The following returns you a string of the timestamp and the name of the file with the most recent timestamp:
find $Directory -type f -printf "%TY-%Tm-%Td-%TH-%TM-%TS %p\n" | sed -r 's/([[:digit:]]{2})\.([[:digit:]]{2,})/\1-\2/' | sort --field-separator='-' -nrk1 -nrk2 -nrk3 -nrk4 -nrk5 -nrk6 -nrk7 | head -n 1
Resulting in an output of the form:
<yy-mm-dd-hh-mm-ss.nanosec> <filename>