Direct Synthesis of Phosphoryltriacetates from White Phosphorus via Visible Light Catalysis

Organophosphorus compounds (OPCs) are widely used in many fields. However, traditional synthetic routes in the industry usually involve multistep and hazardous procedures. Therefore, it's of great significance to construct such compounds in an environmentally-friendly and facile way. Herein, a photoredox catalytic method has been developed to construct novel phosphoryltriacetates. Using fac-Ir(ppy)3 (ppy=2-phenylpyridine) as the photocatalyst and blue LEDs (456 nm) as the light source, white phosphorus can react with α-bromo esters smoothly to generate phosphoryltriacetates in moderate to good yields. This one-step approach features mild reaction conditions and simple operational process without chlorination.

Sustainable Photo- and Electrochemical Transformation of White Phosphorous (P4 ) into P1 Organo-Compounds

Elemental white phosphorous (P4 ) is a crucial feedstock for the entire phosphorus-derived chemical industry, serving as a common precursor for the ultimate preparation of high-grade monophosphorus (P1 ) fine chemicals. However, the corresponding manufacturing processes generally suffer from a deep reliance on hazardous reagents, inputs of immense energy, emissions of toxic pollutants, and the generation of substantial waste, which have negative impacts on the environment. In this context, sustainability and safety concerns provide a consistent impetus for the urgent overall improvement of phosphorus cycles. In this Concept, we present an overview of the most recent growth in photo- and electrochemical synthesis of P1 organo-compounds from P4 , with special emphasis on sustainable features. The key aspects of innovations regarding activation mode and mechanism have been comprehensively analyzed. A preliminary look at the possible future direction of development is also provided.

A new polymorph of white phosphorus at ambient conditions

Phosphorus exists in several different allotropes: white, red, violet and black. For industrial and academic applications, white phosphorus is the most important. So far, three polymorphs of white phosphorus, all consisting of P4 tetrahedra, have been described. Among these, β-P4 crystallizes in the space group P1 and γ-P4 in the space group C2/m. α-P4 forms soft plastic crystals with a proposed structure in the cubic space group I43m with the lattice constant a = 18.51 (3) Å, consisting of 58 rotationally disordered tetrahedra and thus is similar to the structure of α-Mn. Here we present a new polymorph, δ-P4. It crystallizes as a sixfold twin with the cell dimensions a = 18.302 (2), b = 18.302 (2), c = 36.441 (3) Å in the space group P212121 with 29 P4 tetrahedra in the asymmetric unit. The arrangement resembles the structure of α-Mn, but δ-P4 differs from α-P4. DFT calculations show δ-P4 to be metastable at a similar energy level to that of γ-P4.

Cooperative Rare-Earth/Lithium-Mediated Conversion of White Phosphorus

The rare-earth/lithium cooperative effect on functionalization of white phosphorus has been investigated. The reaction of diazabutadiene-supported yttrium hydride chelated a LiPPh₂ molecule (LY ⋅ THF)₂ (μ-H)₂ [μ-PPh₂ (Li)] (1, L=N,N'-di(2,6-diisopropylphenyl)-1,4-diazabutadiene) with P₄ gave two novel mixed Y/Li multinuclear polyphosphorus complexes (LY ⋅ THF)₂ [cyclo-P₃ ]Li(THF)₃ (2) and [Li(THF)₄ ]⁺ [(LY ⋅ THF)₃ (norborane-P₇ )Li(THF)]^- (3), accompanied with the elimination of diphosphorus compound Ph₂ PPPh₂ (4) and H₂ . However, the comparative reaction of yttrium hydride (LY ⋅ THF)₂ (μ-H)₂ with P₄ afforded a trinuclear yttrium pyramid-P₄ complex (LY ⋅ THF)₃ (μ₃ -P(PH)₃ ) (5). Further investigations show that 5 cannot continuously react with LiPPh₂ to form 2 and 3, and LiPPh₂ reacted with P₄ to form a Zintl-P₇ lithium complex (TMEDA⋅Li)₃ (Zintl-P₇ ) (6) and 4. These results indicated that the cooperation of Y/Li for activation of P₄ is a key for the formation of 2 and 3. All new compounds have been characterized by NMR spectroscopy and single-crystal X-ray diffraction studies.

Conversion of E4 (E4 =P4 , As4 , AsP3 ) by Ni(0) and Ni(I) Synthons - A Comparative Study

The reactivity of white phosphorus and yellow arsenic towards two different nickel nacnac complexes is investigated. The nickel complexes [(L¹ Ni)₂ tol] (1, L¹ =[{N(C₆ H₃ ⁱ Pr₂ -2,6)C(Me)}₂ CH]^- ) and [K₂ ][(L¹ Ni)₂ (μ,η^1 : 1 -N₂ )] (6) were reacted with P₄ , As₄ and the interpnictogen compound AsP₃ , respectively, yielding the homobimetallic complexes [(L¹ Ni)₂ (μ-η² ,κ¹ :η² ,κ¹ -E₄ )] (E=P (2 a), As (2 b), AsP₃ (2 c)), [(L¹ Ni)₂ (μ,η^3 : 3 -E₃ )] (E=P (3 a), As (3 b)) and [K@18-c-6(thf)₂ ][L¹ Ni(η^1 : 1 -E₄ )] (E=P (7 a), As (7 b)), respectively. Heating of 2 a, 2 b or 2 c also leads to the formation of 3 a or 3 b. Furthermore, the reactivity of these compounds towards reduction agents was investigated, leading to [K₂ ][(L¹ Ni)₂ (μ,η^2 : 2 -P₄ )] (4) and [K@18-c-6(thf)₃ ][(L¹ Ni)₂ (μ,η^3 : 3 -E₃ )] (E=P (5 a), As (5 b)), respectively. Compound 4 shows an unusual planarization of the initial Ni₂ P₄ -prism. All products were comprehensively characterized by crystallographic and spectroscopic methods.

Generation of a π-Bonded Isomer of [P4 ]4- by Aluminyl Reduction of White Phosphorus and its Ammonolysis to PH3

By employing the highly reducing aluminyl complex [K{(NON)Al}]₂ (NON=4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene), we demonstrate the controlled formation of P₄ ^2- and P₄ ^4- complexes from white phosphorus, and chemically reversible inter-conversion between them. The tetra-anion features a unique planar π-bonded structure, with the incorporation of the K⁺ cations implicit in the use of the anionic nucleophile offering additional stabilization of the unsaturated isomer of the P₄ ^4- fragment. This complex is extremely reactive, acting as a source of P^3- : exposure to ammonia leads to the release of phosphine (PH₃ ) under mild conditions (room temperature and pressure), which contrast with those necessitated for the direct combination of P₄ and NH₃ (>5 kbar and >250 °C).

Photocatalytic Arylation of P4 and PH3 : Reaction Development Through Mechanistic Insight

Detailed 31 P{1 H} NMR spectroscopic investigations provide deeper insight into the complex, multi-step mechanisms involved in the recently reported photocatalytic arylation of white phosphorus (P4 ). Specifically, these studies have identified a number of previously unrecognized side products, which arise from an unexpected non-innocent behavior of the commonly employed terminal reductant Et3 N. The different rate of formation of these products explains discrepancies in the performance of the two most effective catalysts, [Ir(dtbbpy)(ppy)2 ][PF6 ] (dtbbpy=4,4'-di-tert-butyl-2,2'-bipyridine) and 3DPAFIPN. Inspired by the observation of PH3 as a minor intermediate, we have developed the first catalytic procedure for the arylation of this key industrial compound. Similar to P4 arylation, this method affords valuable triarylphosphines or tetraarylphosphonium salts depending on the steric profile of the aryl substituents.

Transition-Metal-Mediated Functionalization of White Phosphorus

Recently there has been great interest in the reactivity of transition-metal (TM) centers towards white phosphorus (P4 ). This has ultimately been motivated by a desire to find TM-mediated alternatives to the current industrial routes used to transform P4 into myriad useful P-containing products, which are typically indirect, wasteful, and highly hazardous. Such a TM-mediated process can be divided into two steps: activation of P4 to generate a polyphosphorus complex TM-Pn , and subsequent functionalization of this complex to release the desired phosphorus-containing product. The former step has by now become well established, allowing the isolation of many different TM-Pn products. In contrast, productive functionalization of these complexes has proven extremely challenging and has been achieved only in a relative handful of cases. In this review we provide a comprehensive summary of successful TM-Pn functionalization reactions, where TM-Pn must be accessible by reaction of a TM precursor with P4 . We hope that this will provide a useful resource for continuing efforts that are working towards this highly challenging goal of modern synthetic chemistry.

Hydrolysis of Element (White) Phosphorus under the Action of Heterometallic Cubane-Type Cluster {Mo3PdS4}

Reaction of heterometallic cubane-type cluster complexes—[Mo₃{Pd(dba)}S₄Cl₃(dbbpy)₃]PF₆, [Mo₃{Pd(tu)}S₄Cl₃(dbbpy)₃]Cl and [Mo₃{Pd(dba)}S₄(acac)₃(py)₃]PF₆, where dba—dibenzylideneacetone, dbbpy—4,4′-di-tert-butyl-2,2′-bipyridine, tu—thiourea, acac—acetylacetonate, py—pyridine, with white phosphorus (P₄) in the presence of water leads to the formation of phosphorous acid H₃PO₃ as the major product. The crucial role of the Pd atom in the cluster core {Mo₃PdS₄} has been established in the hydrolytic activation of P₄ molecule. The main intermediate of the process, the cluster complex [Mo₃{PdP(OH)₃}S₄Cl₃(dbbpy)₃]⁺ with coordinated P(OH)₃ molecule and phosphine PH₃, have been detected by ³¹P NMR spectroscopy in the reaction mixture.

Oedème pulmonaire lésionnel par inhalation de vapeurs d’acide phosphorique traité par vni

White phosphorus injuries are considered both thermal and chemical burns. They should be well known, especially in military and terrorism contexts. This type of burn causes a life-threatening systemic toxicity from hypocalcemia, cardiac arrhythmia and respiratory complications by inhalation of phosphoric acid vapours. We report a case of a non-cardiogenic pulmonary edema complicating a white phosphorus burn in a young serviceman.

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.

Nacnac-Cobalt-Mediated P4 Transformations

A comparison of P4 activations mediated by low-valent β-diketiminato (L) cobalt complexes is presented. The formal Co0 source [K2 (L3 Co)2 (μ2 :η1 ,η1 -N2 )] (1) reacts with P4 to form a mixture of the monoanionic complexes [K(thf)6 ][(L3 Co)2 (μ2 :η4 ,η4 -P4 )] (2) and [K(thf)6 ][(L3 Co)2 (μ2 :η3 ,η3 -P3 )] (3). The analogue CoI precursor [L3 Co(tol)] (4 a), however, selectively yields the corresponding neutral derivative [(L3 Co)2 (μ2 :η4 ,η4 -P4 )] (5 a). Compound 5 a undergoes thermal P atom loss to form the unprecedented complex [(L3 Co)2 (μ2 :η3 ,η3 -P3 )] (6). The products 2 and 3 can be obtained selectively by an one-electron reduction of their neutral precursors 5 a and 6, respectively. The electrochemical behaviour of 2, 3, 5 a, and 6 is monitored by cyclic voltammetry and their magnetism is examined by SQUID measurements and the Evans method. The initial CoI -mediated P4 activation is not influenced by applying the structurally different ligands L1 and L2 , which is proven by the formation of the isostructural products [(LCo)2 (μ2 :η4 ,η4 -P4 )] [L=L3 (5 a), L1 (5 b), L2 (5 c)].

CpPEt2 As4 -An Organic-Substituted As4 Butterfly Compound

Cp^PEt₂ As₄ (Cp^PEt =C₅ (4-EtC₆ H₄ )₅ ) (1) is synthesized by the reaction of Cp^PEt. radicals with yellow arsenic (As₄ ). In solution an equilibrium of the starting materials and the product is found. However, 1 can be isolated and stored in the solid state without decomposition. As₄ can be easily released from 1 under thermal or photochemical conditions. From powder samples of Cp^PEt₂ As₄ , yellow arsenic can be sublimed under rather mild conditions (T=125 °C). A similar behavior for the P₄ -releasing agent was determined for the related phosphorus compound Cp^BIG₂ P₄ (2; Cp^BIG =C₅ (4-nBuC₆ H₄ )₅ ). DFT calculations show the importance of dispersion forces for the stability of the products.

Influence of the nacnac Ligand in Iron(I)-Mediated P4 Transformations

A study of P4 transformations at low-valent iron is presented using β-diketiminato (L) Fe(I) complexes [LFe(tol)] (tol=toluene; L=L(1) (1 a), L(2) (1 b), L(3) (1 c)) with different combinations of aromatic and backbone substituents at the ligand. The products [(LFe)4 (μ4 -η(2) :η(2) :η(2) :η(2) -P8 )] (L=L(1) (2 a), L(2) (2 b)) containing a P8 core were obtained by the reaction of 1 a,b with P4 in toluene at room temperature. Using a slightly more sterically encumbered ligand in 1 c results in the formation of [(L(3) Fe)2 (μ-η(4) :η(4) -P4 )] (2 c), possessing a cyclo-P4 moiety. Compounds 2 a-c were comprehensively characterized and their electronic structures investigated by SQUID magnetization and (57) Fe Mössbauer spectroscopy as well as by DFT methods.

Probing the Structure, Dynamics, and Bonding of Coinage Metal Complexes of White Phosphorus

A series of cationic white phosphorus complexes of the coinage metals Au and Cu have been synthesised and characterised both in the solid state and in solution. All complexes feature a P4 unit coordinated through an edge P-P vector (η(2)-like), although the degree of activation (as measured by the coordinated P-P bond length) is greater in the gold species. All of the cations are fluxional on the NMR timescale at room temperature, but in the case of the gold systems fluxionality is frozen out at -90 °C. Electronic structure calculations suggest that this fluxionality proceeds via an η(1)-coordinated M-P4 intermediate.

Functionalization of P4 using a Lewis acid stabilized bicyclo[1.1.0]tetraphosphabutane anion

Reacting white phosphorus (P4 ) with sterically encumbered aryl lithium reagents (aryl=2,6-dimesitylphenyl or 2,4,6-tBu3 C6 H2 ) and B(C6 F5 )3 gives the unique, isolable Lewis acid stabilized bicyclo[1.1.0]tetraphosphabutane anion. Subsequent alkylation of the nucleophilic site of the RP4 anion gives access to non-symmetrical disubstituted bicyclic tetraphosphorus compounds. This novel method enables PC bond formation in a controlled fashion using white phosphorus as starting material.

The overall patterns of burns

Burn patterns differ across the whole world and not only in relation to lack of education, overcrowding, and poverty. Cultures, habits, traditions, psychiatric illness, and epilepsy are strongly correlated to burn patterns. However, burns may also occur because of specific religious beliefs and activities, social events and festivals, traditional medical practices, occupational activities, and war.