Tin(IV) and organotin(IV) derivatives of novel β-diketones

Abstract

Abstract The synthesis of three 1-(4-trifluoromethylphenyl)-3-methyl-4-R1(CO)-5-pyrazolone proligands LH (L1H; R1=C6H5: L2H; R1=CH3: L3H; R1=CF3) and their interaction with R3Sn(IV) acceptors (R=Me, Bun, Ph) are reported. When R=Me or Bun, aquo (4-acylpyrazolonate)SnR3(H2O) derivatives are obtained and the anionic donors 4-acylpyrazolonate (L−) act in the O–monodentate form. These triorganotin complexes are not stable in chlorohydrocarbon solvents and decompose to R4Sn and bis(4-acyl-5-pyrazolonate)2SnR2. When R=Ph, stable (4-acyl-5-pyrazolonate)SnPh3 derivatives, both in solution and in the solid state, are obtained. The crystal structure of (1-(4-trifluoromethylphenyl)-3-methyl-4-acetylpyrazolon-5-ato)triphenyltin(IV) shows a five-coordinate tin atom in a strongly distorted cis-bipyramidal trigonal environment (axial angle=161.2(2)°) with the acylpyrazolonate donor acting as an asymmetric O2–bidentate species (Sn–O(1)=2.081(6) A: Sn–O(2)=2.424(5) A). Electronic effects are responsible for the different behavior shown by these trialkyl and triphenyl derivatives.