Self-assembled Transition Metal Coordination Frameworks of ...

Manganese(ll) complexes
.l
70­
60­
50­
40­
30­
2: 41;: /\\
20­
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0 "ll ' | ' | ' |
/
' 1 " *
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| '
1'
600 500 400 300 200 100
Wavenumber (cm")
Fig. 5.14. Far IR spectrum of Mn(II) thiocarbohydrazone square complex 19.
ab '\s»»""“\./ "M X /\ / _. /V
V \/\/\ /\ /\
0° /’ \\ /"\V/ \¥/‘\/f\V/\\ F P /%\
\/ \/ \ /\ c \\j/
_ I | P -1 1- r"'" t 1 1 | | -' 1 | r
§ 8% 4% III 21!) 1%
wavenumber (crn")
Fig. 5.15. Far IR spectrum of dimanganese(Il) thiocarbohydrazone 20.
The electronic spectral data of Mn(lI) complexes in DMF solution are listed
in Table 5.2 and the spectra are given in Figs. 5.16 and 5.17. The intraligand n —) 7!‘ *
transitions of free ligands have suffered considerable shift in complexes. The ground
state for an Mn(II) ion having d5 configuration is 6A,g and the transitions from this
state is doubly forbidden. However, some low intense bands are seen in some cases,
but may be obscured by even the very weak tail of an intraligand transition tailing into
the visible region [43]. For the light colored complexes 21, 22 and 23 the possible
fragmentation makes the absorbance values nonreliable. However, for the
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