2–
12
REACTIONS OF THE closo-DODECABORATE ANION B12 H
53
ing mixture of the products (0.8 g) was dissolved in
CH3CN (25 mL). A solution of nickel(II) nitrate (5 g in
20 mL of H2O) was added under stirring to the resulting
solution, and its color changed from pale yellow to
blue. Then, 2,2'-dipyridyl (0.5 g) dissolved in acetoni-
trile (50 mL) was poured to the mixture. After 30 min,
a pink finely crystalline precipitate was formed, filtered
off, and recrystallized from acetonitrile, yielding pink
crystals. Visually the best crystals were grown from a
mixture of halogen-substituted products prepared by
prolong passing of HI. Of them, a crystal for X-ray dif-
fraction analysis was selected.
Elemental analyses for carbon, hydrogen, and
nitrogen were conducted on a CHNS-3 FA 1108 ele-
mental analyzer (Carlo Erba). Boron was determined
by atomic absorption spectroscopy using electrothermal
atomization on HGA-700 (model 2100) and HGA-72
(model 403) spectrophotometers (Perkin-Elmer) [13].
Elemental analysis data are given in Table 2.
IR spectra of the compounds were recorded as
Nujol mulls on an Infralyum FT-02 FT-IR spectrophotom-
eter (Lyumeks NPF AP) in the range 4000–400 cm–1.
Assignment of the most informative absorption bands
observed in the IR spectra of chlorosubstituted closo-
dodecaborates is presented in Table 3.
The 11B NMR spectra of solutions of the substances
under study in acetonitrile were recorded on a Bruker
AC-200 spectrometer at a frequency of 64.297 MHz with
internal deuterium lock. Boron trifluoride etherate was
used as the external reference. The 11B NMR data of
chlorosubstituted closo-dodecaborates are given in
Table 4.
Table 1. Reaction conditions, yields of products, and data of
mass spectrometry
Molecular
Hydrogen Compounds present Con-
weight
halide
in reaction mixture tent, %
of (CatAn)–
Temperature 60°C, synthesis time 1 h
HCl, HBr, HI (Bu4N)2B12H12
47
384.46
419.30
(Bu4N)2B12H11Cl
49
Temperature 80°C, synthesis time 1 h
HCl, HBr, HI (Bu4N)2B12H12
28
45
24
384.50
419.32
452.30
(Bu4N)2B12H11Cl
(Bu4N)2B12H10Cl2
Temperature 80°C, synthesis time 5 h
HCl
HBr
(Bu4N)2B12H11Cl
(Bu4N)2B12H10Cl2
(Bu4N)2B12H11Cl
(Bu4N)2B12H10Cl2
(Bu4N)2B12H10ClBr
(Bu4N)2B12H11Cl
(Bu4N)2B12H10Cl2
(Bu4N)2B12H10ClI
85
11
24
58
12
16
62
17
419.36
452.47
419.35
452.91
497.64
419.42
453.34
544.21
HI
Table 2. Maxima of some absorption bands observed in the
IR spectra of chlorosubstituted closo-dodecaborates, cm–1
Compound
ν(H–B) ν(B–Cl) ν(C≡N)
(Bu4N)2(B12H11Cl)
(Bu4N)2(B12H10Cl2)
2479
2475
2474
960
962
962
–
–
The electrospray ionization mass spectra (ESI/MS,
microspray, 4500 V) of solutions of the compounds
under consideration were measured on a Bruker
Esquire 3000 plus mass spectrometer in a water–aceto-
nitrile (50%) mixture with an additive of formic acid
(0.2%). The average analytical concentration of sam-
ples for ESI/MS was 1.00 0.20 mg/mL of the solution.
The molecular weights of the singly charged anions
(CatAn)– obtained from the spectra by the analysis of
the reaction mixtures are presented in Table 1.
Ni(Bipy)3(B12H10.668Cl1.332) ·
· 3CH3CN · 0.464H2O
2252
anisotropic approximation. The Cl(2), O(1w), and
H(C) atoms of the bipyridyl molecule were refined
independently in the isotropic approximation, and the
other H atoms were refined imposing different con-
straints. The H atoms of an acetonitrile molecule were
refined in idealized positions using the riding model
with the thermal displacement parameters Uiso = 1.2Ueq
of the C(12) atom. The H(3B) and H(4B) atoms of the
polyhedral anion were also refined in the riding model
in the idealized positions but their parameters Uiso were
refined independently. The positions of the H(1B) and
H(2B) atoms, whose site occupancies were 0.635 and
0.922, respectively, were fixed. The final refinement
estimates were R1 = 0.0418, wR2 = 0.0960 for 1819
reflections with I > 2σ(I); R1 = 0.1316, wR2 = 0.1211
for a full set of 4050 reflections; S = 0.976. The maxi-
mum and minimum residual electron densities were
X-ray diffraction. A set of reflections was obtained
on a CAD4 automated diffractometer (λMoKα radia-
tion, graphite monochromator, ω scan mode, 1.61° < θ <
27.96°) from a crystal 0.36 × 0.33 × 0.33 mm in size
covered with a layer of Fluorolube fluorinated oil.
Absorption correction was applied using the azimuthal
scan method. The crystals are trigonal: a = 14.2168(6) Å,
c = 37.954(3) Å, Z = 6, V = 6643.5(7) Å3, ρcalcd
1.268 g/cm3, µ(Mo) = 0.559 mm–1, space group R3 .
=
The structure was solved by direct methods. All
hydrogen atoms were located in difference Fourier syn-
theses. The site occupancies of the Cl(1), Cl(2), and
O(1w) atoms were 0.366(3), 0.078(3), and 0.155(5),
respectively. All non-hydrogen atoms, except Cl(2) and
O(1w), were refined by the least-squares method in the 0.320 and –0.235 e/Å3, respectively.
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 52 No. 1 2007