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Mono-, di-, and tetra-aurated derivatives of barbituric acid, including a new type of polynuclear gold compound. Crystal structure of 1,3-bis(triphenylphosphinegold)-5,5-diethylbarbituric acid

1986; Elsevier BV; Volume: 317; Issue: 1 Linguagem: Inglês

10.1016/s0022-328x(00)99350-1

1872-8561

Flavio Bonati, Alfredo Burini, Bianca Rosa Pietroni, Bruna Bovio,

Organometallic Compounds Synthesis and Characterization

Reaction of barbituric acid (2,4,6-pyrimidinetrione) or its derivatives with LAuCl (L = triphenylphosphine) gave 3-LAu-5,5-diethyl-, 1,3-(L'Au)2-5,5-diethyl- (L′ = L or L′ = Cy3P), 1,3-dimethyl-5,5-bis(LAu)-, or 1,3,5,5-tetrakis-(LAu)barbituric acid, which were characterized as N-, N,N′-, C,C′-, or N,N′,C,C-gold derivative,s respectively, by IR, 1H, 13C and 31P NMR spectroscopy. In the case of 1,3-(LM)(L″M)-5,5-diethylbarbituric acid compounds with M = gold and L″ either Cy3P, Ph3As, or (4-tolyl)3P, or ML = ML″ = HgMe were prepared. An X-ray diffraction study of 1,3-(LAu)2-5,5-Et2-pyrimidin-2,4,6-trione · 3C6H6 revealed that (a) the heterocyclic ring is planar, (b) there is no inter- or intra-molecular Au ⋯ Au interaction, and (c) the coordination around each gold atom is approximately linear (PAuN 178.3(4)°, with AuN 2.022(12) and AuP 2.233(5) Å. The molecular parameters are compared with those for barbituric acid and other barbiturates.