Themed collection Phosphorus Chemistry: Discoveries and Advances

Welcome to this themed issue of Dalton Transactions entitled “Phosphorus Chemistry: Discoveries and Advances”.

TADDOL derivatives and the Ca²⁺-salts of tartaric acid derivatives were found to be versatile and generally applicable resolving agents for the preparation of the enantiomers of P-stereogenic heterocyclic phosphine oxides and phosphinates.

The precise functionalization of N₃P₃Cl₆ for the synthesis of smart dendrimers, and their uses.

The insertion of electrophilic terminal phosphinidene complexes [RP–M] into A–H bonds (A = B, C, N, O, Si) has been reviewed and some new mechanistic proposals have been made.

The wide variety of accessible poly(organophosphazenes) is a consequence of the unusual macromolecular substitution approach to their synthesis.

Reaction of (1,4-C₆H₄)[N(PCl₂)₂]₂ with ^tBuNH₂ in the presence of Et₃N gives the bridged phosph(III)azane (1,4-C₆H₄)[N(μ-PNH^tBu)₂N^tBu]₂ (1H₄), which can be deprotonated to give the tetraanion (1,4-C₆H₄)[N(μ-PN^tBu)₂N^tBu]₂⁴⁻ (1⁴⁻). The latter represents a new type of phosphazane ligand.

A series of enantiopure MOP-phosphonite ligands, with tailored steric profiles, have been synthesised and are proven to be very successful in high-yielding, regio- and enantioselective catalytic hydrosilylation reactions of substituted styrenes, affording important chiral secondary alcohols.

Catalytic hydrophosphination of alkenes using a chiral, air-stable primary phosphine, (R)-MeO-MOPH₂, proceeds under mild conditions with a zirconium catalyst to selectively furnish anti-Markovnikov, air-stable secondary phosphine or tertiary phosphine prodcuts with slight modification of the protocol.

We report the synthesis by RAFT polymerization of well-defined diblock copolymers bearing carbamoylmethylphosphonate moieties which proved to sorb gadolinium.

An efficient P–C bond-formation through iron-catalyzed cross coupling of P–H/C–O bonds is developed for the first time. This reaction proceeds efficiently to produce the corresponding valuable α-alkoxyphosphorus compounds under mild conditions with a wide generality.

This study describes the synthesis, characterization and reactivity of a series of mono and dicationic phosphines bearing dihydroimidazolium and amidinium substituents. Their remarkable effect in Au(I) and Pt(II) catalysis is also described.

Tuning the ligand properties of chiral P–C cage compounds: selective mono oxidation of P₅-deltacyclene opens the gate to a phosphinious acid ligand.

The bicyclic aminophobanes have significantly different chemistry from their acyclic analogues Cy₂PNHR′.

For the first time, it has been shown the deoxofluorination of metal-coordinated phosphorous oxyacids is feasible using a safe and environmentally friendly “F” source and affords fluorophosphines in a mild and selective way.

The coordination behaviour of hexakis(3-pyridyloxy)cyclophosphazene (L) towards divalent metal ions is described.

Novel bicyclic P,N-heterocyclic ligands and the first P- and P,N-coordinated LM(0)(CO)₅, LRh(COD)Cl, (LPd(All)Cl)₂PdCl₂ and (LPdCl₂)₂ transition metal complexes thereof are presented.

Synthesis and physical properties of polyaromatic hydrocarbons containing phosphole and thiophene rings at the edge.

Cu(I) complexes with novel cyclic phosphine ligands were obtained. Phosphorescence spectra display emission in broad spectral range of 471–615 nm.

Important aspects of the synthesis, reactivity and coordination chemistry of 2,4,6-triphenylphosphinine and 2,4,6-triphenylphosphabarrelene have been revisited.

Reductive PPh₂⁻/OH⁻ and PPh₂O⁻/PPh₂⁻ coupling processes allow the preparation of tri- or hexanuclear Pt(II) complexes with PPh₂⁻, PPh₂O⁻ or PPh₂OPPh₂ bridging ligands.

Ditopic tris(pyrazolyl)phosphines are synthesized and coordinated to Cu(I), leading to monomers and to a polymeric complex, depending on the ligand substituents.

The synthesis of the first phophanylphosphonate, Mes*PH–PO(OEt)₂ (2-H), in which the P(III) centre is not coordinated by a metal fragment is reported.

The group 6 metal mono-, bis- and tris-ferrocenylphosphine complexes [M(CO)₅(PH₂Fc)], cis-[M(CO)₄(PH₂Fc)₂] and fac-[M(CO)₃(PH₂Fc)₃] (M = Cr, Mo, W; Fc = Fe(η⁵-C₅H₄)(η⁵-C₅H₅)) were prepared and fully characterised. The coordinated FcPH₂ ligand of [W(CO)₅(PH₂Fc)] undergoes hydrophosphination with alkene substrates bearing EWGs, yielding the corresponding secondary phosphine complexes.

The optical, electrochemical, and photophysical properties of α,α′-linked phosphole–thiophene π-systems bearing boryl, phosphino, or phosphonio groups were studied.

The propargyl phosphanes Ph₂PCH₂CCER₃ (R₃E = ⁿBu₃Sn, Ph₃Sn, Me₂PhSi, Pr₃Si, ⁿBu₃Si) and (Me₃Si)₂PCH₂CCSiPhMe₂ are obtained in high yield; in contrast quenching PhCCCH₂MgX with ClP(NEt₂)₂ preferentially affords (>70%) the novel phosphinoallene (Et₂N)₂PC(Ph)CCH₂.

Random and block phosphazene copolymers with stannyl groups have been used as recyclable tin reagents in the Stille reaction. The block copolymer can be recycled without significant release of tin, but its efficiency decreased after three cycles, an effect related to the self-assembly of the polymer.

The nucleophilic properties of the title compound [(2,6-i-Pr₂C₆H₃N)₂(Cl)W(η²-t-Bu₂PP)]Li·3DME (1) were investigated in reactions with selected electrophilic reagents such as MeI, M(CO)₅THF (M = Cr, Mo, W), AlCl₃, and GaCl₃.

The reaction between a triphosphenium salt and S,N-heterocyclic carbenes grants phosphamethine cyanines with a different electronic structure than those of their NHC-ligated analogues.

Stereoselective syntheses of [3]ferrocenophanes with functional P–E–P motifs (E = SiX₂) are reported in which the Si–X bonding depends on the molecular vicinity.

The quantitative halogen-promoted dephosphonylation of AA^P occurs via pentacoordinate phosphorus derivative 3 with the formation of phosphoric acid, carbonyls and nitrogen.

The synthesis and characterization of a phosphido-boratabenzene rhodium complex is reported. The species acts as a precatalyst for the hydrogenation of alkenes at room temperature and atmospheric pressure.

A series of 2-phosphino-1,3-diphosphonium trifluoromethanesulfonate salts has been prepared and comprehensively characterized.

The reaction of Li/Cl phosphinidenoid pentacarbonylmetal(0) complexes with bis(2-pyridyl)ketone led to overcrowded oxaphosphirane derivatives. They can undergo deoxygenation by Ti(III) reagents or ring expansion via P–C cleavage followed by P–N cyclization.

A highly modular solid-phase synthetic approach is presented which provides facile access to libraries of recyclable phosphine–phosphite ligands in quantitative yield requiring only minimal work-up.

A tridentate ligand framework containing a central N-heterocyclic phosphenium cation (NHP⁺) has been coordinated to nickel. Among the compounds reported is a series of [(PPP)Ni]₂^0/+/2+ dimers in three different redox states.

Systematic X-ray analysis, ¹³C NMR spectroscopy and computational studies revealed the existence of Pt → C(aryl) π* back donation in P–C–P platinum(II) pincer complexes.

The reaction chemistry of complexes (THF)_0–2E[P₃Nb(ODipp)₃]₂ (E = Sn, Pb; Dipp = 2,6-ⁱPr₂C₆H₃) featuring the metallophosphide ligand {E(cyclo-P₃)₂} is investigated.

L(Cr,Mo,W)(CO)₅ coordination of N,P-disubstituted phosphaamidines stabilizes molecules prone to isomerization. NMR spectra are consistent with the average mirror symmetry.

Bond activation of silyl compounds, assisted by the cooperative action of non-coordinating anions, is achieved using Cu(I) complexes coordinated with a PNP-pincer type phosphaalkene ligand, [Cu(X)(BPEP-Ph)] (X = PF₆, SbF₆).

Intramolecular interconversion of nickel phosphanido hydride complexes ([NiH{P(Ar)(H)}(dtbpe)]) occurred in three steps: first, hydride proton migrates to phosphorus, then P-Aryl moiety rotates around the P–Ni bond and finally the back migration of one proton to Ni.

The parent phosphinidene–carbene adduct NHCPH reacts with chlorophosphanes yielding NHC-supported chlorodiphosphanes, which can be transformed to novel P₄-rings and reactive 1,2-diphosphenes.

Hydroalumination of alkynyl-aminophosphines afforded an AlP₂C₂ heterocycle via P–N bond activation and a transient phosphaallene.

The mechanism showing both inter- and intramolecular pathways of the phosphazene–phosphazane rearrangement of N₃P₃Cl₅O(CH₂)₂OC(O)CMeCH₂ (8) has been determined.

The reaction of arylbis(alkynyl)phosphanes with the frustrated P/B Lewis pair mes₂PCH₂CH₂B(C₆F₅)₂ gives phosphane/borane functionalized phospholes by a sequence of 1,1-carboboration reactions.

The syntheses, structures, and bonding properties of bicyclic tetraphosphanes as well as their Lewis acid adducts are discussed.

Thermochemical data for the homolytic P–P bond fission in tetraaminodiphosphanes (R₂N)₂P–P(NR₂)₂ were determined experimentally and computationally. The results confirm that radical formation is favoured by entropic and structural relaxation effects, and disfavoured by dispersion forces. Unlike aminophosphenium cations, the radicals display no strong preference for a planar (R₂N)₂P unit.

A general synthesis of P-stereogenic compounds via DoLi–electrophilic quenching of phosphinic amides and subsequent derivatizations is reported.

Cationic and neutral Pd complexes featuring an original phosphine–pyridine–iminophosphorane (PNN) ligand were synthesised. In particular, an unexpected borylated complex was isolated by reaction with B(C₆F₅)₃.

Borane adducts of peri-substituted bis(phosphines) eliminate hydrogen at room temperature, without the presence of catalysts. These reactions are the first examples of “spontaneous” phosphine–borane dehydrocoupling.

A building set for chiral phosphorus. The principle of stereotopic face differentiation is successfully applied to a PC bond. A divergent ligand synthesis is feasible after reduction of the chiral auxiliary.

Novel palladium(II) complexes with the title ligands have been prepared and tested as precatalysts in Suzuki couplings of aryl chlorides.

Reactions of the protonated heptaphosphide dianion, [HP₇]²⁻, with one equivalent of E[N(SiMe₃)₂]₂ (E = Ge, Sn, Pb) give rise to novel derivatized cluster anions [P₇EN(SiMe₃)₂]²⁻ (E = Ge (1), Sn (2) and Pb (3)). 1 readily decomposes in solution at room temperature to afford the dimeric product [(P₇Ge)₂N(SiMe₃)₂]³⁻ (4).

A GaCl₃-mediated rearrangement of a bicyclic phosphorus–nitrogen–silicon heterocycle gives phosphenium ion intermediates which are suitable for the activation of P₄.

P–S bond cleavage occurs in the title reactions to give arylphosphinidene complexes which may not bear a sulphido ligand.

The synthesis and characterization (experimental and DFT) of sterically encumbered triple-decker complexes of the very rare class of P_n ligand complexes of manganese is reported.

The last five years have seen a huge advance in organophosphorus chemistry with respect to compounds with strong chromic responses to external stimuli. This Frontier article briefly summarizes these trends in order to especially highlight the broad versatility of phosphole-based scaffolds in chromic materials.

This Frontier highlights the recent progress in the preparation of organophosphorus compounds via transition metal-catalysed dehydrogenative couplings of P(O)H compounds with Z–H compounds.