How do I format serialized data to be used by Ajax

string json1 = [{"id":1,"col1":"11","col2":"22","col3":"33"}]

ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "javascript", "Javascript:GetDateTime(" + json1 + ");", true);

"Error Code: Status: [object Object] Ex: error"

    <script  type="text/javascript src="http://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script type="text/javascript">
        function GetDateTime(json1) {
            $.ajax
            ({
                type: "POST",
                url: "Default.aspx/GetServerDateTime",
                data: json1,
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: function (result) {
                    alert(result.d);
                },
                error: function (status, ex) {
                    alert("Error Code: Status: " + status + " Ex: " + ex);
                }
            });
        }
    </script>