32335-53-8Relevant academic research and scientific papers
Synthesis, characterization and crystal structure of triphenylphosphine copper(I) methylpyruvate thiosemicarbazones
Belicchi-Ferrari, Marisa,Bisceglie, Franco,Buluggiu, Enrico,Pelosi, Giorgio,Tarasconi, Pieralberto
, p. 1160 - 1168 (2009)
This paper reports the synthesis of a series of methylpyruvate thiosemicarbazone derivatives containing, on the terminal nitrogen, substituents of different nature and size and namely, ethyl, phenyl and methylphenyl. These ligands were reacted with bis(triphenylphosphine)copper(I) nitrate and acetate to produce the respective complexes: [Cu(PPh3)2(Et-Hmpt)]2(NO3)2 (1), [Cu(PPh3)2(Ph-Hmpt)]NO3 (2), [Cu(PPh3)2(MePh-Hmpt)]NO3 (3), [Cu2(O2CCH3)(Et-pt)(PPh3)2] · H2O (4), [Cu(Ph-mpt)(PPh3)] (5) and [Cu2(MePh-mpt)2(PPh3)2] (6). All of them were characterized by elemental analysis, IR, 1H NMR, EPR spectroscopy and, for compounds 1, 2, 4, and 6, by X-ray crystallography. The characterization revealed that the coordinating behaviour of the ligands is influenced by a series of factors, predominant among which is the hard soft nature of the atoms involved in the interactions with the metal centre. The complexes obtained from the nitrate copper(I) salt are formed by cationic molecules with a nitrate as a counterion, while those derived from the acetate salt present deprotonated ligands and a few unexpected features. In particular, one of the compounds (4) is a mixed valence dinuclear complex with an acetate oxygen and the thiosemicarbazone sulfur acting as bridging between the two Cu(I) and Cu(II) ions. Another one (6) presents instead a Cu(I)-Cu(I) sulfur bridged binuclear cluster.
Investigations into bis(triphenylphosphine)copper(I) complexes with cyclic derivatives of methylpyruvate thiosemicarbazones
Belicchi-Ferrari, Marisa,Bisceglie, Franco,Buluggiu, Enrico,Pelosi, Giorgio,Tarasconi, Pieralberto
, p. 2134 - 2141 (2011/01/05)
The syntheses of four compounds, obtained by the reaction of methylpyruvate thiosemicarbazone (Hmpt) and its methyl (Me-Hmpt) and allyl (Allyl-Hmpt) derivatives with bis(triphenylphosphine)copper(I) acetate, are reported. The compounds [Cu(PPh3)2(ptc)(Hpt c)]·H2O (1), [Cu(PPh3) 2(Me-ptc)] (2), [Cu2(PPh3) 2μ-S(Me-pt)μ-S(Me-ptc)]·H2O (3) and [Cu(PPh3)2(Allyl-ptc)] (4) [H2pt = pyruvic acid thiosemicarbazone and Hptc = cyclized pyruvic acid thiosemicarbazone, Me = methyl and Allyl are radical substituents on the amino nitrogen] were characterized by elemental analysis, IR, 1H NMR, and by X-ray crystallography. Compound 3 was also studied by EPR because of the presence in the compound of two copper atoms in two different oxidation states. During the complexation reaction, the thiosemicarbazone ligands tend to undergo a cyclization reaction that leads to the formation of a six-member heterocyclic ring. All four compounds present the [Cu(PPh3)2] + fragment and constant but different coordination situations. Compound 1 contains two cyclic ligand molecules, one protonated and the other deprotonated, bound as monodentate through the sulfur. Compounds 2 and 4 present a single deprotonated cyclic SN bidentate ligand molecule, while compound 3 contains copper(I) and copper(II), and two ligand molecules, one of which is linear and behaves as SNO tridentate and the other is cyclic and behaves as bridging μSN.
