Tris(acenaphthyl) and bis(acenaphthyl) substituted pnictogens (iPr2P-Ace)3E (2-4) (E = As, Sb, Bi; Ace = acenaphthene-5,6-diyl) and (iPr2P-Ace)2EPh (5 and 6), (E = As, Sb) were synthesised and fully characterised by multinuclear NMR, HRMS, elemental analysis and single crystal X-ray diffraction.The molecules adopt propeller-like geometries with the restricted rotational freedom of the sterically encumbered iPr2P-Ace groups resulting in distinct NMR features. In the tris(acenaphthyl) species (2-4) the phosphorus atoms are isochronous in the 31 P{ 1 H} NMR spectra, and the rotation of the three acenaphthyl moieties around E-Cipso bond is locked. On the other hand, the bis(acenaphthyl) species show a fluxional behaviour, resulting in an AX to A2 spin system transition in the 31 P{ 1 H} VT NMR spectra. This allowed elucidation of remarkable through-space couplings of 8TS JPP 11.5 Hz (for 5) and 25.8 Hz (for 6) at low temperature. In addition, detailed lineshape analysis of the thermodynamic parameters of the restricted rotation of the "propeller blades" in 5 was performed in the intermediate temperature region and also at coalescence. The lone pairs on the pnictogen atoms in 2-6 are oriented such that they form a bowl shaped area which is somehow buried within the molecule.2

Eight novel germanium compounds of the type [R 2 Ge(E-Ar-E)], where R = Me, Ph; E-Ar-E = an aromatic bidentate chalcogen ligand, were successfully synthesised. The effects of changing 3 variables within the series were investigated. These variables included the chalcogen (E = S/Se), aromatic backbone (Ar = Nap/Biphenyl) and R group (Me/Ph) employed. The choice of aromatic backbone had the greatest effect on the structure. A substantial change in geometry around the germanium centre was observed within the solid state structures depending on whether the backbone was naphthalene or biphenyl. This affected the stability of the compound and resulted in the visible decomposition of two selenium complexes over several days. All novel compounds were characterised by multinuclear NMR, IR, mass spectroscopy and single crystal X-ray diffraction.