tibble contains a function call

I have a tibble call that uses a function.
tibble(
compound1 = pair_ids[1],
compound2 = pair_ids[2],
results <- mcs_to_smiles(cid(s1),cid(s2),sdfset),
mcs_size = res[3]

)
The header label is the function call
"results <- mcs_to_smiles(cid(s1),cid(s2),sdfset)"

I would like the header label to be "smiles". However I can't make this happen. If I move the function call outside the tibble It is not transferred to the tibble (i.e. smiles <- results). Looks like a syntax issue, but I have not found the answer. Thanks for your help.
clearly my R skills to not extend to tibble.

Try changing results<- to smiles = and see if that helps.

When I do smiles = mcs_to... the tibble is empty. Apparently this syntax prevents the tibble from being filled??

You might want to post a very short reproducible example that others can run to see if someone can find the bug. It's possible that the bug isn't in creating the tibble, for example.