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The porphyrin handbook - Kadish K.M.

Kadish K.M. The porphyrin handbook - Academic press, 2000. - 368 p.
Download (direct link): kadishsmishgulilard2000.djvu
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UV-Vis 22
73 74 trans-1,2-cyclohexanediol 12.8 CHC1, 288
UV-Vis 22
74 74 cis-1,2-cyclohexanediol 9.8 CHCh 288
UV-Vis 22
75 74 frans-2-hydroxymethylcyclohexanol 18.8 CHCh 288
UV-Vis 22
76 74 cis-2-hydroxymethylcyclohexanol 15.2 CHCh 288
UV-Vis 22
77 76 cyclohexanol 2.6 CHCh 288
UV-Vis 22
78 76 letrahydropyrane 7.1 CHCh 288
UV-Vis 22
79 76 2-hydroxymethyltetrahydropyrane 6.8 CHCh 288
UV-Vis 22
80 76 cyclohexanemethanol 3.9 CHC1, 288
UV-Vis 22
81 76 trans-1,2-cyclohexanediol 11.8 CHCh 288
UV-Vis 22
82 76 cis-1,2-cyclohexanediol 9 CHCh 288
UV-Vis 22
83 76 fra".?-2-hydroxymethylcyclohexanol 13.8 CHCh 288
UV-Vis 22
84 76 ci\s-2-hydroxymethylcyclohexanol 10.7 CHCh 288
UV-Vis 22
85 78 dimethyl L-tartrate 18.9 CHCh 288
UV-Vis 235
86 78 diethyl l.-tartrate 20.1 CHCh 288
UV-Vis 235
87 78 diisopropyl i -tartrate 23.9 CHCh 288
UV-Vis 235
88 78 di-sec-butyl l.-tartrate 24.1 CHCh 288
UV-Vis 235
89 78 di-tert-butyl i.-tartrate 20.4 CHC1, 288
UV-Vis 235
90 78 diethyl meso-tartrate 15.0 CHCh 288
UV-Vis 235
91 78 diethyl 2-hydroxysuccinate 4.7 CHCh 288
UV-Vis 235
92 78 (2/?,3/?)-dihydroxybutane 5.3 CHCh 288
UV-Vis 235
93 65 diethyl L-tartrate 11.9 CHCh 288
UV-Vis 235
94 64 diethyl L-tartrate 8.6 CHCh 288
UV-Vis 235
95 66 diethyl L-tartrate 28.7 CHC1, 288
UV-Vis 235
74
75
76
mannoside > /?-mannoside > /?-glucoside > a-glucoside ~ /i-galactoside >
a-galactoside. The selectivity of zinc porphyrin roughly follows this
order, showing that, in broad terms, the porphyrin is an indiscriminate
receptor.
[5,l5-Bis(8-quinolyl)porphyrinato]zinc 74 was found to be a good
receptor for sugar derivatives, particularly octyl mannoside in CHC1>22-
84 Binding affinities toward carbohydrates were compared between three
zinc porphyrin hosts. Host 74 has one Lewis acid site and two Lewis base
sites; hosts 76 and 77 have three Lewis acid sites. The binding free
energies ( -AG) for glucoside, mannoside and galacloside were 19.8-26.4
for 74, 13.2-16.0 for 76, and 17.8-19.7kJ/mol for 77. Host 74 exhibited a
much
OH
OH
77
higher affinity toward carbohydrate, indicating that the combination of
Lewis acid and Lewis base is important for carbohydrate recognition. The
complexation-induced shifts of the OH protons of pyranosides bound to 74
were explained by assuming that the 6-OH and the 3-OH groups are hydrogen
bonded to the quinolyl nitrogens and the 4-OH group is coordinated to the
zinc (Figure 11). Based on this conformation, the advantage of the
mannoside over glucoside resides in the fact that the mannoside has 2,3-
cis-dihydroxy groups, which can intramolecularly assist the hydrogen
bonding to the quinolyl nitrogen, while glucoside has trans-2,3-dihydroxy
groups, which are less effective in assisting the hydrogen bonding.85~88
Induced CD studies
46 / Porphyrins and Metalloporphyrins as Receptor Models
303
NO,
78

6h 6h h
79
80
t\-
,s- N'
1N iV-
+
Zn
Figure 11. Proposed hydrogen-bonding networks of host 74 mannoside
complex.
also gave important information about the complexation modes. The
mannoside-porphyrin complex showed distinct bisignate Cotton effects,
even at 288 K, and the Cotton effects were somewhat increased by lowering
the temperature. In contrast, the glucoside-porphyrin complex showed weak
Cotton effects in the Soret region at 288 K, and upon cooling to 223
bisignate Cotton effects appeared. Therefore mannoside was fixed even at
room temperature, while glucoside was mobile in the binding pocket of
porphyrin at room temperature, and upon cooling, glucoside was rigidly
fixed.
Shinkai et al. reported sugar recognition in water by use of boronic
acid appended porphyrins.*4 A cationic porphyrin bearing boronic acid 81
and 82 binds the anionic guest in water, the binding affinity of which is
controlled by the addition of sugars. When sugar was added and formed a
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