The first complexes of a sterically unhindered phosphaalkyne have been studied by UK chemists. 

Phosphaalkynes - molecules which contain a phosphorus-carbon triple bond - are versatile starting materials for many reactions including the synthesis of organophosphorus cages, heterocycles and coordination complexes. Taking advantage of newly developed routes to the simple methyl phosphaalkyne, Cameron Jones and colleagues at Cardiff University have examined its coordination chemistry for the first time.

The chemistry of phosphaalkynes stabilised by bulky substituents has been a developing area for many years, but, despite its importance, the chemistry of the simple derivative methyl phosphaalkyne has remained unknown. According to Jones, this has been a goal for phosphorus chemists for some time and is particularly interesting because methyl phosphaalkyne is an analogue of propyne, which is an important industrial feedstock.

John Nixon, FRS, professor of chemistry at the University of Sussex, UK, and an expert in the coordination chemistry of phosphorus, is enthusiastic about the chemists' work. He explained that while the presence of bulky t-butyl groups in phosphaalkynes can provide kinetic stability, it also introduces its own steric effect on reaction pathways. 'Their initial results show that as well as exhibiting some similar behaviour to the t-butyl phosphaalkyne systems, other synthetic pathways can result using the much smaller methyl-containing derivative,' said Nixon.

One of the next challenges for chemists is the linear polymerisation of phosphaalkynes with the hope of finding useful optical or electronic properties. 'This has never been achieved because of the propensity of phosphaalkynes to form cyclic oligomers and cage complexes,' said Jones. 'With methyl phosphaalkyne, we see the potential to realise this goal.'

Caroline Moore