presented method as a tool in optimizing charge transfer is shown for a homologous series of organometallic pigments. The presented work allows facile calculation of a novel, relevant quantity describing charge transfer processes at the atomic level. © 2017 Wiley Periodicals, Inc.

A Short Covalent Synthesis of an All-Carbon-Ring [2]Rotaxane

While the current supramolecular syntheses of [2]rotaxanes are generally efficient, the final product always retains the functional groups required for non-covalent preorganization. A short and high-yielding covalent-template-assisted approach is reported for the synthesis of a [2]rotaxane. A terephthalic acid template core preorganizes the covalently connected ring precursor fragments to induce a clipping-type cyclization over the thread moiety. Cleavage of the temporary ester bonds that connect the ring and thread fragments liberates the [2]rotaxane.

Metalate-Mediated Functionalization of P4 by Trapping Anionic [Cp*Fe(CO)2(η1-P4)]- with Lewis Acids

The development of selective functionalization strategies of white phosphorus (P₄) is important to avoid the current chlorinated intermediates. The use of transition metals (TMs) could lead to catalytic procedures, but these are severely hampered by the high reactivity and unpredictable nature of the tetrahedron. Herein, we report selective first steps by reacting P₄ with a metal anion [Cp*Fe(CO)₂]⁻ (Cp*=C₅(CH₃)₅), which, in the presence of bulky Lewis acids (LA; B(C₆F₅)₃ or BPh₃), leads to unique TM‐substituted LA‐stabilized bicyclo[1.1.0]tetraphosphabutanide anions [Cp*Fe(CO)₂(η¹‐P₄⋅LA)]⁻. Their P‐nucleophilic site can be subsequently protonated to afford the transient LA‐free neutral butterflies exo,endo‐ and exo,exo‐Cp*Fe‐ (CO)₂(η¹‐P₄H), allowing controllable stepwise metalate‐mediated functionalization of P₄.

Iminophosphanes: Synthesis, Rhodium Complexes, and Ruthenium(II)-Catalyzed Hydration of Nitriles

Highly stable iminophosphanes, obtained from alkylating nitriles and reaction of the resulting nitrilium ions with secondary phosphanes, were explored as tunable P-monodentate and 1,3-P,N bidentate ligands in rhodium complexes. X-ray crystal structures are reported for both κ¹ and κ² complexes with the counterion in one of them being an unusual anionic coordination polymer of silver triflate. The iminophosphane-based ruthenium(II)-catalyzed hydration of benzonitrile in 1,2-dimethoxyethane (180 °C, 3 h) and water (100 °C, 24 h) and under solvent free conditions (180 °C, 3 h) results in all cases in the selective formation of benzamide with yields of up to 96%, thereby outperforming by far the reactions in which the common 2-pyridyldiphenylphosphane is used as the 1,3-P,N ligand.

Reactivity of the geminal phosphinoborane tBu2PCH2BPh2 towards alkynes, nitriles, and nitrilium triflates

The reactivity of the geminal phosphinoborane tBu₂PCH₂BPh₂ towards terminal alkynes, nitriles and nitrilium salts is investigated.

Selective [3+1] Fragmentations of P4 by "P" Transfer from a Lewis Acid Stabilized [RP4 ]- Butterfly Anion

Two [3+1] fragmentations of the Lewis acid stabilized bicyclo[1.1.0]tetraphosphabutanide Li[Mes*P₄ ⋅ BPh₃ ] (Mes*=2,4,6-tBu₃ C₆ H₂ ) are reported. The reactions proceed by extrusion of a P₁ fragment, induced by either an imidazolium salt or phenylisocyanate, with release of the transient triphosphirene Mes*P₃ , which was isolated as a dimer and trapped by 1,3-cyclohexadiene as a Diels-Alder adduct. DFT quantum chemical computations were used to delineate the reaction mechanisms. These unprecedented pathways grant access to both P₁ - and P₃ -containing organophosphorus compounds in two simple steps from white phosphorus.

Insertion of phenyl isothiocyanate into a P-P bond of a nickel-substituted bicyclo[1.1.0]tetraphosphabutane

A new reaction mode for bicyclo[1.1.0]tetraphosphabutanes is reported. The C[double bond, length as m-dash]S and C[double bond, length as m-dash]N bonds of phenyl isothiocyanate reversibly insert into a P-P bond of [{CpNi(IMes)}2(μ-η(1):η(1)-P4)] (, IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene), forming isomers and . X-ray crystallography and (31)P{(1)H} NMR spectroscopy revealed similar bicyclo[3.1.0]heterohexane structures for these compounds.

Synthesis, characterization and biological activity of fluorescently labeled bedaquiline analogues

Labeling the tuberculosis drug bedaquiline with a fluorescent alkynyl-BODIPY moiety does not disrupt its antibacterial properties.

Functionalization of P4 in the coordination sphere of coinage metal cations

Selective functionalization of white phosphorus is achieved by addition of ArLi to unique cationic coinage metal η²–P₄ complexes.