Synthesis of 2-(substituted methyl)quinolin-8-ols and their complexation with Sn(II)

Article abstract of DOI:10.1039/a908636f

A new method for the synthesis of 2-(substituted methyl)quinolin-8-ol is described. 2-Methyl-8-methoxyquinoline 3 was prepared as a key building block; lithiation of 3 with LDA and subsequent addition of alkyl halides followed by reaction in 48% HBr afforded the 2-alkylquinolin-8-ols 6a,b. On the other hand, the use of alkanediyl dihalides as the electrophile gave bis(quinolin-8-ol) derivatives containing an alkyl bridge 12. The complexation of 2-alkyl-8-hydroxyquinolines with SnCl₂ in alkaline methanol produced the bis(quinoIin-S-ol) complexes 13a,b, whereas in the case of the bis(quinolin-S-ol) derivatives, intractable solids were obtained. The molecular structure of 13b was elucidated by X-ray analysis. The Royal Society of Chemistry 2000.

Full text of DOI:10.1039/a908636f

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Synthesis of 2-(substituted methyl)quinolin-8-ols and their
complexation with Sn(II)
Chitoshi Kitamura,* Naoyuki Maeda, Noboru Kamada, Mikio Ouchi and Akio Yoneda
1
Department of Applied Chemistry, Faculty of Engineering, Himeji Institute of Technology,
Shosha 2167, Himeji 671-2202, Japan
Received (in Cambridge, UK) 29th October 1999, Accepted 17th January 2000
A new method for the synthesis of 2-(substituted methyl)quinolin-8-ol is described. 2-Methyl-8-methoxyquinoline 3
was prepared as a key building block; lithiation of 3 with LDA and subsequent addition of alkyl halides followed by
reaction in 48% HBr afforded the 2-alkylquinolin-8-ols 6a,b. On the other hand, the use of alkanediyl dihalides as
the electrophile gave bis(quinolin-8-ol) derivatives containing an alkyl bridge 12. The complexation of 2-alkyl-8-
hydroxyquinolines with SnCl2 in alkaline methanol produced the bis(quinolin-8-ol) complexes 13a,b, whereas in
the case of the bis(quinolin-8-ol) derivatives, intractable solids were obtained. The molecular structure of 13b was
elucidated by X-ray analysis.
8-methoxy-2-methylquinoline 3 as a key building block. How-
Introduction
ever, few practical methods for the synthesis of 3 have been
As an N,O-bidentate ligand, quinolin-8-ol is used for the iden-
reported so far.8,9 We have succeeded in a simple and convenient
tification of metals.1 Its applications as a component for
preparation of 3 by reaction of 2 with iodomethane in acetone
in the presence of K2CO3 in 90% yield (Scheme 1). Reaction of
molecular electronic devices2 and as a new supramolecular
motif3 are of current interest. Recently, we determined the
unique nonplanar two-blade-screw structure of the bis(2-
methylquinolin-8-olato)tin() complex 1 by X-ray analysis.4
The interesting structural characteristics led us to investigate
the steric effect of the substituent at the 2-position in the
quinolin-8-olate ligand. However, to date, there have been only
a few reports on the preparation of quinolin-8-ols possessing a
substituent at the 2-position.5 In recent years, we have studied
the synthesis of new 2-substituted-quinolin-8-ols and their
complexes. It is known that a carbanion derived from 2-methyl-
quinoline by deprotonation reacts with electrophiles to give
the corresponding substituted methyl derivatives.6 Therefore
we intended to adopt the methodology for the synthesis of
OH-protected quinolin-8-ol. We report here a new method
for the preparation of 2-(substituted methyl)quinolin-8-ol
Scheme 1
derivatives, using 2-methylquinolin-8-ol 2 as the starting
material, and their complexation with Sn().
3 with LDA generated the carbanion 4 as an intermediate, and
subsequent addition of iodomethane or 1-bromopropane pro-
duced the 2-(substituted methyl)quinolines 2-ethyl-8-methoxy-
quinoline 5a or 2-butyl-8-methoxyquinoline 5b in 45 and 73%
yields, respectively (Scheme 1). It is known that treatment of
2-methylquinolines with a strong base such as LDA yields
stable quinolin-2-ylmethanide carbanions such as 4. However,
use of n-butyllithium as a nucleophilic strong base affords
Results and discussion
We needed a temporary protecting group for the quinolinol that
was stable under basic conditions and that could be removed by
acidic reagents. A methyl group was introduced as a protecting
group because 8-methoxyquinoline can be easily converted to
quinolin-8-ol with HBr under reflux.7 We therefore regarded
DOI: 10.1039/a908636f
J. Chem. Soc., Perkin Trans. 1, 2000, 781–785
This journal is © The Royal Society of Chemistry 2000
781

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a butyl adduct as the main product because n-butyllithium
attacks the carbon atom of quinoline at the 2-position. These
results suggest that the development of the synthesis of a
variety of 2-(substituted methyl)quinolines could be promis-
ing with other electrophiles. Deprotection by treatment of 5a,b
with 48% HBr under reflux furnished the corresponding
quinolin-8-ol derivatives, 2-ethylquinolin-8-ol 6a5 and 2-n-
butylquinolin-8-ol 6b5 in 52 and 77% yield, respectively
(Scheme 1). This synthetic path has offered a simple method for
synthesis of 2-(substituted methyl)quinolin-8-ols.
because they had the same Rf values, and so we abandoned
the isolation of 9. As Jones and Russell had reported that the
ethylene-bridged bis-quinoline compound was formed in the
presence of oxygen,11 we prepared the bis(8-methoxyquinoline)
derivative with the ethylene spacer 8 by coupling with an oxidiz-
ing reagent. Treatment of 3 with LDA followed by addition of
CuCl2 yielded the homo-coupling product 8 in 18% yield. The
bis(8-methoxyquinoline) derivative 8 was then heated with 48%
HBr to give a bis(quinolin-8-ol) derivative 10 in 80% yield
(Scheme 4). In order to synthesize a bis(quinolin-8-ol) deriv-
Interestingly, quenching of the carbanion 4 with trimethyl-
silyl chloride gave a complex mixture, and only 2-bis(trimethyl-
silyl)methyl-8-methoxyquinoline 7 could be isolated (Scheme
2). Although we tried various reaction conditions (different
Scheme 2
concentrations of LDA and trimethylsilyl chloride; different
temperatures and times), mono- and tris(trimethylsilyl)methyl-
quinolines were never obtained. This result seems strange since,
in the case of 2-methylpyridine, mono-, bis- and tris(trimethyl-
silyl) compounds can be prepared according to the proportion
of base and electrophile added.10 Although the oxygen atom
of 8-methoxyquinoline is probably involved in lithiation and dis-
proportionation of the carbanion, we were not able to explain
this result.
Scheme 4
ative containing a longer linkage than ethylene, we carried out
the reaction with a longer alkanediyl dihalide. The action of 3
on LDA followed by addition of 1,4-dibromobutane afforded
only the bis(8-methoxyquinoline) derivative with a hexamethyl-
ene spacer 11 in 73% yield; deprotection with 48% HBr sub-
sequently yielded the bis(quinolin-8-ol) derivative 12 in 95%
yield (Scheme 5).
Next we tried the synthesis of other 2-(substituted methyl)-
quinoline compounds. The bis(quinolin-8-ol) derivative is a
prospective metallo-supramolecular ligand.3 However, the
complexes of quinolin-8-ol with many metal ions have not been
utilized in the field of metallo-supramolecular chemistry since
they are formed in the trans-planar conformation. On the other
hand, the bis(quinolin-8-olato)tin() complex has a non-
planar screw-like structure.4 Therefore, the tin() complex of the
bis(quinolin-8-ol) derivative seems a more likely candidate for
a new supramolecular architecture such as a neutral double-
stranded helix. We therefore attempted the synthesis of
bis(quinolin-8-ol) derivatives by use of alkanediyl dihalides as
the electrophile in the reaction depicted in Scheme 1. First
we performed the reaction of the carbanion derived from 3
and LDA with 1,2-dibromoethane (Scheme 3). However, we
Scheme 5
We examined the complexing ability of the prepared
quinolin-8-ol molecules as ligands with Sn(). Reaction of
quinolinolates derived from 5a,b with SnCl2 produced the stable
yellow solids 13a,b in 69 and 35% yields, respectively (Scheme 6).
In contrast, complexation of the bis(quinolin-8-ol) derivatives
Scheme 3
gained a mixture of two products, the ethylene-bridged bis-
(8-methoxyquinoline) 8 (homo-coupling product) and the
tetramethylene-bridged bis(8-methoxyquinoline) 9 (substitu-
1
tion product), which were identified from their H NMR and
MS spectra. We repeated the reaction carefully but still failed
to isolate 9 exclusively. Separation of 8 and 9 was impossible
Scheme 6
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[138.2(2)Њ] and O–Sn–O [96.0(2)Њ] bond angles due to the effect
of the lone pair of electrons on Sn(), indicating the presence of
axial asymmetry.4 The dihedral angle between the two ligands
is nearly vertical at 85.9Њ. The molecular structure of the
bis(quinolin-8-olato)tin() fragment in 13b was almost identical
with that of 1. The effect of one lone pair of electrons was
1
observed in the H NMR spectrum; thus the signals of the
methylene protons at C(10) and C(11) exhibited two broad sing-
lets at 2.02 and 3.34 ppm, respectively. The alkyl group of
C(11), C(12) and C(13) is almost perpendicular to the plane
of the quinoline and C(10). The orientation of the two alkyl
groups looks like part of a double helix. The intermolecular
distances for C(10)–C(10A), C(11)–C(11A), C(12)–C(12A) and
C(13)–C(13A) are 7.35, 8.68, 7.30 and 9.37 Å, respectively. The
almost equal length of C(10)–C(10A) and C(12)–C(12A)
suggests that the complex with longer alkyl chains may form
alkyl double-helicates.
Conclusion
We have presented a new method for the synthesis of 2-alkyl-
quinolin-8-ols and bis(quinolin-8-ol) derivatives with alkyl
linkages. The method would be useful in preparation of other
quinolin-8-ols substituted at the 2-position. The complexation
chemistry of the prepared quinolin-8-ols was also examined.
The bis(quinolin-8-ol)–Sn() complexes were difficult to iden-
tify. The Sn() complex of 2-butylquinolin-8-ol was character-
ized by X-ray analysis and showed a unique structure like part
of a double helix. Bis(quinolin-8-olato)tin() may now become
a new component in metallo-supramolecular chemistry.
Experimental
All reactions were carried out under a nitrogen atmosphere
unless indicated otherwise. Mps were determined on a Yanaco
Melting Point apparatus and are uncorrected. 1H NMR spectra
were recorded on a Bruker DRX500 FT spectrometer at 500
MHz or on a JEOL EX270 FT spectrometer at 270 MHz,
respectively. Chemical shifts are given in ppm; coupling con-
stants, J, are quoted in Hz. Electron impact mass spectra were
obtained at 70 eV on a Shimadzu QP-1000EX or a Shimadzu
GC/MS-QP5000 by a direct-inlet system. Elemental analysis
was carried out on a Yanaco MT-5 CHN recorder. High
resolution mass determinations (HRMS) were obtained on a
Shimadzu Kratos Concept 1s mass spectrometer. THF was
distilled from LiAlH4 prior to use. 1.5 M LDAؒTHF in cyclo-
hexane was purchased from Aldrich. All other reagents were
used without purification.
Fig. 1 Molecular structure of 13b showing 50% probability displace-
ment ellipsoids, in (a) side view and (b) top view. H atoms have been
omitted for clarity.
10 and 12 with Sn() gave yellow solids, but we could not iden-
tify them by NMR, MS and elemental analysis because the
solids obtained were insoluble in any organic solvents, and were
slightly inflammable.
A polymeric complex containing the bis(quinolin-8-ol)
derivative and Sn(), such as 14, is probably formed under the
2-Methyl-8-methoxyquinoline (3)8
To a mixture of 2-methylquinolin-8-ol (8.01 g, 50.3 mmol) and
K2CO3 (39.5 g, 286 mmol) in acetone (100 ml), a solution of
iodomethane (11.4 g, 80.1 mmol) in acetone (20 ml) was added.
In the dark, the reaction mixture was stirred at rt for 12 h. After
filtration, the resulting solution was evaporated. Short column
chromatogaphy on silica gel with chloroform and recrystal-
lization from hexane–AcOEt (5:1) gave 3 (7.84 g, 90%) as a
white solid; mp 127–128 ЊC (lit.,8 122–124 ЊC); δH (270 MHz,
CDCl3) 2.80 (s, 3H, CH3), 7.40 (d, 1H, J 8.6, 3-quinH), 7.49
(dd, 1H, J 7.9 and 7.6, 6-quinH), 7.58 (dd, 1H, J 7.6 and 1.3,
7-quinH), 7.80 (dd, 1H, J 7.9 and 1.3, 5-quinH), 8.01 (d, 1H,
J 8.6, 4-quinH) (Anal. Calcd for C11H11NO: C, 76.28; H, 6.40;
N, 8.09. Found: C, 76.06; H, 6.52; N, 8.01%).
conditions we used. To avoid this troublesome characterization,
the design and synthesis of soluble bis(quinolin-8-ol) ligands
are required. Fortunately, we succeeded in our X-ray analysis of
13b. The molecular structure showed some interesting features
(Fig. 1). Complex 13b has a non-planar, two-bladed conform-
ation and a C2 axis lying on the bisectors of the N–Sn–N
2-Ethyl-8-methoxyquinoline (5a)
To an ice-cooled solution of 3 (1.73 g, 10.0 mmol) in THF (20
ml), 1.5 M LDAؒTHF in cyclohexane (10 ml) was added drop-
wise, and the mixture was stirred for 1 h at 0 ЊC. Iodomethane
(2.14 g, 15.1 mmol) was then added dropwise. After removal of
J. Chem. Soc., Perkin Trans. 1, 2000, 781–785
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the ice-bath, the reaction mixture was allowed to warm to rt
and was then stirred for 2 h. The resulting mixture was poured
into water, extracted with chloroform, washed with brine, and
dried over Na2SO4. After removal of the solvent, the residue
was chromatographed on silica gel using hexane–AcOEt (2:1)
and recrystallized from hexane to afford 5a (835 mg, 45%) as a
pale yellow solid; mp 70–71 ЊC; δH (270 MHz, CDCl3) 1.40 (t,
3H, J 7.6, CH3), 3.08 (q, 2H, J 7.6, CH2), 4.07 (s, 3H, OCH3),
7.03 (dd, 1H, J 7.9 and 1.6, 7-quinH), 7.32–7.42 (m, 3H, 3,5,6-
quinH), 8.04 (d, 1H, J 8.5, 4-quinH); m/z (EI) 157 (44%), 158
(39), 186 (100), 187 (Mϩ, 66).
(5 ml), 1.5 M LDAؒTHF in THF (5 ml) was added dropwise.
The mixture was stirred at 0 ЊC for 1 h, then CuCl2 (323 mg,
2.40 mmol) was added. After removal of the ice-bath, the reac-
tion mixture was allowed to warm to rt and stirred for 26 h. To
remove the precipitates of Cu salts, the mixture was filtered.
The filtrate was poured into water, extracted with chloroform,
washed with brine, and dried over Na2SO4. After removal of the
solvent, the residue was purified by column chromatography on
silica gel using chloroform–AcOEt (3:1) to yield 8 as a pale
yellow solid (63 mg, 18%); mp 174.5–175 ЊC; δH (270 MHz,
CDCl3) 3.61 (s, 4H, 2CH2), 4.11 (s, 6H, 2OCH3), 7.06 (dd, 2H,
J 7.1 and 1.3, 2 × 7-quinH), 7.33–7.45 (m, 6H, 2 × 3,5,6-
quinH), 8.04 (d, 2H, J 8.6, 2 × 4-quinH); m/z (EI) 344 (Mϩ,
100), 186 (86); HRMS (EI) calcd for C22H20N2O2 344.15248;
found 344.15379.
2-Ethylquinolin-8-ol (6a)5
A mixture of 5a (620 mg, 3.3 mmol) and 48% HBr (5 ml) was
refluxed for 24 h. After cooling to rt, the mixture was neutral-
ized with 5% NaOH and then a pale green precipitate was
observed. The precipitate was extracted with chloroform,
washed with brine, and dried over Na2SO4. After removal of the
solvent, the residue was purified by column chromatography on
silica gel using hexane–AcOEt (2:1) to yield 6a as a pale yellow
oil (298 mg, 52%); δH (270 MHz, CDCl3) 1.39 (t, 3H, J 7.6,
CH3), 2.99 (q, 2H, J 7.6, CH2), 7.13 (dd, 1H, J 7.6 and 1.3,
quinH), 7.25–7.40 (m, 3H, 3,5,6-quinH), 8.03 (d, 1H, J 8.6,
4-quinH); m/z (EI) 172 (100%), 173 (Mϩ, 98); HRMS (EI) calcd
for C11H11NO 173.08406; found 173.08344.
1,2-Bis(8-hydroxyquinolin-2-yl)ethane (10)
The title compound 10 was prepared by the procedure used for
6a. Reaction of 8 (63 mg, 0.19 mmol) with 48% HBr (10 ml)
gave 10 (47 mg, 80%) as a pale yellow solid; mp 201.5–202 ЊC;
δH (270 MHz, CDCl3) 3.59 (s, 4H, 2CH2), 7.14 (dd, 2H, J 7.1
and 1.3, 2 × 7-quinH), 7.30 (dd, 2H, J 7.3 and 1.3, 2 ×
5-quinH), 7.35–7.42 (m, 2H, 2 × 3,6-quinH), 8.06 (d, 2H, J 8.3,
2 × 4-quinH); m/z (FAB) 317 (Mϩ ϩ H) (Anal. Calcd for
C20H16N2O2: C, 75.93; H, 5.10; N, 8.86. Found: C, 75.92; H,
5.11; N, 8.68%).
2-Butyl-8-methoxyquinoline (5b)
1,6-Bis(8-methoxyquinolin-2-yl)hexane (11)
The title compound 5b was prepared by the procedure used for
5a. Reaction of 3 (1.04 g, 6.00 mmol) and 1-bromopropane
(1.10 g, 9.00 mmol) with 1.5 M LDAؒTHF (7.20 mmol) gave 5b
(937 mg, 73%) as a pale yellow solid; mp 32–33 ЊC; δH (270
MHz, CDCl3) 0.96 (t, 3H, J 7.3, CH3), 1.45–1.80 (m, 4H), 3.04
(t, 2H, J 8.1, CH2), 4.07 (s, 3H, OCH3), 7.02 (dd, 1H, J 7.3 and
1.7, 7-quinH), 7.25–7.40 (m, 3H, 3,5,6-quinH), 8.03 (d, 1H,
J 8.6, 4-quinH); m/z (EI) 173 (100%), 186 (27), 214 (24), 215
(Mϩ, 14).
The title compound 11 was prepared by the procedure used for
5a. Reaction of 3 (1.04 g, 6.00 mmol) and 1,4-dibromobutane
(698 mg, 3.30 mmol) with 1.5 M LDAؒTHF (7.20 mmol) gave
11 (937 mg, 73%) as a pale yellow solid; mp 89.5–90 ЊC; δH (270
MHz, CDCl3) 1.50 (t, 4H, J 7.3 Hz, 2CH2), 1.83 (s, 4H, 2CH2),
3.03 (t, 4H, J 8.1, 2CH2), 4.07 (s, 6H, 2OCH3), 7.03 (dd, 2H,
J 7.3 and 1.8, 2 × 7-quinH), 7.30–7.42 (m, 6H, 2 × 3,5,6-
quinH), 8.02 (d, 2H, J 8.3, 2 × 4-quinH); m/z (EI) 173 (100%),
186 (43), 200 (14), 400 (Mϩ, 12) (Anal. Calcd for C26H28N2O2:
C, 77.97; H, 7.05; N, 6.99. Found: C, 77.83; H, 7.27; N, 6.91%).
2-n-Butylquinolin-8-ol (6b)5
The title compound 6b was prepared by the procedure used for
6a. Reaction of 5b (800 mg, 3.97 mmol) with 48% HBr (20 ml)
gave 6b (612 mg, 77%) as a pale yellow oil; δH (270 MHz,
CDCl3) 0.97 (t, 3H, J 7.3, CH3), 1.42–1.80 (m, 4H), 2.96 (t, 2H,
J 7.6, CH2), 7.14 (d, J 7.3, 1H, 7-quinH), 7.25–7.40 (m, 3H,
3,5,6-quinH), 8.03 (d, 1H, J 8.6, 4-quinH); m/z (EI) 159 (100%),
172 (21), 186 (15), 201 (Mϩ, 18); HRMS (EI) calcd for
C13H15NO 201.11536; found 201.11629.
1,6-Bis(8-hydroxyquinolin-2-yl)hexane (12)
The title compound 12 was prepared by the procedure used for
6a. Reaction of 11 (631 mg, 1.58 mmol) with 48% HBr (40
ml) gave 12 (557 mg, 95%) as a pale green solid; mp 93–94 ЊC;
δH (270 MHz, CDCl3) 1.47 (sextet, 4H, J 7.6, 2CH2), 1.85 (t,
4H, J 7.6 Hz, 2CH2), 2.96 (t, 4H, J 7.6, 2 × CH2), 7.14 (dd,
2H, J 7.6 and 1.3, 2 × 7-quinH), 7.26–7.37 (m, 6H, 2 × 3,5,6-
quinH), 8.03 (d, 2H, J 7.9, 2 × 4-quinH); m/z (EI) 172 (100%),
186 (11), 372 (Mϩ, 28) (Anal. Calcd for C24H24N2O2: C, 77.39;
H, 6.49; N, 7.52. Found: C, 77.46; H, 6.55; N, 7.57%).
2-Bis(trimethylsilyl)methyl-8-methoxyquinoline (7)
To an ice-cooled solution of 3 (349 mg, 2.02 mmol) in THF (10
ml), 1.5 M LDAؒTHF in cyclohexane (3.0 ml) was added drop-
wise, and the mixture was stirred at 0 ЊC for 1 h. Then tri-
methylsilyl chloride (548 mg, 5.04 mmol) was added dropwise.
The reaction mixture was stirred at 0 ЊC for 30 min, and after
removal of the ice-bath it was allowed to warm to rt and was
stirred for 1 h. The resulting mixture was poured into water,
extracted with chloroform, washed with brine, and dried over
Na2SO4. After removal of the solvent, the residue was chrom-
atographed twice on silica gel using hexane–AcOEt (3:1) to
afford 7 (222 mg, 45%) as a white solid; mp 63–65 ЊC; δH NMR
(270 MHz, CDCl3) 0.08 (s, 18H, 2Si(CH3)3), 2.40 (s, 1H, SiCH),
4.04 (s, 3H, OCH3), 7.03 (dd, 1H, J 7.6 and 1.7, 7-quinH), 7.27–
7.31 (m, 3H, 3,5,6-quinH), 7.90 (d, 1H, J 8.6, 4-quinH); m/z
(FAB) 318 (Mϩ ϩ H); HRMS (FAB) calcd for C17H28NO2Si2
318.17095; found 318.17070.
Bis(2-ethylquinolin-8-olato)tin(II) (13a)
To 2-ethylquinolin-8-ol 6a (298 g, 1.72 mmol) in methanol (3
ml), sodium (41 mg, 1.79 mmol) was added. After evolution
of hydrogen gas ceased, tin() chloride (162 mg, 0.85 mmol) in
methanol (5 ml) was added and the mixture was stirred for 1 h
at room temperature. Filtration afforded a yellow solid (185 mg,
69%); mp 176–178 ЊC; δH 1.59 (t, 6H, J 7.6, 2CH3), 3.39 (br s,
4H, 2CH2), 6.90 (d, 2H, J 7.6, 2 × 7-quinH), 7.00 (d, 2H, J 7.5,
2 × 5-quinH), 7.34 (d, 2H, J 7.6 and 7.5, 2 × 6-quinH), 7.39 (d,
2H, J 8.4, 2 × 3-quinH), 8.19 (d, 2H, J 8.4, 2 × 4-quinH); MS
(FAB) m/z 464 (Mϩ) (Anal. Calcd for C22H20N2O2Sn: C, 57.06;
H, 4.35; N, 6.05. Found: C, 57.34; H, 4.50; N, 6.13%).
Bis(2-butylquinolin-8-olato)tin(II) (13b)
The title compound 13b was prepared by the procedure used
for 13a. Treatment of 2-n-butylquinolin-8-ol 6b (544 mg, 2.70
mmol) with SnCl2 (256 mg, 1.35 mmol) in alkaline methanol
1,2-Bis(8-methoxyquinolin-2-yl)ethane (8)
To an ice-cooled solution of 3 (346 mg, 2.00 mmol) in THF
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solution afforded 13b (494 mg, 35%) as a yellow solid; mp
149.5–150 ЊC; δH (500 MHz, CDCl3) 1.03 (t, 6H, J 7.6, 2CH3),
1.56 (sextet, 4H, J 7.6, 2CH2), 2.02 (br s, 4H, 2CH2), 3.34 (br s,
4H, 2CH2), 6.88 (d, 2H, J 7.9, 2 × 7-quinH), 7.00 (d, 2H, J 8.0,
2 × 5-quinH), 7.30–7.47 (m, 4H, 2 × 3,6-quinH), 8.16 (d, 2H,
J 8.4, 2 × 4-quinH); m/z (FAB) 519 (Mϩ) (Anal. Calcd for
C26H28N2O2Sn: C, 60.14; H, 5.44; N, 5.40. Found: C, 59.94; H,
5.45; N, 5.37%).
Acknowledgements
The authors thank the Institute for Molecular Science for carry-
ing out the measurements of MS spectra and the X-ray anal-
ysis. This work was supported by the Joint Studies Program
(1998–1999) of the Institute for Molecular Science.
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M. C. Giacovazzo, A. Guagliardi and G. Polidori, J. Appl.
Crystallogr., 1994, 27, 435.
13 DIRDIF94: P. T. Beurskens, G. Admiraal, G. Beurskens, W. P.
Bosman, R. de Gelder, R. Israel and J. M. M. Smits, The
DIRDIF94 program system, Technical Report of the Crystallo-
graphy Laboratory, University of Nijmegen, The Netherlands, 1994.
14 teXsan for Windows: Crystal Structure Analysis Package, Molecular
Structure Corporation, 1997.
X-Ray crystal structure determination of complex 13b
Crystal data: C26H18N2O2Sn, Mr = 519.21, monoclinic, C2/c,
a = 11.836(1), b = 19.401(2), c = 10.580(1) Å, β = 110.81(1)Њ,
V = 2271.0(4) Å3, Dx = 1.518 g cmϪ3, Z = 4, µ = 11.5 cmϪ1
,
T = 75 K.† A yellow needle prepared by slow evaporation from
Et2O was used for data collection with a Rigaku RAXIS-IV
imaging plate area detector with graphite-monochromated Mo-
Kα radiation (λ = 0.71070 Å) from a rotating-anode generator
operating at 50 kV and 100 mA. Indexing was performed from
3 oscillation images which were exposed for 5 minutes. The data
were collected to a maximum 2θ value of 51.3Њ. In a total of
156Њ range, 13 oscillation images were collected, each of which
was exposed for 30 minutes. A total of 2135 reflections was
collected. The data were corrected for Lorentz and polarization
effects. The structure was solved by direct methods12 and
expanded using a Fourier technique.13 Hydrogen atoms were
included but not refined. The final cycle of full-matrix least-
squares refinement was based on 1997 observed reflections
(I > 3σ(I)) and 141 variable parameters and converged with
R = 0.050 and Rw = 0.067. All calculations were performed with
teXsan for Windows.14
† CCDC reference number 207/391. See http://www.rsc.org/suppdata/
p1/a9/a908636f for crystallographic files in .cif format.
Paper a908636f
J. Chem. Soc., Perkin Trans. 1, 2000, 781–785
785