conclusion that the ferromagnetic component of the couplings is nearly constant across the series of complexes examined here. Turning to the antiferromagnetic contributions for the copper and nickel complexes, the two scanning techniques show a similar behaviour: the absolute coupling strength of the σ contribution in the copper complex remains within a narrow range of -87 to -83 cm -1 , and a slightly wider window of -67 to -46 cm -1 in the nickel complex. The δ-coupling contribution remains 5-6 orders of magnitude smaller than the σ component.