Abstract/Summary

Different synthetic-methods were explored to pursue novel gallium and germanium sulphides. Materials were characterised using single-crystal and powder Xray diffraction. Elemental analysis, thermogravimetric analysis, Fourier-transform infrared spectroscopy and diffuse reflectance spectroscopy were used to analyse materials further. Energy-dispersive X-ray analysis was performed when the metalcontent was ambiguous. Hybrid T3 supertetrahedra [Ga10S16(L)4] 2- were formed, where T3 denotes a tetrahedron with three [GaS4] 5- tetrahedra along each edge and L is a pyridine-based ligand. Discrete-cluster based [C12H13N2]0.5[C6H8N]1.5[Ga10S16(NC6H7)4](C6H7N)0.5 was synthesised, using an ionic liquid as a structure-directing agent, in 4-methylpyridine (4- MPy). [C6H8N]2[C12H14N2][Ga10S16(NC6H7)4]2(C12H12N2)(C6H7N)2, consisting of discrete T3 units and [C3H3N2C4H9CH3][C6H8N][Ga10S16(NC6H7)2(NC6H6)2](C6H7N)0.5, containing chains of clusters linked via ethylenedipyridine (EDPy), were also synthesised using this method. Materials containing T3-supertetrahedra were also synthesised solvothermally in 4-MPy. [NC6H8]2.5[N2C4H6][C3H5N2]0.5[Ga20S32(N2C12H12)2(NC6H7)5] consisted of dimers of T3 clusters linked via EDPy, whereas [C6H8N]4[Ga10S16(NC6H7)3(NC6H6)] - [Ga10S16(NC6H7)4](C6H7N)2 contained a 1:2 ratio of dimers to discrete clusters. [C6H8N]6[Ga20S32(NC6H7)6(N2C12H12)][Ga10S16(NC6H7)3(C6H6N)](C6H7N)6 contained both dimers and chains. The synthesis of a tetrahedron of supertetrahedra [C6H8N]14[Ga10S20]7(NC2H7)4(NC6H7)8(N2C12H12)8 was also optimised throughout this work. Some materials showed photoluminescence, as measured by collaborators; materials absorbed in the UV-region and emitted in the visible region. T2 germanium-sulphides were also synthesised in 4-MPy, including a novel trimer of T2 units [NC6H8]8[Ge12S28] and a polymeric T2-based structure [NC6H8]2[Ge4S9](C6H7N)0.5. Germanium-gallium sulphide frameworks were also produced. [C6H8N]2[Ga2Ge2S8] had the double-diamond structure, whereas [NC6H8][GaGe3S8](NC6H7)(H2O)5 was constructed from single tetrahedra, with a structure which has not been observed before. [(CH3(CH2)5)3P(CH2)13CH3]0.25[NH4]5.75[Ga10S18](NH3) is the first example of a double diamond net of [Ga10S18] 6- clusters, synthesised using an ionic liquid with no amine. The first non-hybrid discrete T3 cluster [Ga10S16(SH)4] 6- was synthesised in polyethylene glycol-400, to give [C9H18N2]6[Ga10S16(SH)4]. [C7H13N2][GaS2], containing chains of [GaS4] 5- tetrahedra, with different packing to those previously observed, was synthesised in 1,5-Diazabicyclo[4.3.0]non-5-ene . Single-crystals of [NH4][Ga3(SO4)2(OH)6] were obtained, where the sulphate was unusually formed from gallium nitrate and sulphur.