Chalcogenated Schiff bases of 5-chloroisatin (L1-L3), 2-(methythio)benzaldehyde (L4), 2-acetylpyridine (L5) and benzaldehyde (L6-L7) have been synthesized. Both the carbonyl groups of 5chloroisatin appear to be reactive (noticed for the first time) for making >C=N bond, of course one at a time only. The 1 H, 13 C{ 1 H}, 77 Se{ 1 H} and 125 Te{ 1 H} NMR spectroscopy have been used to establish the coexistence of two products, which were found in the ratio 53:47 (E = S), 55:45 (E = Se) and 81:19 (E = Te). The larger amount is of the one in which C=O group away from NH is derivatized. The two products are not separable. Palladium complexes (1-4) of Schiff bases of other three aldehydes were synthesized. The ligands as well as complexes were characterized by multinuclear NMR spectroscopy. The crystal structures of [Pd(L4/L5)Cl][ClO 4 ] (1/2) have been solved. The Pd-Se bond lengths are 2.4172(17) and 2.3675(4) Å, respectively for 1 and 2. The Pd-complexes (3-4) of L6-L7 were explored for Suzuki-Miyaura coupling and found promising as 0.006 mol % of 3 is sufficient to obtain good conversion with TON up to 1.58 × 10 4 .
Chalcogenated Schiff Bases: Complexation with Palladium(II) and Suzuki Coupling Reactions. -A series of palladium complexes of chalcogenated Schiff bases are synthesized. Among them, derivatives (I) are applied as catalyst in the Suzuki-Miyaura-cross coupling reaction. Complex (Ia) shows promising activity whilst the corresponding tellurium analogue (Ib) is found to give significantly lower yields. -(SINGH, P.; RAO, G. K.; KARIM, M. S.; SINGH*, A. K.; J.
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