You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[4-[7-(4-ethenylphenyl)-3-methyl-5-[(2-methyldiphosphanyl)methyl]heptyl]phenyl]ethyl-methyl-phosphanylphosphane The above is the IUPAC name of a molecule. Write its molecular formula.
user
C27H42P4
assistant