Organotin(IV) derivatives of novel β-diketones -: Part V.: Synthesis and characterization of di- and triorganotin(IV) derivatives of 4-acyl-5-pyrazolones modified in position 3 of the pyrazole.: Crystal structure of (1,3-diphenyl-4-benzoyl-pyrazolon-5-ato)triphenyltin(IV)

The interaction between R3SnCl, (R3Sn)(2)O. R2SnO or R2SnCl2 acceptors (R = Me, "Bu or Ph) and the two novel beta-diketone proligands (LH = 1,3-diphenyl-4-R-4(C=O)-pyrazol-5-one: L H, R = Ph, (LH)-H-2. R-4 = Me) yields complexes [SnR3(L)(H2O)j (R = Me or "Bu. L = L-1 or L-2), [SnPh3(L)] and [SnR2(L)(2)] (L = L-1 or L-2). The phenyl substituent on position 3 induces instability of the triorganotin derivatives in solution with the formation of SnR2(L)(2) and SnR4 compounds. Moreover, diorganotin derivatives partially dissociate in solution yielding [SnR2(L)(solvent)](2+) I species. When compared with the related 3-methyl species, the crystal structure of (1,3-diphenyl-4-benzoyi-pyrazolon-5-ato)triphenyltin(IV) is not modified by the 3-phenyl substitution. The chemical instability generated by the Ph in position 3 is greater than in positions 1 and 4. In addition, the Ph in position 3 of the pyrazole influences the solution behavior of the free neutral 4-acyl-5-pyrazolones stabilizing a novel amino-diketo tautomeric form. (C) 2002 Elsevier Science B.V. All rights reserved.