Table 2. Selected computational and refinement results for pair (1).

E(M06) is the energy obtained with the M06 density functional in the unrestricted formalism. The correct result with the lower R(F) is highlighted in bold.

	Cu2+	Ni2+
E(M06) crystal geometry (a.u.)	−2856.475	−2724.308
R(F) (%) against theoretical data	0.47	0.47
R(F) (%) whole mol­ecule data set (1a)	2.00	2.63
R(F) (%) whole mol­ecule data set (1b)	1.96	2.59