Supplementary Material (ESI) for Chemical Communications
This journal is © The Royal Society of Chemistry 2001
Communication B103408C
Monocarbaborane chemistry. Preparation and characterisation of [4-CB8H9], the ‘missing’
closo-carbaborane anion.
Tomáš Jelínek,a Bohumil Štíbr,b Josef Holub,a Mario Bakardjiev,c Drahomír Hnyk,c Daniel L Ormsby,a
Colin A. Kilner,a Mark Thornton-Pett,a Hans-Jörg Schanz,b Bernd Wrackmeyerb and John D Kennedyb
a
School of Chemistry of the University of Leeds, West Yorkshire, UK LS2 9JT.
b
Laboratorium für Anorganische Chemie der Universität Bayreuth, Postfach 101251, Bayreuth, Bayern
D-95440.
c
Institute of Inorganic Chemistry of the Academy of Sciences of the Czech Republic, 25068 Řež-by
Prague, The Czech Republic
d
Department of Chemistry of the Imperial College of Science, Technology and Medicine,
Exhibition Road, London, UK SW7 2AY
Electronic Supplementary Information.
NMR spectroscopy and structural and NMR calculations on the [4-CB8H9] anion.
The results of NMR spectroscopy on bulk samples were consistent with the structure derived from the
single-crystal work. The 1H-{11B} and 11B-{1H} spectra of the [4-CB8H9] anion 2 consist of 2 : 4 : 2
patterns of singlets for the cage BH units (quartets and doublets, respectively, in undecoupled spectra),
and 1H and 13C-{1H} NMR spectra of 2 each show a broad singlet due the cage CH group [doublet in
the
13
C-{11B} spectrum, 1J(13C-1H) 182 Hz]. The experimental shifts are also consistent with the
11
B
13
and C shieldings calculated by B3LYP/6-31G*/ GAIO work with various basis sets. The NMR data
are summarised as follows:
Observed NMR data, 294-297K, ordered as: assignment (11B)/ppm [(1H) {(13C)/ppm where
appropriate}] observed splitting from 1J(11B1H)/Hz (relative intensity in parentheses):
[PMePh3]+[CB8H9] (CD3CN solution) BH(5,6) +12.85 [+4.35] 145 (2BH), BH(1,2,7,8) –14.40
[+1.46] 150 (4BH), BH(3,9) –20.3 [+0.60] 135 (2BH) and CH(4) – [+4.10] - (1CH). [PBu4]+[CB8H9]( CDCl3 solution) BH(5,6) +12.80 [+4.37] 145 (2BH), BH(1,2,7,8) –14.30 [+1.42] 148 (4BH), BH(3,9)
–20.3 [+0.64] 136 (2BH) and CH(4) – [+4.13 {+44.5}] - (1CH).
Calculated NMR data: DFT-GIAO//B3LYP/6-31G* (11B)/ppm {(13C)/ppm} values for the C2voptimised structure are: B(3,9) +9.7, B(1,2,7,8) –16.0 and B(5,6) –20.9; corresponding HFGIAO/II//MP2(fc)/6-31G* values are: B(3,9) +16.7, B(1,2,7,8) –11.9, B(5,6) –16.9 and C(4) {+47.6};
and HF-GIAO/II//B3LYP/6-31G* values are B(3,9) +11.0, B(1,2,7,8) –18.5, B(5,6) -25.0, and C(4)
{+37.2}.
Supplementary Material (ESI) for Chemical Communications
This journal is © The Royal Society of Chemistry 2001
Calculated B3LYP/6-31G* symmetry-locked C2v coordinates for the [CB8H9]- anion 2 are as follows;
the coordinates obtained at the other levels of calculation are available from the relevant authors,
d.ormsby@ic.ac.uk and / or hnyk@iic.cas.cz.
B3LYP/6-31G* symmetry-locked C2v structure for [CB8H9] .
B 0.000000 0.895037 -1.151936
B 0.000000 -0.895037 -1.151936
B 1.423182 0.000000 -0.828549
B -1.423182 0.000000 -0.828549
B -0.997431 -0.894222 0.551463
B 0.997431 -0.894222 0.551463
B -0.997431 0.894222 0.551463
B 0.997431 0.894222 0.551463
C 0.000000 0.000000 1.450387
H 0.000000 1.757520 -1.984466
H 0.000000 -1.757520 -1.984466
H 2.463357 0.000000 -1.419365
H -2.463357 0.000000 -1.419365
H -1.657647 1.736627 1.086680
H -1.657647 -1.736627 1.086680
H 1.657647 1.736627 1.086680
H 1.657647 -1.736627 1.086680
H 0.000000 0.000000 2.534208