Let \(\mathbb{R}\) and \(\mathbb{R}^3\) denote the set of real numbers and the three-dimensional vector space over it, respectively. The value of \(\alpha\) for which the set of vectors:
\[
\{[2 \,\, -3 \,\, \alpha], \, [3 \,\, -1 \,\, 3], \, [1 \,\, -5 \,\, 7]\}
\]
does not form a basis of \(\mathbb{R}^3\) is \(\_\_\_\_\).