TY - JOUR
T1 - Structural and Spectroscopic Studies of Transition Metal Nitrite Complexes. V Crystal Structures and Spectra of trans-Tetrrakis(pyridine)dinitritonickel(II)-Pyridine (1/2), trans-Tetrakis(4-methy1pyridine)-dinitritonickel(II) and trans-Tetrakis(pyrazo1e)-dinitritonickel(II)
AU - Finney, Anthony J.
AU - Hitchman, Michael A.
AU - Raston, Colin L.
AU - Rowbottom, Graham L.
AU - White, Allan H.
PY - 1981
Y1 - 1981
N2 - The crystal and molecular structures of the compounds [Ni(py)4(ONO)2], 2py, [Ni(γmpy)4(ONO)2] and [Ni(prz)4(ONO)2] are reported.† All three are trans nitrito complexes, the pyridine (py) compound containing two pyridine molecules of solvation. The aromatic rings in the first two complexes adopt ‘paddle wheel’ conformations with pitch angles varying between 40 and 70°. The nitrite ions are positioned so as to minimize repulsive interactions with the amines, and it seems likely that these groups bond through oxygen rather than nitrogen because this allows a lesser degree of interligand steric interference. The amine rings in [Ni(prz)4(ONO)2] are orthogonal to the plane containing the nickel and coordinated pyrazole nitrogen atoms; the nitrito groups are disordered between two inequivalent positions, each of which involves hydrogen bonding with the pyrazole NH groups. The nitrite infrared frequencies are similar to those observed for other nickel(II) nitrito complexes except that the antisymmetric NO stretching mode of one of the groups in the pyrazole complex is much lower in energy than expected, being in the range normally associated with a nitrogen-bonded or chelated nitrite group. It is suggested that this deviation may be caused by the hydrogen bonding in the complex. The electronic spectra of the compounds yield 10Dq values of 9100 and 8500 cm-1 for the nitrite ligands in [Ni(py)4(ONO)2] and [Ni(prz)4(ONO)2], respectively, placing the nitrito group towards the weaker end of the spectro-chemical series.
AB - The crystal and molecular structures of the compounds [Ni(py)4(ONO)2], 2py, [Ni(γmpy)4(ONO)2] and [Ni(prz)4(ONO)2] are reported.† All three are trans nitrito complexes, the pyridine (py) compound containing two pyridine molecules of solvation. The aromatic rings in the first two complexes adopt ‘paddle wheel’ conformations with pitch angles varying between 40 and 70°. The nitrite ions are positioned so as to minimize repulsive interactions with the amines, and it seems likely that these groups bond through oxygen rather than nitrogen because this allows a lesser degree of interligand steric interference. The amine rings in [Ni(prz)4(ONO)2] are orthogonal to the plane containing the nickel and coordinated pyrazole nitrogen atoms; the nitrito groups are disordered between two inequivalent positions, each of which involves hydrogen bonding with the pyrazole NH groups. The nitrite infrared frequencies are similar to those observed for other nickel(II) nitrito complexes except that the antisymmetric NO stretching mode of one of the groups in the pyrazole complex is much lower in energy than expected, being in the range normally associated with a nitrogen-bonded or chelated nitrite group. It is suggested that this deviation may be caused by the hydrogen bonding in the complex. The electronic spectra of the compounds yield 10Dq values of 9100 and 8500 cm-1 for the nitrite ligands in [Ni(py)4(ONO)2] and [Ni(prz)4(ONO)2], respectively, placing the nitrito group towards the weaker end of the spectro-chemical series.
UR - http://www.scopus.com/inward/record.url?scp=0012140983&partnerID=8YFLogxK
U2 - 10.1071/CH9812095
DO - 10.1071/CH9812095
M3 - Article
AN - SCOPUS:0012140983
VL - 34
SP - 2095
EP - 2111
JO - Australian Journal of Chemistry
JF - Australian Journal of Chemistry
SN - 0004-9425
IS - 10
ER -