Synthesis, Spectral and Antimicrobial Studies of Some O-Vanillin-2-aminopyridine Schiff Base Complexes of Organyltellurium(IV)

Abstract

The reactions of tellurium(IV) derivatives, TeCl 4 , RTeCl 3 and R 2 TeCl 2 with monobasic ONN tridentate Schiff base ligand derived by the condensation of o-vanillin with 2-aminopyridine have been carried out to give tellurium(IV) complexes, [TeCl 3 (2-APY-{o-Van})], [RTeCl 2 (2-APY-{o-Van})] and [R 2 TeCl(2-APY-{o-Van})]: where R = p-methoxyphenyl, p-hydroxyphenyl, 3-methyl-4-hydroxyphcenyl. The synthesized Schiff Base (2-APY-{o-VanH}) and their complexes were characterized by elemental analyses, conductivity measurements, FT-IR and proton NMR spectral studies. The Schiff base and some of their tellurium(IV) complexes display antifungal and antibacterial activities.

N-(2-Pyridyl)-5-chlorosalicylideneimine Schiff Base and its Tellurium(IV) Complexes: Synthesis, Characterization and In Vitro Biological Activities

“…The IR spectrum of the ligand indicate that the υ (C=N) band 31,38,41,66,70 of the ligand at 1613 cm -1 is due to the azomethine linkage which were shifted towards lower frequency 22,38,41,66,[70][71][72] indicating that the ligand coordinate to tellurium metal ions via the azomethine nitrogen 73,74 .…”

“…The absence of a singlet in high frequency region (δ 13.460 ppm), which typically corresponds to phenolic hydrogen indicates that N-2-pyridyl-5-chlorosalicylideneimine binds tellurium by deprotonated phenolic oxygen. The singlet that appears at δ 9.392 ppm is ascribed to azomethine hydrogen, which is less shielded after coordination through azomethine nitrogen 38,41,50,51,70,78 and appear in the downfield region 10.254-10.271 δ ppm. The complex multiplets found in the spectrum of complexes in the δ 6.840-8.651 ppm region corresponds to coupled hydrogen atoms of aromatic rings.…”

“…Tellurium(IV) chloride is also known to form adducts with amides 31,32 and thiourea 33 , thus reflecting its acceptor behaviour 7,8,[34][35][36][37][38][39][40][41] . The present study has thrown light on the chelating behaviour of Schiff base derived from 5-chlorosalicylaldehyde and 2-aminopyridine towards organyltellurium(IV) chlorides which are known 7,8, to act as Lewis acids.…”