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Reduction of high spin paramagnetic complex [(κ2-P, P′-PCH2PCy)FeCl2] 2 by two electrons under N2 resulted in the formation of two isomeric low spin diamagnetic complexes 3trans and 3cis [Fe(κ3-P,C,P′-PCPCy)(H)2(N2)]. Cristallization allowed isolation of complex 3d [Fe(κ3-P,C,P′-PCPCy)(H)2]2(μ-N2), characterized by X-ray diffraction, Mössbauer and Raman spectroscopies. DFT calculations rationalized the facile double α,α CH bond insertion into a single sp3 CH2 moiety, as well as the fast exchange positions of the hydrides in the cis dihydride complex observed by NMR spectrocscopy. [ABSTRACT FROM AUTHOR]

The reduction of [Ni(DME)Cl2] with 2 equiv. of bis(trimethylsilyl)-1,4-tetramethyldihydropyrazine in the presence of a ligand L and an excess of olefin cleanly leads to [Ni(L)(alkene)2] complexes. When reduction is performed in the presence of 1,5-cyclooctadiene (COD), [Ni(COD)2] is obtained. Such an approach also allows access to the NiI dimer [Ni(bis(dicyclohexylphosphino)propane)Cl]2. [ABSTRACT FROM AUTHOR]

The two electron reduction of iron complexes [(PRP2Cy)Fe(Cl)2] (R = Ph or tBu) 2a–b afforded complexes [(PRP2Cy)Fe(N2)2] 4a–b. Protonation of 4a at the metal center and subsequent reduction to Fe(i)–H species lead to complex [(PPhP2Cy)Fe(N2)(H)2] 6avia a spontaneous disproportionation reaction. Complex 4a behaves as one of the most efficient monometallic Fe-catalysts reported to date for N2-to-N(SiMe3)3 functionalization under atmospheric pressure. [ABSTRACT FROM AUTHOR]

We report the water-assisted synthesis of indium nanoparticles (In NPs). We found that a precise amount of water was necessary to allow the formation of the desired 7 nm In NPs: the oxidation of the In surface by water inhibits the growth of NPs as well as subsequent reactivity with white phosphorus (P4). A novel surface activation method based on the use of organosilanes is presented. [ABSTRACT FROM AUTHOR]

A direct method for white phosphorus functionalization by hydride sources is presented. Excess BH4− in n-butylamine produces HP4− as the major P-containing species. Reaction with LiBEt3H forms the borane-stabilized phosphanide Li(PH2)(BEt3)2, which may be used to synthesize various phosphines. Triethylborane may be replaced by BH3, resulting in the formation of LiPH2(BH3)2. [ABSTRACT FROM AUTHOR]

The treatment of Li2C(PPh2NMes)2 (1, Mes = 2,4,6-Me3C6H2) with hexachloroethane yielded the corresponding carbenoid 2 in good yields. The reactivity of 2 was studied with BH3·SMe2 to give a zwitterionic boronium species 4, also a stable carbenoid. Both carbenoid species were found to be excellent catalysts for the CO2 reduction by BH3·SMe2. [ABSTRACT FROM AUTHOR]

Gold phosphide (Au2P3) is known as a crystalline metastable phase at the macroscale. In this paper, the formation of Au2P3 nanostructures is investigated. Here, white phosphorus (P4) is used as a soluble phosphorus donor and reacted on 16 nm gold nanoparticles, in a strategy similar to the one previously used for the production of various metal phosphide nanoparticles including Ni2P, Pd5P4, PdP2, Cu3P and InP. Moderate temperature (250 °C for up to 6 h) gives a reaction limited to the surface of the nanoparticles, while the unreacted P4 stays in solution. This surface modification is then optimized by reducing the stoichiometry of P4 to Au : P = 10 : 1 and lowering the temperature to 110 °C. Interestingly, this surface modification shields the plasmon band against ligand exchange with thiols, providing more robust nanoparticles. The reaction is then conducted under harsh conditions (320 °C for 3 h) to produce crystalline Au2P3. This triggered the aggregation of the starting nanoparticles into larger nanostructures such as nanowires. Moreover, the formation of composite Au2P3–Au nanostructures is observed, where the gold phosphide domains are systematically larger than the unreacted gold nanoparticles. This suggests that gold is particularly reluctant to form gold phosphide, which relates to the metastable character of this phase. [ABSTRACT FROM AUTHOR]

P4reaction with metal NPs (In, Pb, Zn) provides an easy access to the corresponding metal phosphide NPs in a soft and stoichiometric reaction. Size-influence on the reactivity is investigated in the case of indium. [ABSTRACT FROM AUTHOR]

The stoichiometric reaction of [Rh(COD)Cl]2 with the anion resulting from the deprotonation of dppm(BH3)2 yielded a new alkyl Rh(I) complex; the coordination modes of the BH3 groups are discussed on the basis of X-ray data, variable temperature multinuclear NMR experiments and DFT studies. [ABSTRACT FROM AUTHOR]

A bulky 1-phosphabarrelene, 2, was obtained from the reaction of a phosphinine with benzyne; two palladium complexes of 2 were successfully employed in the Suzuki-Miyaura coupling of several aryl chlorides with phenylboronic acid at a relatively low catalyst loading, and activated aryl chlorides were coupled at room temperature in the absence of strong bases. [ABSTRACT FROM AUTHOR]

Reduction of high spin paramagnetic complex [(κ2-P, P'-PCH2PCy)FeCl2] 2 by two electrons under N2 resulted in the formation of two isomeric low spin diamagnetic complexes 3trans and 3cis [Fe(κ3-P,C,P'-PCPCy)(H)2(N2)]. Cristallization allowed isolation of complex 3d [Fe(κ3-P,C,P'-PCPCy)(H)2]2(μ-N2), characterized by X-ray diffraction, Mössbauer and Raman spectroscopies. DFT calculations rationalized the facile double α,α CH bond insertion into a single sp3 CH2 moiety, as well as the fast exchange positions of the hydrides in the cis dihydride complex observed by NMR spectrocscopy.

The reduction of [Ni(DME)Cl2] with 2 equiv. of bis(trimethylsilyl)-1,4-tetramethyldihydropyrazine in the presence of a ligand L and an excess of olefin cleanly leads to [Ni(L)(alkene)2] complexes. When reduction is performed in the presence of 1,5-cyclooctadiene (COD), [Ni(COD)2] is obtained. Such an approach also allows access to the NiI dimer [Ni(bis(dicyclohexylphosphino)propane)Cl]2.

The two electron reduction of iron complexes [(P R P 2 Cy )Fe(Cl) 2 ] (R = Ph or tBu) 2a-b afforded complexes [(P R P 2 Cy )Fe(N 2 ) 2 ] 4a-b. Protonation of 4a at the metal center and subsequent reduction to Fe(i)-H species lead to complex [(P Ph P 2 Cy )Fe(N 2 )(H) 2 ] 6avia a spontaneous disproportionation reaction. Complex 4a behaves as one of the most efficient monometallic Fe-catalysts reported to date for N 2 -to-N(SiMe 3 ) 3 functionalization under atmospheric pressure.

A direct method for white phosphorus functionalization by hydride sources is presented. Excess BH4(-) in n-butylamine produces HP4(-) as the major P-containing species. Reaction with LiBEt3H forms the borane-stabilized phosphanide Li(PH2)(BEt3)2, which may be used to synthesize various phosphines. Triethylborane may be replaced by BH3, resulting in the formation of LiPH2(BH3)2.

The treatment of Li2C(PPh2NMes)2 (1, Mes = 2,4,6-Me3C6H2) with hexachloroethane yielded the corresponding carbenoid 2 in good yields. The reactivity of 2 was studied with BH3·SMe2 to give a zwitterionic boronium species 4, also a stable carbenoid. Both carbenoid species were found to be excellent catalysts for the CO2 reduction by BH3·SMe2.

Room temperature reversible C-H activation mediated by a designed diphosphine platinum complex is presented. These findings are demonstrated through mechanistic studies involving kinetics, isotopic effects, and corroborated by DFT calculations. The coupling between two unactivated aromatic derivatives is also demonstrated.

Early transition metal nucleophilic carbene complexes have been used as stoichiometric carbene transfer agents in a transmetalation process.

Enantiopure undecagold clusters protected by chiral atropisomeric diphosphine ligands (P^P) have been synthesized by the stoichiometric reduction of the corresponding (P^P)(AuCl)(2) complexes with NaBH(4). The molecular mono-disperse [Au(11)(P^P)(4)Cl(2)]Cl species have been thoroughly characterized using an array of analytical techniques. (31)P NMR experiments suggested the presence of a slow intramolecular ligand exchange process. Circular dichroism measurements showed that enantiomeric clusters display mirror-image chiroptical activity. Such undecagold clusters containing two chloride ligands bound to the peripheral Au(I) atoms were expected to display a carbophilic Lewis acidity similar to the well-documented molecular Au(I) complex catalysts. Chloride abstraction, performed to generate active Au(+) sites, induced the Au(11) cluster evolution to larger gold clusters and nanoparticles, together with Au(I) complexes, which, in fact, perform the catalysis. This result was corroborated by running an asymmetric tandem hydroarylation-carbocyclization reaction, for which the enantiomeric excesses obtained with Au(11) clusters are similar to those reported using Au(I) complexes.

Metathesis reactions of UCl(4) with Li(2)C(Ph(2)PS)(2) in Et(2)O only afforded the tris-carbene complex [{Li(OEt(2))}(2)U{=C(Ph(2)PS)(2)}(3)] (1), while the bis- and mono-carbene compounds [U{=C(Ph(2)PS)(2)}(2)(THF)(2)] (2) and [{Li(THF)(2)}(2)U{=C(Ph(2)PS)(2)}Cl(4)] (3) were obtained by treatment of UCl(4) with Li(2)C(Ph(2)PS)(2) in a mixture of THF and toluene. The bis-carbene complex 2 was also obtained either from the comproportionation reaction of 1 and UCl(4) or protonolysis reaction of U(NEt(2))(4) with H(2)C(Ph(2)PS)(2) and was transformed into the mono-carbene complex [U{=C(Ph(2)PS)(2)}Cl(2)(THF)(2)] (4) by further reaction with UCl(4). The utility of these complexes as precursors is illustrated by the synthesis of the biscyclopentadienyl derivative [Cp(2)U{=C(Ph(2)PS)(2)}] (5) by treatment of 3 with TlCp. The crystal structures of [U{=C(Ph(2)PS)(2)}(2)(py)(2)].1.5py.0.5THF and 5.toluene are reported.

The reactivity of the geminal dianion of tetraisopropyl methylenediphosphonate, 3, with [ZrCl4(THF)2] affords a trinuclear structure 5 in which an unprecedented triscarbene-Zr dianionic fragment is found. The overall trinuclear arrangement is assembled by PO bridging moieties. The X-ray crystal structure of 5 is presented. The reaction of complex 5 with stoichiometric amounts of pyridine affords a dinuclear complex 6 whose formulation was ascertained by an X-ray crystal structure. Complexes 5 and 6 cleanly react with aldehydes (R1)(H)CO to afford the corresponding olefin of general formula [((OiPr)2P=O)2C=C(R1)(H)]. DFT calculations which were carried out on the model complex of 5t and a hypothetical monometallic Zr complex [Zr(3)Cl2(OMe2)2] 8t indicate that the Zr-C bond only features a weak pi-interaction between the carbon atom and a vacant orbital at the metal. The polarization of the orbital towards the carbon center is consistent with the observed nucleophilic character of the carbene complexes described here.

White phosphorus, P4, was reacted in a stoichiometric manner with Ni(0) complexes or particles to produce nanoparticles of nickel phosphide.

The stabilisation of the carbene centre in a complex can be achieved either by the metal moiety or the carbon substituents. The balance between these two stabilising effects determines the nature of the M=C bond and therefore the reactivity of the metal complexes. Introducing two vicinal phosphorus groups as substituents of the carbene centre proved to be rewarding, since depending on the coordination number of this atom different electronic properties are observed. Indeed, a sigma(3)-P atom possesses a lone pair that can interact with a carbene centre by destabilising its vacant p(pi) orbital. On the contrary a sigma(4)-P group presents low lying sigma* orbitals which can be involved in delocalising electronic density in the carbene p(pi) orbital by negative hyperconjugation. Therefore, PCP carbene complexes can exhibit either an electrophilic or nucleophilic reactivity depending on the nature of the phosphorus group and the metal centre. Carbenes complexes of early and late transition metals, but also of lanthanides are discussed in this perspective.

A new type of stable radical ligand featuring a 1,1-bis-phosphinosulfide alkene backbone has been prepared and characterized on the basis of X-ray diffraction, EPR and DFT studies.

Cyclic voltammetry and EPR spectroscopy show that cationic phospholium groups are good electron acceptors whose reduction leads to a neutral radical where the unpaired electron is mainly delocalized on the carbon atoms of the five-membered ring. DFT calculations together with the crystal structure of phospholiums indicate that the electron addition causes a drastic diminution of the exocyclic CPC angle. The SOMO of reduced phospholium is compared to the SOMO of the phosphole radical anion.

New kinetically stabilized mono- and bis-phosphaalkene ligands (2 and 3, respectively) were synthesized via the phospha-Wittig approach. Ligand 3 was characterized by X-ray diffraction. The coordinating behaviour of the bidentate ligand was investigated towards group 11 metal centers in order to test its capacity to bind two coordination sites located in a trans-fashion. The [Au(3)][BF4], [Ag(3)(H2O)][BF4] and [Cu(3)(CH3CN)][BF4] complexes 4 , 5 and 6, respectively, were characterized by X-ray diffraction. The peculiar geometries of 4 and 6 were rationalized by means of DFT calculations.

New samarium carbene complexes have been synthesized and characterized by X-ray diffraction analysis; the carbenic nature was assessed by reactivity studies.

Reaction of a tetraphenyl-1,2-diphosphinyl dianion with [FeCl2(THF)1.5] or [Ru(COD)(acac)2] yields dianionic complexes which further react with Ph3SnCl to afford the corresponding bis(1,4-diphosphabutadiene) complexes.

A palladium(II) complex of a S-P-S pincer ligand featuring a metallated ylidic P-atom efficiently catalyzes the coupling between pinacolborane and various iodoaryls to yield the corresponding arylboronic esters (TON between 5100 and 76,500).