COMMUNICATIONS
[1] M. M. Lespieau, C. Prÿvost, Mem. Soc. Frib. Sci. Nat. Chim. 1925, 704.
[2] a) F. Straus, L. Kollek, Ber. Dtsch. Chem. Ges. B 1926, 59, 1664; b) F.
Straus, L. Kollek, H. Hauptmann, Ber. Dtsch. Chem. Ges. B 1930, 63,
1886.
[3] K. Gao, N. S. Goroff, J. Am. Chem. Soc. 2000, 122, 9320.
[4] a) E. L. Martin, W. H. Sharkey, J. Am. Chem. Soc. 1959, 81, 5256;
b) A. Bach, D. Lentz, P. Luger, M. Messerschmidt, C. Olesch, M.
Patzschke, Angew. Chem. 2002, 114, 311; Angew. Chem. Int. Ed. 2002,
41, 296.
1438C. We have produced 3 in gram quantities without
difficulty and can keepsolid samples in the freezer indef-
initely. Nonetheless, compound 3 decomposes much more
readily in solution than 1.
The weakness of carbon iodine bonds makes compound 3 a
promising precursor to all-carbon and carbon-rich molecules
and materials. Compound 3 also offers another Lewis acid for
the crystal engineer©s toolbox. Carbon iodides have previously
found use as components in designed materials by acting as
Lewis acid templates. For example, diiodoacetylene and other
carbon iodides can determine the spacing of ions in multi-
component conducting solids.[18] The stability of 3 in pyridine
solution indicates that it can survive Lewis acid base inter-
actions without decomposition, making it a suitable candidate
for such multicomponent systems.
[5] B. Heinrich, A. Roedig, Angew. Chem. 1968, 80, 367; Angew. Chem.
Int. Ed. Engl. 1968, 7, 375.
[6] Although no iodocumulenes are reported in the literature, several
iodoallenes are known, including tetraiodoallene, C3I4; see: a) F. Kai,
S. Seki, Chem. Pharm. Bull. 1965, 13, 1374; b) F. Kai, S. Seki, Chem.
Pharm. Bull. 1966, 14, 1122; c) A. M. Snider, P. F. Krause, F. A. Miller,
J. Phys. Chem. 1976, 80, 1262.
[7] No precipitate is formed in solvents in which 3 is moderately soluble,
and the isolated product is 2.
[8] a) A. D. Becke, J. Chem. Phys. 1996, 104, 1040; b) Gaussian98
(RevisionA.5), M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E.
Scuseria, M. A. Robb, J. R. Cheeseman, V. G. Zakrzewski, J. A.
Montgomery, R. E. Stratmann, J. C. Burant, S. Dapprich, J. M.
Millam, A. D. Daniels, K. N. Kudin, M. C. Strain, O. Farkas, J. Tomasi,
V. Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C. Adamo,
S. Clifford, J. Ochterski, G. A. Petersson, P. Y. Ayala, Q. Cui, K.
Morokuma, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B.
Foresman, J. Cioslowski, J. V. Ortiz, B. B. Stefanov, G. Liu, A.
Liashenko, P. Piskorz, I. Komaromi, R. Gomperts, R. L. Martin, D. J.
Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, C.
Gonzalez, M. Challacombe, P. M. W. Gill, B. G. Johnson, W. Chen,
M. W. Wong, J. L. Andres, M. Head-Gordon, E. S. Replogle, J. A.
Pople, Gaussian, Inc., Pittsburgh, PA, 1998.
[9] Detailed TLC data are available in the Supporting Information.
[10] D. A. Plattner, K. N. Houk, J. Am. Chem. Soc. 1995, 117, 4405.
[11] 1,2-Addition of halogens: a) Y. I. Porfir©eva, A. A. Petrov, L. B.
Sokolov, Russ. J. Gen. Chem. 1964, 34, 1884; Y. I. Porfir©eva, A. A.
Petrov, L. B. Sokolov, Zh. Obshch. Khim. 1964, 35, 1714; b) Y. I.
Porfir©eva, E. S. Turbanova, A. A. Petrov, Russ. J. Gen. Chem. 1964,
34, 4026; Y. I. Porfir©eva, E. S. Turbanova, A. A. Petrov, Zh. Obshch.
Khim. 1964, 34, 3966; c) L. A. Dorofeeva, Y. I. Porfir©eva, A. A.
Petrov, Russ. J. Org. Chem. 1972, 8, 2049; L. A. Dorofeeva, Y. I.
Porfir©eva, A. A. Petrov, Zh. Org. Khim. 1972, 8, 2002; d) L. A.
Dorofeeva, Y. I. Porfir©eva, A. A. Petrov, Russ. J. Org. Chem. 1973, 9,
454; L. A. Dorofeeva, Y. I. Porfir©eva, A. A. Petrov, Zh. Org. Khim.
1973, 9, 449; e) J. J. Wright, M. S. Puar, B. Pramanik, A. Fishman, J.
Chem. Soc. Chem. Commun. 1988, 413; 1,4-addition or mixtures: f) V.
Grignard, Tchÿoufaki, Recl. Trav. Chim. Pays-Bas 1929, 48, 899;
g) B. G. Shakhovskoi, M. D. Stadnichuk, A. A. Petrov, Russ. J. Gen.
Chem. 1964, 35, 1715; B. G. Shakhovskoi, M. D. Stadnichuk, A. A.
Petrov, Zh. Obshch. Khim. 1964, 35, 1714.
Cumulene 3 is surprisingly easy to prepare and to isolate in
a pure form, is surprisingly stable in the solid state, and
disproportionates surprisingly readily in solution. It is one
more example of the unusual chemistry of carbon and
iodine.
ExperimentalSection
3: I2 (340 mg, 1.32 mmol) was added to a solution of 1 (400 mg, 1.32 mmol)
in hexanes (5 mL). Aluminum foil was used to wrapthe reaction vessel.
The reaction mixture was stirred vigorously at room temperature for
15 min, forming a yellow precipitate. The yellow powder was filtered and
washed with hexanes to yield crude product (604 mg, 82%). The crude
products from three iterations were combined and recrystallized from
cyclohexanone/hexanes to yield pure 3 as fine yellow needles (1.47 g, 67%
total). M.p. 143 1448C; MS (EI): m/z (%): 556 (24) [Mþ (C4I4)], 429 (45)
[MþꢀI], 302 (100) [Mþꢀ2(I)], 175 (28) [Mþꢀ3(I)], 127 (27) [Iþ].
2: Iodine (2.52 g, 9.93 mmol) was added to a solution of 1 (1.0 g, 3.3 mmol)
in methanol (30 mL). After stirring at room temperature for 2 h, the
precipitate was filtered and washed with hexanes to yield 2 as a yellow
powder. The material left in solution was not recovered, and no yield was
determined. M.p. 165 1668C; MS (EI)[19]: m/z (%): 682 (22) [MþꢀI], 556
(34) [Mþꢀ2(I)], 429 (34) [Mþꢀ3(I)], 302 (100) [Mþꢀ4(I)], 175 (38)
[Mþꢀ5(I)], 127 (50) [Iþ]. To prepare cocrystals of 2 and 1,7-phenanthroline,
compound 2 (0.14 g, 0.25 mmol) was dissolved in acetone (3 mL). A
solution of 1,7-phenanthroline (0.045 g, 0.25 mmol) in methanol (2 mL)
was added dropwise to this solution with stirring. The solution, in a small
vial, was cooled to ꢀ108C, forming small crystals.
X-ray structure analysis: X-ray intensity data were measured on
a
[12] Other 1,4-additions, without halogens: a) Y. Morimoto, Y. Higuchi, K.
Wakamatsu, K. Oshima, K. Utimoto, N. Yasuoka, Bull. Chem. Soc.
Jpn. 1989, 62, 639; b) T. Kusumoto, T. Hiyama, Bull. Chem. Soc. Jpn.
1990, 63, 3103; c) G. Dyker, S. Borowski, G. Henkel, A. Kellner, I.
Dix, P. G. Jones, Tetrahedron Lett. 2000, 41, 8259.
[13] NMR spectroscopic calculations carried out in the deMon-NMR
program: a) V. G. Malkin, O. L. Malkina, D. R. Salahub, Chem. Phys.
Lett. 1996, 261, 335; b) A. Stamant, D. R. Salahub, Chem. Phys. Lett.
1990, 169, 387; c) D. R. Salahub, R. Fournier, P. Mlynarski, I. Papai, A.
St-Amant, J. Ushio in Density FunctionalMethods in Chemistry (Eds.:
J. Labanowski, J. Andzelm), Springer, New York, 1991.
[14] Spin-orbit coupling contribution, by sum-over-states density-func-
tional perturbation theory (SOS-DFPT), AMFI(1e þ 2e)/F64/IGLO-
II: a) M. Kaupp, O. L. Malkina, V. G. Malkin, P. Pyykkˆ, Chem. Eur. J.
1998, 4, 118; b) M. Kaupp, O. L. Malkina, V. G. Malkin, J. Comput.
Chem. 1999, 20, 1304; c) O. L. Malkina, B. Schimmelpfennig, K.
Kaupp, B. A. Hess, P. Chandra, U. Wahlgren, V. G. Malkin, Chem.
Phys. Lett. 1998, 296, 93.
[15] Scalar contribution to chemical shift: Perdew-86/IGLO-II þ ECP;
a) J. P. Perdew, Phys. Rev. B 1986, 33, 8822; b) J. P. Perdew, Y. Wang,
Phys. Rev. B 1986, 33, 8800; c) W. Kutzelnigg, U. Fleischer, M.
Schindler, NMR: Basic Princ. Prog. 1990, 23, 165; d) M. Dolg, Ph.D.
Bruker AXS diffractometer. The structures were solved by direct methods
and refined by using full-matrix least-squares methods (SHELX97).[20]
Empirical absorption corrections were applied. Compound 3 crystallizes
in space group P21/n, with a ¼ 4.4362(4) ä, b ¼ 17.1459(14) ä, c ¼
12.5217(10) ä,
b ¼ 96.716(2)8,
V¼ 945.90(14) ä3,
Z ¼ 2,
1calcd
¼
4.877 gcmꢀ3, T¼ 293(2) K, 4223 reflections measured, 1352 crystallograph-
ically independent (Rint ¼ 0.068), and 1154 reflections with I > 2s(I),
MoKa ¼ 0.71073 ä, 2qmax ¼ 538, R(Fobs) ¼ 0.034, wR(F2)all ¼ 0.113. Com-
ꢀ
pound 2 forms cocrystals with [1,7]-phenanthroline in the space group P1,
with a ¼ 7.4475(17) ä, b ¼ 10.609(2) ä, c ¼ 14.845(3) ä, a ¼ 103.128(4)8,
b ¼ 103.840(4)8,
g ¼ 91.510(4)8,
V¼ 1105.0(4) ä3,
Z ¼ 2,
1calcd
¼
2.974 gcmꢀ3, T¼ 293(2) K, 6417 reflections measured, 4390 crystallograph-
ically independent (Rint ¼ 0.174), and 3591 reflections with I > 2s(I),
MoKa ¼ 0.71073 ä, 2qmax ¼ 538, R(Fobs) ¼ 0.120, wR(F2)all ¼ 0.379. Unit cells
and ORTEP representations are available as supplementary material.
CCDC-181226 and 181227 contain the supplementary crystallographic
data for this paper. These data can be obtained free of charge via
tallographic Data Centre, 12, Union Road, Cambridge CB21EZ, UK; fax:
(þ 44)1223-336-033; or deposit@ccdc.cam.ac.uk).
Received: March 12, 2002 [Z18877]
Angew. Chem. Int. Ed. 2002, 41, No. 16
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