Chrysler 300m 2.7 overheating.

I have a 2006 Chrysler 300 with a 2.7 l.
Had a mechanic come and change the
thermostat fill it with antifreeze and got
all the air out of the system. The car runs
up till about midway's and stays there
and then all the sudden it jumps up into
the red cut the car off. Let it cool for a
few minutes and then it doesn't want to
crank. Once it cools completely down it
cranks and runs fine. I have seen no
water on the ground other than when it
balls over from being hot. The fans are
working fine, new thermostat, air
evacuated from the system but still
doing the same thing. Does anyone think
it could be the temperature sending unit
that's causing it to fluctuate so much
and run hot