3 JPYb = 93 Hz). The 13 C{ 1 H} NMR shows an interesting trend down Group 2, with regards to the M-CH resonance, with chemical shifts increasing steadily moving from Mg to Ba. This is analogous to the trend noted earlier in the 31 P{ 1 H} NMR spectra of 1-M. Further to this, the 1 JCP coupling constant also steadily increases down the group from 59.4 Hz (1-Mg) to 87.7 Hz