I Take a look at the documentation for dir.create by $1|82\%$

I to create nested directories, 'recursive' must be set to TRUE.

$>$ dir.create

function $($path$,$ showWarnings $=$ TRUE, recursive $=$ FALSE, mode $="0777")$

$.$Internal$($dir$.$create$($path$,$ showWarnings, recursive, as$.$octmode$($mode$)))$