2-Formyl boron-dipyrromethene as a key synthon to prepare functionalized meso-boron dipyrromethenyl porphyrin building blocks

Article abstract of DOI:10.1039/c4ra10807h

A series of functionalized meso-boron dipyrromethenyl porphyrin building blocks were synthesized by condensing one equivalent of readily available 2-formyl boron dipyrromethene (2-formyl BODIPY) with two equivalents of meso-anisyl dipyrromethane and one e

Full text of DOI:10.1039/c4ra10807h

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Graphical Abstract
2-Formyl Boron-Dipyrromethene as Key Synthon to Prepare Functionalized Meso-Boron
Dipyrromethenyl Porphyrin Building Blocks
Sunit Kumar and Mangalampalli Ravikanth*
Indian Institute of Technology, Powai, Mumbai, 400076 India. Fax: 91-22-5723480
Tel: 91-22-5767176; E-mail: ravikanth@chem.iitb.ac.in
A series of functionalized meso-BODIPYnyl porphyrin building blocks were synthesized using
2-formyl BODIPY as key precursor.
OCH3
OCH3
NH
N
N
R
N
N
B
HN
F F
R = CH3
R = OCH3
R = H
R = CN
R = NO2
R = Br
1
2
3
4
5
6
7
OCH3
R = I

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2-Formyl Boron-Dipyrromethene as Key Synthon to Prepare Functionalized Meso-Boron
Dipyrromethenyl Porphyrin Building Blocks
Sunit Kumar and Mangalampalli Ravikanth*
Indian Institute of Technology, Powai, Mumbai, 400076 India. Fax: 91ꢀ22ꢀ5723480
Tel: 91ꢀ22ꢀ5767176; Eꢀmail: ravikanth@chem.iitb.ac.in
Abstract
A series of functionalized mesoꢀboron dipyrromethenyl porphyrin building blocks were
synthesized by condensing one equivalent of readily available 2ꢀformyl boron dipyrromethene
(2ꢀformyl BODIPY) with two equivalents of mesoꢀanisyl dipyrromethane and one equivalent of
functionalized aldehyde under mild acid catalyzed conditions followed by column
chromatographic purification and afforded in 5ꢀ7% yields. The mesoꢀBODIPYnyl porphyrins are
freely soluble in common organic solvents and characterized by mass, spectral and
electrochemical techniques. The presence of BODIPY unit directly at the mesoꢀposition alters
the
πꢀdelocalization of the porphyrin macrocycle. The compounds are weakly fluorescent
because of effective charge transfer between porphyrin and BODIPY units leading to the
formation of low lying charge transfer state. The mesoꢀBODIPYnyl porphyrinꢀBF2ꢀsmaragdyrin
conjugate was synthesized by coupling mesoꢀBODIPYnyl porphyrin building block containing
mesoꢀiodophenyl group with ethynyl BF2ꢀsmaragdyrin under Pd(0) coupling conditions. The
spectral and electrochemical studies indicated that the photoꢀinduced electron transfer is the
predominant process in mesoꢀBODIPYnyl porphyrinꢀBF2ꢀsmaragdyrin conjugate.
Key words: Boronꢀdipyrromethene, porphyrin, functionalization, smaragdyrin, electrochemistry.
1

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Introduction
Boron difluoride dipyrrin complexes (BODIPY) are very efficient fluorophores with wide
range of applications in biological labelling1ꢀ3 and cell imaging, as logic gates and ion sensors,4ꢀ6
and in dyeꢀsensitized solar cells7ꢀ10 and solutionꢀprocessed bulk hyperconjunction solar cells.11,12
BODIPYs exhibits excellent properties such as sharp absorption and fluorescence bands in the
visible region, reasonably high fluorescence quantum yields, large molar absorption coefficients
and are highly stable towards light and chemicals.13ꢀ15 The properties of BODIPYs can be fineꢀ
tuned by introducing substituents at the pyrrole carbons, meso carbon as well as replacing
fluorides present on the boron.13ꢀ15 On the other hand, porphyrins are the most widely
investigated tetrapyrrolic aromatic macrocycles because of their importance in biochemical
processes16ꢀ18 such as oxygen transfer and storage (hemoglobin and myoglobin), electron transfer
(cytochrome c, cytochrome oxidase) and energy conversion (chlorophyll).19ꢀ21 Because of large
cavity and presence of four pyrrole nitrogens, porphyrins form a great number of complexes with
metal ions22ꢀ24 and some nonmetals.25,26 The coordinating environment provided by porphyrins is
very flexible and can be fineꢀtuned to particular oxidation and spin states by varying peripheral
substitution and axial ligands.25
BODIPYs and porphyrins have complementary light absorbing properties. BODIPYs
absorb strongly at ~500 nm whereas porphyrins absorb strongly in 420ꢀ450 nm region and
moderately in 500ꢀ700 nm region.27,28 Thus, the BODIPYꢀporphyrin conjugates resulted by
linking BODIPY to porphyrin either covalently or noncovalently absorb over a broad range in
the visible region which is highly desirable for enhancing the lightꢀharvesting efficiency
throughout the solar spectrum. In recent times, several elegant BODIPYꢀporphyrin conjugates in
which BODIPY and porphyrin units are connected either covalently29 or nonꢀcovalently30 were
2

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synthesized and explored their energy/electron transfer properties. Some of these conjugates
have also been incorporated into dyeꢀsensitized semiconductor solar cells to improve light
harvesting ability of the photoꢀelectrochemical cells.30 However, a perusal of literature revealed
that porphyrins having boronꢀdipyrromethenyl unit as one of its mesoꢀsubstituent is almost
scarce although there are several reports on covalently linked BODIPYꢀporphyrin conjugates.29
This is because of unavailability of proper precursors and appropriate synthetic strategies. Herein
we report mesoꢀboron dipyrromethenyl porphyrins 1ꢀ3 and monoꢀfunctionalized mesoꢀboron
dipyrromethenyl porphyrin building blocks 4ꢀ7 by condensing 2ꢀformyl mesoꢀanisyl BODIPY31
10 with mesoꢀanisyl dipyrromethane 11 and desired substituted benzaldehyde under mild acid
catalyzed conditions. To demonstrate the use of mesoꢀBODIPYnyl porphyrin building blocks,
we prepared mesoꢀBODIPYnyl porphyrinꢀBF2 smaragdyrin conjugate 8 and the preliminary
photophysical studies indicated an efficient energy transfer from mesoꢀBODIPYnyl porphyrin to
BF2 smaragdyrin unit.32
Results and Discussion
The required 2ꢀformyl mesoꢀanisyl BODIPY 10 was prepared by treating mesoꢀanisyl
BODIPY27 with the Vilsmeier reagent in 1,2ꢀdichloroethane at reflux temperature, followed by
column chromatographic purification on silica as reported in literature. The other required
precursor, mesoꢀanisyl dipyrromethane 11 was prepared according to Lindsey’s procedure33 by
condensing pꢀanisyl benzaldehyde with excess pyrrole in the presence of a catalytic amount of
trifluoroacetic acid at room temperature followed by flash silica gel column chromatographic
purification. The desired mesoꢀBODIPYnyl porphyrins and functionalized mesoꢀBODIPYnyl
porphyrins 1-7 were prepared under mild acid catalyzed conditions by condensing one equivalent
of 2ꢀformyl mesoꢀanisyl BODIPY31 10 with two equivalents of mesoꢀanisyl dipyrromethane 11
3

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and one equivalent of appropriate substituited/functionalized aryl aldehyde in the presence of
catalytic amount of trifluoroacetic acid in CH2Cl2 at room temperature followed by oxidation
with DDQ. The progress of the condensation reaction was followed by TLC analysis which
showed one minor fast moving spot and one more polar major spot. The crude compounds were
subjected to alumina column chromatographic purification and the fast moving mesoꢀtetraryl
porphyrins were removed and the desired mesoꢀBODIPYnyl porphyrins 1-7 were collected in 5ꢀ
13
11
19
7% yields. The compounds 1-7 were confirmed by HRꢀMS, detailed 1D, 2D, C, B and F
1
NMR techniques. The molecular structures of compounds 1-7 were deduced by detailed H
1
1
NMR, Hꢀ1H COSY and NOESY spectral studies as outlined below for compound 1. The H
NMR spectrum along with key regions of 1Hꢀ1H COSY and NOESY spectra for compound 1 are
1
shown in Fig. 1. The coupling constants in the H NMR (Fig. 1a) spectrum and crossꢀpeak
1
connectivities in the Hꢀ1H COSY (Fig. 1b) and NOESY (Fig. 1c) spectra were used to identify
all of the proton resonances. To assign all of these resonances, we picked out the ꢀOCH3
resonance of mesoꢀanisyl group (type I) of BODIPY unit which appeared as singlet at 3.87 ppm
corresponding to three protons. The type I methoxy protons showed NOE correlation with ortho
protons (type o) of mesoꢀanisyl group which appeared as doublet at 7.08 ppm. The type o
resonance at 7.08 ppm showed cross peak correlation with a doublet at 7.82 which we identified
as type n protons of mesoꢀanisyl group of BODIPY unit of compound 1. The type n resonance
showed NOE correlation with a doublet at 7.18 ppm which we assigned to the type a pyrrole
proton of BODIPY unit. The resonances at 6.70 ppm and 8.10 ppm were identified as type b and
type c pyrrole protons of BODIPY unit of compound 1 based on their cross peak correlations in
the COSY spectrum. The singlet at 7.74 ppm was ascribed to type d pyrrole proton as this
resonance showed NOE correlation with type n resonance at 7.82 ppm. The other singlet
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resonance at 8.71 ppm was ascribed to type e pyrrole proton. Both type d and type e resonances
showed NOE correlation with a doublet in most downfield region at 9.12 ppm which we
identified as type f pyrrole protons of porphyrin unit of compound 1. The doublet resonance at
8.90 ppm was assigned to type g pyrrole protons of porphyrin unit as this resonance showed
crossꢀpeak correlation with type f resonance at 9.12 ppm. The mesoꢀanisyl protons of porphyrin
unit (type II) which appeared as singlet at 4.10 ppm showed NOE correlation with a resonance at
7.28 ppm which we identified as type m protons of mesoꢀanisyl group of porphyrin unit of
compound 1. The resonance at 8.10 ppm was identified as type l protons of mesoꢀanisyl group of
porphyrin unit based on its crossꢀpeak correlation with a type m resonance at 7.28 ppm. The type
h pyrrole resonance of porphyrin appeared at 8.84 ppm was identified as this resonance showed
NOE correlation with type l resonance at 8.10 ppm. The resonance at 8.84 ppm was assigned to
type i proton based on crossꢀpeak correlation with type h resonance in COSY. The ꢀCH3 protons
of mesoꢀtolyl group (type III) of porphyrin unit appeared as singlet resonance at 2.70 ppm
showed NOE correlation with resonance at 7.54 ppm which we identified as type k protons of
mesoꢀtolyl group of porphyrin unit of compound 1. The type k protons showed crossꢀpeak
correlation with resonance at 8.10 ppm which we assigned to type j protons of mesoꢀtolyl group
of porphyrin. The inner NH proton of porphyrin was appeared as broad singlet at ꢀ2.72 ppm.
1
Thus, all of the signals of compound 1 were assigned on the basis of Hꢀ1H COSY and NOESY
NMR spectroscopic studies. The other compounds 2-7 also showed similar features and all
protons were identified and assigned on similar basis. All compounds showed typical quartet at ~
19
11
ꢀ144 ppm in F NMR and a triplet at 0.99 ppm in B NMR with negligible shifts compared to
mesoꢀphenyl BODIPY.34 We also prepared Zn(II) and Ni(II) derivatives of compound 1 by
treating it with appropriate metal salt in CHCl3 or CH3OH at reflux conditions followed by
5

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column chromatographic purifications to afford corresponding metal derivatives Zn1 and Ni1 in
decent yields. The Zn1 and Ni1 were confirmed by mass spectrometry and 1H, 11B and 19F NMR
techniques.
Photophysical and electrochemical properties
The absorption properties of compounds 1ꢀ7 were studied in CHCl3 and the data is
summarized in Table 1. The comparison of absorption spectra of compound 1 with 5, 10, 15, 20ꢀ
mesoꢀtetra(pꢀtolyl)porphyrin (H2TTP) is shown in Fig. 2a. As is clear from fig. 2 and data in
Table 1 that compounds 1ꢀ7 showed four bands in 450ꢀ700 nm region and one Soret band at 420
nm. The presence of BODIPY unit at the mesoꢀposition of porphyrin unit significantly alters the
electronic properties of the porphyrin and compounds 1ꢀ7 show three well defined Qꢀbands and
one Soret band instead of four wellꢀdefined Qꢀbands observed for mesoꢀtetrararylporphyrins
such as H2TTP. For example compound 1 showed absorption bands at 420, 490, 515, 597 and
663 nm. In these, the bands at 420, 515, 597 and 663 nm are mainly due to porphyrin ring
whereas the band at 490 nm is due to BODIPY unit. Furthermore, the absorption bands of
compounds 1-7 are generally broad with higher extinction coefficients and the Q1 band showed
~20ꢀ25 nm bathochromic shift compared to H2TTP. Thus, the presence of BODIPY unit at the
mesoꢀposition alters the πꢀdelocalization of the porphyrin macrocycle.
The redox properties of compounds 1ꢀ7 along with H2TTP are probed through cyclic
voltammetric studies using 0.1 M tetrabutylammonium perchlorate as supporting electrolyte
(TBAP) in dichloromethane as solvent. The cyclic voltammogram of compound 1 is compared
with H2TTP in Fig. 2b and the data for all compounds 1ꢀ7 along with H2TTP are tabulated in
Table 2. As clear from the fig. 2b and data presented in Table 2 that all compounds 1ꢀ7 showed
two quasiꢀreversible oxidations and three reversible/quasiꢀreversible reductions. For example,
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compound 1 showed two oxidations at 1.06 and 1.23 V and three reductions at ꢀ0.59, ꢀ1.10 and ꢀ
1.49 V. In these, the two oxidations at 1.23 and 1.06 V were exclusively due to porphyrin unit;
the two reductions at ꢀ1.10 and ꢀ1.49 V were due to porphyrin ring whereas the reduction at ꢀ0.59
V was due to BODIPY unit. These assignments were made based on the data of their reference
compounds, BODIPY34 and H2TTP.28 Interestingly, the oxidation and reduction potentials of
porphyrin in compounds 1-7 did not vary much compared to H2TTP28 except the presence of
additional reduction wave corresponding to reduction of mesoꢀBODIPY moiety. However, the
compounds 1-7 are very stable under redox conditions. Furthermore, we realized that compounds
1-7 were completely nonꢀfluorescent although both BODIPY and porphyrin units are decently
fluorescent systems. In fact, it has been demonstrated earlier in several covalently linked
BODIPYꢀporphyrin conjugates, the occurrence of efficient energy transfer from BODIPY unit to
porphyrin unit on selective excitation of BODIPY unit.35ꢀ38 The nonꢀfluorescence behaviour of
compounds 1-7 indicate that there is a possibility of electron transfer instead of energy transfer
between BODIPY and porphyrin moieties in conjugates 1-7. Furthermore, the strong excitonic
interactions between the two moieties also perturb the energy levels leading to the enhancement
of nonradiatve decay processes. However, the detailed studies are required to understand the
excited state dynamics of these compounds.
The absorption spectra of Zn1 and Ni1 showed two Qꢀbands and one strong Soret band
which were bathochromically shifted compared to ZnTTP and NiTTP respectively.39 The
electrochemical studies of Zn1 and Ni1 were carried out in CH2Cl2 using TBAP as supporting
electrolyte and the data were included in Table 2 along with ZnTTP and NiTTP. It is clear from
the data presented in Table 2 that both Zn1 and Ni1 showed one additional reduction at ~ ꢀ0.58
V corresponding to BODIPY moiety along with two oxidations and one or two reductions
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corresponding to metalloporphyrin unit. However, the metalloporphyrin centered oxidations and
reductions of Zn1 and Ni1 were almost in the same potential range of those of ZnTTP and
NiTTP39 respectively.
Covalently linked meso-BODIPYnyl porphyrin-BF2-smaragdyrin conjugate 8
To show the further use of functionalized mesoꢀBODIPYnyl porphyrins, we synthesized
one example of covalently linked mesoꢀBODIPYnyl porphyrinꢀBF2ꢀsmaragdyrin conjugate
under mild Pd(0) coupling conditions as shown in Scheme 2. The reaction was carried out by
coupling of compound 7 with ethynyl BF2ꢀsmaragdyrin32 9 in the presence of catalytic amounts
of [Pd2(dba)3] and AsPh3 at 35° C in toluene/triethylamine for 12 h. The progress of the reaction
was followed by TLC analysis which showed the appearance of new spot corresponding to the
desired compound and almost disappearance of spots corresponding to the starting precursors 7
and 9. After standard workꢀup and silica gel column chromatographic purification afforded the
desired compound 8 in 90% yield. The molecular ion peak in ESꢀMS spectrum confirmed the
1
identity of the compound 8. The comparison of H NMR spectra of compound 8 along with its
1
constituted building blocks 7 and 9 is shown in Fig. 3. In H NMR of compound 8 (Fig. 3c), the
resonances were assigned on the basis of the spectra observed for the corresponding building
blocks 7 (Fig. 3b) and 9 (Fig. 3a). In 1H NMR spectrum of 8 (Fig. 3c), the additional five sets of
signals observed in the region of 9 to 10.4 ppm were due to eight pyrrole protons and two furan
protons of smaragdyrin moiety. As clear from Fig. 3, the 1H NMR of compound 8 was composed
of a super imposition of the spectra of 7 and 9 with negligible shifts in their chemical shifts
indicating that mesoꢀBODIPYnylꢀporphyrin and BF2ꢀsmaragdyrin moieties in compound 8
1
interact weakly and retain most of their individual H NMR spectral features. The compound 8
showed one triplet at 1.01 ppm and one broad resonance at ꢀ12.17 ppm in 11B NMR
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corresponding to boron atom of BODIPY moiety and smaragdyrin macrocycle respectively. It
has been shown earlier that the boron present in the smaragdyrin macrocycle32 experiences
strong macrocyclic ring current effect and appears as broad signal at high field region. Similar
19
observations were made in F NMR spectra recorded for compound 8 which showed a typical
quartet at ꢀ144 ppm for BODIPY moiety and a broad resonance at ꢀ149 ppm corresponding to the
BF2ꢀsmaragdyrin macrocycle. The absorption, electrochemical and fluorescence properties of
compound 8 (Fig. 4) along with its associated reference compounds were studied and the
relevant data were included in Table 1. The comparison of absorption spectra of compound 8
along with its associated reference compounds 7 and 9 is shown in Fig. 4a. As clear from the fig.
4a, the absorption spectrum of 8 in both Qꢀband and Soret region showed the absorption features
of both the moieties and the absorption spectrum of 8 was almost identical to that of the 1:1
mixture of monomers indicating that the two moieties interact weakly and retain their individual
characteristic features. The cyclic voltammogram of compound 8 recorded in CH2Cl2 using
tetrabutylammonium perchlorate as supporting electrolyte showed four reductions at ꢀ0.59, ꢀ0.89,
ꢀ1.07 and ꢀ1.44 V and three oxidations at 0.79, 1.12 and 1.39 V (Fig. 4b). In this, the reduction at
ꢀ0.59 V corresponding to BODIPY moiety; the oxidation at 0.79 V and reduction at ꢀ0.89 V were
exclusively due to smaragdyrin moiety; oxidation at 1.12 V and reduction at ꢀ1.07 V were
exclusively due to porphyrin moiety and the remaining oxidation at 1.30 V and reduction at ꢀ1.44
were due to both porphyrin and smaragdyrin moieties. Thus, the electrochemical study of
compound 8 also showed features of BODIPY, porphyrin and smaragdyrin moieties with slight
shifts in its potential compared to reference monomers.28,32,34 This supports weak interaction
among the BODIPY, porphyrin and smaragdyrin moieties in compound 8. The fluorescence
spectrum of compound 8 recorded at 510 nm where BODIPY unit absorbs exclusively showed
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emission band at 724 nm corresponding to smaragdyrin unit with a quantum yield of 0.016
indicating a possibility of intramolecular energy transfer from mesoꢀBODIPYnyl porphyrin unit
to smaragdyrin unit in compound 8. However, The quantum yield of BF2ꢀsmaragdyrin unit in
compound 8 was quenched by 84% compared to free BF2ꢀsmaragdyrin32 (Ф = 0.10) indicating
that the energy transfer is not the predominant process and there is a possibility of the photoꢀ
induced electron transfer between mesoꢀBODIPYnyl porphyrin and BF2ꢀsmaragdyrin units.
Thus, our preliminary photophysical studies indicated the possibility of both photoinduced
energyꢀ and electron transfer processes, the detailed studies are required to probe excited state
dynamics of compound 8 and mesoꢀBODIPYnyl porphyrins 1-7.
Conclusions
In conclusion, we prepared mesoꢀBODIPYnyl porphyrin building blocks by condensing
2ꢀformyl BODIPY with mesoꢀanisyl dipyrromethane and functionalized aldehyde under mild
acid catalyzed conditions. The presence of BODIPYnyl group directly at one of the mesoꢀ
position alters the
πꢀdelocalization of the porphyrin macrocycle which reflected in their
bathochromically shifted absorption bands and weak fluorescence behaviour. The
electrochemical study indicated that mesoꢀBODIPYnyl porphyrins are stable under redox
conditions. The weak fluorescence of mesoꢀBODIPYnyl porphyrins compared to mesoꢀtetraaryl
porphyrins indicates the possibility of electron transfer between BODIPY and porphyrin moieties
in mesoꢀBODIPYnyl porphyrins. The mesoꢀBODIPYnyl porphyrin was connected covalently to
BF2ꢀsmaragdyrin unit covalently under Pd(0) coupling conditions and the resultant mesoꢀ
BODIPYnyl porphyrinꢀBF2ꢀsmaragdyrin conjugate showed features of both the mesoꢀ
BODIPYnyl porphyrin and BF2ꢀsmaragdyrin units as evidenced by spectral and electrochemical
studies. The steady state fluorescence studies on mesoꢀBODIPYnylꢀBF2ꢀsmaragdyrin conjugate
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also indicated that the photoꢀinduced electron transfer is also possible along with energy transfer
between mesoꢀBODIPYnyl porphyrin and BF2ꢀsmsragdyrin moieties. These types of mesoꢀ
BODIPYnyl porphyrins and mesoꢀBODIPYnyl porphyrinꢀBF2ꢀsmaragdyrin conjugates have
potential applications in molecular electronics and material science.
Experimental Section
General
The chemicals such as BF3·OEt2, trifluoroacetic acid (TFA), and 2, 3ꢀdichloroꢀ5,6ꢀ
dicyanoꢀ1,4ꢀbenzoquinone (DDQ) were used as obtained from Aldrich. All other chemicals used
for the synthesis were reagent grade unless otherwise specified. Column chromatography was
performed on silica (60ꢀ120 mesh) and basic alumina. The 1D, 2D, 13C, 11B and 19F NMR
spectra were recorded in CDCl3 on Bruker 400 and 500 MHz instrument. The frequency for 13C
nucleus is 100 MHz, 470.54 MHz for 19F nucleus, and 160.46 MHz for 11B nucleus.
Tetramethylsilane [Si(CH3)4] was used as an internal standard for 1H and 13C NMR,
19
tetrafluorotoluene as a external standard for F NMR and boric acid as an external standard for
11B NMR. Absorption and steady state fluorescence spectra were obtained with Varian. The
fluorescence quantum yields (Φ) were estimated from the emission and absorption spectra by
comparative method at the excitation wavelength of 420 nm using H2TTP (Φ = 0.11) as
standard.40 Cyclic voltammetric (CV) studies were carried out with BAS electrochemical system
utilizing the three electrode configuration consisting of a glassy carbon (working electrode),
platinum wire (auxiliary electrode) and saturated calomel (reference electrode) electrodes. The
experiments were done in dry dichloromethane using 0.1 M tetrabutylammonium perchlorate as
supporting electrolyte. The high resolution mass spectra (HRMS) were recorded with a Bruker
maxis Impact and QꢀTof micro mass spectrometer. For UVꢀvis and fluorescence titrations, the
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stock solution of all compounds (5×10ꢀ6 and 2.5×10ꢀ6 M) were prepared by using HPLC grade
CHCl3 solvent.
General procedure for the synthesis of compounds 1-7
Samples of βꢀformyl mesoꢀanisyl BODIPY 1031 (100 mg, 0.306 mmol), dipyrromethane
1133 (154 mg, 0.613 mmol) and aldhyde 12 (0.306 mmol) in 50 mL CH2Cl2 were stirred in
presence of 30 ꢀL TFA under nitrogen for 2 h. DDQ was added and the stirring was continued in
air for an additional 1.5 h. The reaction mixture was neutralized with triethylamine and the
solvent was removed on rotary evaporator. The crude product was purified by basic alumina
column chromatography using petroleum ether/dichloromethane (60:40, v/v) and afforded pure
compound (1-7) as a purple solid.
1
Compound 1: 7% Yield (20 mg), H NMR (500 MHz, CDCl3,
δ
in ppm): ꢀ2.72 (s, 2H; NH),
3
2.70 (s, 3H; ꢀCH3), 3.87 (s, 3H; OCH3), 4.10 (s, 6H; ꢀOCH3), 6.70 (dd, J (H, H) = 4.2, 4.1 Hz,
1H; Py), 7.08 (d, 3J (H, H) = 8.7 Hz, 2H; Ar), 7.18 (d, 3J (H, H) = 4.1 Hz, 1H; Py), 7.28 (q, 3J (H,
3
H) = 8.6 Hz, 4H; Ar), 7.54 (q, 3J (H, H) = 7.8 Hz, 2H; Ar), 7.74 (s, 1H; py), 7.82 (d, J (H, H) =
3
8.5 Hz, 2H; Ar), 8.08ꢀ8.13 (m, 7H; Ar, Py), 8.71 ( s, 1H; Py), 8.84ꢀ8.85 (m, 4H; py), 8.90 (d, J
(H, H) = 4.5 Hz, 2H; Py), 9.12 (d, 3J (H, H) = 4.6 Hz, 2H; Py). 11B NMR (160.4 MHz, CDCl3, δ
in ppm): 0.99 (t, 1J (BꢀF) = 28 Hz, B). 19F NMR (470.5 MHz, CDCl3, δ in ppm): ꢀ144.6 (q, 1J (Fꢀ
13
B) = 28 Hz, F). C NMR (100 MHz, CDCl3, δ in ppm): 55.7, 55.8, 112.4, 114.5, 118.8, 120.2,
120.4, 120.5, 120.7, 120.8, 126.6, 127.7, 132.0, 132.9, 134.2, 134.6, 134.7, 134.8, 134.9, 135.8,
135.9, 137.7, 139.3, 144.2, 146.6, 148.8, 159.7, 162.5. UVꢀvis (in CHCl3, λmax/nm, logε) = 420
(5.5), 490 (4.8), 515 (4.8), 597 (4.3), 663 (4.2). HRMS. Calcd for C57H44BF2N6O3 [(M+H)+]: m/z
909.3540. Found: m/z 909.3541.
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1
Compound 2: 6% Yield (20 mg), H NMR (500 MHz, CDCl3,
δ
in ppm): ꢀ2.72 (s, 2H; NH),
3
3
3.86 (s, 3H; OCH3), 4.10 (s, 9H; ꢀOCH3), 6.70 (dd, J (H, H) = 4.3, 4.2 Hz, 1H; Py), 7.08 (d, J
3
(H, H) = 8.9 Hz, 2H; Ar), 7.17 (d, J (H, H) = 4.0 Hz, 1H; Py), 7.28ꢀ7.31 (m, 6H; Ar), 7.75 (s,
3
1H; py), 7.83 (d, J (H, H) = 8.9 Hz, 2H; Ar), 8.10ꢀ8.13 (m, 7H; Ar, Py), 8.71 ( s, 1H; Py), 8.84ꢀ
8.85 (m, 4H; py), 8.90 (d, 3J (H, H) = 4.5 Hz, 2H; Py), 9.12 (d, 3J (H, H) = 4.6 Hz, 2H; Py). 11B
1
NMR (160.4 MHz, CDCl3, δ in ppm): 0.98 (t, J (BꢀF) = 28 Hz, B). 19F NMR (470.5 MHz,
CDCl3, δ in ppm): ꢀ144.6 (q, 1J (FꢀB) = 28 Hz, F). 13C NMR (100 MHz, CDCl3, δ in ppm): 53.6,
55.69, 55.7, 55.8, 110.9, 112.4, 114.5, 118.9, 120.3, 120.4, 126.5, 120.7, 132.0, 132.9, 134.2,
134.6, 134.7, 135.8, 135.9, 144.2, 146.6, 148.8, 159.7, 159.7, 162.5. UVꢀvis (in CHCl3, λmax/nm,
logε) = 421 (5.5), 491 (4.8), 510 (4.8), 598 (4.3), 663 (4.1). HRMS. Calcd for C57H44BF2N6O4
[(M+H)+]: m/z 925.3489. Found: m/z 925.3429.
1
Compound 3: 5 % Yield (15 mg), H NMR (400 MHz, CDCl3,
δ
in ppm): ꢀ2.72 (s, 2H; NH),
3
3
3.86 (s, 3H; OCH3), 4.10 (s, 6H; ꢀOCH3), 6.70 (dd, J (H, H) = 4.2, 4.1 Hz, 1H; Py), 7.08 (d, J
(H, H) = 8.4 Hz, 2H; Ar), 7.17 (d, 3J (H, H) = 4.2 Hz, 1H; Py), 7.27ꢀ7.30 (m, 4H; Ar), 7.74ꢀ7.78
3
3
(m, 4H; Ar, py), 7.83 (d, J (H, H) = 7.8 Hz, 2H; Ar), 8.10ꢀ8.13 (m, 5H; Ar, Py), 8.20 (d, J (H,
H) = 7.7 Hz, 2H; Ar), 8.71 ( s, 1H; Py), 8.82 (d, 3J (H, H) = 4.6 Hz, 2H; py), 8.86 (d, 3J (H, H) =
3
3
11
4.5 Hz, 2H; Py), 8.90 (d, J (H, H) = 4.7 Hz, 2H; Py), 9.12 (d, J (H, H) = 4.6 Hz, 2H; Py). B
1
NMR (160.4 MHz, CDCl3, δ in ppm): 0.99 (t, J (BꢀF) = 28 Hz, B). 19F NMR (470.5 MHz,
CDCl3, δ in ppm): ꢀ144.6 (q, 1J (FꢀB) = 28 Hz, F). 13C NMR (100 MHz, CDCl3, δ in ppm): 55.7,
55.8, 112.4, 114.5, 120.4, 120.4, 125.9,126.9, 128.0, 132.9, 134.8, 135.8, 135.9, 144.3, 159.7,
162.5. UVꢀvis (in CHCl3, λmax/nm, logε) = 420 (5.3), 491 (4.6), 509 (4.5), 596 (4.1), 662 (4.0).
HRMS. Calcd for C56H42BF2N6O4 [(M+H)+]: m/z 895.3383. Found: m/z 895.3329.
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1
Compound 4: 6% Yield (17 mg), H NMR (500 MHz, CDCl3,
δ
in ppm): ꢀ2.71 (s, 2H; NH),
3
3
3.86 (s, 3H; OCH3), 4.09 (s, 6H; ꢀOCH3), 6.71 (dd, J (H, H) = 4.2, 4.1 Hz, 1H; Py), 7.09 (d, J
3
(H, H) = 8.8 Hz, 2H; Ar), 7.18 (d, J (H, H) = 4.2 Hz, 1H; Py), 7.27ꢀ7.30 (m, 4H; Ar), 7.75 (s,
3
1H; py), 7.82 (d, J (H, H) = 8.7 Hz, 2H; Ar), 8.05ꢀ8.09 (m, 2H; Ar), 8.10ꢀ8.12 (m, 5H; Ar, py),
3
8.31ꢀ8.33 (m, 2H; Ar), 8.69 (d, J (H, H) = 4.4 Hz, 2H; py), 8.85 ( s, 1H; Py), 8.89ꢀ8.92 (m, 4H;
3
11
1
py), 9.14 (d, J (H, H) = 4.3 Hz, 2H; Py). B NMR (160.4 MHz, CDCl3, δ in ppm): 0.99 (t, J
(BꢀF) = 28 Hz, B). 19F NMR (470.5 MHz, CDCl3, δ in ppm): ꢀ144.6 (q, 1J (FꢀB) = 28 Hz, F). 13C
NMR (100 MHz, CDCl3, δ in ppm): 55.7, 55.8, 55.8 112.4, 112.5, 114.5, 117.5, 119.2, 120.4,
120.8, 126.6, 130.8, 132.2, 134.2, 134.4, 135.1, 135.2, 135.9, 144.6, 146.4, 147.4 148.9, 159.7,
159.8, 162.5. UVꢀvis (in CHCl3, λmax/nm, logε) = 421 (5.4), 4.90 (4.7), 510 (4.6), 597 (4.3), 662
(4.1). HRMS. Calcd for C57H41BF2N7O3 [(M+H)+]: m/z 920.3336. Found: m/z 920.3337.
1
Compound 5: 7 % Yield (19 mg), H NMR (500 MHz, CDCl3,
δ
in ppm): ꢀ2.72 (s, 2H; NH),
3
3
3.86 (s, 3H; OCH3), 4.10 (s, 6H; ꢀOCH3), 6.72 (dd, J (H, H) = 4.3, 4.2 Hz, 1H; Py), 7.08 (d, J
3
(H, H) = 8.9 Hz, 2H; Ar), 7.18 (d, J (H, H) = 4.3 Hz, 1H; Py), 7.29ꢀ7.31 (m, 4H; Ar), 7.75 (s,
1H; py), 7.82 (d, 3J (H, H) = 8.9 Hz, 2H; Ar), 8.10ꢀ8.12 (m, 5H; Ar, py), 8.37ꢀ8.40 (m, 2H; Ar),
3
8.62ꢀ8.62ꢀ8.65 (m, 2H; Ar), 8.70 (d, J (H, H) = 4.9 Hz, 2H; py), 8.85 ( s, 1H; Py), 8.90ꢀ8.92
(m, 4H; py), 9.14 (d, 3J (H, H) = 4.5 Hz, 2H; Py). 11B NMR (160.4 MHz, CDCl3, δ in ppm): 0.99
1
19
1
(t, J (BꢀF) = 28 Hz, B). F NMR (470.5 MHz, CDCl3, δ in ppm): ꢀ144.6 (q, J (FꢀB) = 28 Hz,
F). 13C NMR (100 MHz, CDCl3, δ in ppm): 55.7, 55.8, 112.2, 112.4, 112.5, 114.6, 116.9, 119.2,
120.9, 122.1, 125.9, 126.6, 128.1, 132.3, 132.9, 134.2, 134.4, 134.7, 135.3, 135.9, 144.6, 146.4,
147.9, 148.9, 149.4, 159.7, 162.5. UVꢀvis (in CHCl3, λmax/nm, logε) = 421 (5.3), 489 (4.7), 511
(4.7), 595 (4.3), 662 (4.1). HRMS. Calcd for C56H41BF2N7O5 [(M+H)+]: m/z 940.3234. Found:
m/z 940.3233.
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1
Compound 6: 7% Yield (21 mg), H NMR (400 MHz, CDCl3,
δ
in ppm): ꢀ2.75 (s, 2H; NH),
3
3
3.86 (s, 3H; OCH3), 4.10 (s, 6H; ꢀOCH3), 6.71 (dd, J (H, H) = 4.2, 4.1 Hz, 1H; Py), 7.08 (d, J
3
(H, H) = 8.8 Hz, 2H; Ar), 7.18 (d, J (H, H) = 4.0 Hz, 1H; Py), 7.28ꢀ7.31 (m, 4H; Ar), 7.75 (s,
1H; py), 7.82 (d, 3J (H, H) = 8.9 Hz, 2H; Ar), 7.84ꢀ7.90 (m, 2H; Ar), 8.06ꢀ8.09 (m, 2H; Ar),
8.10ꢀ8.12 (m, 5H; Ar, py), 8.70 (s, 1H; py), 8.79 ( d, 3J (H, H) = 4.6 Hz, 2H; Py), 8.85ꢀ8.86 (m,
3
3
11
2H; py), 8.87 (d, J (H, H) = 4.7 Hz, 2H; Py), 9.12 (d, J (H, H) = 4.4 Hz, 2H; Py). B NMR
(160.4 MHz, CDCl3, δ in ppm): 0.99 (t, 1J (BꢀF) = 28 Hz, B). 19F NMR (470.5 MHz, CDCl3, δ in
ppm): ꢀ144.6 (q, 1J (FꢀB) = 28 Hz, F). 13C NMR (100 MHz, CDCl3, δ in ppm): 55.7, 55.9, 112.4,
114.5, 120.5, 130.1, 132.9, 135.7, 135.8, 136.0, 136.1, 144.4, 148.8, 159.7, 162.5. UVꢀvis (in
CHCl3, λmax/nm, logε) = 420 (5.4), 490 (4.7), 510 (4.7), 595 (4.3), 662 (4.1). HRMS. Calcd for
C56H41BBrF2N6O3 [(M+H)+]: m/z 973.2488. Found: m/z 973.2493.
1
Compound 7: 6% Yield (20 mg), H NMR (500 MHz, CDCl3,
δ
in ppm): ꢀ2.72 (s, 2H; NH),
3
3
3.86 (s, 3H; OCH3), 4.10 (s, 6H; ꢀOCH3), 6.72 (dd, J (H, H) = 4.2, 4.1 Hz, 1H; Py), 7.08 (d, J
3
(H, H) = 8.9 Hz, 2H; Ar), 7.18 (d, J (H, H) = 4.3 Hz, 1H; Py), 7.28ꢀ7.30 (m, 4H; Ar), 7.74 (s,
3
1H; py), 7.82 (d, J (H, H) = 8.8 Hz, 2H; Ar), 7.92ꢀ7.95 (m, 2H; Ar), 8.08ꢀ8.12 (m, 7H; Ar, py),
8.70 ( s, 1H; Py), 8.79 (d, 3J (H, H) = 4.6 Hz, 2H; py), 8.87 (d, 3J (H, H) = 4.8 Hz, 2H; Py), 8.90
3
3
11
(d, J (H, H) = 4.5 Hz, 2H; Py), 9.12 (d, J (H, H) = 4.4 Hz, 2H; Py). B NMR (160.4 MHz,
CDCl3, δ in ppm): 0.99 (t, 1J (BꢀF) = 28 Hz, B). 19F NMR (470.5 MHz, CDCl3, δ in ppm): ꢀ144.6
(q, 1J (FꢀB) = 28 Hz, F). UVꢀvis (in CHCl3, λmax/nm, log
ε) = 421 (5.3), 491 (4.7), 507 (4.6), 595
(4.3), 662 (4.1). HRMS. Calcd for C56H41BF2IN6O3 [(M+H)+]: m/z 1021.2350. Found: m/z
1021.2349.
Zn1 and Ni1 complexes:
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A solution of compound 1 (10 mg, 0.011 mmol) and an excess of Zn(OAc)2/Ni(OAc)2 in
dichloromethane/methanol (3:1, 30 mL) was refluxed for 4 h. The crude compound was purified
by basic alumina column chromatography using petroleum ether/dichloromethane (50:40, v/v) to
afford pure compound Zn1/ Ni1 as a purple solids.
Compound Zn1: 60% Yield (7mg), 1H NMR (500 MHz, CDCl3,
δ
in ppm): 2.71 (s, 3H; ꢀCH3),
3
3
3.83 (s, 3H; OCH3), 4.10 (s, 6H; ꢀOCH3), 6.70 (dd, J (H, H) = 4.2, 4.1 Hz, 1H; Py), 7.04 (d, J
3
(H, H) = 8.6 Hz, 2H; Ar), 7.15 (d, J (H, H) = 4.2 Hz, 1H; Py), 7.28 (q, 3J (H, H) = 8.6 Hz, 4H;
3
Ar), 7.54ꢀ7.56 (m, 2H; Ar), 7.73 (s, 1H; py), 7.82 (d, J (H, H) = 8.2 Hz, 2H; Ar), 8.07ꢀ8.12 (m,
7H; Ar, Py), 8.71 ( s, 1H; Py), 8.95ꢀ8.96 (m, 4H; py), 8.99ꢀ9.01 (m, 2H; Py), 9.21ꢀ9.23 (m, 2H;
11
1
19
Py). B NMR (160.4 MHz, CDCl3, δ in ppm): 0.99 (t, J (BꢀF) = 28 Hz, B). F NMR (470.5
MHz, CDCl3, δ in ppm): ꢀ144.6 (q, 1J (FꢀB) = 28 Hz, F). UVꢀvis (in CHCl3, λmax/nm, log
ε) = 423
(5.4), 494 (4.6), 557 (4.4), 662 (4.1). HRMS. Calcd for C57H42BF2N6O3Zn [(M+H)+]: m/z
971.2671. Found: m/z 971.2679.
Compound Ni1: 70% Yield (7 mg), 1H NMR (400 MHz, CDCl3,
δ
in ppm): 2.64 (s, 3H; ꢀCH3),
3
3
3.86 (s, 3H; OCH3), 4.05 (s, 6H; ꢀOCH3), 6.68 (dd, J (H, H) = 4.3, 4.2 Hz, 1H; Py), 7.04 (d, J
(H, H) = 8.7 Hz, 2H; Ar), 7.14 (d, 3J (H, H) = 4.0 Hz, 1H; Py), 7.19ꢀ7.22 (m, 4H; Ar), 7.48ꢀ7.50
3
(m, 2H; Ar), 7.54 (s, 1H; py), 7.75 (d, J (H, H) = 8.7 Hz, 2H; Ar), 7.87ꢀ7.92 (m, 6H; Ar, Py),
8.08 ( s, 1H; Py), 8.53 ( s, 1H; Py), 8.74ꢀ8.78 (m, 4H; py), 8.79ꢀ8.80 (m, 2H; Py), 8.98ꢀ9.01 (m,
1
2H; Py). 11B NMR (160.4 MHz, CDCl3, δ in ppm): 0.99 (t, J (BꢀF) = 28 Hz, B). 19F NMR
1
(470.5 MHz, CDCl3, δ in ppm): ꢀ144.6 (q, J (FꢀB) = 28 Hz, F). UVꢀvis (in CHCl3, λmax/nm,
logε) = 417 (5.1), 487 (4.5), 514 (4.4), 538 (4.5), 594 (4.1).
Covalently linked meso-BODIPYnyl porphyrin-BF2-smaragdyrin conjugate 8
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Compound 7 (10 mg, 0.0098 mmol) and 5, 10ꢀ(4ꢀmethylꢀphenyl)ꢀ19ꢀ(4ꢀethynylphenyl)ꢀ25ꢀ
oxasmaragdyrin 934 (7 mg, 0.0098 mmol) were dissolved in dry toluene/Et3N (6 ml, 5:1) in a 25
ml, two necked roundꢀbottomed flask fitted with a reflux condenser, gas inlet and outlet tubes for
nitrogen purging. The reaction mixture was placed in an oil bath preheated to 35 °C. After
purging the flask with nitrogen for 15 min, AsPh3 (3.5 mg, 0.0117 mmol) and Pd2(dba)3 (1.5 mg,
0.0014 mmol) were added, and the reaction mixture was stirred at 35 °C for 12 h. TLC analysis
of the reaction mixture indicated the appearance of a dark new spot apart from the two minor
spots corresponding to the unreacted starting precursor. The solvent was removed under reduced
pressure and the crude compound was purified by basic alumina column chromatography. The
excess AsPh3 and the small amount of unreacted starting precursors were removed with
petroleum ether and the required pure compound 8 was then collected with petroleum
1
ether/CH2Cl2. 90% Yield (13 mg), H NMR (500 MHz, CDCl3,
δ in ppm): ꢀ3.79ꢀ 3.81 (m, 2H;
NH), ꢀ2.69 (s, 2H; NH), 2.81 (s, 6H; CH3), 3.90 (s, 3H; ꢀOCH3), 4.10 (s, 6H; ꢀOCH3), 6.71ꢀ6.73
3
(m, 1H; Py), 7.08ꢀ7.11 (m, 2H; Ar), 7.18ꢀ7.20 (m, 1H; Py), 7.03ꢀ7.34 (m, 4H; Ar), 7.60 (d, J
3
(H, H) = 7.60 Hz, 4H; Ar), 7.74 (d, J (H, H) = 7.7 Hz, 1H; Py), 7.83ꢀ7.86 (m, 2H; Ar), 8.12ꢀ
3
8.17 (m, 7H; Ar, Py), 8.28ꢀ8.33 (m, 8H; Ar), 8.70 (d, J (H, H) = 7.6 Hz, 2H; Ar), 8.74 (s, 1H;
Py), 8.89ꢀ8.94 (m, 4H; Py), 8.98 (d, 3J (H, H) = 4.7 Hz, 2H; Py), 9.01ꢀ9.02 (m, 2H; Py), 9.15 (d,
3J (H, H) = 4.5 Hz, 2H; Py), 9.49 (s, 2H; Oxa), 9.66 (d, 3J (H, H) = 4.3 Hz, 2H; Py), 10.24ꢀ10.25
3
11
(m, 2H; Py), 10.35 (d, J (H, H) = 4.4 Hz, 2H; Py). B NMR (160.4 MHz, CDCl3, δ in ppm):
1.01 (t, 1J (BꢀF) = 27 Hz, 1B), ꢀ12.17 (s, B). 19F NMR (470.5 MHz, CDCl3, δ in ppm): ꢀ144.6 (q,
1J (FꢀB) = 28 Hz, F), ꢀ149.3 (s, 2F). UVꢀvis (in CHCl3, λmax/nm, log
ε) = 422 (5.4), 451 (5.5), 477
(4.9), 593 (4.9), 633 (4.4), 654 (4.5), 709 (4.8). LRMS Calcd for C101H71B2F4IN10O4 [(M+H)+]:
m/z 1584.5322. Found: m/z 1585.5561.
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Acknowledgements
We thank the Department of Science and Technology, Government of India for financial support
and S. K thanks the UGC for a fellowship.
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27. H. L. Kee, C. Kirmaier, L. Yu, P. Thamyongkit, W. J. Youngblood, M. E. Calder, L. Ramos,
B. C. Noll, D. F. Bocain, W. R. Scheidt, R. R. Birge, J. S. Lindsey and D. Holten, J. Phys. Chem.
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Legends
Scheme 1: Synthesis of compounds 1-7.
Scheme 2: Synthesis of compound 8.
Table 1: Absorption data of H2TTP, Zn1, Ni1 and compounds 1-10 recorded in CHCl3.
Concentration of solution used for soret band is 2.5x10ꢀ6 and for Q band is 5x10ꢀ6 M.
Table 2: Electrochemical (V) data of BODIPY, H2TTP, ZnTTP, NiTTP, Zn1, Ni1 and
compounds 1ꢀ9 recorded in CH2Cl2 containing 0.1 M TBAP as the supporting electrolyte
recorded at 50 mVsꢀ1 scan speed.
1
1
Fig. 1: (a) H NMR, (b) Hꢀ1H COSY and (c) NOESY spectrum of compound 1 recorded in
CDCl3.
Fig. 2: (a) Comparison of normalized absorption of H2TTP (red line) and compound 1 black
line) recorded in CHCl3. The inset shows the expansion of soret bands. The concentration used
for Qꢀband spectra was 5x10ꢀ6 M and soret band spectrum was 2.5x10ꢀ6 M. (b) Comparison of
cyclic voltammogram of BODIPY (i), H2TTP (ii) and compound 1 (iii) recorded in CH2Cl2.
1
Fig. 3: Comparison of H NMR spectra of (a) Ethynyl BF2ꢀsmaragdyrin 9, (b) compound 7 and
(c) compound 8.
Fig. 4: (a) Comparison of normalized absorption of compound 7 (black line), compound 9 (red
line) and compound 8 (blue line) recorded in CHCl3. The inset shows the expansion of soret
bands. The concentration used for Qꢀband spectra was 5x10ꢀ6 M and soret band spectrum was
2.5x10ꢀ6. (b) Comparison of cyclic voltammogram of compound 9 (i), 7 (ii) and compound 8 (iii)
recorded in CH2Cl2.
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Scheme 1
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Scheme 2
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Table 1
Compound
Soret band (nm) (log
(molꢀ1dm3 cmꢀ1)
420(5.5)
ε
)
Q bands (nm) (log
(molꢀ1dm3 cmꢀ1)
ε)
517(4.1), 552(3.8), 591(3.5), 648(3.6)
490(4.8), 515(4.8), 597(4.3), 663(4.2)
494(4.6), 557(4.4), 662(4.1)
H2TTP
420(5.5)
423(5.4)
417(5.1)
421(5.5)
420(5.3)
421(5.4)
421(5.3)
420(5.4)
420(5.4)
1
Zn1
Ni1
2
487(4.5), 514(4.4), 538(4.5), 594(4.1)
491(4.8), 510(4.8), 598(4.3), 663(4.1)
491(4.6), 509(4.5), 596(4.1), 662(4.0)
490(4.7), 510(4.6), 597(4.3), 662(4.1)
489(4.7), 511(4.7), 595(4.3), 662(4.1)
490(4.7), 510(4.7), 595(4.3), 662(4.1)
491(4.7), 507(4.6), 595(4.3), 662(4.1)
512(4.7), 593(4.9), 633(4.4), 654(4.5), 709(4.8)
594(4.0), 632(4.2), 652(4.3), 707(4.6)
494(5.0)
3
4
5
6
7
422(5.43), 451(5.5),477(4.9)
8
448(5.5), 476(5.1)
ꢀ
9
10
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Table 2
Compound
E
1/2ox (V/SCE)
E1/2por E1/2por/sma
ꢀ
E1/2red (V/SCE)
E1/2sma E1/2por
E1/2sma
E1/2BDP
E1/2por/sma
ꢀ
ꢀ
ꢀ
ꢀ0.81
ꢀ
ꢀ
ꢀ
BODIPY
ꢀ
1.12
0.90
1.18
ꢀ
1.35
1.21
1.29
1.22
1.23
1.18
1.28
1.20
1.26
1.29
1.27
1.26
1.27
1.30
ꢀ
ꢀ1.07
ꢀ1.17
ꢀ1.14
ꢀ
ꢀ1.40
ꢀ1.39
ꢀ
H2TTP
ꢀ
ꢀ
ꢀ
ZnTTP
ꢀ
ꢀ
ꢀ
NiTTP
0.78
ꢀ
ꢀ0.90
ꢀ1.42
ꢀ1.49
ꢀ1.51
ꢀ
9
1
ꢀ
1.06
0.89
1.16
1.05
1.12
1.15
1.15
1.12
1.13
1.12
ꢀ0.59
ꢀ0.58
ꢀ0.57
ꢀ0.62
ꢀ0.62
ꢀ0.60
ꢀ0.60
ꢀ0.61
ꢀ0.59
ꢀ0.59
ꢀ
ꢀ1.10
ꢀ1.22
ꢀ1.18
ꢀ1.13
ꢀ1.12
ꢀ1.07
ꢀ0.89
ꢀ1.12
ꢀ1.08
ꢀ1.07
ꢀ
ꢀ
Zn1
Ni1
2
ꢀ
ꢀ
ꢀ
ꢀ
ꢀ1.53
ꢀ1.55
ꢀ1.48
ꢀ1.51
ꢀ
ꢀ
ꢀ
3
ꢀ
ꢀ
4
ꢀ
ꢀ
5
ꢀ
ꢀ
ꢀ
ꢀ
6
ꢀ1.46
ꢀ1.44
7
0.79
ꢀ0.89
8
BDP = BODIPY, sma = smaragdyrin, por = porphyrin
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Fig. 1
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(a)
(b)
(i)
(ii)
(iii)
Fig. 2
27

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β-fu
Ar
Ar
β -py
β -py
β -py
Ar
Ar
β -py
NH
(a)
Ar, c
Ar
Ar
Ar
Ar
h+h’
i+I’
f+f’
g+g’
NH
d
a
e
b
(b)
(c)
β-fu
Ar
Ar, c
h+h’, h+h’
i+I’
Ar
Ar
β -py
β -py
β -py
β -py
f+f’
Ar
Ar
Ar
NH
NH
d
a
e
b
Fig. 3
28