Howto add ajax options for select2js

Hi,
I want to populate an advanced select with some datas.
I'm trying to add 'select2js' parameters inside the metabox builder. But it does not work.

In "Select2 options", I added "ajax", and then added the value "url:/admin-ajax.php, dataType:json, data:[action:agrodyn_list_modeles], id_marque:12".

Where am I wrong, please?