Surfactant-Thermal Syntheses, Structures, and Magnetic Properties of Mn–Ge–Sulfides/Selenides

Although
either surfactants or amines have been investigated to direct the
crystal growth of metal chalcogenides, the synergic effect of organic
amines and surfactants to control the crystal growth has not been
explored. In this report, several organic bases (hydrazine monohydrate,
ethylenediamine (en), 1,2-propanediamine (1,2-dap), and 1,3-propanediamine (1,3-dap))
have been employed as structure-directing agents (SDAs) to prepare
four novel chalcogenides (Mn3Ge2S7(NH3)4 (1), [Mn­(en)2(H2O)]­[Mn­(en)2MnGe3Se9] (2), (1,2-dapH)2­{[Mn­(1,2-dap)2]­Ge2Se7} (3), and
(1,3-dapH)­(puH)­MnGeSe4(4) (pu
= propyleneurea) under surfactant media (PEG-400). These as-prepared
new crystalline materials provide diverse metal coordination geometries,
including MnS3N tetrahedra, MnGe2Se7 trimer, and MnGe3Se10 T2 cluster. Compounds 1–3 have been fully characterized by single-crystal
X-ray diffraction (XRD), powder XRD, UV–vis spectra, Fourier
transform infrared spectroscopy, and thermogravimetric analysis. Moreover,
magnetic measurements for compound 1 showed an obvious
antiferromagnetic transition at ∼9 K. Our research not only
enriches the structural chemistry of the transitional-metal/14/16
chalcogenides but also allows us to better understand the synergic
effect of organic amines and surfactants on the crystallization of
metal chalcogenides.