Mixed ligands alkyl/phosphide tetrylenes

Abstract

In this project, three hybrid ligands consisting of a combination of alkyl and phosphide donors linked to bulky substituents were prepared. The first ligand, (Me3Si)2CHSiMe2CH2PHDep, was synthesised by deprotonating one equivalent of DepPH2 using one equivalent of n-BuLi and reacting it with one equivalent of (Me3Si)2CHSiMe2CH2Cl (Dep = 2,6-Et2C6H3). The second ligand, (Me3Si)2CHSiMe2CH2PHDipp, was prepared by reacting one equivalent of DippPH2 with one equivalent of n-BuLi to deprotonate it and then react with one equivalent of (Me3Si)2CHSiMe2CH2Cl (Dipp = 2,6-iPr2C6H3). Meanwhile, the third ligand, (Me3Si)2CHSiMe2CH2PHAr, [Ar = 2,6-Bis(benzhydryl)-4-methylphenyl), was synthesised by reacting one equivalent of ArPH2 with one equivalent of n-BuLi, before reacting the resulting compound with one equivalent of (Me3Si)2CHSiMe2CH2Cl.

Following the synthesis of (Me3Si)2CHSiMe2CH2PHDep and (Me3Si)2CHSiMe2CH2PHDipp, they were analysed using 1H NMR and 31P NMR spectroscopy which revealed the presence of impurities. As a result, we undertook purification processes and attempted to crystallise them but crystallisation and isolation proved challenging. Conversely, analysis of the (Me3Si)2CHSiMe2CH2PHAr, [Ar = 2,6-Bis(benzhydryl)-4-methyl-phenyl] ligand using 31P NMR, 1H NMR and HQSC confirmed that it had been successfully synthesised. To further investigate this ligand, an attempt was made to produce crystals suitable for analysis via X-ray crystallography.

Additionally, an attempt was made to synthesise (ArPH)2Ge, [Ar = 2,6-Bis(benzhydryl)-4- methylphenyl] by reacting one equivalent of ArPH2 with one equivalent of n-BuLi, followed by a reaction with a half equivalent of GeCl2(dioxane). An attempt was also made to prepare {(Me3Si)2CSiMe2CH2PAr}Sn by reacting one equivalent of (Me3Si)2CHSiMe2CH2PHAr with two equivalents of CH3Li for deprotonation, before reacting the resulting (Me3Si)2CLiSiMe2CH2PLiAr with one equivalent of SnCl2. However, both reactions proved unsuccessful