Judging by the ratio of the lattice parameters a:c, the unit cell of Ni(PyC-m-NH 2 ) 2 is less anisotropic than the parent Ni(PyC) 2 ( . Å: . Å versus . Å: . Å for Ni(PyC) 2 ). This appears to be a result of new hydrogen bonding interactions between the amino groups and the carboxylate groups of the neighboring network, which are observed in the Ni(PyC-m-NH 2 ) 2 structure with N-O distances of " Å. The lattice parameter b governs the distance between neighboring diamondoid networks along [ ], which is greater in Ni(PyC-m-NH 2 ) 2 ( . Å) than in Ni(PyC) 2 ( . Å), apparently to accommodate the new functional group. Overall, the distortion of the network gives Ni(PyC-m-NH 2 ) 2 a larger unit cell volume than the parent Ni(PyC) 2 ( . Å 3 versus . Å 3 for Ni(PyC) 2 ). See Sec. S for further details.