M. Peruzzini

The P4Se3 cage molecule as a ligand. Crystal structure of [(N(CH2CH2PPh2)3) Ni(P4Se3]·2C6H6

Abstract The structure of the compound [(np 3 )Ni(P 4 Se 3 )]·2C 6 H 6 , obtained from reaction of the nickel(0) complex (np 3 )Ni (np 3 ue5fb tris(2-diphenylphosphinoethyl)amine) with tetraphosphorus triselenide, P 4 Se 3 , has been determined by X-ray diffraction studies. Crystal data: cubic, space group P 2 1 3, a 17.413(7) A, Z ue5fb 4; final R ue5fb 0.050. The intact P 4 Se 3 entity is coordinated to the metal through the apical phosphorus atom. The small changes occurring in the geometry of the cage molecule upon coordination are analyzed by a comparison with the structure of uncoordinated P 4 Se 3 , which has been refined to R ue5fb 0.045.

Synthesis and structural study of a cobalt complex with the diarsenic-sulfur cyclic unit as a trihapto ligand

Abstract The reaction of Co(BF4)2·6H2O with tetraarsenic trisulfide in the presence of triphos (triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane), yields the compound [(triphos)Co(As2S)]BF4·C6H6 in which the diarsenic-sulfur cyclic unit acts as a trihapto ligand. The structure of the compound has been determined by single-crystal X-ray diffraction methods. The compound crystallizes in the monoclinic P21/n space group with Z = 4 and unit cell dimensions: a = 16.987(7), b = 20.608(7), c = 13.098(5) A, β = 104.83(5)°. The metal atom is in a distorted six-coordinate environment formed by the triphos P atoms and by the atoms of the heterocyclic As2S unit.

Reactivity of arsenic selenides and telluride: Cobalt complexes containing the selena- or tellura-diarsirene cyclic units trihapto-bonded to the metal atom-crystal and molecular structures of [(triphos)Co(As2Se)](BF4)(C2H5OH) and [(triphos)Co(As2Te)](BF4(C6H6)0.5

Abstract The reaction of Co(BF4)2(H2O)6 with arsenic selenides and telluride, As4Se3, As2Se3 and As2Te3 in the presence of 1,1,1-tris(diphenylphosphinomethyl)ethane (triphos), yielded the complexes and The molecular structures of the complexes have been determined by single-crystal X-ray diffraction methods. The isomorphous compounds crystallize in the monoclinic space group P21/n with Z = 4 and unit-cell dimensions: (1) a = 17.034(8) A, b = 20.640(9) A, c = 13.116(6) A, β = 105.37(6)°; (2) a = 17.076(7) A, b = 20.419(9) A, c = 13.215(7) A, β = 105.15(7)°. The metal atom in both compounds is in a six-coordinate environment formed by the triphos P atoms and by the atoms of the heterocyclic As2Se or As2Te unit.

Rhodium(III) and rhodium(I) complexes with tripod tetradentate ligands

Rhodium(III) complexes with the tripod tetradentate ligand tris(2-diphenylphosphinoethyl)amine, np 3 , of formula [RhCl 2 (np 3 )] Y (Y = Cl, PF 6 , BPh 4 ), have been prepared and characterized. One of the coordinated chlorine atoms in these compounds may be replaced by a molecule of acetonitrile. The hydrido complex [RhHCl(Cynp 3 ] BPh 4 ·(CH 3 ) 2 CO has been obtained by reaction of rhodium trichloride hydrate with the tripod ligand tris(2-dicyclohexyl-phosphinoethyl)amine, Cynp 3 , bearing bulky subsitutuents on the phosphorus atoms. All of the above complexes are assigned six-coordinated structures, mainly on the basis of their 1 H and 31 P n.m.r. spectra. The crystal structure of the hydrido complex has been determined by X-ray diffraction analysis. The np 3 derivatives are easily reduced to give five-coordinate rhodium(I) complexes with formulae [RhH(np 3 ] and [RhCl(np 3 )].

Synthesis and reactivity of novel cationic organonickel(II) compexes. X-ray structure of [bis(2-diphenylphosphinoethyl)phenylphosphinenickel-O-methylsulfinate]tetraphenylborate

Abstract Cationic tetracoordinate nickel(II) compounds containing a nickelue5fbcarbon σ bond with general formula [NiR(etp)]Y, (etp ue5fb bis(2-diphenylphosphinoethyl)phenylphosphine, PhP(CH2CH2PPh2)2; R = CH3, CH2C6H5, C6H5; Y = BPh4, PF6) were synthesized by reaction of the complexes [NiX(etp)]Y (X = halogen) with appropriate Grignard reagents. This type of organometallic complexes undergo insertion of sulfur dioxide into the Niue5fbC bond with formation of tetracoordinate O-sulfinate derivatives of nickel(II). The structure of [NiOS(O)CH3(etp)]BPh4 has been determined from three dimensional X-ray data collected by counter methods. The compound crystallized in the triclinic group P 1 with cell dimensions a 16.726(4), a 15.350(4), c 11.632(3) A, α 66.55(4), β 73.37(4), γ 74.75(4)°, Z = 2. The structure was refined by full matrix least-squares methods to a conventional R factor of 0.076. The coordination polyhedron has a distorted square planar geometry. The sulfinate group is linked to the metal through an oxygen atom.

Cleavage of tetraarsenic trisulfide by nickle moieties

Abstract Tetraarsenic trisulfide undergoes cleavage in the presence of triphos-nickel moieties (triphos = 1,1,1-tris(diphenylphosphinomethylethane) to give good yields of compounds containing the cyclic triarsenic unit.

Fast atom bombardment mass spectrometry of cationic complexes containing homo- and hetero-atomic cyclic units trihapto-bonded to the metal atom

Abstract The fast atom bombardment mass spectra of a series of ionic compounds of formula [(triphos)M(η3-E2X)]Y (triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane; M = Ni, E = X = P, Y = BF4 or PF6; M = Co, E = P, X = S or Se; E = As, X = S, Se or Te; Y = BF4) are reported. The cations contain a homo- or hetero-atomic trimembered inorganic ring trihapto bonded to a metal-triphos unit. Both in glycerol and thioglycerol the complexes exhibit a characteristic fragmentation which involves the stepwise loss of the three atoms of the inorganic ring and the ejection of organic radicals from the triphos ligand. Adduct ions with sulphur atoms or sulphur organic radicals are, furthermore, observed in thioglycerol. Such adducts infer interactions of the matrix with: (a) the atoms of the inorganic ring of the complex cations, and (b) the metal atom of the (triphos)M moiety.

Gas-phase studies of phosphorus- and arsenic-chalcogenide cage molecules

Abstract Positive and negative ion chemical ionization and electron impact mass spectra of E 4 X 3 (E = P, As;X = S, Se) cage molecules were investigated. All the molecules undergo analogous cleavages, which are dominated by even-electron ions. Protons affinities of the tetrapnicogen trichalcogenides were evaluated by the chemical ionization mass spectra (CIMS) of the molecules in the presence of reagents, such as methane, isobutane, acetone, ethylacetate and ammonia, whose proton affinity is known. P 4 S 3 , P 4 AsS 3 , P 2 As 2 S 3 , PAs 3 S 3 , P 4 Se 3 and As 4 Se 3 show similar proton affinities, whilst As 4 S 3 exhibits a significantly higher proton affinity. Some correlations are drawn between gas-phase behaviour of these molecules and their reactivity in solution.