The new mercuric complex [Hg(HL) 2 Cl2 ] incorporating salicylaldimine ligand
(HL = 2-((pyridin-3-ylimino)methyl)phenol) was fabricated where the ligand
molecules behaved in a monodentate manner via their pyridine nitrogen
atoms. In addition to elemental characterization, X-ray crystallographic studies
of the complex revealed its packing in a monoclinic crystal system (space
group: I2/a, a = 13.4276(2) Å, b = 6.20950(10) Å, c = 27.7530 (4) Å,
α = γ = 90, and β = 98.1610(10)). Hydrothermal treatment of [Hg(HL) 2 Cl2 ]
with thioacetamide afforded HgS microparticles (HgS μPs; Brunauer–Emmett–
Teller [BET] surface area = 6.205 m 2 /g, diameter = 196.53–259.13 nm, and
average size = 213.27 nm), whereas these microparticles were transformed to
nanoscaled HgS particles (HgS NPs; BET surface area = 14.380 m 2 /g,
diameter = 58.87–90.56 nm, and average size = 72.78 nm) by the action of
ultrasonication. The as-prepared HgS, HgS NPs in particular, afforded remark-
able microbicidal activity against eight strains of filamentous and unicellular
human pathogenic fungi and yeasts in comparison with cycloheximide.
Remarkably, Aspergillus terreus grew up to 34.7 ± 1.88 mm in the absence of
any fungicide, but HgS μPs, HgS NPs, and cycloheximide limited the fungal
growth to 26 ± 0.94, 12.33 ± 1.6, and 28.3 ± 1.7 mm after incubation for 6 days.
Besides, inhibition of Rhodotorula glutinis was of 7.6 ± 0.01 × 107 CFU/ml in
control sample, but experiments included HgS μPs, HgS NPs, and cyclohexi-
mide limited the colony-forming units of R. glutinis to 4.2 ± 0.01 × 10 7 ,
3.5 ± 0.02 × 10 7 , and 5.9 ± 0.05 × 10 7 CFU/ml.