You could try something like this:
15 11 * * * touch “/tmp/$(date +%d-%m-%Y).sql”
To see if your particular cron will run the command out of crontab as a script in and of itself, or if you need to write a script that figures out the date as a string, and then runs your mysqldump command.
“cron” on Redhat Enterprise Linux 5.0 (I think) did not like the “$()” construct, and kept giving me errors about not finding a matching ‘)’.
NOTE: As glenn jackmann notes below, you have to escape all ‘%’ characters.
15 11 * * * touch “/tmp/$(date +\%d-\%m-\%Y).sql”