Abstract
Treatment of benzonitriles 4-XC6H4CN (1) [X = H (1a), F (1b), Cl (1c), Br (1d), I (1e)] with an excess of 2-butanone oxime (Me)Et)C=NOH as a reagent and solvent) in the presence of PdCl2 at 100 degrees C for 12 h affords the symmetrical cationic 2,4-diaryl-1,3,5-triazapentadiene (Htap) palladium(II) complexes [Pd((Htap)(2)]Cl-2 (2') [Htap = HN=C(4-XC6H4) NHC(4-XC6H4)= NH]. Recrystallization of 2' from MeOH/CHCl3 with two equivalents of n-propylamine gives the corresponding neutral triazapentadienate (tap) complexes [Pd(tap)(2)] (2) [tap = HN=C(4-XC6H4)NC(4-XC6H4)=NH; X = H (2a), F (2b), Cl (2c), Br (2d), I (2e)] in good yields. When cyanoguanidine, HN=C(NH2)N((H)C N (3), or sodium dicyanamide NaN(C N)(2) (5) are treated with an excess of primary alcohols, ROH [R = Me, Et, nPr, nBu or (CH2)(2)OMe] in the presence of PdCl2r while being heated for 12 h, the corresponding asymmetrical 2-amino-4-alkoxy-1,3,5-triazapentadienate-Pd-II complexes [Pd{HN=C(NH2)NC(OR)=NH}(2)] (4) [R = Me (4a), Et (4b), nPr (4c), nBu (4d)] or the symmetrical 2,4-dialkoxy-1,3,5-triazapentadienate-Pd-II complexes [Pd{HN=C(OR)NC(OR)=NH}(2)] (6) [R = Me (6a), Et (6b), nPr (6c), (CH2)(2)OMe (6d)], respectively, are formed and isolated as a mixture of isomers in good yields. All these compounds have been characterized by IR, H-1 and C-13 NMR spectroscopy, ESI-MS, elemental analyses and, in the case of 2c, by XRD.