The 31P NMR spectra of 3 and 4 exhibit downfield shifts
when compared with those of complex 2 (37.8 ppm for 3,
33.2 ppm for 4, 7.4 ppm for 2). The 1
H NMR of 4 exhibits
a single resonance (0.04 ppm) which can be assigned to
Al-Me. The 18 protons of SiMe3 resonate as a singlet at
-0.03 ppm, and the aromatic protons of Ph are shown at
7.46-7.79 ppm