03.08.2013 Views

Self-assembled Transition Metal Coordination Frameworks of ...

Self-assembled Transition Metal Coordination Frameworks of ...

Self-assembled Transition Metal Coordination Frameworks of ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Chapter 2<br />

cm" are attributable to the intra-ligand 72' -—> 72' * transitions and at 30120 and 28250<br />

cm" are assigned to n —> 7r * transitions mainly due to carbonyl and thiocarbonyl<br />

groups.<br />

Table 2.2. Electronic spectral data <strong>of</strong> ligands.<br />

Compounds Absorbance features kma, cm" (8 M" cm")<br />

I~l;L' 43480 (12270), 36230 (11390), 28250 (18300)<br />

HZL2 41320 (8140), 37040 (6370), 28900 (12090)<br />

H;L3 46300 (24530), 40650 (20150), 34480 (13990), 27620 (22010), 26040<br />

(15160)<br />

H21.‘ 43860 (26030), 37040 (27110), 30120 (27500)<br />

HQLS 42550 (15930), 37310 (13710), 31450 (18830)<br />

H;L° 47170 (20270), 44640 (19140), 40650 (21610), 38020 (19760), 32260<br />

(21280), 31250 (22330), 29940 (22500), 28740 (20220)<br />

HL7 34720 (139900), 31850 (150500), 30860 (155100), 29410 (165800),<br />

28330(161200)<br />

HL3 36230 (8300), 29590 (9800), 23580 (2270)<br />

The spectra <strong>of</strong> HZLZ and HZLS also show some similar features. The band at<br />

28900 cm" <strong>of</strong> HZLZ is assigned as n —> 7r* transition mainly due to thiocarbonyl<br />

group and at 31450 cm" <strong>of</strong> H2L5 corresponds to that <strong>of</strong> carbonyl group. The remaining<br />

bands are assigned intra-ligand 72' -9 rr * transitions.<br />

The electronic spectra <strong>of</strong> quinoline-derived compounds show many peaks<br />

compared to benzoylpyridine or di-2-pyridyl ketone derived compounds. HZL3 shows<br />

absorbances at 46300, 40650, 34480, 27620 and 26040 cm", while HZL6 exhibits<br />

bands at 47170, 44640, 40650, 38020, 32260, 31250, 29940 and 28740 cm". The<br />

bands at 27620 and 26040 cm" <strong>of</strong> HZL3 and 29940 and 28740 cm" <strong>of</strong> H2L° 616<br />

attributable to the intra-ligand n —> It * transitions. Other bands are assigned to intra­<br />

ligand rr —> fr * transitions.<br />

48

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!