Trans-pyrazolones

Pettinari C, Marchetti F, Pettinari R, Cingolani A, Drozdov A, Troyanov S (2002) Coordination chemistry of bis(pyrazolones) a rational design of nuclearity tailored polynuclear complexes. Part 2. The interaction of organotin(IV) acceptors with 1, 4-bis(5-hydroxy-l-phenyl-3-methyl-lH-pyrazol-4-yl)butane-l, 4-dione. J Chem Soc Dalton Trans 2 188-194... 

The archetype of these molecules contains R1 = R3 = Ph and R2 = Me, and modifications generally involved the R3 fragment. Variations in R1 and R3 have also been reported.161-165 The substituents can greatly influence not only the physico-chemical properties of corresponding metal derivatives, such as solubility in water of bis(acylpyrazolonate)diorganotin(IV) when R1 Me,163 but also their crystal structures when R1 = 4-CF3-Ph trans-octahedral bis(acyl-pyrazolonate)diorganotin(IV) can be isolated in either syn or anti isomeric forms.164,165... 

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