Phosphorus-nitrogen compounds. Part 62. Preparation of tetraaminobis(4-fluorobenzyl)spiro(N/N)cyclotriphosphazenes: Chemical, structural characterizations, antimicrobial, antioxidant and DNA-binding activity studies

Substitution reaction of hexachlorocyclotriphosphazatriene (trimer; N3P3Cl6; HCCP) with N,N'-bis(4-fluorobenzyl)ethane-1,2-diamine (1) gave the starting compound tetrachlorobis(4-fluorobenzyl)monospiro(N/N)cyclotriphosphazene (2). Tetraaminobis(4-fluorobenzyl)spiro(N/N) cyclotriphosphazenes (2a-2c) were synthesized from the substitution reactions of spiro (2) with excess piperidine, ethylpiperazine and phenylpiperazine, respectively, in boiling THF. Elemental analysis, ESI-MS, FTIR, 1H, 13C and 31P NMR data verified the structures of new compounds; and the solid-state crystal structures of 2a and 2b were elucidated using the X-ray crystallography method. Hirshfeld surface (HS) analyses were performed to figure out the intermolecular interactions in these crystals as well. Moreover, the minimum inhibitory, bactericidal and fungicidal concentrations (MIC, MBC and MFC) were determined using the microdilution method, which was used to detect the compounds that have the antimicrobial effects on microorganisms exhibited the effect at which concentration. It was concluded that MIC, MBC and MFC values ranged from 312.5 and > 2500 µM. Furthermore, DNA cleavage and unwinding properties of 2a, 2b and 2c with pBR322 plasmid DNA were examined by agarose gel electrophoresis. Also, compound-DNA incubation and BamHI and HindIII restriction enzyme digestions were realized to provide more insight into changes in DNA conformation. Finally, the antioxidant activity was determined that 2c had the highest antioxidant capacity with a 38.38% radical scavenging activity value.