Sandra Ianelli

Structure and catalytic activity of phosphine-substituted ruthenium carbonyl carboxylates

Abstract The structures of the [{Ru(CO) 2 (μ-OOCCH 3 )L} 2 ] with L = P n Bu 3 , P t Bu 3 or P i Pr 3 have been determined and their catalytic activity tested in the hydrogenation of internal and terminal olefins, of the carbonyl double bond and of both free and esterified carboxylic groups. There is a correlation between the PRuRuP torsion angle and the catalytic activity of the complex.

Syntheses, characterization and X-ray structure of palladium(II) and nickel(II) complexes of tetradentate pyrrole containing ligands

Abstract Palladium(II) and nickel(II) complexes with tetradentate ligands derived from pyrrole 2-carboxaldehyde and various diamines have been synthesized and characterized. The complexes are neutral and the coordination around the metal is square-planar; they are able to activate the molecular hydrogen and to catalyse the homogenous hydrogenation of phenylacetylene. The X-ray structures of N,N′-cycloexylenebis(pyrrol-2-ylmethyleneamine) (H2L4), PdL4 and PdL3 (H2L3, N,N′-propylenebis(pyrrol-2-ylmethyleneamine)) are discussed.

Synthesis, structure, and biological activity of organotion compounds with Di-2-pyridylketone and phenyl(2-pyridyl) ketone 2-aminobenzoylhydrazones

The ligand behavior of di-2-pyridylketone 2-aminobenzoylhydrazone (Hdpa), and phenyl(2-pyridyl)ketone 2-aminobenzoylhydrazone (Hdba) towards organotin derivatives was investigated. The synthesis and the IR and 119Sn NMR spectroscopic characterization of the compounds is reported, together with the X-ray crystal structures of Hdpa and Sn(C6H5)3Cl(OH2).Hdpa, which are discussed and compared. The in vitro evaluation of antimicrobial properties revealed the strong activity of Sn(C6H5)2(Hdpa)Cl2 and Sn(C6H5)3Cl(OH2).Hdpa complexes. None of the compounds showed genotoxicity in the Bacillus subtilis rec-assay and in the Salmonella-microsome test.

Structural characterization of a new ligand mode of 2,6-diacetylpyridine bis(semicarbazone), H2daps

Abstract Four new complexes, [Co( H 2 daps )(OH 2 ) 2 ](CH 3 COO) 2 ·6H 2 O ( I ), [Co( H 2 daps )(OH 2 ) 2 ](NO 3 ) 2 ·H 2 O ( II ) and two polymorph forms of Ni( Hdaps ) 2 ·5H 2 O ( III and IV ), have been prepared by reacting 2,6-diacetylpyridine bis(semicarbazone) ( H 2 daps ) with Co(CH 3 COO) 2 ·4H 2 O, Co(NO 3 ) 2 ·6H 2 O and NiCO 3 ·2Ni(OH) 2 ·4H 2 O. The X-ray structural analysis shows that the cobalt(II) ion is seven-coordinated in a bipyramidal pentagonal arrangement, while coordination around nickel is octahedral; unusually, two molecules of the mono-deprotonated ligand act as tridentate by using only one of their two arms.

Some hexadentate Ni(II)-edta-type complexes containing five-membered diamine rings. The molecular and crystal structure of the trans(O5) isomer of barium(ethylenediamine)-N,N′-diacetato-N,N′-di-3-propionato_)nicklate(II) hexahydrate, trans(O5)-Ba[Ni(eddadp)]·6H2O, and strain analysis of edta-type chelates in relation to their octahedral distortion

Abstract Two paramagnetic octahedral Ni(II)-edta-type complexes, Ba[Ni(eddadp)]·6H2O(1) (eddadp) = ethylenediamine-N,N′-diacetate- N,N′-di-propionate ion) and Ba(Ni(edtp)]· 3H2O(bd2) (edtp = ethylenediamine-tetra-3-propionate Ion) have been prepared and characterized. The ligands used, forming β-alaninate rings, are likely to function as inexandentate with a larger metal ions. Because of the strain in the equatorial plane, as expected, the trans(O5) configuration of complex 1 was found to dominate and this geometry was verified crystallographically. The crystal is monoclinic with the space group C2/c, a = 11.091(3), b = 13.526(4), c = 28.064 A , β = 93.56(2)° and Z = 8 . The IR (carboxylatesregion) and electronic absorption spectra of these complexes are reported. There is no added multiplicity found in the electronic spectra of complexes that generally are seen for octahedral or pseudooctahedral Ni(II) complexes. Spectra of these complexes are discussed in comparison with those of the trans(O5)-[Ni(SS-edds)]2− complex (SS-edds = SS-ethylenediamine-N,N′-disuccinate ion) of known structure. The magnetic measurements are also reported for the complexes studied. Structural parameters and strain analysis data of M-edta-type complexes are discussed in relation to their octahedral distortion.

Aggregative activation and heterocyclic chemistry I complex bases promoted arynic cyclisation of imines or enaminoketones; regiochemical synthesis of indoles

Abstract The complex base NaNH2-t-BuONa allowed expeditious syntheses of indoles by arynic cyclisation of imines or enaminoketones prepared from halogeno anilines and carbonyl derivatives. Unstable imines may be used without purification, complex bases being unsensitive to impurities. It is showed that this kind of reaction may be applied to mixture of substrates suitably halogenated on the benzene ring. Formation of three components aggregates is proposed to explain a number of observations.

Synthesis of N,N-dialkylcarbamato complexes of Group 4 metals (Ti, Zr, Hf) by the metal chloride–NHR2–CO2 system (R = Et or Pri): crystal and molecular structure of [Hf(O2CNPri2)4]

The compounds [M(O2CNR2)4](M = Ti, Zr or Hf; R = Et or Pri) have been prepared by treating the corresponding metal tetrachloride with CO2–NHR2 in toluene. The structure of [Hf(O2CNPri2)4] has been solved by X-ray diffraction methods. Crystal data: monoclinic, space group P21/c, a= 12.756(3), b= 22.131(9), c= 14.548(5)A, β= 113.03(2)° and Z= 4. It consists of monomeric units, the hafnium atom being surrounded by the eight oxygen atoms of the four N,N-diisopropylcarbamato groups in a slightly distorted dodecahedral arrangement. By reaction with anhydrous hydrogen halides HX (X = Cl, Br or I) the hexahalogenometalate(IV) anions, [MX6]2–, as the diethylammonium derivatives, have been obtained in high yields. The redox reaction between [Ti(O2CNEt2)4] and [V(η-C5Me5)2] gives the titanium(III) and vanadium(III) complexes [{Ti(O2CNEt2)3}n] and [V(η-C5Me5)2(O2CNEt2)], respectively.

Tetranuclear copper(II) complexes with polydentate hydrazone ligands: synthesis and X-ray structure

Abstract The synthesis and X-ray crystal structure of two copper(II) complexes, [Cu2(dappc)(OH2)3]2- [Cu2(dappc)(OH2)2(ClO4)]2)6·2H2O (I) (H2dappc=2,6-diacetylpyridine bis(2-pyridinecarbonylhydrazone)) and [Cu2(dapip′)Br]·2H2O, (II) (H3dapip′=2,6-diacetylpyridine 2-pyridinecarbonylhydrazone 2-(2′-pyridine carbonylhydrazono)phenylacetohydrazone) are reported. The interest of both structures pertains mainly to their tetranuclear nature with dimeric units related by an imposed center of symmetry. The structure of compound I is built up from two different complex cations, ClO4− anions and uncoordinated H2O molecules, while that of compound II consists of neutral complex molecules and solvating H2O molecules. During the formation of the latter complex the original H4dapip ligand (H4dapip=2,6-diacetylpyridine bis[2-(2′-pyridinecarbonylhydrazono)phenylacetohydrazone] has undergone a modification through a hydrolysis process, resulting in partial cleavage of one arm to give H3dapip′.

Behaviour of triphenylphosphine-substituted ruthenium carbonyl carboxylates with hydrogen

The reaction between Ru(CO) 2 (MeCO 2 ) 2 (PPh 3 ) 2 , or Ru 2 (CO) 4 (MeCO 2 ) 2 (PPh 3 ) 2 , and hydrogen (100 atm) at temperatures between 80 and 160°C has been investigated. The products formed are ruthenium clusters containing PPh 3 , PPh 2 and PPh ligands. The same products were obtained from Ru 4 ( μ -H) 4 (CO) 8 (PPh 3 ) 4 and hydrogen. Several new complexes were isolated and the crystal structures of Ru 3 ( μ -H) 2 (CO) 8 ( μ 3 -PPh)(PPh 3 ), Ru 4 (CO) 8 ( μ 4 -PPh) 2 ( μ -PPh 2 ) 2 and Ru 4 ( μ -H) 4 (CO) 7 ( μ 4 -PPh)( μ -PPh 2 ) 2 (PPh 3 ) are reported.

Arynic condensation of ketone enolates 181: Efficient access to benzocyclenones and polycyclic indanone derivatives

Abstract It is shown that benzocyclobutenols 1 are excellent starting materials for the obtention of polycyclic aromatic ketones. Thus under basic conditions they lead to benzocyclenedione mono ketals which may be hydrolyzed into the corresponding benzocyclenediones. Under acidic conditions, a transposition takes place leading to indanone derivatives. The mechanism of this transposition is discussed.