
TY  - JOUR
A1  - Robertson, Mark J. 
A1  - Lawrance, Geoffrey A. 
A1  - Maeder, Marcel 
A1  - Turner, Peter 
T1  - Octahedral Complexes of a Mixed <emph type="2">N</emph>,<emph type="2">N</emph>,<emph type="2">O</emph>-Donor Ligand <emph type="2">N</emph>-<emph type="2">trans</emph>-(2&#39;-hydroxycyclohexyl)-2-aminomethylpyridine
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 2004
VL  - 57
IS  - 5
SP  - 483
EP  - 490
KW  - 
UR  - https://doi.org/10.1071/CH03208 
N2  - The unsymmetric mixed-donor Nam,Npy,O-ligand N-trans-(2&#39;-hydroxycyclohexyl)-2-aminomethylpyridine (pyca, 1) was readily prepared by reaction of an epoxide (cyclohexene oxide) with (2-aminomethyl)pyridine. The ligand forms octahedral bis-tridentate complexes, exemplified with isolation of copper(II), nickel(II), zinc(II), and cobalt(III) compounds&#x003B; in addition, a square-planar palladium(II) complex with the ligand behaving as bidentate was prepared. The bis-tridentate octahedral complexes may exist in six geometric isomeric forms, and molecular mechanics analysis was employed to predict the most stable isomer for copper(II), nickel(II), and cobalt(III) complexes. For the copper(II) and cobalt(III) complexes, the predictions match the X-ray crystal structures of the single isomer isolated in each case. Both the copper(II) complex [Cu . 12](ClO4)2 and the cobalt(III) complex [Co . 1 . (1&#8211;H)](ClO4)2 crystallized in the monoclinic space group P21/n (no. 14), with a 9.8400(13), b 15.434(2), c 10.0180(13) &#197;, and &#946; 109.004(2)&#176;, and a 14.162, b 18.583, c 21.596 &#197;, and &#946; 100.04&#176;, respectively. Both complexes adopt distorted octahedral structures. The copper(II) complex exists as the all-trans-fac isomer with Jahn&#8211;Teller elongation of the Cu&#8211;O bond [2.3795(19) &#197;] compared to Cu&#8211;Npy [2.040(2) &#197;] and Cu&#8211;Nam [2.024(2) &#197;] distances. The cobalt(III) complex appears as the cis,cis,trans(Npy) fac isomer, but deprotonation of one of the two alcohol groups leads to all six M&#8211;L distances differing: for each of two similar independent complex cations, Co&#8211;O [e.g. 1.9123(16), 1.9459(16) &#197;], Co&#8211;Nam [e.g. 1.949(2), 1.968(2) &#197;], and Co&#8211;Npy [e.g. 1.938(2), 1.940(2) &#197;] vary, with particularly the deprotonated alcohol bond significantly shorter than the protonated bond, despite a strong hydrogen bonding interaction with the protonated alcohol in the partner complex cation in the unit cell. 
ER  -

