Chemistry Reference
In-Depth Information
Lifetimes increases up to 18-fold and quantum yields up to
F
F
ΒΌ
0.7 have been
measured for some of these dyes in aqueous media.
O
O
NH
HN
N
N
NH
HN
O
O
Rp
O
R
1
R
1
N
N
R
2
R
2
O
21a
: R
1
= CH
2
Ph, R
2
= (CH
2
)
5
COOH
21b
: R
1
, R
2
= (CH
2
)
3
COOH
21c
: R
1
= (CH
2
)
3
SO
3
H, R
2
= (CH
2
)
3
COOH
21d
: R
1
= (CH
2
)
3
SO
3
H, R
2
= (CH
2
)
3
COOEt
21e
: R
1
= (CH
2
)
3
SO
3
H, R
2
= (CH
2
)
3
COO-NHS
O
R
2
R
2
X
1
X
2
N
N
R
1
O
R
1
: X
1
= X
2
= CMe
2
, R
1
= R
2
= H
22a
22b
: X
1
= X
2
= CMe
2
, R
1
= H, R
2
= SO
3
H
22c
: X
1
= X
2
= S, R
1
= Me, R
2
= H
22d
: X
1
= X
2
= Se, R
1
= Me, R
2
= H
22e
: X
1
= CMe
2
, X
2
= C(Me)(CH
2
)
5
COOH, R
1
= H, R
2
= SO
3
H
22e-NHS
: X
1
= CMe
2
, X
2
= C(Me)(CH
2
)
5
COO-NHS, R
1
= H, R
2
= SO
3
H
Conjugation of the squaraine-rotaxane-NHS ester 21e to protein (IgG) results in
a large increase in its fluorescence lifetime. In addition, the encapsulation of the
squaraine dyes in a Leigh-type rotaxane increases the chemical stability towards
hydrogen peroxide and alkaline agents (Fig.
10
). Rotaxane 21e can be considered a
highly-stable, fluorescent label for fluorescence
imaging
, fluorescence
lifetime
, and
single molecule
applications.
Encapsulation of squaraine 23a in diastereomeric
triptycene
-based tetralactam
macrocycles 24a and 24b was described in [
61
]. The synthesis of the macrocyclic
hosts was done by the reaction of pyridine-2,6-dicarbonyl dichloride and 2,7-
diaminotriptycene in dry THF with Et
3
N. Macrocycles 24a and 24b readily form
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