Synthesis and electrospray mass spectrometry of platinum(II) complexes of 5,5-diethylbarbituric acid (Hdebarb); Crystal structure of cis-[PtCl(debarb)(PPh(3))(2)]center dot CH2Cl2

The reactions of 5,5-diethyibarbituric acid (Hdebarb; 1H,3H,5H-5,5-diethylpyrimidine-2,4,6-trione), either as the monosodium salt or free acid in the presence of ancillary base (silver oxide or triethylamine), with platinum(II) halide complexes-yielded mono(barbiturato) complexes cis-[PtX(debarb)L(2)][X = Cl, By or I: L = PPh(3); L(2) = 1,2-bis(diphenylphosphino)ethane (dppe) or 1,1'-bis(diphenylphosphino)ferrocene (dippf)]. A single-crystal structure determination of cis-[PtCl(debarb)(PPh(3))(2)]. CH2Cl2 showed that the plane of the N-bonded barbiturate ligand is approximately perpendicular to the platinum co-ordination square plane, rendering the two ethyl substituents inequivalent. Electrospray mass spectrometry has also been used to study these complexes, with the major ions for cis-[PtX(debarb)L(2)] being [Pt(debarb)L(2)](+) and [Pt(debarb)(NCM)L(2)](+), though molecular ions [M + H](+) are also observed for all complexes. A number of cationic derivatives of the type [Pt(debarb)L(2)L'](+) (L = PPh(3) or L(2) = dppe; L' = pyridine or PPh(3)) are also reported.