Self-assembled Transition Metal Coordination Frameworks of ...

Chapter 4
stability alone could not be used to make the type of assignment [35]. Also it is
reported that, on the whole, EPR studies even of frozen solutions of a wide range of
copper(II) systems, do not show any evidence of pair formation, though EPR triplet
spectra had been observed in a number of copper compounds [42]. The spectra of
compounds ll and 12 show common features. The axial spectra show the presence of
second uncoupled Cu(II) species. The two different species present in 11 resembles
that in 12 as evidenced by the g“ and g i values of the two species A and B. Both
complexes have a similar Cu(H) center as evidenced by an exactly matching
parameters of one of their Cu(II) species (species A).
1")’
/' --H"./I i
mil. .1. l _.|
f
263 28] 330 Q0 343 SE] E
B, [mu
Fig. 4.25. Experimental (black) and simulated best fit (blue) of the EPR spectrum of
complex ll in DMF at 77 K.
160
i”