Direct Synthesis of Two-Dimensional SnSe and SnSe through Molecular Scale Preorganization.

Two-dimensional tin monoselenide (SnSe) and tin diselenide (SnSe) materials were efficiently produced by the thermolysis of molecular compounds based on a new class of seleno-ligands. Main group metal chalcogenides are of fundamental interest due to their layered structures, thickness-dependent modulation in electronic structure, and small effective mass, which make them attractive candidates for optoelectronic applications. We demonstrate here the synthesis of stable tin selenide precursors by reductive bond cleavage in the dimeric diselenide ligand (SeCHN(Me)CHSe) in the presence of SnCl.

Single source precursor route to nanometric tin chalcogenides.

Low-temperature solution phase synthesis of nanomaterials using designed molecular precursors enjoys tremendous advantages over traditional high-temperature solid-state synthesis. These include atomic-level control over stoichiometry, homogeneous elemental dispersion and uniformly distributed nanoparticles. For exploiting these advantages, however, rationally designed molecular complexes having certain properties are usually required.

Molecular Routes to Two-Dimensional Metal Dichalcogenides MX (M = Mo, W; X = S, Se).

New synthetic access to two-dimensional transition metal dichalcogenides (TMDCs) is highly desired to exploit their extraordinary semiconducting and optoelectronic properties for practical applications. We introduce here an entirely novel class of molecular precursors, [M(XEtN(Me)EtX)] (M = Mo, W, X = S, Se), enabling chemical vapor deposition of TMDC thin films. Molybdenum and tungsten complexes of dianionic tridentate pincer-type ligands (HXEt)NR (R = methyl, -butyl, phenyl) produced air-stable monomeric dichalcogenide complexes, [W(SEtN(Me)EtS)] and [Mo(SEtN(Me)EtS)], displaying W and Mo centers in an octahedral environment of 4 S and 2 N donor atoms.

Single-source precursors for alloyed gold-silver nanocrystals - a molecular metallurgy approach.

Multiple silver(I)-aurates(I) have been prepared by salt metathesis reactions that act as efficient single-source precursors to colloidal gold silver alloys with the highest possible atom economy in the chemical synthesis of nanostructures. The CF3 group present on the Au cation acts as an in situ reducing agent and can be converted into CO ligands by simple hydrolysis. This ligand-mediated activation and subsequent decomposition of metal-organic precursors impose a molecular control over the nucleation process, producing homogeneously alloyed (Ag-Au) nanoparticles with an atomic Au:Ag ratio of 1:1.

Molecular Co(II) and Co(III) heteroarylalkenolates as efficient precursors for chemical vapor deposition of Co3O4 nanowires.

Two new cobalt precursors, Co(II)(PyCHCOCF3)2(DMAP)2 (1) and Co(III)(PyCHCOCF3)3 (2), based on Co(II) and Co(III) centers were synthesized using a redox active ligand system. The different chemical configurations of 1 and 2 and differential valence states of cobalt were confirmed by crystal structure determination and comprehensive analytical studies. Whereas 1 could not be studied by NMR due to the paramagnetic nature of the central atom, 2 was unambiguously characterized by multinuclear 1D and 2D NMR experiments in solution.

[(CF3)4Au2(C5H5N)2]--a new alkyl gold(II) derivative with a very short Au-Au bond.

A new gold(II) species [(CF(3))(4)Au(2)(C(5)H(5)N)(2)] with a very short unsupported Au-Au bond (250.62(9) pm) was generated by photo irradiation of a silver aurate, [Ag(Py)(2)][Au(CF(3))(2)], unambiguously characterized by (19)F and (109)Ag NMR studies.