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Title: Solvothermal synthesis of novel inorganic materials
Author: Lees, Rachel Jane Elizabeth
ISNI:       0000 0001 3607 6857
Awarding Body: Heriot-Watt University
Current Institution: Heriot-Watt University
Date of Award: 2007
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Solvothennal and hydrothennal synthesis is widely applied in the generation of . metastable crystalline phases, and is used in this work to prepare a range of novel antimony-sulphide and rare-earth oxy-anion compounds in' the presence of linear, branched and macrocycle amines. The new crystalline phases were characterised using single-crystal X-ray diffraction, elemental analysis, diffuse reflectance spectroscopy and SQUID magnetometry. Transition-metals included in the reactions resulted in the fonnation of both binary antimony-sulphide and ternary transition-metal-antimony-sulphide structures. Binary phases include [Fe(en)3]Sb2Ss.0.55H20, [Fe(en)3hSb4Sg, [T(dien)2]Sb6SIO.xH20 (T= Ni, Co), [Co(en)3]SbgS13 and tNi(en)3]Sb12S19, where discrete [Sb2Sst units, SbS2chains, Sb6SI0 6- and SbgS13 2- layers and a three-dimensional Sbl2Slt framework are charge balanced by transition-I.l1etal-amine complexes. The ternary phases synthesised using tris(2-aminoethyl)amine (tren) and diethylenetriamine (dien) include [Cr(tren)]Sb4S7 chains with [Cr(tren)f+ pendent complexes, and [T(dien)hSblgS30[ T(dien)2] (T= Mn, Fe, Co), in which complex antimony-sulphide chains are bridged via dimeric [T2S2] units to fonn novel layers. The transition-metal ions all exhibit paramagnet~c behaviour and the band gaps of the phases were found to increase from 1.79(4) to 2.46(1) eV with increasing framework density. The first examples of hydrothennal antimony-sulphide reactions using a macrocycle, cyclam, as the structure directing agent resulted in the synthesis of novel , layered and three-dimensional phases of[cyclarnH2]Sb6SIO and [cyclamH2]Sb4S7. By including transition-metal salts in the reaction mixture, it was possible to incorporate transition-metal ions within the macrocyclic rings in [Ni(cyclam)]Sb4S7 and [Co(cyclam)]x[cyclarnH2]J_xSb4S7, where the C02+ occupancy varies between O.08
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available