The crystal and molecular structure of [(pyridine)2Cu(NO3)2]2,C5H5N: a centrosymmetric dimer with bridging nitrato-groups

Infrared Combination Frequencies in Coordination Complexes containing Nitrate Groups in various Coordination Environments. A Probe for the Metal–Nitrate Interaction

“…Bridging through two oxygen atoms to different metal atoms is exemplified by the cr modification of copper nitrate (34). Finally one oxygen atom of the nitrate group may bridge two metal atoms as in the complex Cu,(Py),(NO,), previously described (25).…”

“…The complex dinitrato [bis(2-pyridy1)disulfide]copper(II) has been shown to be octahedral with bidentate nitrate groups (24) and exhibits two combination frequencies separated by 47 cm-'. The complex Cu,(Py),(NO,), has recently been shown by X-ray methods (25) to contain both bidentate and bridging nitrate groups. The presence of the bidentate nitrate groups is shown by two well defined bands at 1720 and 1741 cm-' whilst the bridging bands appear only to give rise to weak absorption at higher energies (see below).…”

The myth of the non-coordinating anion

“…This compound was previously formulated (42) as bidentate, but the anion orientation could not have been predicted from infrared spectra. Interestingly, when alpha-picoline is replaced by pyridine, the removal of steric hindrance allows dimerization to occur (59) and the compound [Cupy2(N03)2]2-py is obtained-a centrosymmetric dimer with bridging and asymmetric bidentate nitrate groups both present. X-ray diffraction studies have been carried out on tetranitratometallates (60).…”