Stereospecific [2+2] photocycloaddition in a pseudodimeric complex between N-ammoniopropylstyrylpyridine and 18-crown-6-containing styrylpyridine

Article abstract of DOI:10.1007/s11172-009-0267-0

A quaternary 4-styrylpyridinium salt having the N-ammoniopropyl substituent forms a pseudodimeric head-to-tail complex with neutral 18-crown-6-containing 4-styrylpyridine in MeCN through H-bonding. This complex undergoes stereospecific [2+2] photocycloaddition due to preorganization of the ethylene bonds in the syn-arranged chromophoric fragments of the components. The structure of the rctt-isomer of the cyclobutane derivative obtained was established by NMR spectroscopy and X-ray diffraction analysis.

Full text of DOI:10.1007/s11172-009-0267-0

Russian Chemical Bulletin, International Edition, Vol. 58, No. 9, pp. 1955—1961, September, 2009
1955
Stereospecific [2+2] photocycloaddition in a pseudodimeric complex between
Nꢀammoniopropylstyrylpyridine and 18ꢀcrownꢀ6ꢀcontaining styrylpyridine
A. I. Vedernikov,a S. K. Sazonov,a L. G. Kuz´mina,b J. A. K. Howard,c M. V. Alfimov,a and S. P. Gromova
aPhotochemistry Center, Russian Academy of Sciences,
7A ul. Novatorov, 119421 Moscow, Russian Federation.
Fax: +7 (495) 936 1255. Eꢀmail: gromov@photonics.ru
bN. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences,
31 Leninsky prosp., 119991 Moscow, Russian Federation.
Fax: +7 (495) 954 1279
cDepartment of Chemistry, University of Durham,
South Road, Durham DH1 3LE, UK
A quaternary 4ꢀstyrylpyridinium salt having the Nꢀammoniopropyl substituent forms a
pseudodimeric headꢀtoꢀtail complex with neutral 18ꢀcrownꢀ6ꢀcontaining 4ꢀstyrylpyridine in
MeCN through Hꢀbonding. This complex undergoes stereospecific [2+2] photocycloaddition
due to preorganization of the ethylene bonds in the synꢀarranged chromophoric fragments of
the components. The structure of the rcttꢀisomer of the cyclobutane derivative obtained was
established by NMR spectroscopy and Xꢀray diffraction analysis.
Key words: styryl dyes, styrylheterocycles, crown ethers, ammonium ions, complexation,
[2+2] photocycloaddition, cyclobutanes, Xꢀray diffraction study.
The selfꢀassembly of organic and bioorganic molecules
into supramolecular assemblies in solutions through relaꢀ
tive weak Hꢀbonds is widely known.1,2 At the same time,
the selfꢀassembly of the photosensitive compounds inꢀ
volving hydrogen bonding is poorly studied, while it is
of great interest due to possible photochemical reactions
within the supramolecular assemblies formed that are not
observed under other conditions. Crownꢀcontaining unꢀ
saturated compounds undergo selfꢀassembly in the presꢀ
ence of different cations.3 These photosensitive compounds
containing the C=C bond are subject to E—Zꢀisomerizaꢀ
tion, electrocyclization, and [2+2] photocycloaddition
(PCA). We suggested that a versatile approach to the selfꢀ
assembly of crownꢀcontaining unsaturated compounds
can make use of the primary ammonium groups incorꢀ
porated into the unsaturated compound itself or a photoꢀ
insensitive substrate. Such type of selfꢀassembly may be
illustrated by the example of the following supramolecuꢀ
lar structures. Bis(18ꢀcrownꢀ6)stilbene forms extremely
stable donor—acceptor complexes with the N,N´ꢀdi(amꢀ
monioalkyl) derivatives of viologen analogs that can serve
as fluorescent molecular sensors for the alkalineꢀearth
metal cations.4,5 18ꢀCrownꢀ6ꢀcontaining bisꢀstyryl dyes
behave as selective optical molecular sensors for diamꢀ
monioalkane ions;6 the stereospecific intramolecular PCA
reaction can proceed in the pseudosandwich headꢀtoꢀ
head complexes of dyes that formed to afford a single
isomer of a cyclobutane derivative.7 Due to the Hꢀbondꢀ
ing between the ammonium groups and the crownꢀether
fragments, the crownꢀcontaining styryl dyes having the
Nꢀammonioalkyl substituent in the heterocyclic residue
form stable headꢀtoꢀtail dimeric complexes wherein
efficient stereospecific autophotocycloaddition8 occurs.
Alternatively, on exposure to light, the formation of a
relatively stable cationꢀ"capped" complex occurs in the
Zꢀform of a dye with intramolecular coordination of
the ammonium group by the crownꢀether fragment.9 The
aboveꢀmentioned phototransformations result in considꢀ
erable hypsochromic shifts in the absorption spectra of
the unsaturated compounds, which can be used for the
design of the systems for optical recording of information.
Recently, we have shown10 that two yellow styryl
dyes of the 4ꢀpyridyl series, one of which contained the
Nꢀammoniopropyl substituent ((E)ꢀ1) and the second one
contained the fragment of 18ꢀcrownꢀ6 ((E)ꢀ2), formed a
sufficiently stable pseudodimeric complex (logK = 3.52)
in MeCN. Due to cooperative action of the binding of the
+
NH3 group of dye 1 with the crownꢀether fragment of
dye 2 and of the stacking interaction between the planar
conjugated fragments, the stereospecific PCA reaction
proceeds in complex (E)ꢀ1•(E)ꢀ2 to form a single isomer
of the cyclobutane derivative rcttꢀ3 (Scheme 1). The photoꢀ
reaction occurs under exposure to visible light due to the
effective intramolecular charge transfer in dyes (E)ꢀ1 and
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1893—1899, September, 2009.
1066ꢀ5285/09/5809ꢀ1955 © 2009 Springer Science+Business Media, Inc.

1956
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 9, September, 2009
Vedernikov et al.
(E)ꢀ2 responsible for considerable absorption in the visible
region (λmax ≈ 400 nm). Stereospecifity is achieved by the
headꢀtoꢀtail synꢀassembly of the chromophoric fragments
disposed one above the other in the pseudodimeric comꢀ
plex (E)ꢀ1•(E)ꢀ2, which favors the approach and parallel
orientation of their ethylene bonds.
in this complex, viz., 1,2,3,4ꢀtetrasubstituted cyclobutane,
was determined by H NMR spectroscopy and additionꢀ
ally confirmed by the Xꢀray diffraction data.
1
The synthesis of a styrylpyridinium quaternary salt with
Nꢀammoniopropyl substituent (E)ꢀ4 was carried out by
quaternization of styrylpyridine (E)ꢀ6 (see Ref. 11) with
3ꢀbromopropylammonium bromide followed by the anion
exchange (bromide by perchlorate) upon treatment with
perchloric acid (Scheme 2). The ethylenic bond in comꢀ
pound 4 has the Eꢀconfiguration according to the value of
JCH=CH equal to 16.2 Hz. The synthesis of 18ꢀcrownꢀ
6ꢀcontaining styrylpyridine (E)ꢀ5 have been described
earlier.12
Scheme 1
Scheme 2
In MeCN, styrylpyridines (E)ꢀ4 and (E)ꢀ5 demonꢀ
strate intense absorption in the nearꢀUV region with λmax
at 349 and 334 nm, respectively (Fig. 1, curves 1 and 2).
Such absorption shift, as compared with (E)ꢀ1 and (E)ꢀ2,
is caused undoubtedly by the absence of electronꢀdonatꢀ
ing substituents in the benzene ring of (E)ꢀ4 in conjugaꢀ
tion with chromophore, and by the presence of the
uncharged pyridine residue in (E)ꢀ5, which complicates
the intramolecular charge transfer from the benzene
fragment to the pyridine fragment of styrylpyridine, which
is responsible for the emergence of the longꢀwave absorpꢀ
tion band. UV irradiation of solutions of free dyes 4 and 5
only resulted in their reversible E—Zꢀisomerization to a
photoꢀsteadyꢀstate mixture of transꢀ and cisꢀisomers and,
on longꢀterm exposure, in the formation of negligible
amounts of the photodegradation products (NMR moniꢀ
toring). The absorption of a solution of a 1 : 1 mixture of
compounds (E)ꢀ4 and (E)ꢀ5 at their concentrations
of 5•10–5 mol L–1 differs insignificantly from the arithꢀ
metical sum of the absorption spectra of the individual
components, which suggests their weak interaction under
these conditions.
We assumed that efficient selfꢀassembly in a pseudoꢀ
dimeric complex occurs in the case of the components
having different substituents in the fragments that are
remote from the binding site built in the host—guest
mode. The nature of these substituents strongly influences
the spectral characteristics of the compounds. Conseꢀ
quently, the PCA reaction can be induced by light of
different wavelength. For example, PCA can be carried
out on exposure to UV light in cases where the ammoꢀ
nium and crownꢀcontaining unsaturated components are
colorless compounds. Such systems are of interest for the
design of phototropic systems for information recording
at the molecular level. Here we present the investigation
into the selfꢀassembly, structural features, and photoꢀ
chemical properties of a pseudodimeric complex of
unsubstituted styryl dye (E)ꢀ4 with 4ꢀstyrylpyridine (E)ꢀ5,
+
the former containing the terminal NH3 group in the
Nꢀsubstituent and the latter containing the fragment of
1
The H NMR study of the solution of a 1 : 1 mixture
18ꢀcrownꢀ6. The stereochemistry of the photocycloadduct
of (E)ꢀ4 and (E)ꢀ5 in MeCNꢀd3 at higher concentrations

[2+2] Photocycloaddition in a pseudodimeric complex Russ.Chem.Bull., Int.Ed., Vol. 58, No. 9, September, 2009 1957
ε•10–4/L mol–1 cm–1
Scheme 3
3
1
2
2
1
3
0
200
250
300
350
400 λ/nm
Fig. 1. The absorption spectra of styrylpyridines (E)ꢀ4 (1), (E)ꢀ5
(2), and the cyclobutane derivative rcttꢀ7 (3) (C = 5•10–5 mol L–1
,
MeCN).
(~1•10–3 mol L–1) showed noticeable change in the
chemical shifts of the majority of the protons of both
components compared to free dyes (E)ꢀ4, (E)ꢀ5, which is
analogous to the effects found previously10 in the system
(E)ꢀ1—(E)ꢀ2. For example, the signals for the methylene
groups of the crownꢀether fragment of compound (E)ꢀ5
are downfield shifted (up to ΔδH 0.09) upon mixing with
dye (E)ꢀ4, which provides evidence of the binding of the
+
18ꢀcrownꢀ6 fragment with the NH3 group. This fact is
caused by the electronꢀaccepting influence of this group
in the complex. Conversely, the signals for the ethylenic
protons and most of the aromatic protons of both compoꢀ
nents are upfield shifted (up to ΔδH –0.19) (Fig. 2). Such
spectral behavior suggests that the chromophoric fragꢀ
ments in complex (E)ꢀ4•(E)ꢀ5 that formed are predomiꢀ
nantly stacked due to the intermolecular stacking interacꢀ
tions of the conjugated systems (Scheme 3).
a
H(2´)
H(3), H(5)
Hb
1
H(6´)
H(2), H(6)
By means of H NMR titration, we determined the
value of the stability constant (logK) for pseudodimeric
complex (E)ꢀ4•(E)ꢀ5, which is equal to 3.47 0.05. This
value differs little from the value of the stability constant
for complex (E)ꢀ1•(E)ꢀ2 (vide supra), which suggests
the crucial contribution of the Hꢀbonding between the
ammonium group and the crown fragment to the stability
of such supramolecular systems and, conversely, sugꢀ
gests weak influence of the stacking interactions of the
chromophoric fragments of the components. Complex
(E)ꢀ4•(E)ꢀ5 was isolated as a solid by slow crystallization
of a solution of an equimolar mixture of components; its
stoichiometry (1 : 1) was confirmed by the data from
1H NMR spectroscopy and elemental analysis.
H(5´)
Ha
b
c
H(2´), H(6´)
H(3), H(5)
Hb
H(3´)—H(5´)
H(2), H(6)
Ha
+
NH3
The UV irradiation of a solution of a mixture of comꢀ
pounds 4 and 5 led to a significant decrease in the longꢀ
wave absorption intensity. The 1H NMR spectrum of
photolyzate displays, along with the signals for the minor
Eꢀ and Zꢀisomers of the starting compounds, a set of
8.5
8.0
7.5
7.0
δ
Fig. 2. The 1H NMR spectra (the region of aromatic protons) for
compound (E)ꢀ5 (a), the equimolar mixture of (E)ꢀ4 and (E)ꢀ5
(b), and compound (E)ꢀ4 (c) (C = 1•10–3 mol L–1, MeCNꢀd3,
30 °C).

1958
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 9, September, 2009
Vedernikov et al.
N(2)
signals suggesting the formation of a new product. The
absorption spectrum of this photoproduct isolated by crysꢀ
tallization is shown in Fig. 1 (curve 3). The absence of the
absorption in the longꢀwave spectral region evidences vioꢀ
lation of conjugation in the photoproduct.
C(9)
C(33)
O(4)
O(5)
O(3)
N(1)
C(10)
N(3)
H(3N)
The structure of the photoproduct was established
based on the analysis of the COSY and NOESY homoꢀ
and heteronuclear spectra. The distinctive feature of these
spectra is the disapperance of the ethylenic proton signals
in the lowꢀfield region and the appearance of four new
oneꢀproton signals in the 1H NMR spectrum in the region
of δ 4.7—4.9 (Fig. 3). The positions and shapes of these
signals (all doublets of doublets) suggest the formation of
a nonsymmetric cyclobutane derivative rcttꢀ7 (an ABCD
spin system with 3JcisꢀH ,H = 10.0 Hz, 3JtransꢀH ,Hc = 7.5 Hz,
C(32)
O(2)
N(3A)
O(6)
O(1)
O(2´)
Fig. 4. The structure of the principal crystal component of
rcttꢀ7•0.5HClO4•C6H6•H2O. The nonhydrogen atoms are
depicted as thermal ellipsoids with 40% probability. The
Hꢀbonds are shown as dashed lines. The atom N(3A) was
obtained through symmetry operation.
a
b
b
3
3JcisꢀH ,H = 10.1 Hz, and JtransꢀH ,H = 8.0 Hz), which
resultcedd from PCA in the psedudaodimeric complex
(E)ꢀ4•(E)ꢀ5 (see Scheme 3). The 13C NMR spectrum of
the photoadduct also contains four new signals in the
typical region of δ 42—47, which correspond to the carꢀ
bon atoms of the nonsymmetric cyclobutane ring (see
Experimental). Note that the charachteristics of the sigꢀ
nals for the cyclobutane ring in the isomer 7 obtained are
very close to analogous signals of rcttꢀ3 (see Ref. 10). As
in the system (E)ꢀ1—(E)ꢀ2, the headꢀtoꢀtail synꢀarrangeꢀ
ment of the conjugated fragments of compounds (E)ꢀ4
and (E)ꢀ5 preꢀconditions the chromophoric fragments of
the components for the PCA reaction to form a single
isomer of the cyclobutane derivative among 16 theoretiꢀ
cally possible. Thus, the cooperative effect of two types
of weak intermolecular interactions in the stabilization of
the supramolecular complex (E)ꢀ4•(E)ꢀ5, viz., complexaꢀ
tion of the NH3+ group with the crownꢀether fragment and
stacking interactions of the planar conjugated fragments,
provides superior stereospecifity of the photoprocess.
We succeeded in determining the structure of the
cyclobutane derivative rcttꢀ7 that formed by Xꢀray difꢀ
fraction analysis. The structure of the principal compoꢀ
nent of the crystal is shown in Fig. 4. The pyridine resiꢀ
dues of two neighboring cyclobutane molecules linked
through the symmetry center are joined by the Hꢀbond
C5N(3)...H(3N)...N(3A)C5 to form the protonated pair.
The isotropic refinement of the H(3N) atom shows that
it is formally localized at the crystal symmetry center,
although its true position should obviously be shifted with
equal probability towards either the N(3) or N(3A) atom,
since the distance N(3)...H(3N), equal to 1.326(4) Å, is
too large for the ordinary bond H—N+Py. Thus, the crysꢀ
tal of the cyclobutane derivative studied is a protonated
form of rcttꢀ7•0.5HClO4, which is probably formed as a
result of partial dissociation of the ammonium groups
in other molecules of rcttꢀ7. Two perchlorate anions,
Cl(1)O4– and Cl(2)O4–, have complete populations of the
positions; the third anion, Cl(3)O4–, is disordered around
the crystal symmetry center, which is related to the other
system of centers, and has population of the positions
0.50. In addition to the principal component, the solvate
molecules of benzene and water were found in the crysꢀ
talline lattice. The water molecule O(1W) forms the
relative weak Hꢀbond with the oxygen atom of the perꢀ
chlorate anion O(1W)—H(1W)...O(23)—Cl(2)O3–: the
distance H(1W)...O(23) is 2.00(4) Å, the angle at the
hydrogen atom is ~166°. The second hydrogen atom of
the water molecule O(1W) is not located. Apparently, it
can be directed towards the O(11) or O(13) atom of
the Cl(1)O4– anion by forming weak Hꢀbonds with it: the
distances O(1W)...O(11) and O(1W)...O(13) are equal to
3.16 and 2.98 Å, respectively.
The arrangement of four substituents in the cycloꢀ
butane ring of compound 7 directly confirms the conꢀ
clusions drawn on the basis of the NMR spectral data. The
+
N(1)H3 group in the dication forms the intramolecular
coordination with the fragment of 18ꢀcrownꢀ6 of the
neighboring cisꢀsubsituent through three bifurcate Hꢀbonds
N+—H...O; the corresponding distances H...O being in
the range of 2.05(5)—2.34(4) Å, the angles at the H atoms
being 123—155°. Due to the "contracting" effect of the
ammonium group bound in the complex, the dihedral
angle between the planes of the pyridine ring N(2)C5
and the benzene ring of the benzocrown fragment is 35°,
whereas the angle between the planes of the pyridine ring
N(3)C5 and the phenyl substituent cisꢀoriented toward
N(3)C5 is 63°. The carbonꢀcarbon bond lengths in the
Hc
Hd
Hb
Ha
5.0
4.9
4.8
4.7
δ
Fig. 3. The 1H NMR spectrum in the region of cyclobutane
protons of the derivative rcttꢀ7 (DMSOꢀd6, 30 °C).

[2+2] Photocycloaddition in a pseudodimeric complex Russ.Chem.Bull., Int.Ed., Vol. 58, No. 9, September, 2009 1959
2ꢀ(2,3,5,6,8,9,11,12,14,15ꢀdecahydroꢀ1,4,7,10,13,16ꢀbenzoꢀ
hexaoxacyclooctadecynꢀ18ꢀyl)]pyridine ((E)ꢀ5)12 were prepared
according to known procedures.
cyclobutane ring vary in the range of 1.543(5)—1.594(6) Å
and the CAr/Py—C(cyclobutane) bond lengths vary in the
range of 1.498(5)—1.513(6) Å. The endocyclic bond
angles C(9)—C(10)—C(32)—C(33) in the cyclobutane
ring are in the range of 88.4(3)—90.2(3)°, the torsion
angles in this ring are from –14 to 14°, i.e., the cyclobutane
ring has a nonplanar conformation. This fact distinguishes
the nonsymmetric isomer of rcttꢀ7 from the centrosymꢀ
metric 1,2,3,4ꢀtetrasubstituted rcttꢀisomers of the cycloꢀ
butane derivatives obtained by us previously8,12,13 by the
solidꢀphase autophotocycloaddition reaction in the styryl
dyes and neutral styrylheterocycles. In the crystal, the
cyclobutane rings of the centrosymmetric isomers have
the ideal planar conformation, while in solution their
conformational mobility is apparently increased.
Thus, we have established that the styryl dye containꢀ
ing the Nꢀammoniopropyl substituent can form a stable
headꢀtoꢀtail pseudodimeric complex with the neutral
18ꢀcrownꢀ6ꢀcontaining 4ꢀstyrylpyridine in solution due to
the binding of the ammonium group with the crown fragꢀ
ment through Hꢀbonding. In the complex, the ethylenic
bonds of the molecules are pulled together due to the
advantageous stacking interactions caused by the secondꢀ
ary orbital pzꢀinteractions of the conjugated fragments.
synꢀOrientation of the conjugated fragments in the comꢀ
plex results in the stereospecific [2+2] photocycloaddition
reaction to form the single rcttꢀisomer of the cyclobutane
derivative the structure of which was determined by Xꢀray
diffraction analysis. Such pseudodimeric complexes can
be used for creation of the phototropic systems for inforꢀ
mation recording and storage at the molecular level.
1ꢀ(3ꢀAmmoniopropyl)ꢀ4ꢀ[(E)ꢀstyryl]pyridinium diperchlorate
((E)ꢀ4). A mixture of 4ꢀstyrylpyridine (E)ꢀ6 (0.23 g, 1.25 mmol)
and 3ꢀbromopropylammonium bromide (0.82 g, 3.75 mmol)
was heated in the dark for 4 h at 150 °C (oil bath), dissolved with
heating in anhydrous EtOH (3 mL) and then cooled to 5 °C.
The precipitate was filtered off, washed with chloroform (3 mL)
and dried in air. The dibromide salt of the dye (0.23 g, 0.57
mmol) was obtained as a paleꢀyellow powder. The dibromide
salt was dissolved with heating in anhydrous EtOH (4 mL) and
70% perchloric acid (0.20 mL, 2.3 mmol) was added. The mixture
was cooled to 5 °C. The precipitate that formed was filtered off,
washed with cold anhydrous EtOH (3 mL) and dried in vacuo at
80 °C. Compound (E)ꢀ4 (0.18 g) was obtained in the total yield
of 34% as paleꢀyellow crystals. M.p. 232—234 °C (decomp.).
Found (%): C, 43.80; H, 4.45; N, 6.37. C16H20Cl2N2O8.
1
Calculated (%): C, 43.75; H, 4.59; N, 6.38. H NMR (25 °C,
DMSOꢀd6), δ: 2.20 (m, 2 H, CH2CH2N); 2.86 (m, 2 H,
CH2NH3); 4.58 (t, 2 H, CH2N, J = 6.8 Hz); 7.47 (t, 1 H, H(4´),
J = 7.0 Hz); 7.51 (t, 2 H, H(3´), H(5´), J = 7.0 Hz); 7.56 (d,
1 H, CH=CHPy, J = 16.2 Hz); 7.77 (d, 2 H, H(2´), H(6´),
J = 7.0 Hz); 7.78 (br.s, 3 H, NH3); 8.05 (d, 1 H, CH=CHPy,
J = 16.2 Hz); 8.30 (d, 2 H, H(3), H(5), J = 6.8 Hz); 8.96 (d,
2 H, H(2), H(6), J = 6.8 Hz). 13C NMR (30 °С, DMSOꢀd6), δ:
28.39 (СН2СН2N); 35.61 (СН2NH3); 56.69 (CН2N); 123.18
(CH=CHPy); 123.98 (С(3), С(5)); 128.05 (С(2´), С(6´));
129.01 (С(3´), С(5´)); 130.37 (С(4´)); 134.99 (С(1´)); 140.94
(CH=CHPy); 144.22 (С(2), С(6)); 153.02 (С(4)).
Complex (E)ꢀ4•(E)ꢀ5. A solution of dye (E)ꢀ4 (10.0 mg,
22.7 mol) and compound (E)ꢀ5 (10.0 mg, 24.0 mol) in MeCN
(~5 mL) was slowly saturated with vapor of a ~1 : 1 mixture of
benzene and dioxane at room temperature in the dark until a
precipitate formed, which was separated by decantation and
dried in vacuo at 80 °C. Complex (E)ꢀ4•(E)ꢀ5 (8.0 mg, 41%)
was obtained as a paleꢀyellow powder. M.p. 168—170 °C.
Found (%): C, 54.21; H, 5.59; N, 4.48. С39Н49Сl2N3O14•0.5H2O.
Calculated (%): C, 54.23; H, 5.84; N, 4.87.
Experimental
Melting points (uncorrected) were measured in a capillary
on a MelꢀTemp II instrument. Elemental analysis was performed
at the laboratory of microanalysis of the A. N. Nesmeyanov
Institute of Ogranoelement Compounds of the Russian Academy
of Sciences (Moscow). 1Н and 13C NMR spectra were recorded
on a Bruker DRXꢀ500 (500.13 and 125.76 MHz, respectively)
spectrometer in DMSOꢀd6 and MeCNꢀd3 at 25—30 °С using
1ꢀ(3ꢀAmmoniopropyl)ꢀrꢀ4ꢀ[cꢀ2ꢀ(2,3,5,6,8,9,11,12,14,15ꢀ
decahydroꢀ1,4,7,10,13,16ꢀbenzohexaoxacyclooctadecynꢀ18ꢀyl)ꢀ
tꢀ4ꢀphenylꢀtꢀ3ꢀ(4ꢀpyridyl)cyclobutyl]pyridinium diperchlorate
(rcttꢀ7). A solution of dye (E)ꢀ4 (7.7 mg, 17.5 mol) and
compound (E)ꢀ5 (8.0 mg, 19.3 mol) in MeCN (15 mL) was
irradiated with stirring in a quartz cell (5 cm × 4.5 cm × 1 cm)
from the side of its largest face by the light of L8253 Xe lamp
(Hamamatsu, peak power, A9616ꢀ05 light filter (transmission
at 320—420 nm), the light source distance is 10 cm). According
the solvent signal as the internal standard (δ 2.50 and 1.96,
H
respectively, δ 39.43 for DMSOꢀd6). Chemical shifts were
C
measured with the accuracy of 0.01 ppm and the spinꢀspin
coupling constants were measured with the accuracy of 0.1 Hz.
Twoꢀdimensional 1H—1H COSY and NOESY homonuclear
spectra and 1H—13C COSY (HSQC and HMBC) heteronuclear
spectra were used for the assignment of the signals for the
hydrogen and carbon atoms. 2D Experiments were performed
using default parameters included in the software package of
the Bruker company. UV spectra were recored on a Shimadzu
UVꢀ3101PC spectrophotometer in the region of 200—600 nm
with a spacing of 0.5 nm (MeCN, 1 cm quartz cell, room
temperature).
1
to the H NMR spectral data, the photolyzate contained comꢀ
pounds (E)ꢀ4, (Z)ꢀ4, (E)ꢀ5, (Z)ꢀ5, and rcttꢀ7 in molar ratios of
2.2 : 2.9 : 1 : 5.6 : 3.3 and 0.3 : 0.9 : 1 : 1.6 : 8.0 upon irradiation
of the solution for 2 and 10 h, respectively. The reaction mixture
was concentrated to ~5 mL and slowly saturated with vapor of a
~2 : 1 mixture of benzene and dioxane at room temperature
until white crystals formed, which were separated by decantation
and dried in vacuo at 80 °C. Derivative rcttꢀ7 was obtained in a
yield of 12.0 mg (80%). M.p. 224—227 °C. Found (%): C, 53.83;
H, 5.98; N, 4.86. С39Н49Сl2N3O14•H2O. Calculated (%): C, 53.67;
H, 5.89; N, 4.82. 1H NMR (22 °C, DMSOꢀd6), δ: 2.10 (m, 2 H,
CH2CH2N); 2.26 (m, 1 H, CHH´NH3); 2.37 (m, 1 H, CHH´NH3);
3.63 (s, 4 H, 2 CH2O); 3.65, 3.71 (both m, 4 H each, 4 CH2O);
3ꢀBromopropylammonium bromide and 70% perchloric
acid (Aldrich) were used without additional purification. 4ꢀ[(E)ꢀ
1ꢀPhenylꢀ2ꢀvinyl]pyridine ((E)ꢀ6)11 and 4ꢀ[(E)ꢀ1ꢀphenylꢀ

1960
Russ.Chem.Bull., Int.Ed., Vol. 58, No. 9, September, 2009
Vedernikov et al.
3.78 (m, 4 H, 2 CH2CH2OAr´); 3.92 (m, 2 H, 3´ꢀCH2OAr´);
4.08 (m, 2 H, 4´ꢀCH2OAr´); 4.53 (t, 2 H, CH2N, J = 5.9 Hz);
4.66 (dd, 1 H, CHPy″, J = 10.1 Hz, J = 7.5 Hz); 4.72 (dd,
1 H, CHAr´, J = 10.0 Hz, J = 7.5 Hz); 4.83 (dd, 1 H, CHPy,
J = 10.0 Hz, J = 8.0 Hz); 4.91 (dd, 1 H, CHAr′″, J = 10.1 Hz,
J = 8.0 Hz); 6.50 (d, 1 H, H(2´), J = 1.4 Hz); 6.93 (d, 1 H, H(5´),
J = 8.4 Hz); 7.06 (dd, 1 H, H(6´), J = 8.4 Hz, J = 1.4 Hz); 7.10
(br.t, 1 H, H(4′″), J = 7.1 Hz); 7.16 (br.s, 3 H, NH3); 7.20 (br.t,
2 H, H(3′″), H(5′″), J = 7.6 Hz); 7.22 (d, 2 H, H(3″), H(5″),
J = 5.0 Hz); 7.23 (br.d, 2 H, H(2′″), H(6′″), J = 7.7 Hz); 7.95
(d, 2 H, H(3), H(5), J = 6.6 Hz); 8.35 (d, 2 H, H(2″), H(6″),
J = 5.0 Hz); 8.78 (d, 2 H, H(2), H(6), J = 6.6 Hz). 13C NMR
(30 °С, DMSOꢀd6), δ: 28.11 (CH2CH2N); 35.64 (CН2NH3);
42.75 (CHPy); 43.60 (CHAr´); 46.74 (CHPy″); 46.91 (CHAr′″);
57.08 (CH2N); 67.06 (4´ꢀCH2OAr´); 67.16 (3´ꢀCH2OAr´); 68.24
(CH2CH2OAr´); 68.41 (CH2CH2OAr´); 68.53 (2 CH2O); 69.12
(CH2O); 69.19 (CH2O); 69.56 (CH2O); 69.69 (CH2O); 111.60
(С(5´)); 111.66 (С(2´)); 120.35 (С(6´)); 123.58 (С(3″), С(5″));
126.36 (С(4′″)); 127.23 (С(3), С(5)); 127.84 (С(2′″), С(6′″));
127.96 (С(3′″), С(5′″)); 131.03 (C(1´)); 138.60 (C(1′″)); 143.06
(С(2), С(6)); 145.46 (С(4´)); 146.29 (С(3´)); 148.16 (С(2″),
С(6″)); 150.01 (С(4″)); 161.06 (С(4)).
Table 1. Crystal parameters and Xꢀray diffraction data for
rcttꢀ7•0.5HClO4•C6H6•H2O
Parameter
rcttꢀ7•0.5HClO4•C6H6•H2O
Molecular formula
Molecular weight/g mol–1
C45H57.5Cl2.5N3O17
1001.07
Crystal system
Space group
a/Å
b/Å
c/Å
α/deg
β/deg
Triclinic
P–1
9.8403(7)
13.8984(10)
17.5560(12)
83.250(2)
85.424(2)
78.151(2)
2329.8(3)
2
γ/deg
3
V/Å
Z
dcalc/g cm–3
1.427
F(000)
1021
μ(MoꢀKα)/mm–1
Crystal size/mm
Scan mode/region in θ/deg
Intervals of reflection indexes
0.245
0.22×0.12×0.08
ω/1.51—29.00
–13 ≤ h ≤ 13,
–18 ≤ k ≤ 17,
–23 ≤ l ≤ 23
22393
1H NMR titration was performed on a Bruker DRXꢀ500
spectrometer in MeCNꢀd3 at 30 °C. In the course of titraꢀ
tion, the concentration of compound (E)ꢀ5 was maintained at
~1•10–3 mol L–1 and the concentration of compound (E)ꢀ4
ranged from 0 to 3•10–3 mol L–1. The stability constant for
the complex was measured by the change in the signal positions
for the protons of the molecule of (E)ꢀ5 depending on the
ratio C5/C4. The ΔδH values were measured with the accuracy of
0.001 ppm. The HYPNMR program was used for calculation
of the constant.14
Number of measured reflections
Number of independent
12237
reflections with Rint = 0.0743
Number of reflections with I > 2σ(I)
Number of refinement parameters
4525
665
RꢀFactors over I > 2σ(I)
over all reflections
GOOF
R1 = 0.0849, wR2 = 0.2036
R1 = 0.2163, wR2 = 0.2520
0.888
Xꢀray diffraction study. The colorless single crystals of the
cyclobutane derivative rcttꢀ7•0.5HClO4 were obtained by slow
saturation of an acetonitrile solution of rcttꢀ7 with vapor of a
mixture of benzene and dioxane at room temperature. The single
crystal of the complex was placed on a Bruker SMARTꢀCCD
diffractometer under the stream of cold nitrogen (Т = 120.0(2) К),
where the measurements of the unit cell parameters and
experimental intensities of reflections at the MoꢀKα radiation
(λ = 0.71073 Å, graphite monochromator, ωꢀscanning techꢀ
nique) were performed. The data interpretation was performed
using the SAINT program.15 The structure was solved by direct
methods and refined by the leastꢀsquares method based on F2
in the anisotropic approximation for all nonhydrogen atoms,
except for the oxygen atoms of the anion Cl(3)O4–. The position
of this anion is strongly disordered, therefore we succeeded in
determining only two its rotamers with the 0.56 : 0.44 ratio of
the populations of the positions (rotation around the center
of mass). Note that numerous weak peaks of the residual electron
density were observed around the Cl(3) atom in the differential
Fourier syntheses, which evidence the presence of its other
positions with minimum populations. However, attempts to
determine these peaks of electron density as the oxygen atoms
with partial populations of the positions failed. The fragment of
the macrocycle O(2)—C(19) is disordered over two conforꢀ
mations of the polyether chain with the 0.64 : 0.36 ratio of
populations of the positions. The above described irregularities
of the anion and the macrocycle strongly decrease the accuracy
of the Xꢀray diffraction experiment. The most of the hydrogen
atoms at the carbon atoms were revealed as a result of the
Residual electron density
(min/max)/e Å–3
–0.553/0.664
differential Fourier synteses, but afterwards their positions were
calculated geometrically and then refined using the riding model.
The hydrogen atoms of the NH3 group were calculated geoꢀ
+
metrically and refined isotropically using the soft geometric
constraints (SADI command). The position of the H(1W) atom
of the water molecule O(1W) was found from the Fourier synꢀ
theses and refined isotropically. The second hydrogen atom of
this molecule was not localized. The Xꢀray diffraction data,
crystallographic parameters, and the results of structure refineꢀ
ment by the leastꢀsquares method are given in Table 1. All
calculations were performed according to the SHELXTLꢀPlus
program.16 The coordinates of the atoms and other experimental
data have been deposited at the Cambridge Crystallographic
Data Center* (No. 696184).
The authors are grateful to P. S. Loginov for his help
in the synthesis of compounds.
This work was performed under financial support
of the Russian Foundation for Basic Research (Projects
Nos. 06ꢀ03ꢀ32434, 06ꢀ03ꢀ33162, 08ꢀ03ꢀ00031, and
* CCDC, 12 Union Road, Cambridge CB21EZ, UK (fax:
(+44)1223 33 6033; eꢀmail: deposit@ccdc.cam.ac). The copy of
data can be received from the authors.

[2+2] Photocycloaddition in a pseudodimeric complex Russ.Chem.Bull., Int.Ed., Vol. 58, No. 9, September, 2009 1961
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09ꢀ03ꢀ00444), the Division of Chemistry and Materials
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No. 7), and the Royal Society of Chemistry of the United
Kingdom (Personal Grants for L. G. Kuz´mina and
J. A. K. Howard).
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