Di-tert-butylphenylphosphine ($\mathrm{P}{(}^{\mathrm{t}}\mathrm{Bu}{)}_2\mathrm{Ph}$)

Di-tert-butylphenylphosphine is the bulky mixed alkyl/aryl phosphine $\mathrm{P}{(}^{\mathrm{t}}\mathrm{Bu}{)}_2\mathrm{Ph}$. Its tert-butyl substituents strongly influence steric interactions at a metal.