RELATIONSHIP BETWEEN H-D SPIN-SPIN COUPLING AND INTERNUCLEAR DISTANCEIN MOLECULAR-HYDROGEN COMPLEXES

An essentially identical linear relationship between the spin-spin cou pling constant J(HD) and internuclear separation r(HH) in closed-shell ''eighteen electron'' eta(2)-H-2 molecular hydrogen complexes is both predicted by quantum chemical calculations for complexes of the type [Os(II)(NH3)(4)L(eta(2)-H-2)] for a wide range of trans ligands L and found experimentally for a series of complexes of Fe, Cr, Ru, and Os, also containing a variety of ligands. Simple electronic structural con siderations are proposed in order to provide a preliminary interpretat ion of these remarkable results.