Synthesis, characterization, and antibacterial studies of some vanadium complexes with hexamethyl tetraazamacrocycles

• Published in: Inorganic and nano-metal chemistry Vol. 52; no. 9; pp. 1265 - 1272
• Main Authors: Debanath, Eshita, Shil, Ratul Kumar, Rabi, Saswata, Palit, Debashis, Dey, Benu Kumar, Roy, Tapashi Ghosh
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.08.2022
• Subjects: antimicrobial activities; spectroscopic studies; substitution and anion exchange reactions; Tetraazamacrocyclic ligands; vanadium complexes
• ISSN: 2470-1556; 2470-1564
• DOI: 10.1080/24701556.2022.2047071

The hexamethyl tetraazacyclotetradecadiene diperchlorate ligand salt, Me 6 [14]diene.2HClO 4 (L 1 .2HClO 4 ) on reduction yielded two isomeric C-chiral ligands "tet-a" and "tet-b". Open air reactions of the ligands, L 1 .2HClO 4 , "tet-a," and "tet-b" with vanadyl acetylacetonate produced octahedral green complexes, [VOL 1 (acac)](ClO 4 ), [VO("tet-a")(H 2 O)](ClO 4 ) 2 , and [VO("tet-b")(acac)](ClO 4 ), respectively, in which vanadium was in +4 oxidation state. The complex [VOL 1 (acac)](ClO 4 ) underwent axial substitution with KCNS, KBr, KI, and NaNO 2 in the ratio of 1:12 in ethanol to yield axial substitution products, [VOL 1 (SCN)](ClO 4 ) 2 , [VOL 1 Br](ClO 4 ) 2, [VOL 1 I](ClO 4 ) 2 , and [VOL 1 (NO 2 )](ClO 4 ) 2 , respectively, in which vanadium was in +5 oxidation state. On the other hand, [VO("tet-b")(acac)](ClO 4 ) underwent simultaneous axial substitution and anion exchange reactions with KCNS and KBr in the same ratio to furnish corresponding vanadium(V) complexes, [VO("tet-b")(SCN)](SCN) 2 and [VO("tet-b")Br]Br 2 , respectively. These complexes were characterized on the basis of elemental, spectroscopic, magneto-chemical, and conductometric analyses. The antibacterial activities of the ligands and their complexes have been investigated toward different Gram-positive and Gram-negative bacteria.