No.
The fraction two-thirds is already in its simplest form.
Two-thirds
66.66(repeating)%
12/162
66 and 2/3%
11/12
66.666666667% would be 2/3 as a fraction.
thiry three and one third
2/3 = 0.67 or 67%
2/1
No - an equivalent fraction to 2/3 would be 16/24.