the SHELXTL software package. The crystallographically unique
anions were resolved into disordered positions. All non-hydrogen atoms
were anisotropically refined and all hydrogen atoms were isotropically
amine) and the other which posited a redistribution reaction
+
1
resulting in a mixture of cations of formulas L L BH
2
1
+
2
, L
2 2
BH
2
2+
+
2
and L
2
BH . However, after extensive computational evaluations
2 2
refined. Crystal data for [(N-alkylimidazole)(amine)BH ] Tf N : for-
and an exhaustive VT, multinuclear and multidimensional NMR
study of this system, we favor the former scenario. The clearest
mula C 17BF , M 5 434.20, Triclinic, a 5 9.1544(14),
9
H
6 4 4 2
N O S
˚
b 5 10.1383(16), c 5 10.7424(17) A, a 5 77.628(3), b 5 72.260(3),
3
˚
11
c 5 80.393(3)u, V 5 922.0(2) A , T 5 173(2) K, space group P-1, Z 5 2,
m(MoKa) 5 0.369 mm , independent reflections 5 2628, Rint 5 0.0129,
evidence in support of this arises from the proton decoupled B-
21
spectrum of the mixture, which exhibits only two peaks (23.82
R1 5 0.0348, wR2 5 0.0869 [I . 2s(I)]. CCDC 268268. See http://
dx.doi.org/10.1039/b504631a for crystallographic data in CIF or other
electronic format.
(a) J. J. Golding, D. R. Macfarlane, L. Spiccia, M. Forsyth,
B. W. Skelton and A. H. White, Chem. Commun., 1998, 1593; (b)
J. Fuller, R. T. Carlin, H. C. DeLong and D. Haworth, J. Chem. Soc.,
Chem. Commun., 1994, 299; (c) J. D. Holbrey, W. M. Reichert,
M. Nieuwenhuyzen, O. Sheppard, C. Hardacre and R. D. Rogers,
Chem. Commun., 2003, 476; (d) J. D. Holdrey, W. M. Reichert and
R. D. Rogers, Dalton Trans., 2004, 2267.
11
and 27.98 ppm, rel. Et OBF ). Note that the B-resonance from
2
3
2
2
+
2
a separately prepared sample of the salt L BH Tf N (itself a
2
2
9
mobile RTIL) is observed at 28.46 ppm. Finally, we observe that
the minor cation component of the system is cleanly and
irreversibly converted into the major component cation upon
6
thermolysis in dmso-d . Despite the existence of dmso-supported
20
11
boronium ions, no additional peaks were observed in the B-
NMR during this procedure, also militating against a redistribu-
tion reaction.
10 J. M. Garrett and G. E. Ryschkewitsch, Inorganic Syntheses, ed. R. W.
Parry, McGraw-Hill, New York, 1970, vol. 12, p. 132.
1 (a) C. M. Gordon, in Ionic Liquids in Synthesis; P. Wasserscheid and
1
Overall, the present results demonstrate that imidazole-derived
boronium ions constitute a useful complement to the more familiar
dialkylimidazolium ions for the formulation of new ionic liquids.
Preliminary work (vide supra) has also now revealed that
T. Welton, Eds.; Wiley-VCH: Weinheim, 2003; pp. 17–19; (b) C. Hilgers
and P. Wasserscheid, in Ionic Liquids in Synthesis; P. Wasserscheid and
T. Welton, Eds.; Wiley-VCH: Weinheim, 2003; pp. 21–24; (c)
T. M. Bockman and J. K. Kochi, J. Am. Chem. Soc., 1989, 111,
4669; (d) S. Pommeret, J.-C. Mialocq, B. Tokarczyk and W. Jarzeba,
Res. Chem. Intermed., 2001, 27, 7–8, 795.
+
bis(alkylimidazole)BH2 ions are also capable of forming RTIL,
+
and work is in progress to evaluate bis(amine)BH2 ions for this
12 For representative examples see: (a) A. Kumar and S. S. Pawar, J. Org.
Chem., 2004, 69, 1419; (b) A. Aggarwal, N. L. Lancaster, A. R. Sethi
and T. Welton, Green Chem., 2002, 4, 24; (c) M. J. Earle,
P. B. McCormac and K. R. Seddon, Green Chem., 1999, 1, 23; (d)
C. W. Lee, Tetrahedron Lett., 1999, 40, 2461.
purpose as are studies on other boronium ion variants and
applications.
JHD thanks ChevronTexaco for sponsorship of this research,
2
and Rhodia for a gift of LiTf N. AW and EAS thank the
1
3 (a) J. H. Davis, Jr. and J. D. Madura, Tetrahedron Lett., 1996, 37, 2729;
(b) J. H. Davis, Jr. and J. D. Madura, unpublished.
Alabama Supercomputing Authority for computational resources.
Research at UA has been supported by the U.S. Environmental
Protection Agency’s STAR program through grant number RD-
1
4 DFT optimizations were carried out on an SGI Altix 350 super-
computer using the Gaussian 03 suite of programs (Ref. 15). The
B3LYP density functional was chosen along with the 6-31G(d,p) basis
set. Optimizations were followed by NMR calculations (Ref. 16) using
the B3LYP/6-311 + G(2d,p) density. Electrostatic potentials on the
isodensity surface and electrostatically derived charges were generated
via the Spartan program on an SGI Octane workstation (Ref. 17).
83143201-0. (Although the research described in this article has
been funded in part by EPA, it has not been subjected to the
Agency’s required peer and policy review and therefore does not
necessarily reflect the views of the Agency and no official
endorsement should be inferred).
1
5 Gaussian 03, Revision C.02, M. J. Frisch, G. W. Trucks, H. B. Schlegel,
G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr.,
T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar,
J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega,
G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota,
R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao,
H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross,
C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev,
A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala,
K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V. G.
Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O. Farkas,
D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman,
J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J. Cioslowski,
B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi,
R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng,
A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson,
W. Chen, M. W. Wong, C. Gonzalez and J. A. Pople, Gaussian, Inc.,
Wallingford CT, 2004.
Notes and references
1
R. D. Rogers and K. R. Seddon, in Ionic Liquids as Green Solvents –
Progress and Prospects, ed. R. D. Rogers and K. R. Seddon, ACS
Symp. Ser. 856, ACS, Washington, DC, 2003, p. xiii.
2
3
(a) M. Freemantle, Chem. Eng. News, 2004, 82, 45, 44; (b)
M. Freemantle, Chem. Eng. News, 2004, 82, 18, 26.
K. R. Seddon, in The International George Papatheodorou Symposium:
Proceedings, S. Boghosian, V. Dracopoulos, C. G. Kontoyannis and
G. A. Voyiatzis, Eds.; Institute of Chemical Engineering and High
Temperature Chemical Processes: Patras, 1999; p. 131.
4
5
E. B. Carter, S. L. Culver, P. A. Fox, R. D. Goode, I. Ntai,
M. D. Tickell, R. K. Traylor, N. W. Hoffman and J. H. Davis, Jr.,
Chem. Commun., 2004, 630.
While irregular, the ‘‘boronium ion’’ terminology is generally used to
. See: (a) K. C. Nainan and
(
x21)+
16 J. R. Cheeseman, G. W. Trucks, T. A. Keith and M. J. Frisch, J. Chem.
Phys., 1996, 104, 5947.
7 Spartan, Version 5.1.1, Wavefunction, Inc., Irvine, CA, 1998.
describe ions of the type [L
x
BR42x
]
G. E. Ryschkewitsch, Inorg. Chem., 1968, 7, 1316; (b) J. E. Douglass,
J. Am. Chem. Soc., 1962, 84, 121.
1
6
7
R. Frankel, J. Kniczek, W. Ponikwar, H. Noth, K. Polborn and
W. P. Fehlhammer, Inorg. Chim. Acta, 2001, 312, 23.
(a) N. E. Miller and E. L. Muetterties, J. Am. Chem. Soc., 1964, 86,
18 The B3LYP density functional was utilized along with the cc-pVTZ
basis set, with and without solvation correction. See: M.-H. Baik and
R. A. Friesner, J. Phys. Chem. A, 2002, 106, 7407.
1
033; (b) J. E. Douglass, J. D. Fellman, R. Carpenter, H.-M. Shih and
19 (a) A. G. Avent, P. A. Chalconer, M. P. Day, K. R. Seddon and
T. Welton, J. Chem. Soc., Dalton Trans., 1994, 3405; (b) A. Elaiwi,
P. B. Hitchcock, K. R. Seddon, N. Srinivasan, Y. M. Tan, T. Welton
and J. A. Zora, J. Chem. Soc., Dalton Trans., 1995, 3467; (c) P. Bonhote,
A.-P. Dias, N. Papageorgiou, K. Kalyanasundaram and M. Gratzel,
Inorg. Chem., 1996, 35, 1168.
Y.-F. Chiang, J. Org. Chem., 1969, 34, 3666; (c) J. E. Douglass,
J. D. Fellman, R. Carpenter, H.-M. Shih and Y.-F. Chiang, J. Org.
Chem., 1969, 34, 3666; (d) M. L. Denniston, M. Chiusano, J. Brown and
D. R. Martin, J. Inorg. Nucl. Chem., 1976, 38, 379.
Data were collected on a Siemens CCD area detector-equipped
˚
diffractometer with MoKa (l 5 0.71073 A) radiation and solved using
8
20 K. R. Koch and S. Madelung, Polyhedron, 1991, 10, 2221.
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