Controlling the activation of white phosphorus: formation of phosphorous acid and ruthenium-coordinated 1-hydroxytriphosphane by hydrolysis of doubly metalated P4

Stability and passivation of 2D group VA elemental materials: black phosphorus and beyond

Since the successful isolation of graphene in 2004, two-dimensional (2D) materials have become one of the focuses in material science owing to their extraordinary physical and chemical properties. In particular, 2D group VA elemental materials exhibit fascinating thickness-dependent band structures. Unfortunately, the well-known instability issue hinders their fundamental researches and practical applications. In this review, we first discuss the degradation mechanism of black phosphorus (BP), a most studied group VA material. Next, we summarize the methods to enhance BP stability with the focus of multifunctional passivation. Finally, we briefly discuss the protection strategies of other emerging group VA materials in recent years. This review provides insight for the degradation mechanism and protecting strategy for 2D group VA elements materials, which will promote their potential applications in electronics, optoelectronics, and biomedicine.

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.

Ruthenium mediated halogenation of white phosphorus: synthesis and reactivity of the unprecedented P4Cl2 moiety

The transition metal mediated functionalization of P4 is an approach to develop a more sustainable production of organophosphorus compounds. In this paper a ruthenium complex is presented, in which the P4 unit can be selectively converted into new P4R2 molecules in a two-step synthesis. The unsaturated 16 electron species [RuX(Cp*)(PCy3)] (Cp* = C5Me5, X = Cl, Br) reacts with a half equivalent of P4 affording a bimetallic complex bearing a planar P4X2 moiety as a ligand. The latter eliminates chloride anions under reduction with magnesium. In this process the butadiene-like P4Cl2 ligand is converted into two weakly bound P2 units which bridge the ruthenium centers. In the presence of n-BuLi, the P4Cl2 unit can be selectively alkylated, yielding the planar organophosphorus ligand P4nBu2. A detailed analysis of the electronic properties and solid state structures of the compounds combined with DFT calculations and AIM analyses demonstrate that the P4 unit in all complexes acts as an electronically highly flexible, non-innocent ligand.

pH-Dependent Degradation of Layered Black Phosphorus: Essential Role of Hydroxide Ions

The practical application of layered black phosphorus (LBP) is compromised by fast decomposition in the presence of H₂ O and/or O₂ . The role of H₂ O is controversial. Herein, we propose a hydroxide ion (OH^- )-initiated degradation mechanism for LBP to elucidate the role of H₂ O. We found that LBP degraded faster in alkaline solutions than in neutral or acidic solutions with or without O₂ . Degradation rates of LBP increased linearly from pH 4 to 10. Density functional theory (DFT) calculations showed that OH^- initiated the decomposition of LBP through breaking the P-P bond and forming a P-O bond. The detection of hypophosphite, generated from OH^- reacting with P atoms, confirmed the hypothesis. Protons acted in a way distinctive from OH^- , by inducing deposition/aggregation or forming a cation-π layer to protect LBP from degradation. This work reveals the degradation mechanism of LBP and thus facilitates the development of effective stabilization technologies.

Crystal structure of a P4-bridged (η 5-pentamethyl-cyclopentadienyl)(η 5-adamantylcyclopentadienyl) titanium(III)complex, C50H66P4Ti2

C50H66P4Ti2, orthorhombic, P21212 (no. 18), a = 14.3799(5) Å, b = 15.4444(6) Å, c = 9.5555(5) Å, V = 2122.17(16) Å3, Z = 2, Rgt(F) = 0.0338, wRref(F2) = 0.0643, T = 153(2) K.

Activation of white phosphorus by low-valent group 5 complexes: formation and reactivity of cyclo-P4 inverted sandwich compounds

We report the synthesis and comprehensive study of the electronic structure of a unique series of dinuclear group 5 cyclo-tetraphosphide inverted sandwich complexes. White phosphorus (P4) reacts with niobium(III) and tantalum(III) β-diketiminate (BDI) tert-butylimido complexes to produce the bridging cyclo-P4 phosphide species {[(BDI)(N(t)Bu)M]2(μ-η(3):η(3)P4)} (1, M = Nb; 2, M = Ta) in fair yields. 1 is alternatively synthesized upon hydrogenolysis of (BDI)Nb(N(t)Bu)Me2 in the presence of P4. The trinuclear side product {[(BDI)NbN(t)Bu]3(μ-P12)} (3) is also identified. Protonation of 1 with [HOEt2][B(C6F5)4] does not occur at the phosphide ring but rather involves the BDI ligand to yield {[(BDI(#))Nb(N(t)Bu)]2(μ-η(3):η(3)P4)}[B(C6F5)4]2 (4). The monocation and dication analogues {[(BDI)(N(t)Bu)Nb]2(μ-η(3):η(3)P4)}{B(Ar(F))4}n (5, n = 1; 6, n = 2) are both synthesized by oxidation of 1 with AgBAr(F). DFT calculations were used in combination with EPR and UV-visible spectroscopies to probe the nature of the metal-phosphorus bonding.

Iodine activation of coordinated white phosphorus: formation and transformation of 1,3-dihydride-2-iodidecyclotetraphosphane

Double stabilization: Previously unknown polyphosphorus compounds are obtained by activation of white phosphorus (P(4)) coordinated between two CpRu(PPh(3))(2) moieties with iodine, and subsequent hydrolysis. The polyphosphorus compounds (P(4) H(2) I, P(4) H(2), P(3) H(5); see scheme, Cp=cyclopentadienyl) are all stabilized by coordination to two ruthenium centers.

Zwitterionic and cationic P(5)-clusters from four-membered phosphorus-nitrogen-metal heterocycles

A general route for the functionalization of P(4) mediated by four-membered phosphorus-nitrogen-metal heterocycles is introduced yielding novel phosphorus-rich clusters.

NMR studies on the novel heterobimetallic complexes [M(dppm)(Ph(2)PCH(2)PPh(2)PPPP) {Pt(PPh3)2}]OTf (M = Rh, Ir) derived from the stepwise activation of white phosphorus

The solution structures of the novel heterobimetallic complexes [Ir(dppm)(Ph(2)PCH(2)PPh(2)PPPP){Pt(PPh(3))2}]OTf and [Rh(dppm)(Ph(2)PCH(2)PPh(2)PPPP){Pt(PPh(3))(2)}]OTf derived from the reaction of Rh and Ir--P(5) precursors with [Pt(C2H4)(PPh3)2] have been unambiguously assigned on the basis of 1H NMR and 31P{1H} NMR data. The results are in agreement with the regio-selective insertion of the {Pt(PPh3)2} moiety resulting in a new pentaphosphorus topology which agrees with the formal formation of a unique phosphonium(+)-tetraphosphabutadienide(2-) ligand.