Ligand orbitals, exchanged electron

Percentage of "Exchanged Electron" Residing in Metal (M) and Ligand (L) Orbitals... 

The complex [(VO)2(dana)2] (dana = l,5-bis(p-methoxyphenyl)-l,3,5-pentanetrionato) was prepared and temperature dependent Xm measurements show antiferromagnetic behaviour with J = —80 cm 1.902 The / value is much lower than with [M2(dana)2(py)2] (M = Co, Cu) and this probably results from a different spatial orientation of the exchanging electrons if the unpaired electron is considered to be initially in a dxy orbital, a direct metal-metal interaction may be possible as the V—V distance is large (ca. 3.0-3.2 A V atoms are probably 0.5-0.6 A out of the plane and possibly one above and one below the ligand plane902), one would expect a weak exchange for the direct V—V interaction. 

Figure 14). The Keggin structure can therefore accommodate as many as 24 additional electrons in this fashion. Indeed, an additional eight electrons (32 in all ) can be accommodated in nonbonding molecular orbitals, two electrons per trimeric unit. Each bears a terminal exchangeable water ligand (thereby keeping the anion charge low), and the browns have been shown to participate in atom-transfer processes, for example, equation (5).

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