Self-assembled Transition Metal Coordination Frameworks of ...

Chapter 6
band at 19160 and 23920 cm" of 29 are assigned MLCT bands and is seen at 19610
3.5- 1 2
and 24750 cm" for 28. The bands at 43100 and 36760 cm" of 28 are assigned 1t—>1t*
and at 29760 cm" as n—>1t* transitions.
so 107
25
Q 0.2 ­
36° do W::eIen?h (nrjlo m no M 30° w‘£°v°l°:gth($) no mo 90°
29 in l0'4M DMF "‘ 28'ethl a“°
Fig. 6.16. Electronic spectra of Zn(H) carbohydrazone square grids.
The Cd(H) squares 30 and 31 show similar features (Fig. 6.17). The CT bands
are seen at ~22450 and at ~l9200 cm" but reverses in absorptivity. Also, the n—>1c*
transition band assigned at 28570 cm" for 30 show only marginal change from 28250
cm" of H2L', while that of 31 at 27700 cm" shows considerable shift from 28900 cm"
of HZLZ.
0.0-
These differences
0.1may
be attributed to change of ligand and deprotonation on
coordination in 31 compared to the nondeprotonated ligand form in 30.
250
05
Q 0.4 O .
E 0.3­
.0
3
Q 0.2a . < 0.1­
0 0 * 0.0 ­
@.ao".ao'.ao".ao'1a.'.ao'.a» *’"‘=.;°'.ao".a