(Ph)3PBr][Br7], [(Bz)(Ph)3P]2[Br8], [(n-Bu)3MeN]2[Br20], [C4MPyr]2[Br20], and [(Ph)3PCl]2[Cl2I14]: extending the horizon of polyhalides via synthesis in ionic liquids

The five polyhalides [(Ph)(3)PBr][Br(7)], [(Bz)(Ph)(3)P](2)[Br(8)], [(n-Bu)(3)MeN](2)[Br(20)], [C(4)MPyr](2)[Br(20)] ([C(4)MPyr] = N-butyl-N-methylpyrrolidinium), and [(Ph)(3)PCl](2)[Cl(2)I(14)] were prepared by the reaction of dibromine and iodine monochloride in ionic liquids. The compounds [(Ph)(3)PBr][Br(7)] and [(Bz)(Ph)(3)P](2)[Br(8)] contain discrete pyramidal [Br(7)](-) and Z-shaped [Br(8)](2-) polybromide anions. [(n-Bu)(3)MeN](2)[Br(20)] and [C(4)MPyr](2)[Br(20)] exhibit new infinite two- and three-dimensional polybromide networks and contain the highest percentage of dibromine ever observed in a compound. [(Ph)(3)PCl](2)[Cl(2)I(14)] also consists of a three-dimensional network and is the first example of an infinite polyiodine chloride. All compounds were obtained from ionic liquids as the solvent that, on the one hand, guarantees for a high stability against strongly oxidizing Br(2) and ICl and that, on the other hand, reduces the high volatility of the molecular halogens.     

Synthese und Kristallstrukturen von [(Ph3As)2CCN–MnBr3], [(Ph3As)2CCN–CoBr3] und [(Ph3As)2CCN]+CuBr2–

Syntheses and Crystal Structures of [(Ph₃As)₂CCN–MnBr₃], [(Ph₃As)₂CCN–CoBr₃], and [(Ph₃As)₂CCN]⁺CuBr₂^– The di(arsa)acetonitrilium bromide [(Ph₃As)₂CCN]Br reacts with the anhydrous dibromides of manganese and cobalt in acetonitrile to form the molecular complexes [(Ph₃As)₂CCN–MBr₃] [M = ( 1 ), Co( 2 )] with zwitterionic structures. With copper(I)bromide, however, the ionic compound [(Ph₃As)₂CCN]⁺CuBr₂^– ( 3 ) is formed. All complexes are characterized by IR spectroscopy and by crystal structure analyses. 1 and 2 crystallize isotypically with each other in the space group P 1 with two formula units per unit cell. The MBr₃^– fragments in the molecular complexes are connected to the N atom of the [(Ph₃As)₂CCN]⁺ cation showing bond angles C–N–Mn of 156.9° and C–N–Co of 161°, and distances Mn–N of 215.6 pm and Co–N of 201 pm. In 3 , on the other hand, (space group C2/c, Z = 4) the ions [(Ph₃As)₂CCN]⁺ and the linear Br–Cu–Br^– ion are to be found concurrent but separate.     

[(Ph3PCH2)(Ph3P)PtCl][AlCl4], ein in CH2Cl2-lösung dreifach koordinierter kationischer platin(II)-komplex

The interaction of cis-[(Ph₃PCH₂)(Ph₃P)PtCl₂] with aluminium(III) chloride in CH₂Cl₂ affords the three coordinate cationic platinum(II) complex [(Ph₃PCH₂)(Ph₃P)PtCl][AlCl₄] which is a useful starting material for platinum complexes with four different ligands. With Ph₃As and Me₂S the cationic phosphorus ylide complexes [(Ph₃PCH₂)(Ph₃P)(Ph₃As)PtCl][AlCl₄] and [(Ph₃PCH₂)(Ph₃P)(Me₂S)PtCl][AlCl₄] are formed. 851 V 3     

Facile Ar-CF3 bond formation at Pd. Strikingly different outcomes of reductive elimination from [(Ph3P)2Pd(CF3)Ph] and [(Xantphos)Pd(CF3)Ph

Facile and highly selective perfluoroalkyl-aryl reductive elimination from a metal center (Pd) has been demonstrated for the first time. At temperatures as low as 50-80 degrees C, [(Xantphos)Pd(Ph)CF3] undergoes remarkably clean decomposition to produce CF3Ph in high yield and selectivity. In contrast, analogous trifluoromethylpalladium aryls stabilized by rigid cis-chelating ligands such as dppe are completely unreactive at temperatures up to 130-140 degrees C. Decomposition of [(Ph3P)2Pd(Ph)CF3] in the presence of PhI in benzene at 60 degrees C does not produce PhCF3 but rather leads to [(Ph3P)2Pd(Ph)I] and [Ph4P]+[(Ph3P)Pd(CF3)3]- in a 2:1 ratio with high selectivity.     

Synthesis and structural characterisation of [(Ph3P)AuCo(CO)3(PPh3)]

Summary [(Ph₃P)AuCo(CO)₃(PPh₃)] has been synthesised from [(Ph₃P)AuCo(CO)₄], PPh₃v and Me₃NO in acetonitrile. Its molecular structure, determined by single-crystal x-ray crystallography, consists of an almost linear P-Au-Co-P arrangement in which the Co atom is in a slightly distorted trigonalbipyramidal geometry, with the Au and P atoms occupying the apical sites. The Au-Co bond length of 2.450(1) ? is shorter than that reported for [(Ph₃P)AuCo(CO)₄]. The carbonyl ligands are bent towards the Au atom and the mean Au-Co-C angle is 81(1)°.     

Shape and size control of Ag2Se nanocrystals from a single precursor [(Ph3P)3Ag2(SeC{O}Ph)2

Monodispersed Ag2Se nanocubes and faceted nanocrystals have been synthesized by hexadecylamine (HDA) induced thermolysis of [(PPh3)3Ag2(SeC{O}Ph)2] in a mixture of TOP (tri-n-octyl phosphine) and HDA in the temperature range 95-180 degrees C.     

Study of the reactions and reaction mechanisms of phosphine (Ph3P) and of phosphite ((PhO)3P) with sulphur (S8)

The reactions of sulphur with phosphine and phosphite were investigated by low-energy electron impact mass spectrometry and fast atom bombardment mass spectrometry. A previously reported mechanism of the Ph₃P–S₈ reaction was supported and a possible mechanism for the (PhO)₃P–S₈ reaction is proposed.     

Selective hydrogenation of alkene in (3-trifluoromethyl) phenyldiazirine photophor with Wilkinson's catalyst for photoaffinity labeling

Selective hydrogenation of carbon-carbon double bond in the presence of nitrogen-nitrogen double bond in (3-trifluoromethyl) phenyldiazirine achieved with Wilkinson's catalyst.     

Mechanisms of catalyst poisoning in palladium-catalyzed cyanation of haloarenes. remarkably facile C-N bond activation in the [(Ph3P)4Pd]/[Bu4N]+ CN- system

Reaction paths leading to palladium catalyst deactivation during cyanation of haloarenes (eq 1) have been identified and studied. Each key step of the catalytic loop (Scheme 1) can be disrupted by excess cyanide, including ArX oxidative addition, X/CN exchange, and ArCN reductive elimination. The catalytic reaction is terminated via the facile formation of inactive [(CN)4Pd]2-, [(CN)3PdH]2-, and [(CN)3PdAr]2-. Moisture is particularly harmful to the catalysis because of facile CN- hydrolysis to HCN that is highly reactive toward Pd(0). Depending on conditions, the reaction of [(Ph3P)4Pd] with HCN in the presence of extra CN- can give rise to [(CN)4Pd]2- and/or the remarkably stable new hydride [(CN)3PdH]2- (NMR, X-ray). The X/CN exchange and reductive elimination steps are vulnerable to excess CN- because of facile phosphine displacement leading to stable [(CN)3PdAr]2- that can undergo ArCN reductive elimination only in the absence of extra CN-. When a quaternary ammonium cation such as [Bu4N]+ is used as a phase-transfer agent for the cyanation reaction, C-N bond cleavage in the cation can occur via two different processes. In the presence of trace water, CN- hydrolysis yields HCN that reacts with Pd(0) to give [(CN)3PdH]2-. This also releases highly active OH- that causes Hofmann elimination of [Bu4N]+ to give Bu3N, 1-butene, and water. This decomposition mode is therefore catalytic in H2O. Under anhydrous conditions, the formation of a new species, [(CN)3PdBu]2-, is observed, and experimental studies suggest that electron-rich mixed cyano phosphine Pd(0) species are responsible for this unusual reaction. A combination of experimental (kinetics, labeling) and computational studies demonstrate that in this case C-N activation occurs via an S(N)2-type displacement of amine and rule out alternative 3-center C-N oxidative addition or Hofmann elimination processes.     

Synthesis and crystal structure of [(Ph3P)2N] [Ni2(CO)6H]

The interstitial dihydride dianion [Ni₁₂(CO)₂₁H₂]^2? is readily converted by carbon monoxide (25°C, 1 atm) into a mixture of tetracarbonylnickel and a new colourless hydride carbonyl monoanion, which has been characterized by X-ray diffraction as [Ni₂(CO)₆H]^?.     

Highly efficient photocatalytic Suzuki coupling reaction by Pd_3P/CdS catalyst under visible-light irradiation

Monodispersed palladium phosphide(Pd_3P)(5.2 ± 0.5 nm) was firstly applied to photocatalytic Suzuki coupling reaction under visible light irradiation with CdS nanoflake as a photo sensitizer.This heterogeneous system exhibited high yields to corresponding products and excellent stability in alcohol solvent at room temperature.     

Solvent-free mechanochemical synthesis of two Pt complexes: cis-(Ph3P)2PtCl2 and cis-(Ph3P)2PtCO3

Cis-(Ph3P)2PtCl2 and cis-(Ph3P)2PtCO3 were prepared mechanochemically from solid reactants in the absence of a solvent; cis-(Ph3P)2PtCl2 was obtained in 98% yield after ball-milling of polycrystalline PtCl2 and Ph3P; the mechanically induced solid-state reaction of cis-(Ph3P)2PtCl2 with an excess of anhydrous K2CO3 produced cis-(Ph3P)2PtCO3 in 70% yield; the formation of transition metal complexes as a result of mechanochemical solvent-free reactions has been confirmed by means of solid-state 31P MAS NMR spectroscopy, X-ray powder diffraction and differential thermal analysis.     

The visible chemiluminescence of the reaction F + CH3F

By using molecular beam apparatus the visible (450–900 nm) chemiluminescence of the reaction F + CH₃F was investigated. Seven vibronic bands of HCF (Ã₁A-XA') and four vibrational bands of HF ground state overtone transitions were obtained. The relative vibrational state distributions of HF (V'=4,5,6) states and the rotational temperature of HF (V'=3) state were obtained. The analyses show that the two kinds of spectra were caused by the secondary reaction F+CH₃F. The results may be helpful to explain the contradictory results of the experiments in F+CH₃F system.     

[(THF)2Na(Ph2N)2Sm{N(SiMe3)2}2], ein Amido-Komplex des Samariums mit sandwichartig koordiniertem Natriumion

[(THF)₂Na(Ph₂N)₂Sm{N(SiMe₃)₂}₂], an Amido Complex of Samarium with a Sandwich-like Coordinated Sodium Ion The title compound has been prepared from Sm[N(SiMe₃)₂]₃, NaN(SiMe₃)₃, and HNPh₂ in THF solution forming yellow-green single crystals, which were characterized by a crystal structure determination. The complex forms an ion pair in which the sodium ion is coordinated by two THF molecules and by two phenyl groups of the diphenylamido groups in a sandwich-like fashion. The samarium atom is tetrahedrally coordinated by the four nitrogen atoms of the NPh₂^– and the N(SiMe₃)₂^– ligands.