This document discusses optical spectroscopy and imaging of porphyrins and phthalocyanines. It describes self-aggregation of these molecules in homogeneous solutions and assembled systems like: 1) Porphyrin dimers and aggregates studied using absorption and fluorescence spectroscopy to understand solvent and environmental effects. 2) Amino acid derivatized porphyrins that self-assemble in water-ethanol mixtures, characterized using techniques like DLS and TEM. 3) Porphyrins and phthalocyanines encapsulated in layer-by-layer assembled polyelectrolyte microcapsules and the energy transfer between encapsulated molecules. 4) Plasmon enhanced fluorescence of phthalocyanines

1. Optical Spectroscopy and Imaging of Porphyrins
and Phthalocyanines:
Self-Aggregation, Microencapsulation and
Plasmon Enhanced Emission
Raquel Alexandra Morais Teixeira
2012
INSTITUTO
SUPERIOR
TÉCNICO

2. Porphyrins
Conjugated aromatic system
18+4 electrons p
1
Porphyrin dimers in dye-
sensitized solar cells (DSSCs)
Photodynamic Therapy (PDT)
Biomimetic Models
Materials Chemistry
Catalysis
Supramolecular
Chemistry
Photodiagnosis
Cancer therapy (PDT)
Porphyrin Syntheses
Sensors
T1
S0
S1
S2
Soretband
IC
ISC
Phospho-
rescence
Q(1,0)
Q(0,0)
Q(0,1)
2
1
0
2
1
0
2
1
0
2
1
0
Diagrama de Jablonski simplificado

3. Porphyrins
Strongly coupled dye units in a J-agg.
H-dimer J-dimer
Porphyrins Aggregates: Exciton Theory
E0
E
Parallel
M D
E’’
E’
E0
E
Head-to-tail
M D
E’’
E’
Blue Shift Red Shift
E0
E
Head-to-tail
M D
E’’
E’
Band Splitting
Oblique
2
AD Schwab et al. Nanolett. 2004, 4, 1261
Photoconductivity of self-assembled porphyrin nanorods

4. 3D Self-Assembled Systems
Layer-by-layer assembly of polyelectrolyte microcapsules
Lipid-coated MCs
Space confinement of porphyrins and phthalocyanines
a) Encapsulation of charged or hydrophobic porphyrins (and phthalocyanines).
b) Encapsulation of silver/gold nanoparticles.
c) Distance control: porphyrin-porphyrin, porphyrin-phthalocyanine, porphyrin/phthalocyanine-
nanoparticles.
3

5. Plasmon-Enhanced Fluorescence
Fluorophore near a metallic surface
(nanoparticle)
Metal-fluorophore interactions result in increased
rates of excitation and emission (thicker arrows)
Plasmophores exhibit increased brightness and reduced decay times (increased photostability)
Nanoparticle
Size
Shape
Fluorophore-Nanoparticle
Distance
Orientation
Spectral overlap
Metal Enhanced Fluorescence (MEF)
Combination of two cooperative near-field
interactions:
(i) an electric field enhancement effect;
(ii) an induced plasmon effect.
   0
2
0
0
,

p
mum rr


nrr
rr







nrr 



1
4

6. Outline
We present the construction of confined systems prepared by self-
assembly methods:
 Porphyrin dimer and porphyrin aggregates in homogeneous
solutions and in surfactants/lipids self-assembled systems
 Porphyrins/Phthalocyanines in layer-by-layer assembled PE
microcapsules
 Porphyrins/Phthalocyanines and metal nanoparticles in layer-by-
layer assembled PE microcapsules
 Lipid coated PE microcapsules with Pph/Pc and gold core-PE
multilayer-Pc@lipid bilayer nanoparticles
5

7. Solvent Effects on a Flexible
Porphyrin Dimer

8. Porphyrin Covalent Dimer
H4DTPP in methanol
400 500 600 700
0.5
1.0
1.5
2.0
2.5
Absorbance(x10
-1
)
Wavelength (nm)
400 500 600 700
0.5
1.0
1.5
2.0
2.5
Intensity(a.u.)
Absorbance(x10
-1
)
Wavelength (nm)
0.1
0.3
0.5
0.7
0.9
1.1
exc
=425 nm
350 400 450 500
0.0
0.2
0.4
0.6
0.8
1.0
em
= 640 nm
Intensity(a.u.)
Wavelength (nm)
400 500 600 700
0.5
1.0
1.5
2.0
2.5
Intensity(a.u.)
Absorbance(x10
-1
)
Wavelength (nm)
0.1
0.3
0.5
0.7
0.9
1.1
exc
=375 nm
exc
=425 nm
350 400 450 500
0.0
0.2
0.4
0.6
0.8
1.0
em
= 540 nm
em
= 640 nm
Intensity(a.u.)
Wavelength (nm)
Tetrahedron Letters 2007, 48, 3145 6

9. Porphyrin Covalent Dimer
Dioxane-water mixtures
510 540 570 600 630 660 690
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Intensity(a.u.)
Wavelength (nm)
0-55 (% v/v)
water
exc=375 nm
0 15 30 45 60
0
5
10
15
20
Int540/Int650(%)
% water (v/v)
360 390 420 450
1
2
3
4
5
6
7
Intensity(a.u.)
Wavelength (nm)
0-55 (% v/v) water
em=540 nm
ACN-Tol mixtures
400 410 420 430 440 450
0.0
0.1
0.2
0.3 0
0.09
0.20
0.36
0.60
0.77
1
Absorbance
Wavelength (nm)
x(Tol)
7

10. Self-Assembly of Amphiphilic
Porphyrins

11. Amino Acid Derivatized Porphyrins
N HN
NH
H
N
O
O
O
O
N
H
O
O
NNH
N HN
N
H
O
O
O
O
N
H
O
O
Fluorescence lifetime decays
• pH=1: PpIX-2Gly diacid form (6.3 ns)
• pH=4: diacid form (6.9 ns) + larger aggregates
(2 ns)
• pH=12: monomer (15.5 ns) + H-dimers (3.9 ns)
+ larger aggregates (0.8 ns)
8
Protoporphyrin IX
(PpIX)
PpIX-2Gly

12. Amino Acid Derivatized Porphyrins
MGG
400 500 600
0
1
2
3
4
5
Extinction(x10
-1
)
Wavelength (nm)
water
0.1% EtOH
0.25% EtOH
0.5% EtOH
1% EtOH
ethanol
x1/2
Absorption spectra
350 400 450 500 550 600
0.0
0.5
1.0
1.5
2.0
2.5
water
1% EtOH
2% EtOH
5% EtOH
10% EtOH
Intensity(a.u.)
Wavelength (nm)
Resonance Light Scattering (RLS)
J. Phys. Chem. B 2012, 116, 2396 9

13. Amino Acid Derivatized Porphyrins
25ºC45ºC
0 20 40 60 80 100 120
0.2
0.3
0.4
Extinction@443nm
Time (min) -8
-7
-6
-5
3.2 3.3 3.4
lnk
103/T (K-1)
R
2
=0.9968
A
B C
A) [MGG]=1M; 25% EtOH; 35ºC
B) Kinetic profiles of MGG aggregation at
different temperatures
C) Arrhenius plot: Ea=96 kJ mol-1
Water-ethanol binary mixtures
300 400 500 600 700
0
1
2
3
4
0 300 600 900 1200
1.5
2.0
2.5
3.0
3.5
4.0
Extinction(x10)
Time (s)
Extinction(x10
-1
)
Wavelength (nm)
0 20 min
10

14. Amino Acid Derivatized Porphyrins
DLS
1.5 ns
7.5 ns
[MGG] = 50 M in water
20 M 2 M
1.5 ns
7.5 ns
[MGG] = 50 M in water-ethanol (25% v/v)
20 M 2 M
FLIM
TEM
Morphology and size of MGG aggregates in water-ethanol mixtures
2 m
water-EtOH (1%)
200 nm
water-EtOH (10%)
2 m
water-EtOH (25%)
Hydrodynamic radius of MGG aggregates in water-
ethanol mixtures
11

15. Polyelectrolyte Microcapsules with
Porphyrins and Phthalocyanines

16. Polyelectrolyte Microcapsules
TEM images: MnCO3-(PAH/PSS)5-PAH microcapsules
TMPyP TSPP AlPcS4
Polyelectrolytes: positive PAH and negative PSS
Templates: MnCO3, CaCO3 and commercial PS
Fluorophores: TSPP, TMPyP, ZnTMPyP and AlPcS4
12
PAH
PSS

17. Polyelectrolyte Microcapsules
Porphyrin covalently linked to polyelectrolyte PAH
TCPP
20 m
750 cnts
8 ns
11 ns
20 m
pH=5.6 pH=7.0
0 5 6 7 8 9 10 11 12 13 14
0
5
10
15
20
25
pH=5.6
pH=7.0
Frequency(counts)
Average Lifetime (ns)
PAH-TCPP
1/ns A1(%) 2/ns A2(%) 3/ns A3(%) avg/ns
pH=5.6 10.1 79 3.6 17 0.5 4 8.7
pH=7.0 11.2 86 4.2 11 0.6 3 10.1
13

18. Energy Transfer in Polyelectrolyte MCs
CaCO3-(PAH/PSS)4-TMPyP-PAH-AlPcS4
400 500 600 700
0
2
4
6
8
Absorbance(x10
-2
)
Wavelength (nm)
[AlPcS4
]
600 650 700 750 800
0.0
0.5
1.0
1.5
2.0 exc=430 nm
Intensity(a.u.)
Wavelength (nm)
[AlPcS4
]
8 10 12 14 16 18 20
10
2
10
3
10
4
Counts
Time [ns]
[AlPcS4]
exc = 445 nm
em = 650 nm
9 10 11 12
10
2
10
3
10
4
exc = 445 nm
em = 680 nm
Counts
Time [ns]
Rise time
14

19. Plasmon-Enhanced Fluorescence
in LbL-Assembled Systems

20. AlPcS4
hu
Au Au Au
Plasmon-Enhanced Emission in Films
0
100 cnts
0
6 ns
5 m
0
6 ns
0
100 cnts
5 m
With AuNPs - 7PE layers
Fluorescence Lifetime Imaging Microscopy (FLIM)
Control 7 PE layers
15

21. Plasmon Effects in PE Microcapsules
A
5000 nm
B
1000 nm
AgNPs
PAH+
PSS-
A B
AgNPs
PAH+
PSS-
A B Nanoparticles
Silver, gold
Fluorophores
Several ionic porphyrins
Phthalocyanine
Phthalocyanine inside a lipid bilayer
coating the MC
16

22. Plasmon Effects in PE Microcapsules
5 m 1 m5 m 1 m
2 ns
5 ns
2 ns
5 ns
(PAH/PSS)6-PAH-AlPcS1@lipid BL
2 ns
5 ns
5 m 1 m5 m 1 m
(PAH/PSS)4-PAH-AuNPs-PAH-AuNPs-(PAH/PSS)4-PAH-
AlPcS1@lipid BL
Phthalocyanine inside a lipid bilayer
- Highly polydisperse microcapsules (fluorescence intensity and lifetime fluctuations both
between different capsules and inside each capsule).
- Both quenching and MEF of phthalocyanine due to AuNPs are observed.
- Plasmon effects greatly “diluted” within the microcapsules.
17

23. Plasmon Effects in AuNP-PE ML-AlPcS1@lipid BL
A - 5 PAH/PSS layers
B - 9 PAH/PSS layers
C - 21 PAH/PSS layers
D - 31 PAH/PSS layers
DMPC vesicles with AlPcS1
DMPC bilayer with AlPcS1
Gold nanoparticle
18

24. Plasmon Effects in AuNP-PE ML-AlPcS1@lipid BL
19
1 2 3 4 5 6 7
10
0
10
1
10
2
10
3
3L
5L
9L
13L
15L
25L
31L
MCs
Glass
Frequency(Counts)
avg (ns)
Dispersion plot of Intensity vs. lifetime
A B C
E F
0
4 ns
0
4 ns
0
4 ns
5 m 5 m
5 m
D
0
5 ns
5 m
A B C
E F
0
4 ns
0
4 ns
0
4 ns
0
4 ns
0
4 ns
5 m 5 m 5 m
5 m 5 m
D
0
5 ns
5 m
25 layers
31 layers
A B C
E F
0
4 ns
0
4 ns
0
4 ns
0
4 ns
0
4 ns
5 m 5 m 5 m
5 m 5 m
D
0
5 ns
5 m
5 layers 9 layers 13 layers
E
0
5 m
D
0
5 ns
5 m15 layers
4

25. Main Achievements
This work helped to clarify important aspects about these systems of growing
complexity, such as:
- The driving forces for intra- and intermolecular interactions as well as for the different
self-assembly processes studied;
- The importance of the confinement effect and distance control to the photoinduced
processes investigated;
- The utmost relevance of FLIM technique in revealing important details of the
photoactive confined systems which are totally hidden in ensemble measurements.
20