“…Thus X-ray derived M-L bond lengths may be affected by crystal packing and conformational effects and only few M-L bond stretches can be unambiguously assigned (M-H, certain M-Cl and few others); CO stretching frequencies have also been used [13]. NMR investigations are usually based on the values of one bond coupling constants, which can be considered an estimate of the M-L bond strength [1,[13][14][15][16][17][18][19], but this technique can be used only when both M and the donor atom of L are NMR active ( 195 Pt-31 P, 103 Rh-31 P, etc.). 2 J MC and 3 J MH have also been employed [1,20].…”