Investigation into the solid state chemistry of beryllosilicates, sulfimide complexes and nosean compounds
thesisposted on 18.04.2013, 08:31 by Amy MacLucas
The similar chemical properties of sulfur, selenium and tellurium have been used to enable investigation of altering the size of occluded species, AOx (A = sulfur, selenium, tellurium and x = 0, 3 or 4), within sodalite based framework materials. Geomimetic synthesis of nosean Na8[AlSiO4]6AOx where A = sulfur, selenium, tellurium and x = 0, 3 or 4 has been investigated and a synthesis method for pure nosean selenate has been reported. Beryllosilicate and beryllogermanate sodalite compounds M8[BeSiO4]6A2 where M = Fe, Mn, Zn, Co, etc. and A = S, Se, Te have also been geomimetically synthesised and the magnetic effect of interchanging the original occluded sulfide for selenide resulted in a change in symmetry from P 3n to P222 at low temperature. Controlled mixed-metal beryllium compounds were targeted in order to investigate the effect of each M and combinations thereof. Unusual grinding effects have been observed for blue square planar Cu(Ph2SNH)2Cl2, whereby a reversible colour change to green occurs on grinding or application of a sheer force. Evidence points towards the possibility that a sheer effect, induced by way of grinding, causes a twisting of the ligands, inducing a reversible colour change, with properties tending towards those of the pseudo-tetrahedral allogon in the square planar polymorph. Anion metathesis has been found to occur within a system containing [Cu(Ph2SNH)4]Cl2, Ph2SNH.H2O and NaBF4. There is evidence indicating that, on grinding, an additional Ph2SNH ligand can be coordinated to the copper centre. This would be the first example of a purely solid state reaction in which the maximum coordination number for a ligand could be controlled by the counterion.