Can I use sys.clipboard to enter otherwise unsupported characters?

1) What happened when you tried it from the clipboard?  That's the easiest way to find out if something works and if it doesn't you can tell us what did happen and we can go from there.  

2)  This may be of some help, especially the notes about unicode at the bottom of the page

https://support.smartbear.com/testcomplete/docs/reference/language/all/string-routines-chr.html