Structural Investigations of α‑MnS Nanocrystals and Thin Films Synthesized from Manganese(II) Xanthates by Hot Injection, Solvent-Less Thermolysis, and Doctor Blade Routes

Manganese­(II) xanthate
complexes of the form [Mn­(S2COR)2(TMEDA)], where
TMEDA = tetramethylethylenediamine and R =
methyl (1), ethyl (2), n-propyl (3), n-butyl (4), n-pentyl (5), n-hexyl (6), and n-octyl (7), have been synthesized and structures elucidated using single-crystal
X-ray diffraction. Complexes 1–7 were
used as molecular precursors to synthesize manganese sulfide (MnS).
Olelyamine-capped nanocrystals have been produced via hot injection, while the doctor blading followed by thermolysis
yielded thick films. Free-standing polycrystalline powders of MnS
are produced by direct thermolysis of precursor powders. All thermolysis
techniques produced cubic MnS, as confirmed by powder X-ray diffraction,
scanning electron microscopy, energy-dispersive X-ray spectroscopy,
and Raman spectroscopy. Magnetic measurements reveal that the α-MnS
nanocrystals exhibit ferromagnetic behavior with a large coercive
field strength (e.g., 0.723 kOe for 6.8 nm nanocrystals).