Distyryl 1,2-Bis(2-pyridylmethoxy) benzene substituted near-infrared BODIPY photosensitizers: synthesis and spectroscopic studies

Article abstract of DOI:10.1007/s12039-021-01934-1

Near-infrared BODIPY photosensitizers with symmetrical 2,6-diiodo 3,5-distyryl 1,2-Bis(2-pyridylmethoxy) benzene were synthesized to study the singlet oxygen (¹O₂) photosensitizing efficiency as triplet photosensitizer as well as flu

Full text of DOI:10.1007/s12039-021-01934-1

J. Chem. Sci. ( 2 0 2 1 ) 1 3 3 : 6 3
Ó I n d ia n A c a d e m y o f S c i en c es
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REGULAR ARTICLE
Special Issue on B ey o n d C l a s s i c a l C h e mi s t r y
Distyryl 1,2-Bis(2-pyridylmethoxy) benzene substituted near-
infrared BODIPY photosensitizers: synthesis and spectroscopic
studies
a , b
G A Y A T H R I T H U M U G A N T I , P O U L O M I M A J U M D A R a n d S U RY A P RA K A S H S IN G H
a
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P o l y m e r s a n d F u n c t i o n a l M a t e r i a l s D i v i s i o n , C S I R - I n d i a n I n s t i tu te o f C h e m i c a l T e c h n o l o g y , U p p a l R o a d,
T a r n a k a , H y d e r a b a d , T e l a n g a n a 5 0 0 6 0 7 , I n d i a
b
A c ad e m y o f S c i e n t i fi c a n d I n n o v a t i v e R e s e a r c h ( A c S I R N e w D e l h i ) , N e w D e l h i , I n d ia
E - m a i l : s p s i n g h @ i i c t . r e s . i n
G a y at h r i T h u m u g a n t i a n d P o u l o m i M a j u m d a r h a v e c o n t r i b u te d e q u a ll y t o t h i s w o r k .
M S r e c e i v e d 1 8 M a r c h 2 02 1 ; r e v i s e d 3 M a y 2 0 2 1; a c c e p t e d 6 M a y 2 0 2 1
Abstract. N e a r - i n f ra r e d B O D I PY p h o to s e n s i t i z e r s w i t h s y m m e t r i c a l 2 , 6 - d ii o d o 3 , 5 - d is t y r y l 1 , 2 -B i s ( 2 -
1
p y r i d y l m e t h o x y ) b e n z e n e w e re s y n t h e s i z e d t o s t u d y t h e s i n g l e t o x y g e n ( O ) p h o to s e n s i t iz in g e f fi c i en c y a s
2
t r i p l et p h o t o s e n s i t i z e r a s w e l l a s fl u o r e s c e n t s e n s o r s f o r m e t a l c a t i o n r e c o g n i t i o n . M o d e r a t e s i n g l e t o xy ge n
1
( O ) q u a n t u m y i e l d ( UD) w a s o b t a i n e d f o r t h e p h o to s e n s i t iz e r s . E m i s s i o n i n t e n s i t y o f t h e p h o to s e ns i ti z er s
2
2?
2 ?
i n cr ea s e d ca. b y 1 . 4 - 2 - f o l d u p o n a d d i t io n o f H g a n d F e i o n s . T h e d i s c u s s e d r e s u l ts a r e u s e f u l t o d es i gn
n e ar - i n f r a r e d p h o t o s e n s i t i z e r s w i t h l o n g l iv e d t r i p l e t e x c it e d s t a t e s f o r v a r i o u s a p p l i c a t io n s s u c h a s P D T,
fl u o r e s c e n t b i o i m a g i n g a n d s e n s o r m a te r ia l s .
1
Keywords. B O D IP Y ; n e a r - i n fr a r e d ( N I R ) ; s i n g l e t o x y g e n ( O ) ; 1 , 2 - b i s ( 2 - p y r id y l m e t h o x y ) b e n z e n e; m e t al
c at i o n s ; p h o t o d y n a m i c t h e r a p y ( PD T ) ; d i s t y r y l .
2
1. Introduction
p h o t o d am a g e t o t i s s u e s a n d l e s s b i o a u t o - fl u o r e s -
1 0 -1 3
c en ce ,
B O D IP Y p h o t o s en s i t i z er s e x h i b i t i n g
I n t h e p a s t d e c a de s , n e a r - in fr a r e d ( N IR ) fl u o r e s c en t
d y e s b a s e d o n 4 , 4 -D i fl u o r o - 4 -b o r a 3 a , 4 a - d i a z a -s- i n -
a b s o r p t i o n a n d e mi s s i o n i n t h e N I R r eg i o n ( 6 5 0 n m –
9 0 0 n m ) a r e m o r e i d ea l f o r P D T .
d a c e n e ( B O D I P Y ) h a ve d ra w n e n o r m o u s a t t e n t i o n a s
1- 8
A n i d e a l p ho t o s e n s i t i z e r w h i c h is th e k e y c om p on e nt o f
P D T sh o ul d e x h i b i t st r o n g a b s o r p t i o n a t N I R w a v e l e n g t h s
( 6 5 0– 9 00 n m ) f o r d e ep ti ss ue pe n et r a t i on , g en e r a te hi gh
fl u o r e s ce nt p r o b e s a n d b i o im a g in g m a te ri a l s .
I
n
a d d i t i o n , B O D I PY , l ik e P h t h a lo c y a n i n e s h a v e b e e n
e x p l o r e d a s p h o t o s e n s i ti z e r s f o r p h o to dy n a m i c t h er a p y
9
( P D T ) o w i n g t o i ts s t r on g t e n de n c y t o a b s o rb a t v i s -
1
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d ar k t o xi ci t y a nd e n ha nc e t h e se l e c t i v e im mu n e r es p on s e
a ga i n s t di se a se d t i s su e s w i t ho u t a f f ec t i ng th e h e al t hy t i s -
1 4
s ue s. M o s t c o m m o nl y u s e d po r ph y r i n- ba s e d ph o t o s e n -
i b l e r e g i o n w i t h s t r on g a b s o rb a n c e , t o e m it n a r r o w
e m i s s i o n p e a k s w i t h h ig h q u a n t um y ie ld , q u i te i n s e n -
s i t i v e t o t h e p o l a r i ty a n d p H o f t h e r e s p e c ti v e s u r -
r o u nd i n g m a k i n g t he m c o m p a r a t i v e ly s t a b l e t o
p h y si o l o g i ca l c o nd i ti o n s a n d t o p e r m it t he t u n i n g o f
p h o t o p h y s i c a l p r o pe r t ie s o n s l i gh t s t r u c tu ra l m o d i fi-
c at i o n s . M o r e o v e r, d u e t o c e l lu la r i m a g i n g i n t h e N I R
r e g i o n h a s d e e p t is s u e p e rf o r a ti on , n eg l i g i b l e
s it i z e r s f o r P D T e xh ib i t w e a k a b sor p t io n i n th e v i s i b l e
r e gi o n a n d in du c e s i d e ef f e c t s on p ho t o ir r a d i a t i on , d a m -
a gi ng th e no r m a l t i s sue s . T hu s , d e s i gni ng a nd d e v e lo pi n g
p ho t o se n s i t i z e r s w it h s t r on g a b s o r p t i on i n t h e NI R r egi o n
a n d st ro ng fl uo r e s c e n c e al o n g w i t h l on g- l i ve d t r i p l e t
e xc i t ed st at es i . e . s at i s f a ct or y i nt er sy st e m c ro ss i n g ( I S C ) t o
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Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1007/s12039-021-
01934-1.

6 3 P a g e 2 o f 9
s e ns i t i z e s i n g l e t ox y ge n ( O ) h a s b e c om e a c h a l -
J. Chem. Sci. ( 2 0 2 1 ) 1 3 3 : 6 3
1
2 . 2 Synthesis of Bodipy dyes 1 and 2
2
1 4 ,1 5
l e n ge .
P h o t o s e ns i t i z e r s e x h i b i t i n g l o n g- l i ve d t r i p l e t
2 6
2 7
2
6
2
7
B o d i p y d y e s ( 1a) , (1b) , (2a) , ( 2b) a n d c o m p o u n d
(3) w e re s y n t h e s i ze d f o l l o w i n g t h e l i t e r at u r e m e t h o d s.
2 . 3 Synthesis of compound BDPY-DBPMB
e xc i t ed s t a t e a s w e l l as s t ro n g flu or e sc en ce c an be u se d f o r
v a r i ou s a pp l i ca t i o ns s uc h a s P D T, fl uo r e s c e nt b i o i m a gi ng
1 6-2 1
a nd s en s or s m at e r i a l s .
2
8
C o n ce rn i n g t h e s e a s pe c t s , w e h a ve p re p a r e d t w o
B O D I PY p h o t o s e ns it i z e r s BDPY-DBPMB a n d
NBDPY-DBPMB w i th 1 , 2- bi s ( 2 - p yr i d y l met h o x y )
b e n z e n e d i s t y r y l m o i e t y a t 3 , 5 - p o s i ti o n s o f t he B O D I P Y
c o r e t o a p p r o a c h t he a b s o r p ti o n / e m is s i o n i n t h e N I R
w a v e l e n g t h . F u r t h e r , 2 , 6- i o d i n a t io n o f BODIPY c o r e
T o a s o l u t i o n o f 2a ( 0 . 2 0 0 m mo l , 1 1 5 m g ) a nd c o m -
p o u n d 3 ( 0 . 4 0 0 m mo l , 1 2 8 m g ) i n d r y b e n z e n e ( 2 0 m L ) ,
a ce t i c a ci d ( 0 . 6 m L ) a n d p i p e ri d i n e ( 1 . 0 m L ) w er e
a d d e d . T h e r e ac t i o n m i x t u r e w a s h e a t e d a t 8 0 °C u n d e r
r e flu x w i t h a D e an S t a r k t r a p t o r em o v e t h e w a t e r g e n -
e r at ed b y t h e c o n d en s at i o n . T h e r ea c t i o n w a s m o n i t o re d
i n c r e as e s t h e r a t e o f s i n g l e t t o t ri p le t s t a te i nt e r s y s t e m
2 2 -2 5
c r o s s i n g ( I S C ) .
1
A s a r e s u l t, g e n e r a t io n o f s i n g l e t
o x y g e n ( O ) q u a n tu m y ie ld (UD) w i t h l o n g- l iv e d t r i p l e t
2
b y T L C ( CH C l / M e O H = 9 5 / 5 , v / v a s e l u e n t ) . A ft er
3
e x c i t ed s t a t e s i s i n c r e a s e d d u e t o h e a v y a t o m e f f ec t o f
i o d i n e . T h e p h o t op h y s ic a l p r o pe r t ie s h a v e b e e n m ea -
s u r e d w i t h a s t e a d y s t a te a n d t im e - re s o l v e d s p e c -
t r o s c op y. BDPY-DBPMB a n d NBDPY-DBPMB w e re
c o n s u mp t i o n o f a l l t h e s t ar t i n g m at er i al s , t h e r e a c t i o n
m i x t u r e w a s c o o l ed t o r o o m t e m p e ra t u r e. T h e s o l v e n t
w a s e v a p o r a t e d u n d e r r e d u c ed p r e s s u r e , a n d t h e c r u d e
p r o d u ct t h u s o b t a i n e d w a s p u r i fie d b y c o l u m n c h r o -
u s e d a s t r i p l et p h o t o s e n s i ti z e r s f o r g e n e r a t io n o f s i n g l e t
1
o x y g e n ( O ) . B O D IP Y fl u o r o p h o r e BDPY-DBPMB
m at o g r a p h y ( s i l i c a g e l , C H Cl / M e O H = 9 5 / 5 , v / v a s
3
2
e l u e n t ). T h e g r e e n s o l i d w a s o b t a i n e d a s c o m p o u n d
BDPY-DBPMB. Y i e l d : 4 4 % ( 1 0 4 m g ) . M AL D I -
H R M S : c al cd ( [ C H B F I N O ] ?) , m/z = 1 1 8 0 . 1 6 ,
a n d NBDPY-DBPMB b e a r i n g 2 , 6- di s t y ry l 1 , 2 -b i s ( 2 -
p y r i dy l me t ho x y ) b e n z e n e , u s e d a s l ig a n d f o r d et e ct i o n
o f v a r i o u s m et a l c a t io n s , e x hi b it s i nc re a s e d fl u o r e s -
5 7 4 5
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c en c e w i t h H g a n d F e i o n s , r e s p e c ti v e l y .
M H z ) : 8 . 6 1-8 . 5 8 ( m, 4 H ) , 8 . 0 2 ( d , 2 H , J = 1 6 H z) ,
7 . 7 2 - 7 . 6 6 ( m, 6 H ) , 7 . 6 2 ( d , 2 H , J = 8 H z ), 7 . 5 8 ( d , 2 H ,
J = 8 H z ) , 7 . 5 3-7 . 4 7 ( m, 5 H ) , 7 . 2 3-7 . 2 1 ( m , 6 H ) ,
2. Experimental
7 . 1 6-7 . 1 3 ( m, 2 H ) , 6 . 9 4 ( d , 2 H , J = 8 H z ), 5 . 3 7 ( s , 4 H ) ,
1 3
5 . 3 5 ( s , 4 H ) , 1 . 4 3 ( s , 6 H ) . C N M R (d, p p m i n C DC l ,
3
2 . 1 Materials and Physical measurements
1 0 0 M H z) : d1 5 7 . 1 7 , 1 5 0 . 4 6 , 1 4 9 . 6 4 , 1 4 9 . 2 0 , 1 4 8 . 5 3 ,
1 4 5 . 7 4 , 1 3 9 . 1 4 , 1 3 8 . 6 7 , 1 3 6 . 8 2 , 1 3 5 . 2 8 , 1 3 2 . 9 8 , 1 3 0 . 6 4 ,
1 2 9 . 4 5 , 1 2 8 . 3 4 , 1 2 2 . 6 7 , 1 2 2 . 0 5 , 1 2 1 . 4 4 , 1 2 1 . 2 4 , 1 1 7 . 4 5 ,
1 1 4 . 2 0 , 1 1 3 . 6 0 , 8 3 . 2 9 , 7 1 . 9 7 , 7 1 . 5 9 , 1 7 . 5 2 .
A ll th e s yn th et ic pr ec ur so rs we re c ommer ci al ly av ai la bl e
a nd u sed a s r ec ei ve d. S olv en ts w ere d ri ed an d d ist il led
1
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p rio r to sy nth es is. H an d C N M R s p e c t r a w e r e r e c o r -
d ed o n a B ruk er -A van ce 4 00 an d 1 00 MH z s pec tro met er ,
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F lu or ol og -3 (S pex mod el , J ob in Yvo n) sp ec tr ofl uor ome -
te r. E lec tro nic a bs or pt io n s pe ct ra w ere rec ord ed on a
S hi mad zu (Mo del UV -36 00) sp ec tr op ho to met er .
A bs or ptio n sp ec tr a w ere r ec or de d on a S hi ma dzu U V-
3 60 0, U V/V IS s pe ct ro ph otome te r. H ig h res olu tio n mas s
sp ect ra (H RMS) w er e d et er min ed o n a MA LD I T OF
S hi mad zu B io te ch Ax ima P erfo rma nce 2 .9 .3 .2 01 10 624 :
Mo de Re flec tro n-H iR es, P owe r: 85 sp ec tr ome te r. T he
tr an si en t a bso rp tio n sp ec tr a w ere re co rd ed o n a L KS- 20
la se r n an os ec on d fl as h p ho to ly si s ki ne ti c sp ec tr ome te r
u sin g OC R-1 2 Se ri es Q ua nt a R ay N d:Y AG l as er . T he
la se r e ne rg y w as 11 0 mJ at 3 55 nm. 2 00 W x en on la mp
(mo del 37 67) o n an O ri el o pt ic al b en ch ( mod el 11 20 0)
w it h a g ra ti ng mo noc hr oma to r, w as us ed as a li gh t so urc e
to c arry o ut t he P hot o- bl ea ch in g ex per imen ts . Or ie l
p ho to di od e d et ec ti on sy ste m (mo de l 70 72) w as u se d to
mai nt ai n co ns ta nt in te ns it y t hr ou gho ut th e irr ad ia ti on .
T o a s o l u t i o n o f 2b ( 0 . 2 0 0 m mo l , 1 2 4 m g ) a nd c o m -
p o u n d 3 ( 0 . 4 0 0 m mo l , 1 2 8 m g ) i n d r y b en ze n e
( 2 0 m L ) , a ce t i c a ci d ( 0 . 6 m L ) a n d p i p e ri d i n e ( 1 . 0 m L )
w e r e a d d e d . T h e r e af t er t h e s y n t h e t i c p r o c e d u r e i s
s i mi l a r t o t h at o f c o m p o u n d BDPY-DBPMB; a d a r k
g r e e n s o l i d w a s o b t a i n e d a s c o m p o u n d NBDPY-
DBPMB. Y i e l d : 4 1 % ( 1 0 0 m g ) . M A L D I- H RM S :
c al c d ( [ C H B F I N O ? H ]?) , m/z = 1 2 2 6 . 1 6 ,
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7 . 6 2 ( d , 2 H , J = 8 H z ), 7 . 5 9-7 . 5 4 ( m, 4 H ) , 7 . 5 1-7 . 4 7
( m, 2 H ) , 7 . 2 8-7 . 2 7 ( m, 2 H ) , 7 . 2 5-7 . 2 1 ( m , 4 H ) ,
7 . 1 7-7 . 1 4 ( m, 2 H ) , 6 . 9 6-6 . 9 4 ( m, 2 H ) , 5 . 3 7 ( s , 4 H ) ,
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J. Chem. Sci. ( 2 0 2 1 ) 1 3 3 : 6 3
P a g e 3 o f 9 6 3
1 4 5 . 7 4, 1 3 9 . 99 , 1 3 9 . 1 5 , 1 3 6 . 8 3 , 1 3 5 . 29 , 1 3 2 . 9 8 , D M SO . T h e s o l u t i o n w a s a l l o w ed t o s t an d f o r 2 m i n
1 3 0 . 6 5, 1 2 9 . 45 , 1 2 8 . 3 5 , 1 2 4 . 5 8 , 1 2 2 . 68 , 1 2 2 . 0 5 , b e f o r e t a k i n g e ac h s p e c t r a l m ea s u re m en t .
1 2 1 . 4 4, 1 2 1 . 24 , 1 1 7 . 45 , 1 1 4 . 21 , 1 1 3 . 62 , 8 3 . 2 8 , 7 1 . 9 7 ,
7 1 . 5 8 , 1 7 . 5 2.
3. Results and Discussions
2 . 5 Singlet oxygen (1O2) quantum yields (UD)
by DPBF assay
O u r a p p r o a c h t o p r e p a r e 2 , 6 -d i i o d o 3 , 5 -s y m m et r i c
d i s t y ry l B O D IP Y p h o t o s en s i t i z er s BDPY-DBPMB
a n d NBDPY-DBPMB h a s b e e n r at i o n al i z e d o n t h e
f ac t t o e x t e n d t h e a b s o r p t i o n / e mi s s i o n i n t h e N IR
w a v e l e n g t h a s w e l l a s t o a cc e s s e ffi c i e n t s i ng l e t - t o -
t r i p l e t i n t e rs y s t em c ro s s i n g ( I SC ) b y h e a v y a t o m e f f ec t
S ch em e 1.
1
S i n g l et o x y g e n ( O ) q u a n t um y ie ld s ( UD) o f t h e
2
p h o t o se ns i t i z e r s
DBPMB w e r e m e a s u r e d u s i ng M e t h y l e n e B l u e ( M B )
BDPY-DBPMB
a
n
d
N
B
D
P
Y
-
2
9
-
3
1
(
U
=
0
.
4
9
i
n
D
M
S
O
)
a
s
s
t
a
n
d
a
r
d
.
Q
u
a
n
t
u
m
D
y i e l d s f o r s i n g l e t o x y g e n g e n e r a t io n i n D M S O ( 2 0 0 ll )
w e r e d e t e r m i n e d b y m o ni t or in g t he p h o to ox id a t i o n o f
1 , 3 - di p h e n y l i s ob e nz o f u r a n ( D P B F ) ( 2 ll , 8 9 1 0-3 M )
s e n s i t i z e d b y d i f f e r e n t c o n c e n tr a ti o n s o f t he p h o t o -
F i r s t , w e a t t a c h e d t h e i o d i n e a t o m t o t h e B OD I P Y
fl u o r o p h o r e c o r e 1 t o a cc e l e r at e t h e I SC . T h e 2 - f o l d
K n o ev en ag e l c o n d e n s at i o n r ea c t i o n o f 2 , 6 - d i i o d o
B O D IP Y 2 w i t h 3 , 4 -b i s ( 2 - p y r i d y l m et ho x y ) b e n z a l d e -
h y d e 3 l e d t o t h e f o r m at i o n o f 3 , 5 -d i s t y r y l B OD I P Y
p h o t o s en s i t i z e r s BDPY-DBPMB ( y i e l d = 4 4 % ) a n d
NBDPY-DBPMB ( y i e l d = 4 1 % ). T h e m ol ec u l a r
s t ru ct u r e o f BDPY-DBPMB a n d NBDPY-DBPMB
s e n s i t i z e r s BDPY-DBPMB a n d NBDPY-DBPMB in
1
DMSO. D P B F w a s u s e d a s t h e O t ra pp in g a g e n t .
2
T h e p h o t o s en si t i ze r s w e r e i rr a d ia t e d w i t h 6 4 0 – 7 2 0 n m
w a v e l e n g t h u s i n g W a l d m a n n P D T -1 2 0 0 L a m p
( W a l d m a nn , V i l l i n g e n - S c h w e n n i ng e n , G e r m a n y ) a t a
1
1
3
w e re c o n fi r me d b y H N M R , C N M R a n d M A L DI -
H R M S . T h e d a t a w e re r e l i a b l e w i t h t h e p r e v i o u s l y
3 2
r e p o r t e d d i s t y ry l B O D IP Y d e r i v a t i v e s . T h e c h a r a c-
2
l
i
g
h
t
d
o
s
e
o
f
2
0
J
/
c
m
.
A
b
s
o
r
b
a
n
c
e
a
t
4
1
0
n
m
a
t
r
e
g
-
u l a r i n t e r v a l s w a s r e c o rd e d i n a m i c r o p l a t e r e ad er
( M u l t i s k a n S p e c tr u m E l i s a R e a d e r , T h e r m o F i s h e r
S c i e n t i fi c) t o e s t i m a t e t h e q u e n c h e d a b s o rb a n c e o f
D P B F . T h e s l o p e o f t he c u r v e s o f a b s o rb a n c e m a x i m a
o f D PB F a t 4 1 0 n m v e r s u s i rr a d ia t io n t im e f o r e ac h
p h o t o s en si t i ze r w e r e c a l c u l a te d. S i n g l e t o x y g e n
q u a n t u m y i e l d (UD) w e r e c a l c u l a te d a c c o rd in g t o t h e
e q u a t i o n ( e q n ( 1) ) :
t e r i z a t i o n s p e c t r a a re g i v e n i n t h e S u p p l e m e n t a ry
I n f o r m at i o n .
T h e U V - V i s a b s o r p t i o n F i g u re 1a a n d e m i ss i o n
F i g u r e 1 b s p e c t r a o f t h e d i i o d o s t y r y l B O D IP Y BDPY-
DBPMB a n d NBDPY-DBPMB w e re s t u d i e d i n
D M S O . BDPY-DBPMB a n d NBDPY-DBPMB d i s -
p l ay ed a b s o r p t i o n i n t h e N I R r eg i o n d u e t o t h e l a r g e
3
-
1
ꢀ
ꢁꢀ
ꢁ
e
x
t
e
n
d
e
d
p
-
c
o
n
j
u
g
a
t
i
o
n
a
t
6
7
1
n
m
(
e
=
9
.
4
1
0
M
ms a m
ms t d
Fs t d
-
1
4
-
1
-
1
c
m
)
a
n
d
6
8
2
n
m
(
e
=
1
.
2
2
1
0
M
c
m
)
,
UDs am ¼ UDs t d
ð1 Þ
Fs a m
r es p e ct i v e l y . T h e e mi s s i o n s p e c t r a w e r e o b s e r v e d a t
7 0 8 n m a n d 7 2 4 n m f o r BDPY-DBPMB a n d NBDPY-
DBPMB, r es p e ct i v e l y T a b l e 1. E l ec t r o n -d o n at i n g
b i s ( p y r i d i n - 2 - y l me t h o x y ) g r o u p ( p u s h ) a t 3 , 5 -p os i t i o n s
a n d e l e c t r o n - w i t h d ra w i n g n i t r o g r o u p ( p u l l ) a t t h e p a r a
p o s i t i o n o f 8 - p h e n y l i n t h e e l e ct r o n d e fi ci en t B O DI P Y
c o r e ( p u l l ) o r i g i n a t e s a s t ro n g e l e ct r o n p u s h - p u l l e f f e ct
i n t h e NBDPY-DBPMB d y e ( Sc h e m e 2 ) . T h u s , t h e
r ed s h i f t (ca.1 6 n m ) f o r n i t r o s u b s t i t u e n t i n NBDPY-
DBPMB i s a t t r i b u t ed t o t h e p r e s e n c e o f s t ro n g e l e c -
t r o n p u s h - p u l l s u b s t i t u e n t s t o a B O D IP Y fl u o r o p h o re
( Sc h e m e 2) t h ro u g h t h e f o r ma t i o n o f i n t r am o l e c u l a r
w h e r e ‘‘ s a m ’’ a n d ‘‘ s t d ’’ d e s i g n a te t he ‘‘ ph o t o s en s i -
t i ze r s BDPY-DBPMB a n d NBDPY-DBPMB’’ a n d
‘‘ M B ’’ , r e s p e c t i ve l y . ‘‘ m’’ i s t he s l o pe o f d i f fe r en ce i n
c h a n g e i n a b s o r b a n c e o f D P B F ( a t 4 2 5 n m ) w i t h t h e
i r r a d i a t i o n t i me , ‘‘F’’ i s t he a b s o r p ti o n c o r r ec t i o n
f a c t o r , w h i c h i s g i v e n b y F = 1-1 0-O D ( O D i s t h e
a b s o r b a n ce a t t h e i rr a d i a t io n w a v e l e n g th ).
2
.
6
M
e
t
a
l
I
o
n
S
e
n
s
i
n
g
S t o c k s o l u t i o n s ( 2 0 9 1 0-3M ) o f a l l t he m e t al s a l t s
( C a C l , N a C l , Z n C l , L i C l , C d C l , H g C l , C s Br ,
3 3 -3 5
c
h
a
r
g
e
-
t
r
a
n
s
f
e
r
(
I
C
T
)
s
t
a
t
e
i
n
p
o
l
a
r
s
o
l
v
e
n
t
.
BDPY-DBPMB a n d NBDPY-DBPMB e x h i b i t S t o k e s
s h i f t s a t 3 7 n m a n d 4 2 n m , r es p e ct i v e l y . T h o u g h
NBDPY-DBPMB s h o w s r e d - s h i f t e mi s s i o n , l a r g e
S t o k e s s h i f t w a s n o t o b s er v ed a s c o m p a re t o NBDPY-
DBPMB.
2
2
2
2
C u C l , P d C l , F e B r , M gB r , N i C l a n d K C l ) w e r e
2
2
2
2
2
p r e p a r e d i n D M S O /d i s t i l l e d w a t e r ( 9 0 :1 0 ) . S t o c k
s o l u t i o n s o f p h o t o s e n s i ti z e r s ( 1 9 1 0-3 M ) BDPY-
DBPMB a n d NBDPY-DBPMB w e r e p re p a r e d i n

6 3 P a g e 4 o f 9
J. Chem. Sci. ( 2 0 2 1 ) 1 3 3 : 6 3
Scheme 1. S y n t h e s i s o f t h e B O D I PY d y e s BDPY-DBPMB a n d NBDPY-DBPMB. R e a g e n t s a n d c o n d i t io n s : i ) N I S
( 2 e q . ) , d r y D C M , r . t . , 4 h . ; ( i i ) 3 , 4 - b i s ( p y r i d i n - 2 - y l m e t h o x y ) b e n z a l d e h y d e 3 ( 2 e q . ) , d r y b e n z e n e , p i p e r i d i n e , A c O H , 8 0 °C ,
r e fl u x .
a
b
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
BDPY-DBPMB
BDPY-DBPMB
NBDPY-DBPMB
NBDPY-DBPMB
400
500
600
700
800
650
700
750
800
Wavelength / nm
Wavelength / nm
Figure 1. ( a ) N o r m a l i z e d U V- Vi s a b s o r p t i o n s p e c t r a o f BDPY-DBPMB a n d NBDPY- DBPMB a n d ( b ) n o r m al i ze d
fl u o r es c en c e s p ec t r a o f BDPY-DBPMB a n d NBDPY-DBPMB. ( ke x = 6 3 0 n m , c = 1 . 0 9 1 0 -5 M i n D M S O ) .
T h e n a n o s e co nd t im e - re s o lv e d t ra ns ie n t d if f er e n c e a b s o r p t i o n o f t r i p l e t e x c i t e d s t at e o f BDPY-DBPMB
a b s o r p t i o n s p e c t r a s t u d i e s w e r e c a rr i e d o u t t o i n v e s t i - F i g u r e 2 a . I n a d d i t i o n , b l ea c h i n g b a n d a t 6 7 1 n m a l i k e
g a t e t h e t r i p l e t e xc i te d s t a te s o f t h e r e p o rt e d d i i o d o t h e U V - V i s a b s o r p t i o n s p e c t r a F i g u re 1 a a ri s e s d u e t o
p h o t o se ns i t i z e r s F i g ur e 2 a n d F i g u r e S 7 , S u p p l em e n - t h e d e p l et i o n o f g r o u n d s t at e o f BDPY-DBPMB
t a r y I n f o r m a t i o n i n D M S O . U p o n 3 5 5 n m p u l s e d l a s e r p h o t o s en s i t i z er . T h e l i f et i m e o f t h e BDPY-DBPMB
e x c i t a t i o n , p o s i t i v e t ra ns ie n t a b s o rp t io n ( T A ) b a n d s a t a n d NBDPY-DBPMB t r a n s i en t s , w e r e f o u n d t o b e
4 4 0 n m , 5 4 0 n m a n d 7 7 0 n m w e r e o b s e rv e d d u e t o t h e 0 . 6 5 ls a n d 1 . 4 4 ls , r e s p e ct i v e l y F i g u re 2 b a n d

J. Chem. Sci. ( 2 0 2 1 ) 1 3 3 : 6 3
P
a
g
e
5
o
f
9
6
3
Table 1. P h o t o p h y s i c a l P ro p e r t i e s o f BDPY-DBPMB a n d NBDPY-DBPMB i n D M S O
a
a
c
d
P
h
o
t
o
s
e
n
s
i
t
i
z
e
r
s
ka b s / n m
eb
ke m / n m
UD
sT [ls ]
BDPY-DBPMB
NBDPY-DBPMB
6 7 1
6 8 2
0 . 0 9 4
0 . 1 2 2
7 0 8
7 2 4
0 . 5 1
0 . 4 1
0 . 6 5
1 . 4 4
a
b
c = 1 . 0 9 1 0 -5 M i n D M S O. M o l a r e x t i n c t i o n c o e f fi c i e n t a t t h e a b s o r p t i o n m a x i m a . e:
1 0 M -1 c m -1 . S i n g l e t o x y g e n ( O ) g e n e r a t i o n q u a n t u m y i e l d m e a s u r e d u s i n g m e t h y l e n e b l u e
( UD = 0 . 4 9 i n D M S O) a s a r e f e r e n c e T r i p l e t e x c it e d s t a t e l if e t im e s , m e a s u r e d b y n a n o s e c o n d
t i me - r e s o l v e d t r a n s i e n t a b s o r p t i o n s .
5
c
1
2
d
T h e p h o t o s t a b i l i t y o f BDPY-DBPMB a n d NBDPY-
DBPMB p h o t o s en s i t i z er s w e r e d e t e r mi n e d o n c o n -
t i n u o u s i r r a d i a t i o n w i t h 2 0 0 W x e n o n l a m p f o r 2 h .
T h e p r e -a n d p o s t - i r r a d i a t i o n e x h i b i t ed i d e n t i c a l
a b s o r b a n c e s p e c t r a i n d i c a t i n g h i g h p h o t o s t a b i l i t y o f
t h e p h o t o s en s i t i z er s F i g u re 3 .
D u e t o t h e p r e s e n c e o f h e a v y i o d i n e a t o m , t h e
p h o t o s en s i t i z er s BDPY-DBPMB a n d NBDPY-
DBPMB, e x h i b i t i n g t r i p l e t e x c i t e d l i f et i m e o f 0 . 6 5 ls
a n d 1 . 4 4 ls , r es p e ct i v e l y a re e x p l o r ed f o r t h e s i n g l e t
1
1
o x y g e n ( O ) g e n e r at i o n . T h u s , O p h o t o s en s i t i zi n g
a b i l i t y o f BDPY-DBPMB a n d NBDPY-DBPMB a s
t r i p l e t p h o t o s en s i t i z er s w e re s t u d i e d via t h e b l e a ch i n g
2
2
1
o f 1 , 3 -d i p h en y l is o b en zo f u r an ( D PB F ) a s t h e
s c a v e n g e r i n D M SO a n d m et h y l en e b l u e a s s t a n d a r d
1
F i g u r e 4 a n d T a b l e 1 . S i n g l e t o x y g e n ( O ) q u a n t u m
O
2
2
Scheme 2. D i p o l a r ‘‘ Pu s h – P u l l ’’ c h ro m o p h o re s s u r r o u n d -
i n g B O D I P Y c or e.
y i el d ( UD) v a l u es o f t h e p h o t o s en s i t i z er s BDPY-
DBPMB a n d NBDPY-DBPMB w e re 5 1 % a nd 4 1 % ,
r e s p e ct i v e l y . S i n c e , t h e a b s o r p t i o n o f BDPY-DBPMB
F i g u r e S 7 , S u p p l e m e n t a r y i nf or m a ti o n . S i n ce , t h e
d e c a y l i f e t i m e o f t ra n s i e n t p o s i t i ve b a n d i s i n ls , t h e
p r e s e n ce o f t h e s i n g l e t e x c i t e d s t a te i s e x c l u d e d . T h e
fl u o r e s ce nc e l i f e t i m e f o r s i n g l e t e x c i t e d s t a te s h o u l d b e
i n t h e v i s i b l e r eg i o n i s s l i g h t l y s t ro n g e r t h an NBDPY-
1
DBPMB, t h e O p h o t o s en s i t i z i n g a b i l i t y o f BDPY-
2
DBPMB i s s o m e w h a t m o r e e f fic i e n t t h an NBDPY-
DBPMB.
2 5 ,3 6
\1 n s .
0.2
0.1
a
b
0.00
-0.03
Δ
Δ
τT= 0.65 μs
0.0
-0.06
-0.09
3.00
2.00
0.80
0.40
0.10
μs
μs
μs
μs
μs
-0.1
0
2
4
6
8
Time / μs
400 500 600 700 800 900
Wavelength / nm
Figure 2. ( a ) N a n o s e c o n d T r a n s i e n t a b s o r p t i o n s p e c t r a o f BDPY-DBPMB a n d ( b ) d e c a y t r a c e s o f BDPY-DBPMB a ft e r
p u l se d e x ci t a t i o n a t 3 5 5 n m l a s e r . c = 1 . 0 9 1 0 -6 M i n D M S O .

6
3
P
a
g
e
6
o
f
9
J. Chem. Sci. ( 2 0 2 1 ) 1 3 3 : 6 3
a
b
0.4
0.3
0.2
0.1
0.0
0.3
BDPY-DBPMB
NBDPY-DBPMB after 2 hrs
BDPY-DBPMB
NBDPY-DBPMB after 2 hrs
0.2
0.1
0.0
400
500
600
700
800
400
500
600
700
800
Wavelength / nm
Wavelength / nm
Figure 3. A b s o r p t i o n s p e c t r a o f ( a ) BDPY-DBPMB a n d ( b ) NBDPY-DBPMB, u p o n t w o h o u r s i r r a d ia ti o n w i t h o ri e l
l a m p ( 2 0 0 W x e no n l a m p , m o d e l 3 7 6 7 ) o n a n O ri e l o p t i c a l b e n c h ( m o d e l 1 1 2 0 0 ) .
a
0.60
0.45
0.30
0.15
0.00
0.60
0.45
0.30
0.15
b
0 s
0 s
.......
.......
.......
.......
20 s
20 s
400
500
600
700
800
400
500
600
700
800
Wavelength / nm
Wavelength / nm
c
d
0.5
0.4
0.3
0.2
0.1
0.0
BDPY-DPBMB
NBDPY-DPBMB
Methylene Blue
0.06
0.04
0.02
0.00
0 s
.......
.......
20 s
0
5
10
Time / s
15
20
400
500
600
700
800
Wavelength / nm
Figure 4. D e c r ea s e i n U V- Vi s a b s o r p t i o n o f D P B F a t ka b s = 4 1 0 n m u s i n g p h o to s e n s i ti z e r s : ( a ) BDPY-DBPMB;
( b) NBDPY-DBPMB; ( c ) Methylene Blue a s t h e s t a n d a r d . ; ( d ) P l o t s o f DA o f D P B F vs I r r a d i a t i o n t im e w i t h
p h o t o s en s i t i ze r s BDPY-DBPMB, NBDPY-DBPMB a n d M e t h y l e n e B lu e .
1
S i n g l e t o x y g e n ( O ) p h o to s e ns it i z in g a b i li t y o f t h e t r i flu o ro ac e t i c a ci d ( T F A ) t o p h o t o s en s i t i z e r s BDPY-
2
t r i p l et p h o t o se ns i t i z e r s c a n b e s w it c h e d O N o r O F F b y DBPMB a n d NBDPY-DBPMB s o l u t i o n i n D MS O
c h a n g i n g t h e p H o f s o l u t i o n . T h i s t e c hn iq ue h as b e e n w a s i n v e s t i g at ed . N o v i s i b l e c o l o u r c h a n g e a n d s h i f t i n
u s e d t o d e s i g n t a r ge ti n g P D T r e a g e n t s t o s e l e c t i v el y a b s o r p t i o n s p e c t r a F i g u re S 8 a a n d F i g u r e S 8 c , S u p -
g e t a c t i va t e d b y t h e a c i d i c m i c r o e n v i ro nm e nt o f t h e p l em e n t a r y I n f o r m at i o n w a s o b s er v ed o n p r o t o n at i o n
1 4 ,3 7 ,3 8
t
u
m
o
u
r
t
i
s
s
u
e
.
T h us , t he e f f e c t o f a d d i t i o n o f o f p y ri d y l m o i e t y o f p h o t o s en s i t i z e r s BDPY-DBPMB

J. Chem. Sci. ( 2 0 2 1 ) 1 3 3 : 6 3
P a g e 7 o f 9 6 3
a 300
250
200
150
100
50
120
90
60
30
0
b
0
DYE2 Li+ Cs2+ K+ Cu2+ Zn2+ Na+ Mg2+ Ni+
Ca2+ Hg2+ Pd2+ Cd2+
Metal Ions Fe2+
DYE1 Li+ Cs2+ K+ Cu2+ Zn2+ Na+ Mg2+ Ni+
Metal Ions Fe2+ Ca2+ Hg2+ Pd2+ Cd2+
Figure 5. H i s t o g r a m o f ( a ) BDPY-DBPMB ( DY E 1 ) a n d ( b ) NBDPY-DBPMB ( D Y E 2 ) , b a s e d o n e m is s i o n i n t e n s i t i es a t
7 2 4 n m i n D M S O /d i s t i l l e d w a t e r ( 9 0 : 1 0 ) u p o n a d d i t io n o f v a r io u s m e t a l i o n s ( 8 0 e q . ) . ke x = 6 3 0 n m , c = 5 . 0 9 1 0 -6 M i n
D M S O .
a n d NBDPY-DBPMB. O n l y m i n u t e c h a n ge i n e mi s - p h o t o i n d u ce d e l e c t r o n t r a n s f e r ( PE T ) m ec h a n i s m
s i o n i n t e n s i t y o f BDPY-DBPMB a n d NBDPY- b e t w e e n t h e e l e ct r o n d o n at i n g l i g a n d 1 , 2 - b i s (2 -
DBPMB w a s o b s e r v e d a f t e r p r o to n a ti o n b y T F A p y ri d y l m e t h o x y ) b e n z e n e a n d B O D IP Y fl u o r o p h o re .
2
?
F i g u r e S 9 b a n d S 9 d , S u p p l e m e n t a r y I nf or m a t i o n , O n a d d i t i o n o f H g , t h e P E T p r o c e s s i s s w i t c h e d o f f
p o s s i b l y e i t h e r d u e t o t h e e l e c t ro n a c c e p t i n g c h a ra c t e r t h ro u g h t h e c o m p l e x a t i o n o f t h e 1 , 2 -b i s ( 2 - p y r i d y l -
o f t h e B O D I P Y o r t h e i n t e r a c t iv e e f f e c ts o f t h e p r o - m et h o x y ) b e n z e n e P E T d o n o r e n h a n c i n g t h e e m i s s i o n
t o n a t e d n i t r o g e n o f p y r id y l m o i e t y i n d uc e s p u s h - p u l l i n t e n s i t y . O n t h e o t h e r h a n d , e mi s s i o n i n t e n s i t y i s
2
?
e f f e c t i n B O D I P Y c o re , c h a n gi n g t h e i nt e r m o l e cu l a r d e c re a s e d f o r BDPY-DBPMB i n t h e p r e s e n c e o f C u
2?
p a c k i n g a n d m o l e c u l a r c o n f o r m a t io n u p o n a c i d p r o - a n d P d , a n d f o r NBDPY-DBPMB i n t h e p r e s en c e o f
1 7
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q u a n t u m y i e l d (UD) o f t he p h o to s e ns it i z e r s BDPY- c re p a n c y f o r i o n s e l e c t i v i t y b y BDPY-DBPMB a n d
DBPMB a n d NBDPY-DBPMB w a s f o u nd ( T a b l e S 1 , NBDPY-DBPMB i s s t i l l n o t c l e a r. T h e s e r e s u l t s i m p l y
S u p p l e m e n t ar y I n fo rm a t i o n ) .
T o s t u d y t h e s e n s i ti v it y o f l ig a n d 1 , 2 - b i s ( 2 -p y r i d y l - DBPMB c o u l d b e u t i l i ze d a s fl u o r e s c en t s e n s o rs f o r t h e
t h at p h o t o s en s i t i z e r s BDPY-DBPMB a n d NBDPY-
2?
2 ?
m e t h o x y ) b e n z e n e i n BDPY-DBPMB a n d NBDPY- s e l e c t i v e d e t e c t i o n o f H g a n d F e .
DBPMB a s s e n s o rs, a b s o rp t io n/ e m i s s i o n s p e c tr a o f t h e
BDPY-DBPMB a n d NBDPY-DBPMB u p o n a d d i t i o n
2 ?
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4. Conclusions
2
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2?
2
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2
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2 ?
2?
2?
Z n , L i?, C d , H g , C s?, C u , P d , F e , M g ,
2 ?
N i a n d K ? w e r e m e a s u r e d i n D M S O / d is t il l e d w a t e r
I n c o n c l u s i o n , w e p r e p a re d t w o s y m m et ri ca l d i i o d o
1 , 2 -b i s ( 2 - p y ri d y l met h o x y ) b e n z e n e -d i s t y r y l p h o t o s e n -
s i t i z e r s , BDPY-DBPMB a n d NBDPY-DBPMB i n
g o o d y i el d s w h i ch s h o w b o t h N I R a b s o r p t i o n / e m i ss i o n
a n d s h o r t - l i v ed t r i p l e t e x c i t e d s t at es . T h e B O DI P Y
( 9 0 : 10 ). A b s o r p t i on / e m is s i on s p e c tr a e x hi b i t e d n o
p e r t i n e n t b a t h o ch ro m i c o r h y p s o c h ro m i c s h i f t F i g -
u r e s S 1 0 a n d S 1 1 , S u p p l e m e n t a r y I n f o r m a t i o n . N o
s i g n i fi ca nt c h a n g e s w e r e o b s e r v e d i n t h e a b s o r p t i o n
s p e c t r o s c o p y o f BDPY-DBPMB a n d NBDPY-
DBPMB F i g u r e S 1 0, S u p p l e m e n t a r y I n f o r m at i o n .
H o we ve r, t h e e m is s i o n i n t e n s i t y o f BDPY-DBPMB
a n d NBDPY-DBPMB i nc re a s e d 1 . 5 - fo ld a n d 2 - f o l d
u p o n t h e a d d i t i o n o f 8 0 e q u i v a l e n ts o f H g a n d F e ,
r e s p e c t i v el y F i g u r e 5 a n d F i g u r e S 1 1 , S u p p l e m e n t a ry
I n f o r m a t i o n w h e r e a s t he o th e r c a t io ns c o ul d n o t i n d u c e
a n y s i g n i fi c an t e n ha nc e m e n t i n t h e e m is s i o n s p e c t r a .
T h e p r o b a b l e b i nd i n g m e c h a n is m i s d e p i c t e d i n F i g -
u r e 6. O n p h o t o i r r a d ia t i o n o f BDPY-DBPMB, e mi s -
s i o n o f t h e B O D I P Y m o i e t ie s q u e n c h e d b y a
d y es w e r e u s e d a s t r i p l e t p h o t o s en s i t i z e r s t o s t u d y t h e
1
O p h o t o s en s i t i z i n g e f fic a cy a s w e l l a s fl u o r es c e n t
2
s
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.
I
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2?
2
?
c at i o n s H g a n d F e , ca.1 . 5 -f o l d a n d 2 - f o l d e m i s -
s i o n i n t e n s i t y w a s i n cr e a s ed f o r t h e r es p e ct i v e p h o t o -
s e n s i t i z e r s BDPY-DBPMB a n d NBDPY-DBPMB.
B as ed o n t h e p r e s e n t w o r k , f u r t h er e f fo rt s t o d e s i g n
a n d d e v e l o p N I R B O D IP Y p h o t o s en s i t i z er s w i t h
h y d r o p h i l i c f u n c t i o n a l g r o u p a n d m u l t i - f u n ct i o n a l
a p p l i c at i o n s s u c h a s P D T , l u mi n e s ce n t b i o i m a gi n g a n d
fl u o r e s c en t s e n s o r m at er i al s , a re u n d e rw a y i n o u r l a b .
2
?
2
?

6 3 P a g e 8 o f 9
J. Chem. Sci. ( 2 0 2 1 ) 1 3 3 : 6 3
Figure 6. P r o b ab l e b i n d i n g m e c h a n i s m o f p h o t o s e n s i ti z e r s BDPY-DBPMB a n d NBDPY- DBPMB c o m p l e x ed w i t h
H g a n d F e 2 ?, r e s p e c t i v e l y .
2 ?
5 . D z y u b a S V 2 0 2 0 B O D I P Y D y e s a s P r o b e s a n d S e n s o rs
t o S t u d y A m y lo i d - b- R e l a t e d P r o c e s s e s Biosensors 10
1 9 2
6 . N i Y a n d W u J 2 0 1 4 F a r - r e d a n d N e a r I nf r ar e d
B O D I PY D y e s : S y n t h e s i s a n d A p p li c a t i o n s f o r F l u o-
r e s c e n t p H P r o b e s a n d B io - i m a g i n g Org. Biomol. Chem.
12 3 7 7 4
7 . C h e n C , T i a n R , Z e n g Y , C h u C a n d L i u G 2 02 0
A c t i v a t a b l e F l u o r e sc e n c e P r o b e s f o r T u r n - O n a nd
R a t io m e t r i c B io s e n s i n g a n d B io im a g in g : F o r m N I R - I
t o N I R- I I Bioconjugate Chem. 31 2 7 6
Supplementary Information (SI)
A l l t h e c h ar ac t er i z a t i o n s p e c t r a a n d a b s o r p t i o n / e m is s i o n
s p e c t r a i n p r e s en c e o f T F A o f BDPY-DBPMB a n d
1
NBDPY-DBPMB, O p h o t o s e n s i t i z i n g a b i l i t y o f BDPY-
2
DBPMB a n d NBDPY-DBPMB i n p r e s e n c e o f D P BF , a n d
a b s o r p t i o n / em is s i o n s p e c t r a o f BDPY-DBPMB a n d
NBDPY-DBPMB u p o n a d d i t i o n o f v a ri o u s m e t a l i o n s a r e
g i v en i n F i g u r e s S 1 - S1 1 . S u p p l e m e n t a r y I n f o r m a t i o n i s
a v a i l a b l e a t w w w . i a s . a c . i n / c h e m s c i .
8 . X i a S , F a n g M , W a n g J , B i J , M a z i W , Z h a n g Y , e t a l.
2 0 1 9 N e a r - i n f r a r e d F l u o r e s c e n t P r o b e s w i t h B O D I P Y
D o n o r s a n d R h o d a m i n e a n d M e r o c y a n i n e A c c e pt o rs f or
R a t io m e t r i c D e t e r m i n a t io n o f L y s o s o m a l p H V a ri a nc e
Sens. Actuat. 294 1
9 . P r i e t o - M o n t e r o R , P r i e t o - C a s t a n e d a A , S o l a - L l a n o R ,
A g a r r a b e i t i a A R , G a r c i a - F r e s n a d i l l o D , L o p e z - A r b el o a
I , e t a l . 2 0 2 0 E x p lo r in g B O D I P Y D e r iv a t i v e s a s S i n gl e t
O x y g e n P h o t o s e n s i t iz e r s f o r P D T Photochem. Photo-
biol. 96 4 5 8
Acknowledgement
P M t h an k s D S T W o m e n S c i e n t i s t - A G ra n t ( SR / W O S - A /
C S - 4 2 / 2 0 1 9 ) f o r f u n d i n g . S PS a c k n o w l e d g e s fi n a n c i a l
s u p p or t f r o m D S T - S E R B ( E M R / 2 0 1 7 / 0 0 1 5 0 6 ) . C S I R - I I CT
C o m m u n i ca ti o n N o . : I IC T / P u b s . / 2 0 2 1 / 0 7 2 .
1 0 . N u r u n n a b i M , K h a t u n Z , R e e c k G R , L e e D Y a nd L ee
Y 2 0 1 3 N e a r I n f r a - r e d P h o t o l u m i n e s c e n t G r ap h en e
n a n o p a r t i c l e s G r e a t l y E x p a n d T h e i r U s e i n N o ni n v a s i v e
B io m e d i c a l I m a g in g Chem. Commun. 49 5 0 7 9
1 1 . Z h a o Q , H u a n g C a n d L i F 2 0 1 1 P h o s p h o r e s c e n t H e av y -
m e t a l C o m p l e x e s f o r B io im a g i n g Chem. Soc. Rev. 40
2 5 0 8
1 2 . M y o c h i n T , K i y o s e K , H a n a o k a K , K o ji m a H , T er ai T
a n d N a g a n o T 2 0 1 1 R a t io n a l D e s i g n o f R a t i om e tr i c
N e a r - i n f r a r e d F l u o r e sc e n t p H P r o b e s w i t h V a r io u s p K a
V a l u e s , B a s e d o n A m i n o c y a n i n e J. Am. Chem. Soc. 133
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1 3 . Y u F , L i P , L i G , Z h a o G , C h u T a n d H a n K 2 01 1 A
N e a r - I R R e v e r s ib le F l u o r e sc e n t P r o b e M o d u l a te d b y
S e l e n i u m f o r M o n i t o r i n g P e r o x y n i t r i te a n d I m a gi n g i n
L i v i n g C e l ls J. Am. Chem. Soc. 133 1 1 0 3 0
1 4 . M a j u m d a r P , N o mu la a n d Z h a o J 2 0 1 4 A c t i v at -
a b l e T r i p l e t P h o t o s e n s i t iz e r s : M a g i c B u l le t s f o r T ar -
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