1156
Can. J. Chem. Vol. 78, 2000
alcohol–hexane solution. Yield 0.917 g, 55%, mp 119°C.
UV–vis (CH2Cl2 solution) λ (nm) (ε, M–1 cm–1): 347 (6800),
518 (200). IR ν (cm–1): 2948vw, 1760vs, 1664w, 1467m,
1446s, 1379vs, 1323vs, 1229m, 1109s, 1027w, 964w, 785m,
electronically). This material has also been deposited with
the Cambridge Crystallographic Data Centre. Copies of the
data can be obtained, free of charge, on application to the
Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, U.K.
(Fax: 44-1223-336033 or e-mail: deposit@ccdc.cam.ac.uk).
1
711m, 625m, 554m, 484s, 381m, 325m, 249m. H NMR
(400.0 MHz, CDCl3, TMS) δ: 3.52 (s). 13C NMR
(100.5 MHz, CDCl3, TMS) δ: 186.24, 154.91, 30.07. Anal.
calcd.(%): C 29.28, H 2.95, N 13.66; found: C 30.08, H
2.81, N 13.94.
Computations
Quantum chemical calculations were carried out using the
commercially available suite of programs Gaussian 94 (47).
Density functional calculations (16, 17) (DFT) were per-
formed using the hybrid BECKE3LYP functional (which
uses a mixture (22) of Hartree–Fock and DFT exchange
along with DFT correlation: the Lee-Yang-Parr correlation
functional together with the Becke’s gradient correction)
(23), Schafer, Horn, and Ahlrichs’ (24) pVDZ basis set for
C, H, N, O, S, and Se were used for all calculations. Numer-
ical integration was performed using the FineGrid option,
which indicates that a total of 7 500 points are used for each
atom. After a geometry optimization performed starting
from structural data (where available) regularized to satisfy
the C2v symmetry, harmonic frequencies were obtained us-
ing the second derivatives of the DFT energy, computed by
numerical differentiation of the DFT energy gradients.
Finally NBO (29) calculations have been performed for each
molecule using the converged density matrix corresponding
to the equilibrium geometries. All point group representa-
tions refer to the model molecules disposed on the xy plane
with the C(1)=X bond lying on the y axis. Calculations have
been performed on an IBM Risc 6000 550H, DECServer
4000, and on a VAIER Intel Pentium III 450 MHz Personal
Computer running Linux.
Synthesis of 3eEt, C7H10N2O2Se
3eEt was synthesized following the route outlined for
3eMe. Yield 1.658 g, 65%, mp 111°C. UV–vis (CH2Cl2 solu-
tion) λ (nm) (ε, M–1 cm–1): 350 (6200), 524 (200). IR ν (cm–1):
2971w, 1766vs, 1454m, 1430m, 1396vs, 1242vs, 1117s,
1074m, 1049w, 1010vw, 901w, 875w, 641m, 367m, 488s,
1
441w, 395w, 325m, 247vw, 225w, 198w, 187w. H NMR
(400.0 MHz, CDCl3, TMS) δ: 4.12 (q, 2H), 1.30 (t, 3H). 13C
NMR (100.5 MHz, CDCl3, TMS) δ: 184.48, 154.81, 38.89,
13.14. Anal. calcd. (%): C 36.06, H 4.32, N 12.28; found: C
36.84, H 4.72, N 12.28.
Synthesis of 3eBu, C11H18N2O2Se
3eEt was synthesized following the route outlined for
3eMe. Yield 1.227 g, 70%. m p 35°C. UV–vis (CH2Cl2 solu-
tion) λ (nm) (ε, M–1 cm–1): 352 (5600), 525 (200). IR ν (cm–1):
2960m, 2933w, 2874w, 1767vs, 1434m, 1395vs, 1291m,
1209s, 1164w, 1130m, 1089w, 1061w, 957vw, 703vw, 573w,
1
495m, 397 w, 300w, 249vw. H NMR (400.0 MHz, CDCl3,
TMS) δ: 4.05 (t, 2H), 1.70 (m, 2H), 1.37 (m, 2H), 0.96
(t, 3H). 13C NMR (100.5 MHz, CDCl3, TMS) δ: 185.20,
154.99 (s), 43.60, 29.81, 19.85 (s), 13.53. Anal. calcd. (%):
C 45.68, H 6.27, N 9.69; found: C 46.80, H 7.01, N 9.86.
Acknowledgments
X-ray crystallography
The project was carried out as a part of the “Progetto
Finalizzato Materiali Speciali per Tecnologie Avanzate II” of
the “Consiglio Nazionale delle Ricerche.” We wish to ac-
knowledge the Advanced Materials Laboratory (LaMI) un-
der the auspices of the European Union and Regione
Basilicata for financial support. We also wish to thank Dr.
Francesco Usai for help in the synthesis.
Crystal data for 3eEt: C7H10N2O2Se, fw 233.13,
orthorhombic, space group P212121 (no. 19), a = 5.249(1),
b = 10.406(3), c = 16.647(1) Å, U = 909,3(3) Å3, Z =
4, µ(Mo-Kα) = 40.48 cm–1, ρcalc = 1.703 g cm–3; 1721 reflec-
tions measured, 1580 unique (Rint = 0.018). Intensity data
were collected at room temperature with an Enraf–Nonius
CAD4 diffractometer using graphite-monochromatised
Mo-Kα radiation. Lorentz, polarization, and a semiempirical
absorption correction (41) were applied to all the data. The
structure was solved by direct methods (MULTAN) (42) and
refined by full-matrix least-squares with anisotropic displace-
ment parameters for all the non-hydrogen atoms. The final R
and Rw indices were 0.030 and 0.044 for 1339 reflections
with I > 3σ(I). All H atoms were seen in difference Fourier
maps, but not refined. Sources of neutral atomic scattering
factors for all atoms are given in ref. (43). Anomalous dis-
persion effects were included in Fc; and the values for δf ′
and δf′′ were those of ref. (44). All the calculations were
performed using Personal SDP software (45, 46). Atomic
coordinates, displacement parameters, bond lengths and an-
gles have been deposited as supplementary material and may
be purchased from the Depository of Unpublished Data,
Document Delivery, CISTI, National Research Council
order_electronic_e.shtml for information on ordering
Supporting information
Table S1. giving details of the data collection and refine-
ment, atomic coordinates, displacement parameters, bond
lengths and angles for 3eEt. Optimized geometries in Carte-
sian coordinate form and frontier Kohn–Sham orbital ener-
gies at the BECKE3LYP level for all compounds reported in
Scheme 3.
References
1. F.A. Devillanova and G. Verani. Aust. J. Chem. 33, 279
(1980).
2. F.A. Devillanova and G. Verani. Tetrahedron, 37, 1803 (1981).
3. H. Biltz and E. Topp. Chem. Ber. 46, 1401 (1913).
4. M. Ponomareff. Bull. Soc. Chim. Fr. 18, 97 (1872).
5. P. Brix and J. Voss. J. Chem. Res. Miniprint, 8, 2218 (1993).
6. H. Bredereck. Chem. Ber. 101, 1863 (1968).
© 2000 NRC Canada