You may need to reformat the date value before it is inserted into the db. To do this you will need to make use of the date function in php.
The format for the date you would like to get would look like this:
date("Y-m-d h:i:s", strtotime($_POST['dateCreated']));
If you need the time to be in 24 hour format you would use G instead of h in the date function. What this formatting is doing is taking the dateCreated and making it into a timestamp with the strtotime function. This timestamp is then formated with the string in the date function. You will want to do this to the value in the insert statement, so rather than just inserting the posted value you will insert this formatted version of the posted value.
Here is a link to the pages for these functions: