When you configure a grid date-column with a custom format, the value configured in 'format' is parsed using JSON.parse. This requires the use of double quotes for both keys and values.

var a = "{0:dd/MMMM/yyyy}";    // example from docs
JSON.parse(a);    // SyntaxError: JSON.parse: expected property name or '}'

var b = '{"0":"dd-MM-yyyy"}';
JSON.parse(b);    // jey! 

However, if you use the latter, the generated template goes fubar with the message:

"Invalid template:' ... <td>${kendo.format("{"0":"dd-MM-yyyy"\}",theDataField)}</td> ... "

This makes sense when you look at the quote mismatch..