Meso-thiaporphyrinoids revisited: Missing of sulfur by small metals

Article abstract of DOI:10.1002/chem.201203255

Facile synthesis of meso-aryl-substituted 5,15-dithiaporphyrins and 10-thiacorroles has been achieved by sulfidation of α,α'- dichlorodipyrrin metal complexes with sodium sulfide in DMF. Thiacorrole metal complexes exhibit distinct aromaticity due to 18 π-conjugation including the lone pair on sulfur, whereas dithiaporphyrins are nonaromatic judging from ¹H NMR spectra, X-ray analysis, and absorption spectra. We have found that Ni^II and Al^III dithiaporphyrin complexes undergo smooth thermal sulfur extrusion reaction to give the corresponding thiacorrole complexes, whereas free base, Zn^II, Pd^II, and Pt ^II dithiaporphyrin complexes did not exhibit the similar reactivity. The DFT calculations have elucidated a reaction pathway involving an episulfide intermediate, which can explain the markedly different reactivity among dithiaporphyrin metal complexes.

Full text of DOI:10.1002/chem.201203255

FULL PAPER
DOI: 10.1002/chem.201203255
meso-Thiaporphyrinoids Revisited: Missing of Sulfur by Small Metals
Hiroki Kamiya, Takeshi Kondo, Takafumi Sakida, Shigeru Yamaguchi, and
Hiroshi Shinokubo*[a]
Abstract: Facile synthesis of meso-aryl-
substituted 5,15-dithiaporphyrins and
10-thiacorroles has been achieved by
sulfidation of a,a’-dichlorodipyrrin
metal complexes with sodium sulfide in
DMF. Thiacorrole metal complexes ex-
hibit distinct aromaticity due to 18p-
conjugation including the lone pair on
sulfur, whereas dithiaporphyrins are
nonaromatic judging from 1H NMR
spectra, X-ray analysis, and absorption
spectra. We have found that NiII and
AlIII dithiaporphyrin complexes under-
go smooth thermal sulfur extrusion re-
action to give the corresponding thi-
ACHTUNGTRENNaUNG corrole complexes, whereas free base,
ZnII, PdII, and PtII dithiaporphyrin
complexes did not exhibit the similar
reactivity. The DFT calculations have
elucidated
a reaction pathway in-
AHCTUNGTRENNvGUN olving an episulfide intermediate,
which can explain the markedly differ-
ent reactivity among dithiaporphyrin
metal complexes.
À
Keywords: aromaticity · C C bond
formation · nickel · porphyrinoids ·
sulfur
Introduction
but rather acts as a substituent to the normal porphyrinic p
system.
Porphyrins, pyrrole NH of which is replaced with a chalco-
gen atom, namely, core-modified porphyrins, have attracted
considerable attention due to their remarkable properties
(Scheme 1).[1,2] This modification significantly changes struc-
In contrast to core modifications, meso-modified porphy-
AHCTUNGTREGrNNUN ins have heteroatoms directly on the p-conjugation circuit
(Scheme 1), and consequently the heteroatom substitution
at the meso-positions should have significant impact to their
electronic structures. In particular, incorporation of 3p or
higher atomic orbitals on the heteroatom in the macrocyclic
p-conjugated system would lead to intriguing features.
In 1972, for meso-dithiaporphyrins, Broadhurst, Grigg,
and Johnson reported the synthesis of octaalkyl-5,15-dithia-
porphyrin from dipyrrolyl sulfide precursors (Scheme 2).[6,7]
They also reported a unique sulfur extrusion reaction of
5,15-dithiaporphyrin to 10-thiacorroles at very high tempera-
ture in the presence of triphenylphosphine. However, after
this pioneering work, these systems have not been explored
further, probably due to synthetic difficulties of these meso-
Scheme 1. Structures of representative thiaporphyrinoids. Core-modified
porphyrin (21-thiaporphyrin), 10-thiacorrole, and 5,15-dithiaporphyrin.
The bold lines indicate the cyclic p conjugation.
tural, photophysical, and electronic features, as well as coor-
dination behavior at the central cavity.[3] In addition, ex-
panded core-modified porphyrins were reported to have ex-
tremely large two photon cross-sections.[4,5] However, in
core-modified porphyrins, the chalcogen atom does not di-
rectly participate in the macrocyclic conjugation pathway,
[a] H. Kamiya, T. Kondo, T. Sakida, Dr. S. Yamaguchi,
Prof. Dr. H. Shinokubo
Department of Applied Chemistry
Graduate School of Engineering, Nagoya University
Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan)
Fax : (+81)52-789-5113
E-mail: hshino@apchem.nagoya-u.ac.jp
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201203255.
Scheme 2. Formation of 5,15-dithiaporphyrin and 10-thiacorroles from di-
pyrrolyl sulfides by Grigg et al.
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thiaporphyrinoids.[8] Furthermore, there have been no prece-
dent reports on the synthesis of meso-aryl-substituted meso-
thiaporphyrinoids, nature of which would be finely tuned by
the aryl substituents, similar to the case of meso-aryl-substi-
tuted porphyrins.
(Figure 1). In complex 2Zn, the two dipyrrin moieties are
substantially bent at the sulfur atoms with a dihedral angle
of 143.88 (Figure 1b). This folded conformation of the dipyr-
rin plane is structurally closely related to porphodi-
Recently, we have established synthesis of NiII azacorroles
from a NiII dipyrrin complex 1 through Pd-catalyzed Buch-
wald–Hartwig amination.[9] Meanwhile, Matano et al. have
independently developed a highly efficient synthetic proce-
dure for 5,10-diazaporphyrins from dipyrrin metal com-
plexes.[10] We further extended this strategy to preparation
of 16p-antiaromatic norcorrole NiII.[11] We next undertook
incorporation of sulfur to the porphyrin skeleton at the
meso-positions through nucleophilic sulfidation of halogen-
ated dipyrrin precursors 1. Now we have accomplished a
facile metal-templated synthesis of meso-aryl-substituted 10-
thiacorroles and 5,15-dithiaporphyrins, which allowed de-
tailed investigation on the structures and properties of this
intriguing class of old-but-new porphyrinoids.
Results and Discussion
Synthesis and structural characterization: The synthetic pro-
tocol of meso-thiaporphyrinoids is illustrated in Scheme 3.
Figure 1. X-ray crystal structures of 3Ni: a) top view; b)side view and of
2Zn: c) top view; d) side view; and e) oblique view of the dimeric struc-
ture. meso-Aryl substituents were omitted for clarity. The thermal ellip-
soids were scaled to the 50% probability level.
AHCTUNGTRENNUNG
methenes.[12] Thus, dithiaporphyrin 2 can be referred to as
thia-calix[4]phyrins. One of the sulfur atoms is bound to the
zinc center in another molecule of 2Zn to form a dimeric
structure in the solid state (Figure 1e). The zinc atom is also
ligated by acetonitrile used for recrystallization.[13] In sharp
contrast, thiacorrole NiII 3Ni has a highly planar structure
with a mean plane deviation of 0.036 ꢁ (Figure 1a and b).
Importantly, the carbon–sulfur bond length is 1.69 ꢁ, which
is substantially shorter than that in 2Zn (1.75 ꢁ) and a typi-
Scheme 3. Sulfidation of a,a’-dichlorodipyrrin complexes 1.
We found that treatment of a,a’-dichlorodipyrrin ZnII com-
plex 1Zn with sodium sulfide hydrate in DMF at 658C gave
5,15-dithiaporphyrin free base 2H in 53% yield along with a
small amount of 2Zn. To investigate the effect of the central
metals upon this cyclization reaction, sulfidation of the cor-
responding NiII dipyrrin complex 1Ni was examined under
the similar conditions. Surprisingly, 10-thiacorrole NiII com-
plex 3Ni was obtained as a sole product in 41% yield from
1Ni. None of 5,15-dithiaporphyrin NiII complex 2Ni was de-
tected in the reaction mixture.
À
cal C S bond length (1.82 ꢁ). The shrunk bond length is
À
due to the partial double bond character of the C S bond in
3Ni, indicating effective delocalization of the lone pair on
sulfur to the p system.
The structures of these thiaporphyrinoids were un-
Aromaticity of 5,15-dithiaporphyrin and 10-thiacorrole: The
1H NMR spectrum of 3Ni exhibited four doublet peaks for
b-pyrrolic protons in the aromatic region (d=7.9–8.4 ppm).
ACHTUNGTRENNUNG
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Thiaporphyrinoids Revisited: Missing of Sulfur by Small Metals
FULL PAPER
Consequently, thiacorrole NiII 3Ni is concluded to be a dis-
tinctly aromatic porphyrinoid. To support aromaticity of
3Ni, the nucleus-independent chemical-shift (NICS) calcula-
tions by the DFT method at the B3YP/631SDD level of
theory were further performed (631SDD denotes a basis set
consisting of SDD for Ni and Zn and 6–31G(d) for the
rest).[14] The NICS values at the points “a” and “b” (indicat-
ed in Figure 1a) were calculated to be d=À15.0 and
À11.5 ppm, respectively, supporting strong aromatic charac-
ter of 3Ni. The aromaticity of 3Ni clearly indicates that the
lone pair in the 3p orbital on sulfur actually participates in
the 18p conjugation as depicted in Scheme 1. Importantly,
Grigg et al. reported that meso-protons of octaalkyl-10-thi-
2Ni in excellent yields. PdII and PtII complexes 2Pd and 2Pt
were also obtained from the reaction of 2H with palladium
chloride and platinum chloride. Interestingly, nickel inser-
tion at 1108C in toluene at reflux gave NiII thiacorrole 3Ni
in 43% yield. Furthermore, 2Ni was converted to 3Ni in
75% yield at 1008C within 2 h in the presence of triphenyl-
phosphine (2.0 equiv) to trap the liberated sulfur atom. For-
mation of triphenylphosphine sulfide was confirmed by the
1H NMR spectrum of the crude product. Grigg et al. report-
ed that this type of sulfur extrusion occurred at 2148C in
4.5 h in the case of ZnII octaalkyldithiaporphyrin.[6,16] This
may indicate that meso-aryl-substituted dithiaporphyrins un-
dergo more facile thermal sulfur extrusion reaction than b-
alkyl-substituted ones. Interestingly, no desulfur reaction
was observed for 2H, 2Zn, 2Pd, and 2Pt under the same
conditions or at even elevated temperature, namely, at
1808C. These results strongly suggest the critical role of the
central metals in the reactivity of dithiaporphyrin metal
complexes.
To examine the origin of the specific reactivity of the
nickel complex, structural analysis of 2Ni was essential. We
were pleased to get nice crystals of dithiaporphyrin NiII and
PtII complexes 2Ni and 2Pt. X-ray analysis of these com-
plexes showed that the folding angle of the two dipyrrin
planes in 2Ni is 117.68, which is much smaller than those in
2Zn (143.88) and 2Pt (134.38; Figure 2). The average dis-
tance of the a-carbons in 2Ni is 2.64 ꢁ, whereas those in
2Zn and 2Pt are 2.79 and 2.71 ꢁ, respectively. On the basis
of these different structural factors, we speculated that a
smaller metal ion induces more severe bending of the two
dipyrrin units in the dithiaporphyrin complex 2, resulting in
a shorter distance between two reacting a-carbons to facili-
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
ACHTUNGTRENNUNGaromatic thiaannulenes with odd numbered rings were re-
ported.[15] In contrast, dithiaporphyrin 2H and its metal
complexes exhibited no significant upfield shift of b-protons
in their 1H NMR spectra, thus indicating nonaromatic
nature in spite of the potential 20p-electronic system. Due
À
to the substantially bent structure and the long C S bond,
meso-dithiaporphyrin can be rather regarded as a sulfur-
bridged dipyrrin dimer, lacking in effective global p conju-
gation over the macrocycle. This situation was again sup-
ported by the NICS calculation: the NICS values at the
points “c” and “d” (indicated in Figure 1c) are d=6.5 and
2.6 ppm, revealing marginal antiaromaticity of 2Zn.
Metalation behavior of 5,15-dithiaporphyrin free base: With
free base 2H in hand, metal insertion of 2H was then exam-
ined (Scheme 4). Treatment of 2H with zinc(II) acetate and
nickel(II) acetylacetonate at room temperature successfully
gave the corresponding ZnII and NiII complexes 2Zn and
Scheme 4. Metalation of dithiaporphyrin 2H. Reaction conditions: a) Ni-
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
A
Figure 2. X-ray crystal structures of 2Ni a) top view; b) side view and of
2Pt: c) top view and d) side view. meso-Aryl substituents are omitted for
clarity. The thermal ellipsoids were scaled to the 50% probability level.
43% yield for 3Ni; f) AlCl3 (10 equiv), pyridine, reflux, then PPh3
(2.0 equiv), toluene, reflux, 73% yield for 3Al.
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H. Shinokubo et al.
tate carbon–carbon bond formation. To prove this hypothe-
sis, the thermal reactivity of AlIII dithiaporphyrin 2Al, which
was prepared from 2H and AlCl3 in pyridine according to
the procedure for insertion of aluminum to regular porphy-
ACHTUNGTRENNUNG
rins, was checked (Scheme 4 f).[17] To our delight, AlIII thi-
ACHTUNGTRENNUNGacorrole 3Al was isolated in 73% yield in two steps from
1
2H upon heating the crude AlIII complex 2Al. The H NMR
spectrum of 3Al displays all b-pyrrolic protons in the aro-
matic region, indicating its strong aromaticity of 3Al as
nickel complex 3Ni.
Reaction mechanism on the basis of DFT calculations: Now
we propose the plausible reaction mechanism of the sulfur
extrusion reaction, which starts with thermal episulfide for-
mation (Scheme 5). The cyclic array of electrons arising
Figure 3. Calculated structures of intermediates and transition states.
from 2Ni to TS1-Ni was calculated to be Ea =30.3 kcalmolÀ1
(Figure 4). We then found that episulfide A-Ni underwent
facile sulfur migration to 1,2-episulfide B-Ni and then 2,3-
episulfide C-Ni with almost no barriers: the activation ener-
gies are only 1.4 and 0.5 kcalmolÀ1, respectively. The energy
of 2,3-episulfide C is substantially lower than other inter-
mediates, because C should have aromatic stabilization due
to retrieval of the 18p-conjugation network. Then phos-
Scheme 5. Proposed reaction mechanism.
À
from the lone pair on sulfur of 2M provides the episulfide
intermediate A, which reasonably explains the critical factor
of the folding angle and the distance of the a-carbons. Be-
cause of the highly strained structure, involvement of bisepi-
sulfide intermediate A’ is not likely. The sulfur atom is even-
tually attacked by triphenylphosphine to afford thiacorrole
3M.[18,19] Initially we expected that replacement on sulfur of
intermediate A would directly give 3M, but we then found
that this step is not so straightforward by the DFT calcula-
tions.
phine (PH3) attacks C Ni and displaces the sulfur atom to
from 3Ni and phosphine sulfide (PH3=S). The activation
energy of the sulfur removal process was calculated to be
The reaction mechanism was investigated by computa-
tional method with the hope to understand a marked differ-
ence in the desulfurization reactivity between 2Ni and 2Pt.
Initial geometries were obtained from the crystal structures
of 2Ni and 2Pt. To reduce the calculation cost, two mesityl
groups were replaced by hydrogen atoms. The structures
were fully optimized with the B3LYP/631SDD level. Zero-
point energy and thermal-energy corrections were conduct-
ed for all optimized structures. The obtained transition
states gave single imaginary frequencies and IRC calcula-
tions supported the transition structures.
By gradual reducing the distance between two a-carbons,
we could locate the transition state TS1-Ni, which was con-
firmed to lead to episulfide intermediate A-Ni by the IRC
calculation (Figure 3). The activation energy of this step
Figure 4. Calculated energy diagrams for sulfur extrusion of 2Ni and 2Pt
at the B3LYP/631SDD level. The relative energy [kcalmolÀ1] of each spe-
cies is shown in parenthesis.
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Thiaporphyrinoids Revisited: Missing of Sulfur by Small Metals
FULL PAPER
24.0 kcalmolÀ1. Therefore, the rate-limiting step of the over-
all sulfur extrusion reaction from 2Ni to 3Ni is the forma-
lations, which indicated involvement of the d orbital on NiII
in HOMO and decrease of the HOMO–LUMO gap of 3Ni
(Figure S18 in the Supporting Information). The absorption
spectrum of ZnII dithiaporphyrin 2Zn consists of a strong
absorption band at l=451 nm and a redshifted weak one at
l=529 nm, whereas 2Ni exhibited a rather broad absorp-
tion spectrum (Figure 5b). The absorption property of di-
thiaporphyrin complexes varies significantly depending on
the central metals. These results suggest that the dithiapor-
phyrin ligand is flexible enough to accommodate various
metal ions, inducing the structural change with the bending
of the dipyrrin units. This feature is somewhat similar to
those observed for calix[4]phyrin metal complexes.
Electrochemical properties of metal complexes of meso-
thiaporphyrinoids were investigated by cyclic voltammetry,
which was performed in a dichloromethane solution with
Bu4NPF6 as electrolyte (Figure S16 in the Supporting Infor-
mation). Two reversible reduction and two reversible oxida-
tion waves were observed, except for 2Zn. Due to strong
electron donation from sulfur to the p system, these thiapor-
phyrinoids have rather low oxidation potentials. Of them,
the first oxidation potential of ZnII dithiaporphyrin 2Zn was
À0.08 V (vs. ferrocene/ferrocenium cation). The differences
between the first oxidation and first reduction potentials for
3Ni and 3Al are 2.03 and 2.20 V, respectively. The narrower
electrochemical HOMO–LUMO gap of 3Ni than 3Al is in
good agreement with the optical analysis and the DFT cal-
culations.
À
tion of the initial episulfide A Ni. Similar intermediates
and transition states were also obtained for the correspond-
ing PtII complexes. The activation energy for the rate-limit-
ing step is 40.7 kcalmolÀ1, which is substantially higher than
that of the nickel complex. Figure 4 shows the energy dia-
gram of the two reaction pathways for 2Ni and 2Pt, which
indicate relative energies of intermediates and transition
states on the basis of the energy levels of the final products
3Ni and 3Pt. Obviously, PtII dithiaporphyrin 2Pt is more
stable than 2Ni, because 2Pt lacks distortion due to the
bending of the dipyrrin units. Consequently, we concluded
that the inherent relative instability of 2Ni mainly decreases
the activation energy of the episulfide formation to facilitate
the sulfur extrusion reaction.
Absorption spectra and electrochemistry: In line with dis-
tinct aromaticity of 10-thiacorroles observed in their
1H NMR spectra, the UV/Vis absorption spectra of 3Ni and
3Al exhibited diagnostic features of aromatic porphyrins in-
cluding Soret bands and Q bands (Figure 5a). However, the
Soret band of 3Ni is split and the Q-bands are redshifted in
comparison to those of 3Al. This is probably due to interac-
tion of the nickel center with frontier orbitals of the macro-
cyclic ligand. This scenario was supported by the DFT calcu-
Conclusion
A facile synthesis of meso-aryl-substituted 5,15-dithiapor-
phyrins and 10-thiacorroles by sulfidation of a bis(a,a’-di-
chlorodipyrrinato) metal complexes has been achieved. 10-
Thiacorrole NiII and AlIII complexes exhibited distinct aro-
maticity due to 18p electrons including the lone pair on
sulfur. In contrast, 5,15-dithiaporphyrins are nonaromatic
due to lack of macrocyclic p conjugation. 5,15-Dithiapor-
phyrin metal complexes showed some similarity to calix[4]-
phyrins in terms of the folded structure of two dipyrrin
units, thus indicating potential utility in molecular-recogni-
tion applications. Moreover, the crucial role of the central
metals in the sulfur extrusion reaction of dithiaporphyrins to
thiacorroles has been elucidated on the basis of X-ray dif-
fraction analysis and DFT calculations. Further investigation
of the reactivity and applications of these meso-thiaporphy-
AHCTUNGTREGUNrNN inoids is currently underway in our laboratory.
Experimental Section
Synthesis of free base dithiaporphyrin 2H: A Schlenk tube containing
compound 1Zn (102 mg, 0.14 mmol) and Na2S·9H2O (101 mg,
0.42 mmol) was evacuated and then refilled with N2. Dry DMF (7 mL)
was added and mixture was heated at 658C for 15 h in oil bath with stir-
ring. After the reaction mixture was cooled to RT, the mixture was
passed through a short silica-gel pad (CH2Cl2), and the solvent was
Figure 5. UV/Vis absorption spectra of a) 10-thiacorroles 3m and b) 5,15-
dithiaporphyrins 2m recorded in CH2Cl2.
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H. Shinokubo et al.
evaporated in vacuo. The mixture was purified by silica-gel column chro-
777.1557 [M+]; found: 777.1542. Crystal data: C36H29.75Cl0.25N4PtS2; Mw =
786.46; monoclinic; space group C2/c (No. 15); a=14.4983(17), b=
14.5316(17), c=14.8111(17) ꢁ; b=98.520(2)8; V=3086.0(6) ꢁ3; Z=4;
1calcd =1.693 gcmÀ3; T=153(2) K; R=0.0230 [I>2.0s(I)]; Rw =0.0584 (all
data); GOF=1.059 [I>2.0s(I)].[20]
Synthesis of NiII thiacorrole 3Ni: A Schlenk tube containing compound
1Ni (36.2 mg, 50 mmol) and Na2S·9H2O (24.0 mg, 0.10 mmol) was evacu-
ated and then refilled with N2. Dry DMF (5 mL) was added, and mixture
was stirred at 1008C for 20 h in oil bath. After cooling the reaction mix-
matography (CH2Cl2/hexane) to give 2H (43.4 mg, 74.2 mmol) in 53%
1
yield as black solid along with a trace amount of 2Zn. H NMR (CDCl3):
d=2.11 (s, 12H), 2.33 (s, 6H), 6.25 (d, J=4.0 Hz, 4H), 6.31 (d, J=
4.0 Hz, 4H), 6.90 (s, 4H), 13.00 ppm (s, 2H); 13C NMR (CDCl3): d=
19.97, 21.07, 120.23, 127.81, 129.18, 133.03, 136.87, 137.63, 138.33, 142.40,
and 145.43 ppm; lmax (e [MÀ1 cmÀ1])=419 (5400), 483 nm (1300); HRMS
+
(ESI-MS): m/z calcd for C36H33N4S2
:
585.2141 [M+H+]; found:
585.2134.
Synthesis of ZnII dithiaporphyrin 2Zn: A two-necked round bottom flask
ture to RT, the mixture was passed through
a short silica-gel pad
(CH2Cl2), and the solvent was evaporated in vacuo. The mixture was pu-
rified by silica-gel column chromatography (CH2Cl2/hexane) to give 3Ni
(12.6 mg, 20.7 mmol) in 41% yield as black solid. 1H NMR (CDCl3): d=
1.93 (s, 12H), 2.55 (s, 6H), 7.17 (s, 4H), 7.98 (d, J=4.5 Hz, 2H), 8.28–
8.33 (m, 6H) ppm; 13C NMR (CDCl3): d=20.85, 21.34, 117.84, 120.98,
127.46, 127.75, 128.77, 131.53, 133.61, 135.04, 137.51, 137.77, 138.23,
139.76, 146.23 ppm; lmax (e [MÀ1 cmÀ1])=390 (6000), 406 (5300), 524
(760), 564 (420), 627 (300), 674 nm (740); HRMS (ESI-MS): m/z calcd
for C36H30N4SNi+: 608.1539 [M+]; found: 608.1543. Crystal data:
C36H30N4NiS; Mw =609.41; monoclinic; space group P21/c (No. 14),;a=
12.534(14), b=27.71(3), c=8.139(9) ꢁ; b=101.92(2)8; V=2766(5) ꢁ3;
Z=4; 1calcd =1.463 gcmÀ3; T=153(2) K; R=0.0946 [I> 2.0s(I)]; Rw =
0.2191 (all data); GOF=1.242 [I> 2.0s(I)].[20]
Synthesis of AlIII thiacorrole (3Al): A two-neck round bottom flask con-
taining compound 2H (13.5 mg, 23.1 mmol) and AlCl3 (30.7 mg,
0.231 mmol) was evacuated and then refilled with N2. Pyridine (5 mL)
was added to the flask, and mixture was stirred at reflux for 5 h. The mix-
ture was passed through a short Al2O3 pad (CHCl3) and evaporated in
vacuo. To the residue, PPh3 (12.1 mg, 46.2 mmol) and toluene (5 mL) was
added, and mixture was heated at refluxed for 12 h. The solvent was
evaporated, and the residue was purified by silica-gel column chromatog-
raphy (CHCl3/methanol). Recrystallization from methanol/H2O gave 3Al
(10.0 mg, 16.8 mmol) in 73% yield as green solid. 1H NMR (CDCl3): d=
1.65 (s, 6H), 2.16 (s, 6H), 2.55 (s, 6H), 7.17 (s, 4H), 7.26 (s, 4H), 8.25 (d,
J=4.0 Hz, 2H), 8.40 (d, J=4.0 Hz, 2H), 8.50 (d, J=4.0 Hz, 2H),
8.57 ppm (d, J=4.0 Hz, 2H); 13C NMR (CDCl3): d=20.84, 21.61, 21.62,
118.80, 121.00, 128. 08, 128.22, 130.97, 131.17, 131.26, 135.22, 138.14,
138.32, 138.91, 139.11, 141.10, 144.66, 145.21 ppm; lmax (e [MÀ1 cmÀ1])=
407 (23000), 425 (150000), 512 (6300), 610 nm (11000); HRMS (ESI-
MS): m/z calcd for C36H30N4SAl+: 577.2001 [MÀOH+]; found: 577.1989.
containing compound 2H (9.0 mg, 15.4 mmol) and Zn(OAc)2·2H2O
AHCTUNGTRENNUNG
(32.9 mg, 0.15 mmol) was evacuated and then refilled with N2. To the
flask, CH2Cl2 (9 mL), methanol (2 mL), and a few drops of Et3N were
added, and mixture was stirring at RT for 12 h. The solvent was evapo-
ACHTUNGTRENNUNGrated, and the crude material was purified by recrystallization (CH2Cl2/
methanol) to give 2Zn (9.0 mg, 13.9 mmol) in 90% yield as red solid.
1H NMR (CDCl3): d=2.11 (s, 12H), 2.32 (s, 6H), 6.08 (d, J=4.0 Hz,
4H), 6.27 (d, J=4.0 Hz, 4H), 6.86 ppm (s, 4H); 13C NMR (CDCl3): d=
8.25, 19.98, 21.06, 117.88, 127.58, 131.88, 136.65, 143.99, 150.79 ppm: lmax
(e [MÀ1 cmÀ1])=451 (12000), 496 (1600), 529 nm (3900); HRMS (ESI-
MS): m/z calcd for C36H30N4S2Zn+: 646.1198 [M+]; found: 646.1180. Crys-
tal data: C38H33N5S2Zn; Mw =689.18; monoclinic; space group P21/n (No.
14); a=12.023(5), b=11.397(5), c=24.232(5) ꢁ; b=99.004(5)8; V=
3280(2) ꢁ3; Z=4; 1calcd =1.396 gcmÀ3
;
T=293(2) K; R=0.0518 [I>
2.0s(I)]; Rw =0.1301 (all data); GOF=1.045 [I>2.0s(I)].[20]
Synthesis of NiII dithiaporphyrin 2Ni: A two-necked round bottom flask
containing compound 2H (53.0 mg, 90.6 mmol) and NiACHTNUTRGNEUNG(acac)2·xH2O
(232 mg, 0.91 mmol) was evacuated and then refilled with N2. To the
flask, CH2Cl2 (10 mL) was added, and mixture was stirred at RT for 13 h.
The mixture was passed through a short Celite pad (CH2Cl2) and evapo-
rated in vacuo without heating. The mixture was purified by recrystalliza-
tion (CH2Cl2/methanol) to give 2Ni (54.3 mg, 84.6 mmol) in 93% yield as
red solid. 1H NMR (CDCl3): d=1.85 (s, 6H), 2.33 (s, 6H), 2.45 (s, 6H),
6.16 (d, J=4.5 Hz, 4H), 6.40 (d, J=4.5 Hz, 4H), 6.86 (s, 2H), 6.93 ppm
(s, 2H); 13C NMR (CDCl3): d=19.41, 20.38, 21.08, 117.24, 127.74, 131.56,
132.37, 136.69, 136.91, 137.67, 137.90, 141.13, 150.49 ppm; lmax (e
[MÀ1 cmÀ1])=372 (1300), 417 (2300), 466 (3100), 556 nm (2900); HRMS
(ESI-MS): m/z calcd for C36H30N4S2Ni+: 640.1260 [M+]; found: 640.1259.
¯
Crystal data: C36H30Cl0.25N4NiS2; Mw =650.33; triclinic; space group P1
(No. 2); a=14.118(4), b=14.931(4), c=15.657(4) ꢁ; a=97.809(4)8, b=
106.390(4)8, g=98.193(4)8; V=3079.7(13) ꢁ3; Z=4; 1calcd =1.403 gcmÀ3
;
T=293(2) K; R=0.0447 [I>2.0s(I)]; Rw =0.1232 (all data); GOF=1.041
[I>2.0s(I)].[20]
Synthesis of PdII dithiaporphyrin 2Pd: A two-neck round bottom flask
containing compound 2H (40.0 mg, 68.4 mmol) and PdCl2 (60.6 mg,
0.34 mmol) was evacuated and then refilled with N2. To the flask, dry
CH2Cl2 (0.40 mL) was added, and mixture was stirred at RT for 15 h. The
mixture was passed through a short Celite pad (CH2Cl2) and evaporated
in vacuo. The mixture was purified by silica-gel column chromatography
(CH2Cl2/hexane) to give 2Pd (12.4 mg, 18.0 mmol) in 26% yield as red
solid. 1H NMR (CDCl3): d=2.14 (s, 12H), 2.33 (s, 6H), 6.17 (d, J=
4.5 Hz, 4H), 6.37 (d, J=4.5 Hz, 4H), 6.89 ppm (s, 4H); 13C NMR
(CDCl3): d=19.87, 21.08, 116.44, 127.78, 130.80, 133.11, 136.75, 137.39,
137.64, 142.34, 147.40 ppm; lmax (e [MÀ1 cmÀ1])=364 (2200), 464 (5800),
515 (1100), 550 nm (4200); HRMS (ESI-MS): m/z calcd for
C36H30N4S2Pd+: 608.1539 [M+]; found: 608.1543.
Synthesis of PtII dithiaporphyrin 2Pt: A two-neck round bottom flask
containing compound 2H (40.0 mg, 68.4 mmol) and PtCl2 (91.0 mg,
0.34 mmol) was evacuated and then refilled with N2. To the flask, dry
CH2Cl2 (0.40 mL) was added and mixture was stirring at RT for 15 h.
The mixture was passed through a short Celite pad (CH2Cl2) and evapo-
rated in vacuo. The mixture was purified by silica-gel column chromatog-
raphy (CH2Cl2/hexane) to give 2Pt (7.2 mg, 9.3 mmol) in 14% yield as
red solid. 1H NMR (CDCl3): d=2.13 (s, 12H), 2.34 (s, 6H), 6.29 (d, J=
4.0 Hz, 4H), 6.45 (d, J=4.0 Hz, 4H), 6.90 ppm (s, 4H) ppm; 13C NMR
(CDCl3): d=19.88, 21.09, 115.70, 127.81, 129.86, 132.92, 136.19, 136.79,
137.71, 142.00, 146.77 ppm; lmax (e [MÀ1 cmÀ1])=412 (2100), 461 (2200),
519 (800), 555 nm (3700; HRMS (ESI-MS): m/z calcd for C36H30N4S2Pt+:
Acknowledgements
This work was supported by Grants-in-Aid for Scientific Research (Nos.
24350023 and 23108705 “pi-Space”) from MEXT, Japan. H.S. also ac-
knowledges Daiko Foundation for financial support. S.Y. appreciates the
JSPS Research Fellowship for Young Scientists.
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Published online: November 8, 2012
Chem. Eur. J. 2012, 18, 16129 – 16135
ꢀ 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
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