Late metal salicylaldimine complexes derived from 5-aminosalicylic acid — Molecular structure of a zwitterionic mono Schiff base zinc complex

Abstract

Condensation of salicylaldehyde (2-HOC6H4C(O)H) with 5-aminosalicylic acid (5-H2NC6H3-2-(OH)-CO2H) afforded the Schiff base 2-HOC6H4C(H)=NC6H3-2-(OH)-5-CO2H (a). Similar reactivity with 5-bromosalicylaldehyde was also observed to give 5-Br-2-HOC6H3C(H)=NC6H3-2-(OH)-5-CO2H (b). Reaction of these salicylaldehydes with Pd(II), Cu(II), and Zn(II) salts gave the corresponding bis(N-arylsalicylaldiminato)metal complexes (M = Pd (1), Cu (2), Zn (3)). The molecular structure of the Schiff base compound a has been confirmed by an X-ray diffraction study. Crystals of a were monoclinic, space group P2(1)/c, a = 7.0164(7) Å, b = 11.0088(11) Å, c = 14.8980(15) Å, β = 102.917(2)°, Z = 4. The molecular structure of a novel zwitterionic conformer of 3a was also characterized by an X-ray diffraction study. Crystals of 4 were monoclinic, space group P2(1)/c, a = 9.5284(5) Å, b = 19.5335(11) Å, c = 8.6508(5) Å, β = 90.596(1)°, Z = 4. All new compounds have been tested for their antifungal activity against Aspergillus niger and Aspergillus flavus. Key words: 5-aminosalicylic acid (5-ASA), antifungal, copper, palladium, salicylaldimines, Schiff base, zinc.

Scalable Synthesis and Supramolecular Assembly of trans‐A2B2 Porphyrins with Pendant Carboxylic Functional Groups

“…Search through the Cambridge Structural Database (CSD, ConQuest Version 1.17, 2014) revealed five crystal structures in which aromatic carboxyphenyl groups are engaged with phenolate rings in hydrogen bonds. The resulting O carboxylic ⋅⋅⋅O − phenolate interaction in 4 g was found to be as strong/short as that reported for the archive structure with CSD refcode CAWJOA (2.488(2) Å) . This interaction is part of a wider ring‐like synthon with additional hydrogen bond between the carboxylic acid and the DMA + ion and another N⋅⋅⋅O carboxylic short contact.…”

Diaquabis{2-hydroxy-5-[(pyridin-2-yl)methylideneamino]benzoato-κ2N,N′}zinc(II) dihydrate

“…The title compound is a Schiff base complex; for potential applications of Schiff base compounds, see: Bourque et al (2005); Donald & Osit (2010); Feng et al (2007); Gang et al (2007); Shanta et al (2003).…”

2-Hydroxy-5-(2-hydroxy-3-methoxybenzylideneamino)benzoic acid

“…For general background, see: Yamada (1999); Yang et al (2000). For a related structure, see: Bourque et al (2005).…”

“…The dihedral angle between the two aromatic rings is 13.2 (2)°. The O3-C9-C10-C11 [-5.3 7 (Bourque et al, 2005).…”