
TY  - JOUR
A1  - Crea, J 
A1  - Lincoln, SF 
T1  - The exchange of pyridine on Bis(&#946;-alkanedionato)dipyridinenickel(II) complexes. A nitrogen-14 magnetic resonance study
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1975
VL  - 28
IS  - 7
SP  - 1523
EP  - 1528
KW  - 
UR  - https://doi.org/10.1071/CH9751523 
N2  - A 14N N.M.R. study is reported of the exchange of pyridine (py) on [Ni(bzac)2(py)2] [k(298 K) = (4.6±0.5)x104 s-1, &#916;H? = 38±3 kJ mol-1; &#916;S? = -28±11 J K-1 mol-1], [Ni(bzbz)2(py)2] [k(298 K) = (2.7±0.3)x104 s-1; &#916;H? = 38±3 kJ mol-1; &#916;S? = -34±12 J K-1 mol-1], [Ni(tfac)2(py)2] [k(298 K) = (8.4±0.9)x103 s-1]; &#916;H? = 32±3 kJ mol-1; &#916;S? = -58±11 J K-1 mol-1], and [Ni(hfac)2(py)2] [k(298 K) < 2x103 s-1] in pyridine solution where the rate of pyridine exchange = 2k[nickel(II) complex], bzac = 1- phenylbutane-1,3-dione; bzbz = 1,3-diphenylpropane-1,3-dione; tfac = 1,1,1-trifluoropentane-2,4-dione; and hfac = 1,1,1,5,5,5- hexafluoropentane-2,4-dione. The lability (298 K) of pyridine in the nickel(II) complexes is observed to decrease as the electron withdrawing power, as assessed from appropriate Taft parameters, of the &#946;-alkanedionato ligand increases. 
ER  -

