A novel and convenient synthesis towards 2-pyridylselenium compounds: X-ray crystal structure of 4,4′-dimethyl-2,2′-dipyridyl diselenide and tris(2-pyridylseleno)methane

Article abstract of DOI:10.1016/S0022-328X(02)01627-3

Various 2,2′-dipyridyl diselenides were prepared by a simple and convenient method employing non-cryogenic conditions. The diselenide anion, Se₂^2- formed by reducing elemental selenium with 100% hydrazine hydrate in sodium hydroxide reacts in situ with 2-bromopyridines to afford the title compounds in good to excellent yields. Hydrazine hydrate readily cleaves the selenium-selenium bond in these diselenides to generate 2-pyridylselenolate anion, which reacts with halomethanes to afford 2-pyridylseleno methanes. X-ray crystal structure of 4,4′-dimethyl-2,2′-dipyridyl diselenide (4) and tris(2-pyridylseleno)methane (10) is described.

Full text of DOI:10.1016/S0022-328X(02)01627-3

Journal of Organometallic Chemistry 658 (2002) 71ꢂ76
/
www.elsevier.com/locate/jorganchem
A novel and convenient synthesis towards 2-pyridylselenium
compounds: X-ray crystal structure of 4,4?-dimethyl-2,2?-dipyridyl
diselenide and tris(2-pyridylseleno)methane
K.K. Bhasin *, Jaspreet Singh
Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India
Received 14 February 2002; received in revised form 25 May 2002; accepted 25 May 2002
Abstract
Various 2,2?-dipyridyl diselenides were prepared by a simple and convenient method employing non-cryogenic conditions. The
diselenide anion, Se22ꢀ formed by reducing elemental selenium with 100% hydrazine hydrate in sodium hydroxide reacts in situ with
2-bromopyridines to afford the title compounds in good to excellent yields. Hydrazine hydrate readily cleaves the selenium-selenium
bond in these diselenides to generate 2-pyridylselenolate anion, which reacts with halomethanes to afford 2-pyridylseleno methanes.
X-ray crystal structure of 4,4?-dimethyl-2,2?-dipyridyl diselenide (4) and tris(2-pyridylseleno)methane (10) is described. # 2002
Elsevier Science B.V. All rights reserved.
Keywords: Diselenide; Pyridyl; Hydrazine; Phase-transfer catalyst
1. Introduction
2. Results and discussion
Symmetrical and unsymmetrical pyridyl selenium
compounds have attracted a great deal of attention
because of their synthetic utility in organic chemistry [1]
and biochemistry [2]. Since they serve as excellent
2.1. Preparation of methyl substituted 2,2?-dipyridyl
diselenide
Elemental selenium suspended in dimethylformamide
reacts with 100% hydrazine hydrate in the presence of
NaOH at room temperature to give dark green solution
containing diselenide anion [7]. The diselenide anion
thus formed reacts in situ with the various 2-bromopyr-
idines to afford the title compounds in good to excellent
yields (Scheme 1).
In the course of our investigations, it was found that
elemental selenium can also be reduced by sodium
hydroxide in the presence of a phase transfer catalyst.
The subsequent reaction with 2-bromopyridines afford
mainly the diselenide along with the corresponding
precursors of metal chalcogenolates M(SeR)n (Mꢁ
/Li,
Zn, Cd, Hg; nꢁ1,2) for the generation of semi-
/
conducting materials [3], a number of methods for their
preparation have been developed. The frequently em-
ployed methods involve expensive reducing agents [4],
require controlled experimental conditions [5,6] and
thus are not practical for large scale preparations.
Therefore, the development of a practical, efficient and
quick process is quite desirable. We herein wish to
report a novel and convenient method for the prepara-
tion of various 2,2?-dipyridyl diselenide and 2-pyridyl-
seleno methanes in high yields along with the X-ray
crystal structure of 4,4?-dimethyl-2,2?-dipyridyl disele-
nide (4) tris(2-pyridylseleno)methane (10).
monoselenides (10ꢂ20%) indicating that the species
/
chemically equivalent Se22ꢀ and Se2ꢀ are formed
(Scheme 2).
2.2. Preparation of 2-pyridylseleno methanes
2,2?-Dipyridyl diselenides can be quantitatively re-
duced to 2-pyridylselenolate anion using 100% hydra-
* Corresponding author. Fax: ꢃ
E-mail address: kkbhasin@pu.ac.in (K.K. Bhasin).
/
91-172-545074
0022-328X/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 3 2 8 X ( 0 2 ) 0 1 6 2 7 - 3

72
K.K. Bhasin, J. Singh / Journal of Organometallic Chemistry 658 (2002) 71ꢂ76
/
Scheme 1. Preparation of 2,2?-dipyridyl diselenide using hydrazine
hydrate (100%).
Scheme 3. Preparation of 2-pyridylseleno methanes.
zine hydrate at room temperature in the presence of
NaOH in aprotic solvents such as n-pentane, n-hexane,
benzene and THF. The anion thus formed reacts readily
with various halomethanes (mono-, di- and trihalo-
methanes) to give the desired compounds in good to
excellent yieids (Scheme 3).
These reactions when carried out in the presence of
phase-transfer catalyst viz.; polyethleneglycol-400 and
tetrabutylammonium bromide, in an effort to improve
the efficiency of the reaction, marginally increases the
yields of the reactions. It, therefore, appears that the
phase-transfer catalyst may not be involved in the
production of the selenolate anion and only catalyzes
the substitution reaction with various halomethanes. As
part of our studies we also examined the solvent effect
on the efficiencies of these reactions employing different
solvents. The efficiency of the reaction in various
Scheme 4. Interfacial mechanism of the reaction for the preparation of
2-pyridylseleno methanes.
solvents is in the following order: benzeneꢀ
/
THFꢀ
/
pentaneꢁhexane. On the basis of our experimental
findings, a tentative interfacial mechanism for the above
reaction is proposed in Scheme 4.
/
reference. The selenium signal in compound 2, 3 and 5
appears at ꢀ
/
576.7, ꢀ
/
584.4 and ꢀ594.3 (d, ppm),
/
respectively. It appears that the methyl group ortho to
the selenium atom releases more electron density into
the pyridine ring, resulting in the reduction of p-
interaction between the pyridine ring and the lone pair
of electrons on the selenium atom, causing increase in
the electron density on the selenium atom in 3,3?-
dimethyl-2,2?-dipyridyl diselenide when compared with
the corresponding diselenides.
The reaction of selenolate anion with iodomethane or
diiodomethane gave the desired compounds in nearly
quantitative yields. In contrast, its reaction with tribro-
momethane gave both the bis(2-pyridylseleno)methane
and tris(2-pyridylseleno)methane in almost equal pro-
portions. 2-Methylseleno picolines are foul smelling
liquids whereas the corresponding bis and tris(2-pridyl-
seleno)methanes are pale yellow crystalline solids. All
the compounds prepared were characterized by elemen-
tal analysis and various spectroscopic techniques viz.,
1H-NMR, 13C-NMR, 77Se-NMR, IR and Mass Spectral
studies. In the 1H-NMR spectra of tris(2-pyridylsele-
no)methane the signal corresponding to the hydrogen
atom attached to the sp3 carbon appears in the aromatic
region (d, 7.32 ppm) because of the cumulative electron-
withdrawing influence of three pyridylseleno moieties.
77Se (completely decoupled)-NMR spectra of methyl
substituted 2,2?-dipyridyldiselenide (2, 3 and 5) were
recorded in CDCl3 employing selenic acid as an external
2.3. Solid state structural features of 4 and 10
In order to understand structural details, single crystal
X-ray diffraction study was carried out. A perspective
view of structure of 4 and 10 with atom numbering
scheme is given in Figs. 1 and 2, respectively, with
selected bond lengths and angles in Table 1.
Each pyridine ring in 4 is substituted at 2 position
˚
C bond length 1.934 (4) A and at 4
with average SeÃ
/
˚
C bond length 1.497 (6) A.
position with average H3CÃ
/
Scheme 2. Preparation of 2,2?-dipyridyl diselenide using PEG-400 and NaOH.

K.K. Bhasin, J. Singh / Journal of Organometallic Chemistry 658 (2002) 71ꢂ
/76
73
Fig. 1. Perspective view of 4,4?-dimethyl-2,2?-dipyridyl diselenide with atom numbering scheme (40% probability level).
ꢀ89.288 (18) responsible for reduced inter-atomic
/
Table 1
˚
Selected bond distances (A) and angles (8) for compound 4 and 10
repulsive interaction between the lone pair of electrons
on selenium atoms. The molecular geometry of the
pyridine ring is normal in terms of bond lengths and
bond angles. Short contacts are observed between Se(2)
Compound 3
Se(1)ÃC(1)
N(1)ÃC(1)
C(2)ÃC(3)
1.938(4)
1.323(6)
1.391(8)
Se(1)ÃSe(1)#1
N(1)ÃC(5)
2.2973(7)
1.344(6)
1.490(6)
˚
˚
and H(2) (2.852 A) and Se(1) and H(8) (2.906 A), which
C(3)ÃC(6)
C(1)ÃSe(1)-Se(2)
N(1)ÃC(1)ÃC(2)
C(2)ÃC(1)ÃSe(1)
C(4)ÃC(3)ÃC(2)
102.47(12) C(1)ÃN(1)ÃC(5) 115.6(4)
are significantly shorter than the sum of the van der
˚
125.0(4)
124.8(3)
116.7(5)
N(1)ÃC(1)ÃSe(1) 110.2(3)
C(1)ÃC(2)ÃC(3) 118.9(4)
N(1)ÃC(5)ÃC(4) 123.7(4)
Waals radii 3.4 A [8]. It is probably the reason for the
Se bond lying close to the plane of the pyridine
rings. A unique feature of this structure is the presence
SeÃ
/
Compound 13
Se(1)ÃC(2)
N(1)ÃC(2)
of intermolecular non-bonded interactions between the
˚
1.918(6)
1.313(8)
Se(1)ÃC(1)
N(1)ÃC(6)
1.939(4)
1.341(8)
selenium-selenium atoms (SeÁ Á ÁSeꢁ/3.878 A).
In the crystal lattice of tris(2-pyridylseleno)methane,
the molecule is located on a three-fold axis with the
bonding at the sp3 carbon regarded as essentially
tetrahedral. The geometry of the 2-pyridylseleno moiety
in the tris(2-pyridylseleno)methane differs substantially
from that in 2,2?-dipyridyl diselenide [3b]. The orienta-
tion of the 2-pyridylseleno ring is such that nitrogen
atoms are in the cis, cis position with respect to the
C(2)ÃSe(1)ÃC(1)
Se(1)#1ÃC(1)ÃSe(1) #2 108.7(3)
N(1)ÃC(2)ÃC(3)
C(4)ÃC(3)ÃC(2)
100.3(3)
C(2)ÃN(1)ÃC(6) 117.9(6)
N(1)ÃC(1)ÃSe(1) 120.7(4)
C(3)ÃC(2)ÃSe(1) 115.9(4)
N(1)ÃC(6)ÃC(5) 122.9(6)
123.3(5)
118.4(6)
Symmetry transformations used to generate equivalent atoms for 3:
#1 ꢀxꢃ1, y, ꢀzꢃ1/2. Symmetry transformations used to generate
equivalent atoms for 13: #1 ꢀyꢃ1, xꢀyꢃ1, z# 2ꢀxꢃy, ꢀxꢃ1, z.
The XÃ
(4) and ꢀ
SeÃSe bond lies ca. in the plane of each pyridine ring.
The CÃSeÃSeÃC torsion angle for this compound is
/
CÃ
/
SeÃ
/
Se, torsion angles, XꢁC or N are 4.38
/
Se(1)Ã
position with respect to the SeÃ
dipyridyl diselenide. The NÃC(2)Ã
C(2)ÃSe(1) bond angles are 120.78 (4) and 115.98 (4),
/
C(1) group, whereas they are in the trans, trans
Se group in 2,2?-
Se(1) and C(3)Ã
/
176.58 (3), respectively, which indicate that
/
/
/
/
/
/
/
/
/
Fig. 2. Perspective view of tris(2-pyridylseleno) methane with atom numbering scheme (40% probability level).

74
K.K. Bhasin, J. Singh / Journal of Organometallic Chemistry 658 (2002) 71ꢂ76
/
respectively, and lies more towards ideal 1208 bond
angle, contrary to that observed in 2,2?-dipyridyl
diselenide. It is proposed that this be due to the absence
of SeÁ Á ÁH repulsive interaction in 10. The angle between
the two pyridine ring planes is 76.88 (4). An unusually
3.1.1. 2,2?-Dipyridyldiselenide (1)
Yield 2.8 g (72%) m.p. 48ꢂ50 8C [4]. H-NMR: d,
1
/
7.07 (q, 2H, 5.5, 1.7, Hz), 7.53 (m, 2H, 1.9, 5.9, 1.7, 5.9,
2.0 Hz), 7.77 (d, 2H, 8.0 Hz), 8.43 (d, 2H, 5.5 Hz).13C-
NMR: d, 121.1, 123.4, 137.3, 149.4, 154.2. IR (KBr,
cmꢀ1): 3060, 2960, 2920, 1565, 1552, 1444, 1105, 1076,
1031, 983, 748, 660. Anal. Calc. for: C10H8N2Se2; C,
38.22; H, 2.54; N, 8.91. Found: C, 37.93, H, 2.13; N,
8.45%.
˚
short SeÁ Á ÁSe contact distance 3.152 A is found between
˚
the two molecules and this distance is 0.848 A shorter
than the accepted van der Waals contact distance [8].
3. Experimental
3.1.2. 6,6?-Dimethyl-2,2?-dipyridyldiselenide (2)
1
Yield 2.9 g (68%) m.p. 62ꢂ
/
63 8C. H-NMR: d, 2.52
(s, 6H), 6.92 (d, 2H, 7.6 Hz), 7.43 (t, 2H, 7.7 Hz), 7. 61
All experiments were carried out in dry oxygen-free
nitrogen atmosphere. Infrared spectra were recorded
between KBr pellets on a Perkinꢂ
(d, 2H, 7.8 Hz). 13C-NMR: d, 24.2, 120.5, 136.0, 137.5,
/
Elmer Model 1430
153.6, 158.5. 77Se-NMR: d, ꢀ576.76. IR (KBr, cmꢀ1):
3060, 2960, 2920, 1580, 1540, 1430, 1120, 1090, 1020,
/
ratio recording spectrometer. H-NMR and 13C-NMR
spectra were recorded in CDCl3 using TMS as an
internal standard on Bruker AC-300F, 300 MHz
spectrometer. 77Se-BCM NMR spectra of the com-
pounds (2, 3 and 5) were recorded on JNM-AL 400
MHz spectrometer. The mass spectra were obtained on
a VG-705 11-250J Mass spectrometer. Carbon, hydro-
gen and nitrogen were estimated micro analytically on
1
840, 780, 660, 540. MS (EI): 344 [M (80Se)]ꢃ (27.1); 264
[MÃ
/
Se]ꢃ (43.3); 183 [MÃ
/
Se2H]ꢃ (81); 92 [MÃ
/
CH3PySe2]ꢃ (100). Anal. Calc. for: C12H12N2Se2; C,
41.86; H, 3.48; N, 8.13. Found: C, 41.08; H, 3.28; N,
8.42%.
3.1.3. 5,5?-Dimethyl-2,2?-dipyridyl diselenide (3)
1
Perkinꢂ/Elmer 2400CHN elemental analyzer. 2-Bromo-
Yield 3.0 g (71%) m.p. 75ꢂ
/
77 8C. H-NMR: d, 2.27
(s, 6H), 7.35 (d, 2H, 8.1 Hz), 7. 68 (d, 2H, 8.1 Hz), 8.27
pyridines were prepared from the corresponding 2-
aminopyridines by employing Craig’s method [9].
(s, 2H). 13C-NMR: d, 17.8, 123.3, 130.7, 136.1, 149.8,
150.7. 77Se-NMR: d, ꢀ
/
584.46. IR (KBr, cmꢀ1): 3030,
3.1. General method for the preparation of various methyl
substituted 2,2?-dipyridyl diselenide
2983, 2914, 1579, 1559, 1446, 668, 1219, 1081, 1040, 910,
822, 723, 592, 479. ME (EI): 344 [M (80Se)]ꢃ (34.3); 263
[MÃ
/
SeH]ꢃ (6.2); 183 [MÃ
/
Se2H]ꢃ (100); 92 [MÃ
/
Method A: To a vigorously stirred mixture of
powdered sodium hydroxide (1.5 g, 38 mmol), selenium
powder (2.0 g, 25 mmol) and dimethylformamide (100
ml), 100% hydrazine hydrate (1 ml, 25 mmol) was added
dropwise at room temperature (r.t.). The mixture was
stirred for 2 h. Methyl substituted 2-bromo pyridine (4.2
g, 25 mmol) was added drop-wise to the reaction
mixture and refluxed for 3ꢂ4 h. After all the 2-bromo
pyridine was consumed was consumed as evidenced by
TLC, the reaction was stopped and diluted with water.
CH3PySe2]ꢃ (60.5). Anal. Calc. for: C12H12N2Se2; C,
41.86; H, 3.48; N, 8.13. Found: C, 41.12; H, 3.35; N,
8.32%.
3.1.4. 4,4?-Dimethyl-2,2?-dipyridyl diselenide (4)
1
Yield 2.8 g (65%) m.p. 96ꢂ
/
98 8C. H-NMR: d, 2.20
(s, 6H), 6.89 (d, 2H, 4.1 Hz), 7.62 (s, 2H), 8.31 (d, 2H,
4.9 Hz). 13C-NMR: d, 21.0, 123.4, 123.9, 148.8, 149.0,
154.0. IR (KBr, cmꢀ1): 3060, 2960, 2920, 1580, 1540,
1460, 1270, 1120, 1080, 840, 700, 500. ME (EI): 344 [M
/
The mixture was extracted with diethyl ether (4ꢄ
/100
(80Se)]ꢃ (36); 263 [MÃ
/
SeH]ꢃ (10.1); 183 [MÃ
/
Se2H]ꢃ
ml) and the organic layer dried over anhydrous sodium
sulphate. Solvent was removed on a rota-evaporator
and the residue was purified by column chromatography
using silica gel and hexane-ethylacetate as eluent (5:1) to
give the pure diselenide.
Method B: To a vigorously stirred mixture of pow-
dered sodium hydroxide (1.5 g, 38 mmol), selenium
powder (2.0 g, 25 mmol) and dimethylformamide (100
ml) was added PEG-400 (0.5 ml). The mixture was
stirred for 2 h. Methyl substituted 2-bromopyridine (4.2
g, 25 mmol) was added drop-wise to the reaction
(100); 92 [MÃ
/
CH3PySe2]ꢃ (63). Anal. Calc. for:
C12H12N2Se2; C, 41.86; H, 3.48; N, 8.13. Found: C,
41.72; H, 3.93; N, 8.2%.
3.1.5. 3,3?-Dimethyl-2,2?-dipyridyl diselenide (5)
Yield 3.2 g (75%) m.p. 142ꢂ
144 8C. 1H-NMR: d,
2.42 (s, 6H), 7.03 (q, 2H, 5.0, 2.5, 4.8 Hz), 7.34 (d, 2H,
/
7.4 Hz), 8.30 (d, 2H, 5.1 Hz). 13C-NMR: d, 20.5, 121.7,
133.5, 136.6, 147.7, 153.0. 77Se-NMR: d, ꢀ
594.36. IR
/
(KBr, cmꢀ1): 3030, 2960, 2920, 1664, 1570, 1543, 1460,
1277, 1060, 785, 635, 575, 470. ME (EI): 344 [M (80Se)]ꢃ
mixture and refluxed for 3ꢂ
/
4 h. After all the 2-
(19.6); 263 [MÃ
/
SeH]ꢃ (24.4); 183 [MÃ
/
Se2H]ꢃ (100); 92
bromopyridine was consumed as evidenced by TLC,
the reaction was stopped and worked up as described
previously.
[MÃ
/
CH3PySe2]ꢃ (62.2). Anal. Calc. for: C12H12N2Se2;
C, 41.86; H, 3.48; N, 8.13. Found: C, 41.45; H, 3.62; N,
8.34%.

K.K. Bhasin, J. Singh / Journal of Organometallic Chemistry 658 (2002) 71ꢂ
/76
75
3.2. General method for the preparation of 2-
pyridylseleno methanes
C11H10N2Se2; C, 40.24; H, 3.04; N, 8.53. Found: C,
40.54; H, 3.60; N, 8.37%.
To a vigorously stirred mixture of powdered sodium
hydroxide (0.25 g, 62.5 mmol), phase-transfer catalyst
(2.5 mmol), 2,2?-dipyridyl diselenide (12 mmol) and
aprotic solvent (40 ml), 100% hydrazine hydrate (0.2 ml,
4 mmol) was added drop-wise at r.t. Stirring was
continued for additional 30 min. A solution of halo-
methane in THF was added drop-wise at 0 8C. After
completion of the reaction as evidenced by TLC, the
reaction was stopped and worked up as described
previously.
3.2.5. Tris(2-pyridylseleno)methane (10)
Yield 1.9 g (50%). m.p. 90ꢂ
/
91 8C; 1H-NMR: d,
7.01ꢂ7.05 (m, 3H, 5.4,1.9, 5.3 Hz), 7.38 (m, 4H), 7.43ꢂ
/
/
7.49 (m, 3H, 1.7, 5.6, 1.8, 5.8, 2.0 Hz) 8.52 (d, 3H 5.5
Hz). 13C-NMR: d, 21.1, 120.7, 15.1, 136.2, 150.0, 156.9.
IR (Neat, cmꢀ1): 2924, 1568, 1455, 1377, 1274, 1145,
1077 982, 876, 698, 613, 450. Anal. Calc. for:
C16H13N3Se3; C, 39.67; H, 2.68; N, 8.68. Found: C,
39.54; H, 2.72; N, 8.59%.
3.3. Crystal structure determination and refinement
3.2.1. 2-Methylseleno pyridine (6)
Yield 0.29 g (80%). 1H-NMR: d, 2.31 (s, 3H), 7.04 (m,
1H, 1.7, 5.2, 6.5 Hz), 7.53 (m, 1H, 1.9, 5.9, 1.7, 5.9 Hz),
7.74 (d, 1H, 1.8, 6.5, 7.9 Hz), 8.52 (d, 1H, 5.3 Hz).13C-
NMR: d, 5.3, 120.7, 123.7, 137.9, 148.6, 152.1. IR
(Neat, cmꢀ1): 3053, 2955, 2928, 1562, 1435, 1252, 1034,
847, 773, 665, 546. Anal. Calc. for: C6H7NSe; C, 41.86;
H, 4.06; N, 8.13. Found: C, 41.42; H, 4.47; N, 8.18%.
Intensity data were collected on a Siemens P4 Single
crystal diffractometer equipped with molybdenum
˚
sealed tube (lꢁ0.71073 A) and highly oriented graphite
/
monochromator using crystal of dimensions 0.34ꢄ
/
0.28ꢄ0.25 mm for 10, mounted in Lindmann glass
/
Table 2
Crystal data and structure refinement details for compound 4 and 10
3.2.2. 2-Methylseleno-6-picoline (7)
Yield 0.29 g (80%). 1H-NMR: d, 2.38 (s, 3H), 2.45 (s,
3H), 6.76 (d, 1H, 7.5 Hz), 7.03 (d, 1H, 7.7 Hz), 7.27 (t,
1H, 7.4, 7.8 Hz). 13C-NMR: d, 5.1, 23.9, 118.9, 120.7,
135.6, 154.6, 158.3. IR (Neat, cmꢀ1): 3053, 2955, 2928,
1562, 1435, 1252, 1034, 847, 773, 665, 546. MS (EI): 187
4
10
Empirical formula
Formula weight
Crystal system, space group Monoclinic, P21/ Rhombohydral
C
12H12N2Se2
C16H13N3Se3
484.17
342.16
c
(Hex. Setting), R3c
Unit cell dimensions
˚
[M (80Se)]ꢃ(25.0); 173 [MÃ
/
CH2]ꢃ (1.6); 107 [MÃ
/
Se]ꢃ
a (A)
˚
10.555(1)
13.195(1)
40.062(3)
90
12.163(1)
12.163(1)
40.062(3)
90
ꢃ
(100); 93 [MÃ
/
SeCH2]ꢃ (20.6); 77 [MÃ
/
SeC2H6] (14.7).
b (A)
˚
c (A)
Anal. Calc. for: C7H9NSe; C, 45.16; H, 4.84; N, 7.53.
Found: C, 45.20; H, 4.97; N, 7.45%.
a (8)
b (8)
g (8)
94.32(1)
120
90
120
3.2.3. 2-Methylseleno-5-picoline (8)
1
Yield 0.3 g (82%). H-NMR: d, 2.10 (s, 3H), 2.32 (s,
3
˚
V (A )
1272.3(2)
4, 1.786
5.786
5132.7(7)
12, 1.880
6.448
Z, Dcalc (Mg mꢀ3
Absorption coefficient
)
3H), 7.0ꢂ
7.13 (m, 2H), 8.15 (s, 1H). 13C-NMR: d, 5.3,
17.6, 123.8, 129.2, 136.5, 150.0, 151.8(g). IR (Neat,
/
(mmꢀ1
F(000)
Max/min transmission
)
cmꢀ1): 3043, 2977, 2928, 1571, 1451, 1083, 830, 616,
664
0.693, 0.454
2784
1.00, 0.810
539, 467.MS (EI): 187 [M (80Se)]ꢃ (28.3); 173 [MÃ
/
u Range for data collection 2.48ꢂ
/23.98
2.138ꢂ25.00
/
CH2]ꢃ (5.6); 107 [MÃ
/
Se]ꢃ (100); 93 [MÃ
/
SeCH2]ꢃ
(8)
Index ranges
(31.3); 77 [MÃ
/
SeC2H6]ꢃ (5.8). Anal. Calc. for:
ꢀ125h 512,
05k 515,
ꢀ105l 50
2134
05h 514,
ꢀ145k 50,
ꢀ475l 50
1885
C7H9NSe; C, 45.16; H, 4.84; N, 7.53. Found: C, 45.25;
H, 4.92; N, 7.37%.
Reflection collected
Independent reflections
1979
1009 [Rintꢁ0.0747]
3.2.4. Bis(2-pyridylseleno)methane (9)
1
Yield 2.7 g (70%). m.p. 65 8C; H-NMR: d, 4.84ꢂ
4.85 (s, 2H), 6.94 (m, 2H, 6.4, 6.0 Hz), 7.28 (d, 2H, 8.1
Hz), 7.36 (m, 2H, 7.5, 7.6, 8.3 Hz), 8.43 (d, 2H, 5.7 Hz).
13C-NMR: d, 15.93, 120.0, 125.1, 135.6, 150.0, 155.8.
[Rintꢁ0.0205]
Full-matrix least- Full-matrix least-
squares on F2
/
Refinement method
squares on F2
1009/0/68
0.984
Data/restraints/parameters 1979/0/148
Goodness-on-fit on F2
Data to parameter ratio
Final R indices, 738
reflections, [I ꢀ2s(I)]
R indices (all data)
1.053
13.4: 1
14.84:1
MS (EI): 330 [M (80Se)]ꢃ (5.6); 316 [MÃ
250 [MÃ
Se]ꢃ (5.8); 235 [MÃ
Se2]ꢃ (54.8); 158 [MÃSe2C6H6N]ꢃ (9.9); 156 [MÃ
Se2C7H6N]ꢃ(100). IR (Neat,
/
CH2]ꢃ (1.3);
R1ꢁ0.0340,
wR2ꢁ0.0807
R1ꢁ0.0456,
wR2ꢁ0.0860
R1ꢁ0.0426,
wR2ꢁ0.0990
R1ꢁ0.0679,
wR2ꢁ0.1069
/
/
SeCH3]ꢃ (2.0); 170 [MÃ
/
/
/
Se2CH2]ꢃ (7.6); 78 [MÃ
/
Largest difference peak and 0.441 and ꢀ0.518 0.976 and ꢀ0.467
cmꢀ1): 2922, 2291, 1573, 1458, 1377, 1321, 1281, 1153,
1142, 1079, 983, 866, 720, 646, 616, 411. Anal. Calc. for:
ꢀ3
˚
hole (e A
)

76
K.K. Bhasin, J. Singh / Journal of Organometallic Chemistry 658 (2002) 71ꢂ76
/
capillaries at 293(2) K. The cell parameters and their
standard deviation crystals of dimensions were obtained
Acknowledgements
by least square to 40 reflections. The 2u ꢂ
/
u scan mode
We are thankful to CSIR, New Delhi for financial
assistance.
was used with variable scan speed ranging from 2.0 to
60.08 minꢀ1 in v. Three reflections were used to
monitor the stability and orientation of the crystal and
were remeasured after every 97 reflections. All other
relevant information about the data collection and the
refinement are presented in Table 2.
The crystal structure of 10 was solved by direct
method using SHELX-97 [10] and also refined on F2
using the same one. All the non-hydrogen atoms were
refined anisotropically. The hydrogen atoms were in-
cluded in the ideal positions with fixed isotropic U
values and were riding with their respective non-hydro-
References
[1] (a) A. Toshimitsu, H. Owada, K. Terao, S. Uemura, M. Okano, J.
Org. Chem. 49 (1984) 3796;
(b) D.H.R. Barton, D. Crich, Tetrahedron 41 (1985) 4347;
(c) D.H.R. Barton, D. Crich, Tetrahedron 41 (1985) 4359;
(d) A. Toshimitsu, H. Owada, K. Terao, S. Uemura, M. Okano, J.
Chem. Soc. Perkin Trans. 1 (1985) 373;
(e) A. Toshimitsu, G. Hayashi, K. Terao, J. Chem. Soc. Perkin
Trans. 1 (1988) 2113.
[2] (a) A.D. Inglot, J. Zielinska, E. Piasecki, L. Syper, J. Mlochowski,
Experimentia 46 (1990) 308;
gen atoms. A weighting scheme of the form wꢁ
[s2(F2o)ꢃ0.0534P)2ꢃ [max(Fo2, 0)ꢃ2*Fo2]/3
2.34P], Pꢁ
was used. The refinement converged to a final R value
of 0.0400, (wR2ꢁ0.0991 for 873 reflections) [I ꢀ2s(I)].
/1/
/
/
/
/
(b) B.-C. Pan, Z.-H. Chen, G. Piras, G.E. Dutschman, E.C.
Rowe, J. Heterocycl. Chem. 31 (1994) 177.
[3] (a) Y. Cheng, T.J. Emge, J.G. Brennan, Inorg. Chem. 33 (1994)
3711;
/
/
The data collection procedure, structure solution and
refinement for 4 were essentially the same as that for 10;
40 reflections for accurate cell parameter determination
(b) C.O. Kienitz, C. Thone, P.G. Jones, Inorg. Chem. 36 (1996)
3990;
(c) D.V. Khasnis, M. Buretea, T.J. Emge, J.G. Brennan, J. Chem.
Soc. Dalton Trans. (1995) 45.
with weighting scheme of the form wꢁ
/
1/[s2(F2o)ꢃ
/
0.0442P)2ꢃ [max(Fo2, 0)ꢃ2*F2o]/3. Full de-
tails are present in Table 2.
/
0.94P], Pꢁ
/
/
[4] (a) A. Toshimitsu, H. Owada, S. Uemura, M. Okano, Tetrahe-
dron Lett. 21 (1980) 5037;
(b) L. Syper, J. Mlochowski, Tetrahedron 44 (1988) 6119;
(c) S.J. Dunne, L.A. Summer, E.I. Nagy-Felsobuki, J. Hetrocycl.
Chem. 29 (1992) 117.
[5] (a) K.K. Bhasin, B.S. Bhandal, J. Singh, K.N. Singh, P. Singh,
Synth. Commun. 9 (2002) 1319;
4. Supplementary material
(b) K.K. Bhasin, J. Singh, K.N. Singh, Phosphorus Sulphur
Silicon 177 (2002) 597.
Crystallographic data for the structure analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC No. 162448 and 162449for com-
pound 4 and 10, respectively. Copies of this information
may be obtained free of charge from the Director,
CCDC, 12 Union Road, Cambridge CB2 IE2, UK (Fax:
[6] A.B. Pierini, A.B. Penenory, R. Rossi, J. Org. Chem. 49 (1984)
486.
[7] L. Syper, J. Mlochowski, Synthesis (1984) 439.
[8] L. Pauling, The Nature of the Chemical Bond, 3rd ed., Ethaea
Cornell University Press, 1900, pp. 244ꢂ255.
/
[9] L.C. Craig, J. Am. Chem. Soc. 56 (1934) 231.
[10] G.M. Sheldrick, SHELX-97, Program for the solution and refine-
ment of crystal structures, University.
ꢃ
/
44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk or
www: http://www.ccdc.cam.ac.uk).