RESUMEN
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.
RESUMEN
Phosphorus heterocycles find applications in the synthesis of π-conjugated compounds and as precursors for optoelectronic materials such as organic light-emitting diodes (OLEDs), electronic switches, and transistors. A high-yield, one-pot synthesis of anionic annulated 1,3,4-azadiphospholides from Na(OCP) and 2-chloropyridines is presented. The synthesis proceeds without the use of transition metals and tolerates a wide range of substrates. Cyano-substituted compounds are especially deeply colored and have absorption maxima which range from λmax =525 to 596â nm. The optical properties are dominated by the spatial separation of an electron acceptor and donor unit within one molecule (push-pull chromophore). The anionic 1,3,4-azadiphospholides are silylated to neutral siloxy compounds with a strong blue-shifted absorption. This reaction can be reversed by addition of fluoride ions, which allows fluoride ions to be detected in optically low concentrations.
RESUMEN
A facile, one-pot synthesis of [Na(OC≡As)(dioxane)x ] (x=2.3-3.3) in 78 % yield is reported through the reaction of arsine gas with dimethylcarbonate in the presence of NaOt Bu and 1,4-dioxane. It has been employed for the synthesis of the first arsaketenyl-functionalized germylene [LGeAsCO] (2, L=CH[CMeN(Dipp)]2 ; Dipp=2,6-i Pr2 C6 H3 ) from the reaction with LGeCl (1). Upon exposure to ambient light, 2 undergoes CO elimination to form the 1,3-digerma-2,4-diarsacyclobutadiene [L2 Ge2 As2 ] (3), which contains a symmetric Ge2 As2 ring with ylide-like Ge=As bonds. Remarkably, the CO ligand located at the arsenic center of 2 can be exchanged with PPh3 or an N-heterocyclic carbene iPr NHC donor (iPr NHC=1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) to afford the novel germylidenylarsinidene complexes [LGe-AsPPh3 ] (4) and [LGe-As(iPr NHC)] (5), respectively, demonstrating transition-metal-like ligand substitution at the arsinidene-like Asâ atom. The formation of 2-5 and their electronic structures have been studied by DFT calculations.
RESUMEN
Phosphinidenes [R-P] are convenient P1 building blocks for the synthesis of a plethora of organophosphorus compounds. Thus far, transition-metal-complexed phosphinidenes have been used for their singlet ground-state reactivity to promote selective addition and insertion reactions. One disadvantage of this approach is that after transfer of the P1 moiety to the substrate, a challenging demetallation step is required to provide the free phosphine. We report a simple method that enables the Lewis acid promoted transfer of phenylphosphinidene, [PhP], from NHC=PPh adducts (NHC=N-heterocyclic carbene) to various substrates to produce directly uncoordinated phosphorus heterocycles that are difficult to obtain otherwise.
RESUMEN
The parent phosphinidene-carbene adduct NHC=PH is a versatile synthon in main group chemistry and can act as an electronically flexible ligand for transition metals. Previously, it could only be synthesized with sterically demanding N-aryl substituents. This paper describes simple methods for the synthesis of NHC=PH adducts with varying steric demand from elemental phosphorus or easily accessible phosphorus sources. Furthermore, the reactivity of NHCs towards PH3 was investigated. It was shown how a NHC inserts into the P-H bond of PH3, which opens up a route to NHC=PH adducts from an imidazolium salt and PH3. The adducts were used in the simple syntheses of bis(phosphinidene) mercury(II) and group 6 pentacarbonyl parent phosphinidene complexes. Their electronic and structural properties were investigated to elucidate the influence of the NHC on the phosphinidene and identify possible applications.
RESUMEN
PH3 reacts with the in situ generated N-heterocyclic carbene DippNHC* (DippNHC* = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) to give the phosphanyl-imidazolidine [(Dipp)NHC*-H]-[PH2]. Upon treatment with an ortho-quinone, [(Dipp)NHC*-H]-[PH2] is dehydrogenated to give the parent phosphinidene-carbene adduct (Dipp)NHC*[double bond, length as m-dash]PH. Alternative routes to [(Dipp)NHC*-H]-[PH2] and (Dipp)NHC*[double bond, length as m-dash]PH employ NaPH2 and (TMS)3P7 (TMS = trimethylsilyl), respectively, as phosphorus sources. The adduct (Dipp)NHC*[double bond, length as m-dash]PH and the related adduct (Dipp)NHC[double bond, length as m-dash]PH ((Dipp)NHC = bis(2,6-diisopropylphenyl)imidazol-2-ylidene) possessing an unsaturated NHC backbone both react with HgCl2 to give the bis(carbene-phosphinidenyl) complexes [((Dipp)NHC*[double bond, length as m-dash]P)2Hg] and [((Dipp)NHC[double bond, length as m-dash]P)2Hg].