Syntheses, silylation, characterization, and antimicrobial and antifertility activities of organoboron derivatives of some bioactive monofunctional bidentate semicarbazones

Some new mononuclear organoboron derivatives of the type PhBL 1–5 (OH) ( 1a – 1e ) were synthesized by the reaction of PhB(OH) 2 and LH (LH = OC(NH 2 )NH:NC(CH 3 ) 4 C 6 H 4 R, where R = H (L 1 H); CH 3 (L 2 H); OCH 3 (L 3 H); Cl (L 4 H); Br (L 5 H)) in 1:1 molar ratio in refluxing tetrahydrofuran (THF). This was followed by the reactions of PhBL 1–5 (OH) with NH(SiMe 3 ) 2 in 2:1 molar ratio in THF to yield new heterodinuclear derivatives of the type PhBL 1–5 (OSiMe 3 ) ( 2a – 2e ). All these newly synthesized complexes were characterized using elemental analyses and their probable structure was proposed on the basis of infrared, 1 H NMR, 13 C NMR, 11 B NMR and 29 Si NMR spectral data and mass spectrometry. Semicarbazone ligands and their corresponding mono‐ and heterodinuclear boron derivatives were screened against pathogenic bacteria ( E. coli and P. aeruginosa ) and fungi ( A. niger and P. peniculosum ) to examine their antimicrobial activities. Representative compounds of each series of mono‐ and heterodinuclear boron derivatives and a ligand were screened for their antifertility activity on male adult Wistar rats.