Template synthesis, structure and spectra of the semiclathrochelate and clathrochelate 1,4-pentadienylboron-capped iron(II) oximehydrazonates

Article abstract of DOI:10.1016/j.ica.2009.11.005

The direct template condensation of diacetylmonooxime hydrazone with the 1,4-pentadienylboronates as Lewis acids on an iron(II) ion matrix led to the 1,4-pentadienylboron-capped semiclathrochelate iron(II) oximehydrazonates. The H⁺-ion-catalyzed macrocyclization of these precursors with an excess of triethyl orthoformate resulted in macrobicyclic complexes with a single apical 1,4-pentadienyl substituent. The complexes obtained were characterized using elemental analysis, MALDI-TOF mass spectrometry, IR, UV-Vis, ¹H, ¹¹B{¹H} and ¹³C{¹H} NMR, ⁵⁷Fe M?ssbauer spectroscopies, and X-ray crystallography. The X-ray diffraction and NMR data for complexes obtained showed the syn,syn,syn-orientation of all ethoxy substituents in 1,3,5-triazacyclohexane capping fragment in relation to a clathrochelate framework.

Full text of DOI:10.1016/j.ica.2009.11.005

Inorganica Chimica Acta 363 (2010) 395–403
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Template synthesis, structure and spectra of the semiclathrochelate and
clathrochelate 1,4-pentadienylboron-capped iron(II) oximehydrazonates
a
b
b
a
Yan Z. Voloshin a, , Irina G. Makarenko , Sergey Y. Erdyakov , Semen V. Svidlov , Anna V. Vologzhanina ,
*
Ekaterina G. Lebed a, Anatolii V. Ignatenko b, Mikhail E. Gurskii b, Yurii N. Bubnov a
a Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991 Moscow, Russia
b Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 17 March 2009
Received in revised form 23 October 2009
Accepted 8 November 2009
Available online 14 November 2009
The direct template condensation of diacetylmonooxime hydrazone with the 1,4-pentadienylboronates
as Lewis acids on an iron(II) ion matrix led to the 1,4-pentadienylboron-capped semiclathrochelate iro-
n(II) oximehydrazonates. The H+-ion-catalyzed macrocyclization of these precursors with an excess of tri-
ethyl orthoformate resulted in macrobicyclic complexes with a single apical 1,4-pentadienyl substituent.
The complexes obtained were characterized using elemental analysis, MALDI-TOF mass spectrometry, IR,
UV–Vis, 1H, 11B{1H} and 13C{1H} NMR, 57Fe Mössbauer spectroscopies, and X-ray crystallography. The X-
ray diffraction and NMR data for complexes obtained showed the syn,syn,syn-orientation of all ethoxy
substituents in 1,3,5-triazacyclohexane capping fragment in relation to a clathrochelate framework.
Ó 2009 Elsevier B.V. All rights reserved.
Keywords:
Macrocycle
Clathrochelate
Iron(II)
Allylboration
Organoboranes
X-ray crystallography
1. Introduction
was explained by steric hindrances between one of the three eth-
oxy groups and the bulky o-carboranyl-containing semiclathroche-
Currently, a number of mono- and binuclear semiclathrochelate
iron(II) and cobalt(II, III) tris-oximehydrazonates with boron-, tin-,
germanium- and antimony-containing capping groups have been
synthesized and characterized [1–10]. Macrocyclization of these
precursors with active carbonyl compounds (for example, formal-
dehyde and trichloroacetaldehyde) leads to macrobicyclic clathr-
ochelate complexes. H+-ion-catalyzed condensation of the iron(II)
semiclathrochelates with triethyl orthoformate (TOF) results in
formation of only isomer of clathrochelate complex. In the case
of boron-capped semiclathrochelates, the isomers of these clathr-
ochelates with syn,syn,syn-orientation of the ethoxy substituents
in relation to the meanplane of 1,3,5-triazacyclohexane capping
group [6] have been isolated, whereas the macrobicyclization of
the tin-, germanium-, and antimony-capped semiclathrochelates
with TOF gave anti,anti,anti-isomers of the corresponding macrobi-
cyclic complexes [6–8]. The change in geometry of the semiclathr-
ochelate precursors from a trigonal-prism (TP) for boron-capped
complexes to a trigonal-antiprism (TAP) for clathrochelates with
other types of capping groups, explains these differences [7–10].
Only for o-carboranylboron-capped iron(II) tris-oximehydrazonate
the formation of the syn,syn,anti-isomer has been observed. That
late ligand in the first stage of macrocyclization with TOF [11].
In this paper, we describe the synthesis and characterization of
boron-capped oximehydrazonate iron(II) semiclathrochelates with
an apical 1,4-pentadienyl substituent and their macrocyclization
with TOF.
2. Experimental
2.1. General information
The reagents used, FeCl2 Á 4H2O, N2H4ÁH2O, TOF, sorbents, and
organic solvents were obtained commercially (Fluka). Diac-
etylmonooxime hydrazone (HDXO) was obtained as described pre-
viously [12]. The penta-1,4-dienylboronates 1–5 were prepared by
allylboration of the R–C„CH acetylenes, where R is CH3, C3H7 and
C6H5, with allyldichloroboranes followed by alcoholysis [13,14].
Analytical data (C, H and N contents) were obtained with a Carlo
Erba model 1106 microanalyzer. Iron content was determined
spectrophotometrically.
The MALDI-TOF mass spectra were recorded using a MALDI-
TOF-MS Bruker Autoflex mass spectrometer in reflecto-mol mode.
The ionization was induced by UV-laser with wavelength 336 nm.
The samples were applied to a nickel plate, 2,5-dihydroxybenzoic
acid was used as a matrix. The accuracy of measurements was 0.1%.
* Corresponding author.
E-mail address: voloshin@ineos.ac.ru (Y.Z. Voloshin).
0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2009.11.005

396
Y.Z. Voloshin et al. / Inorganica Chimica Acta 363 (2010) 395–403
The IR spectra of solid samples (KBr tablets) in the range of 400–
m(C@N–O), 1593 m(C@N–N), 1632, 1647, 1650sh m(C@C) + d(N–H).
4000 cmÀ1 were recorded with a IR200 Thermo Nicolet FT-
spectrophotometer.
MS (MALDI-TOF) m/z: 490 [M ÀBFÀ4 ]+. UV–Vis (CH3CN): kmax, nm
(
e
 10À3 molÀ1 L cmÀ1): 278(8.7), 305(2.2), 342(1.1), 400(0.7),
The UV–Vis spectra of solutions in dichloromethane and aceto-
nitrile were recorded in the range of 230–900 nm with a Lambda 9
Perkin Elmer spectrophotometer. The individual Gaussian compo-
nents of these spectra were calculated using the SPECTRA program.
The 1H, 11B{1H}, and 13C{1H} NMR spectra of the initial com-
pounds and complexes obtained were recorded from their CD3CN
443(2.1), 472(1.3), 480(3.9).
3.3. [FeDXO3(BCH@C(CH3)CH(CH3)CH@CH2)](BF4) (8)
This complex was obtained like the previous one except that the
boronate 3 (0.83 g, 3.7 mmol) was used instead of the boronate 2.
Yield: 0.67 g (58%). Anal. Calc. for C19H35N9O3B2FeF4: C, 38.61; H,
5.97; N, 21.33; Fe, 9.45. Found: C, 38.79; H, 5.79; N, 21.13; Fe,
9.28%. 1H NMR (CD3CN) d, ppm: 1.11 (br s, 3H, CH3CH (R)), 1.64
(s, 3H, CH3 (R)), 2.32 (br s, 18H, CH3(DXO)), 3.64 (m, 1H, –CH–
(R)), 4.85–5.13 (m, 3H, @CH2 (R) + BCH (R)), 5.91 (m, 1H, @CH–
(R)), 6.33 (s, 6H, NH2). 13C{1H} NMR (CD3CN) d, ppm: 14.5, 15.1
(two s, CH3(DXO)), 16.7 (s, CH3CH (R)), 20.4 (s, CH3C@ (R)), 42.0
(s, –CH– (R)), 113.5, 127.1 (br s, C–B (R) + CH2@ (R)), 143.0 (s,
and CDCl3 solutions with
AVANCE-600 spectrometers.
a Bruker AC-200P, AMX-400, and
57Fe Mössbauer spectra were obtained with a NP-255 (Hungary)
spectrometer with a constant acceleration mode. The spectra were
collected with a 256-multichannel amplitude analyzer. The isomer
shift was measured relative to sodium nitroprusside, and an
a-Fe
foil was used for the velocity scale calibration. 57Co in a rhodium
matrix was used as the source, which was always kept at room
temperature. The minimal absorption line-width in the spectrum
@CH– (R)), 151.7 (s,
(R)), 154.1 (s, C@N–O), 160.3 (s, C@N–
C
Me
of a standard sample of sodium nitroprusside was 0.24 mm sÀ1
.
N). 11B{1H} NMR (CD3CN) d, ppm: À0.2 (s, BF4À), 7.1 (br s, RBO3).
IR (KBr)
O) +
1650sh
m m(N–O), 1078, 1110m m(B–
/cmÀ1: 884, 999, 1031
m
(B–F), 1585 m(C@N–O), 1593 m(C@N–N), 1632m, 1645,
3. Synthesis
m
(C@C) + d(N–H). MS (MALDI-TOF) m/z: 504 [MÀBFÀ4 ]+.
UV–Vis (CH3CN): kmax
,
nm
(e
 10À3 molÀ1 L cmÀ1): 233(6.8),
3.1. [FeDXO3(BCH@C(CH3)CH2C(CH3)@CH2)](BF4) (6)
278(12), 304(4.4), 338(1.5), 443(1.7), 453(3.3), 479(5.4).
FeCl2 Á 4H2O (0.65 g, 2.2 mmol) and HDXO (0.8 g, 6.7 mmol)
were dissolved/suspended in acetonitrile (2 ml) and the solution
of the isopropyl boronate 1 (1 g, 4.5 mmol) and triethylamine
(0.31 ml, 2.3 mmol) in acetonitrile (1 ml) was added dropwise to
the stirring reaction mixture under argon. The dark-red reaction
mixture was stirred for 10 min and an excess of NaBF4 (0.5 g)
was added. The reaction mixture was stirred for 3 h and left for
48 h at 4 °C. Then the reaction mixture was filtered through the
Silasorb SPH-300 layer (30 mm), the filtrate was evaporated to a
small volume and precipitated with diethyl ether. The precipitate
was filtered, washed with a small amount of diethyl ether, hexane,
and dried in vacuo. Yield: 0.73 g (55%). Anal. Calc. for C19H35N9O3B2-
FeF4: C, 38.61; H, 5.97; N, 21.33; Fe, 9.45. Found: C, 38.40; H, 6.04;
N, 21.20; Fe, 9.37%. 1H NMR (CD3CN): d, ppm: 1.74 (s, 6H, CH3 (R)),
2.36, 2.39 (two s, 18H, CH3(DXO)), 3.19 (s, 2H, –CH2– (R)), 4.78 (s,
1H, @CH2 (R)), 4.81 (s, 1H, @CH2 (R)), 5.25 (s, 1H, BCH (R)), 6.33 (s,
6H, NH2). 13C{1H} NMR (CD3CN) d, ppm: 15.3, 16.3 (two s,
CH3(DXO)), 22.8, 25.6 (two s, CH3 (R)), 45.1 (s, –CH2– (R)), 111.7
(s, @CH2 (R)), 129.5 (br s, C–B (R)), 145.8, 146.3 (two s,
3.4. [FeDXO3(BCH@C(C6H5)CH2C(CH3)@CH2)](BF4) (9)
This complex was synthesized like the previous one except that
the boronate 4 (0.7 g, 2.7 mmol) was used instead of the boronate
3. Yield: 0.23 g (23%). Anal. Calc. for C24H37N9O3B2FeF4: C, 44.14; H,
5.71; N, 19.30; Fe, 8.55. Found: C, 44.00; H, 5.90; N, 19.10; Fe,
8.35%. 1H NMR (CD3CN) d, ppm: 1.73 (s, 3H, CH3 (R)), 2.30 (s,
18H, CH3(DXO)), 3.17 (s, 2H,–CH2– (R)), 4.66, 4.72 (two s, 2H,
@CH2 (R)), 5.52 (s, 1H, BCH (R)), 6.35 (s, 6H, NH2), 7.22 (m, 3H,
Ph (R)), 7.35 (m, 2H, Ph (R)). 13C{1H} NMR (CD3CN) d, ppm: 14.2,
14.8 (two s, CH3(DXO)), 22.3 (s, CH3 (R)), 51.8 (s, –CH2– (R)),
112.8 (s, @CH2 (R)), 127.1 (s, o-Ph(R)), 128.2 (s, p-Ph(R)), 129.6
(s, m-Ph(R)), 131.5 (br s, B–C (R)), 145.2, 145.7 (two s, ipso-
Ph +
(R)), 150.5 (s,
(R)), 154.4 (s, C@N–O), 160.5 (s,
C
Me
C
Ph
C@N–N). 11B{1H} NMR (CD3CN) d, ppm: À1.5 (s, BF4À), 5.3 (br s,
RBO3). IR (KBr)
m
/cmÀ1: 889, 997, 1038, 1062
m
(N–O), 1080m
m
m
(B–O) +
m
(B–F),
1591m
m(C@N–O) + m(C@N–N), 1637m
(C@C) + d(N–H). MS (MALDI-TOF) m/z: 566 [MÀBFÀ4 ]+. UV–Vis
 10À3 molÀ1 L cmÀ1): 252(5.4), 279(12),
C
Me
(CH3CN): kmax, nm (
305(5.4), 331(2.4), 440(3.6), 451(1.5), 483(5.9).
e
(R)), 154.4 (s, C@N–O), 160.6 (s, C@N–N). 11B{1H} NMR (CD3CN)
d, ppm: À0.5 (s, BF4À), 5.9 (br s, RBO3). IR (KBr)
m
/cmÀ1: 885, 995
m
(N–O), 1080m m(B–O) + m(B–F), 1585 m(C@N–O), 1592 m(C@N–N),
3.5. [FeDXO3(BCH@C(n-C3H7)CH(CH@CH2)2)](BF4) (10)
1632, 1645, 1650
m(C@C) + d(N–H). MS (MALDI-TOF) m/z: 504
[MÀBFÀ4 ]+. UV–Vis (CH2Cl2): kmax, nm (
e
 10À3 molÀ1 L cmÀ1):
This complex was obtained like the previous one except that the
boronate 5 (0.25 g, 1.2 mmol) was used instead of the boronate 4.
Yield: 0.17 g (33%). Anal. Calc. for C22H39N9O3B2FeF4: C, 41.87; H,
6.23; N, 19.98; Fe, 8.85. Found: C, 41.71; H, 6.19; N, 19.69; Fe,
8.70%. 1H NMR (CD3CN) d, ppm: 0.88 (t, 3H, CH3 (Pr), J = 7.3),
280(11), 303(3.7), 315(2.2), 349(0.9), 398(1.2), 452(4.3), 485(5.8).
3.2. [FeDXO3(BCH@C(CH3)CH2CH@CH2)](BF4) (7)
This complex was synthesized like the previous one except that
the boronate 2 (1.09 g, 5.2 mmol) was used instead of the boronate
1. Yield: 0.68 g (46%). Anal. Calc. for C18H33N9O3B2FeF4: C, 37.47; H,
5.76; N, 21.85; Fe, 9.68. Found: C, 37.29; H, 5.61; N, 21.61; Fe,
9.58%. 1H NMR (CD3CN) d, ppm: 1.74 (s, 3H, CH3 (R)), 2.31 (br s,
18H, CH3(DXO)), 2.97 (d, 2H, –CH2– (R) J = 6.6), 4.98 (d, 1H, @CH2
(R), J = 9.5), 5.05 (d, 1H, @CH2 (R), J = 17.1), 5.15 (s, 1H, BCH (R)),
5.84 (ddt, 1H, @CH (R), J = 17.1, 9.5, 6.6), 6.37 (s, 6H, NH2).
13C{1H} NMR (CD3CN) d, ppm: 14.3, 14.7 (two s, CH3(DXO)), 25.6
(s, CH3 (R)), 41.3 (s, –CH2– (R)), 115.5 (s, @CH2 (R)), 139.3 (s,
1.44 (m, 2H, b-CH2 (Pr)), 1.92 (t, 2H, a-CH2 (Pr), J = 8.2), 2.29,
2.30 (two s, 18H, CH3 (DXO)), 4.25 (t, 1H, CH (R), J = 6.9), 5.00–
5.09 (m, 4H, @CH2 (R)), 5.16 (s, 1H, BCH (R)), 5.99 (d, 2H, @CH
(R), J = 17.4, 9.8, 6.9), 6.31 (s, 6H, NH2). 13C{1H} NMR (CD3CN) d,
ppm: 14.3 (s, CH3(Pr)), 14.5, 14.9 (two s, CH3(DXO)), 21.8, 35.1
(two s, CH2 (Pr)), 53.0 (s, CH (R)), 115.0, 115.3 (two s, @CH2 (R)),
125.0 (br s, B–C (R)), 141.3, 142.7 (two s, @CH (R)), 153.4 (s,
C
(R)), 154.3 (s, C@N–O), 160.5 (s, C@N–N). 11B{1H} NMR (CD3CN)
d, ppm: À1.2 (s, BF4À), 6.3 (br s, RBO3). IR (KBr)
m
/cmÀ1: 885, 998
m
m
(N–O), 1081, 1117m m(B–O) + m(B–F), 1586 m(C@N–O), 1591
@CH– (R)), 146.8 (s,
(R)), 154.2 (s, C@N–O), 160.5 (s, C@N–
(C@N–N), 1627, 1637, 1650 m(C@C) + d(N–H). MS (MALDI-TOF)
C
Me
N). 11B{1H} NMR (CD3CN) d, ppm: À0.6 (s, BF4À), 6.1 (br s, RBO3).
m/z:
544
[MÀBFÀ4 ]+.
UV–Vis
(CH3CN):
kmax
,
nm
IR (KBr)
m
/cmÀ1: 883, 1034
m
(N–O), 1081m
m(B–O) +
m
(B–F), 1580
(e
 10À3 molÀ1 L cmÀ1): 280(19), 306(6.3), 346(1.7), 410(2),

Y.Z. Voloshin et al. / Inorganica Chimica Acta 363 (2010) 395–403
397
456(7.8), 486(8.7). 57Fe Mössbauer spectrum (mm sÀ1): IS = 0.42,
QS = 0.27.
112.8 (s, @CH2 (R)), 124.2 (br s, B–C (R)), 143.0 (s, @CH– (R)),
151.2 (s, C@N–O), 153.8 (s,
(R)), 169.6 (s, C@N–N). 11B{1H}
C
Me
NMR (CDCl3) d, ppm: À1.1 (s, BF4À), 5.6 (br s, RBO3). IR (KBr)
m/
m(B–F),
cmÀ1: 909m, 996, 1066
m(N–O), 1103, 1122m
m(B–O) +
3.6. [FeDXO3(HCOC2H5)3(BCH@C(CH3)CH2C(CH3)@CH2)](BF4) (11)
Complex 6 (0.40 g, 0.7 mmol) was dissolved/suspended in ace-
1574
m(C@@N–O), 1611 m(C@N–N), 1630, 1644m m(C@C). MS
(MALDI-TOF) m/z: 672 [MÀBFÀ4 ]+. UV–Vis (CH2Cl2): kmax, nm
(e
 10À3 molÀ1 L cmÀ1): 235(1.8), 261(7.5), 298(2.7), 337(1.8),
tonitrile (2 ml) and trifluoroacetic acid anhydride (5 ll) and an ex-
415(1.4), 457(3.1), 495(7.5), 527(1.6).
cess of triethyl orthoformate (1 ml) were added. The reaction
mixture was left for 72 h and then the reaction mixture was evap-
orated to a small volume and precipitated with water. The precip-
itate was filtered off and dried in air. The solid was reprecipitated
from chloroform with hexane, washed with hexane, and dried in
vacuo. Yield: 0.14 g (27%). Anal. Calc. for C28H47N9O3B2FeF4: C,
44.30; H, 6.24; N, 16.60; Fe, 7.36. Found: C, 44.12; H, 6.04; N,
16.63; Fe, 7.41%. 1H NMR (CDCl3) d, ppm: 1.14 (br s, 9H, CH3(OEt)),
1.74, 1.80 (two s, 6H, CH3 (R)), 2.43, 2.51 (two s, 18H, CH3(DXO)),
3.04 (s, 2H,–CH2– (R)), 3.78 (br s, 6H, CH2(OEt)), 4.78 (s, 2H,
@CH2 (R)), 5.44 (s, 1H, BCH (R)), 6.20 (c, 3H, HC). 13C{1H} NMR
(CDCl3) d, ppm: 14.2, 15.3 (two s, CH3(DXO)), 18.8 (s, CH3(OEt)),
22.5, 25.6 (two s, CH3 (R)), 44.9 (s, –CH2– (R)), 66.4 (s, OCH2),
98.0 (s, HC), 111.4 (s, @CH2 (R)), 127.5 (br s, B–C (R)), 144.8,
3.9. [FeDXO3(HCOC2H5)3(BCH@C(C6H5)CH2C(CH3)@CH2)](BF4) (14)
This complex was synthesized like the previous one except that
the complex 9 (0.23 g, 0.35 mmol) was used instead of the complex
8. Yield: 0.09 g (29%). Anal. Calc. for C33H49N9O3B2FeF4: C, 48.26; H,
6.01; N, 15.35; Fe, 6.80. Found: C, 48.15; H, 6.00; N, 15.43; Fe,
6.90%. 1H NMR (CDCl3) d, ppm: 1.15 (br s, 9H, CH3(OEt)), 1.77(s,
3H, CH3 (R)), 2.19, 2.46 (two s, 18H, CH3(DXO)), 3.18 (s, 2H,–
CH2– (R)), 3.80 (br s, 6H, CH2(OEt)), 4.70, 4.76 (two s, 2H, @CH2
(R)), 5.69 (s, 1H, BCH (R)), 5.98 (br s, 3H, HC), 7.08–7.42 (m, 5H,
Ph (R)). 13C{1H} NMR (CDCl3) d, ppm: 14.0, 14.3 (two s, CH3(DXO)),
19.0 (s, CH3(OEt)), 22.8 (s, CH3 (R)), 51.6 (s, –CH2– (R)), 67.0 (s,
OCH2), 98.8 (s, HC), 112.8 (s, @CH2 (R)), 126.2 (s, p-Ph (R)), 127.5
(s, o-Ph (R)), 128.7 (s, m-Ph (R)), 143.8, 145.1, 151.6 (three s,
148.5 (two s,
(R)), 151.2 (s, C@N–O), 169.9 (s, C@N–N).
C
Me
11B{1H} NMR (CDCl3) d, ppm: À1.0 (s, BF4À), 6.1 (br s, RBO3). IR
(KBr)
m m(N–O), 1102–1120m m(B–
/cmÀ1: 909, 922, 995, 1060
ipso-Ph (R) +
(R) +
(R)), 151.9 (s, C@N–O), 169.8 (s,
O) + m(B–F), 1574 m(C@N–O), 1611, 1618 m(C@N–N), 1633, 1648,
C
Me
C
Ph
C@N–N). 11B{1H} NMR (CDCl3) d, ppm: À1.3 (s, BF4À), 6.3 (br s,
1650
m
(C@C). MS (MALDI-TOF) m/z: 672 [MÀBFÀ4 ]+. UV–Vis
m m(N–O), 1103–
/cmÀ1: 899, 920, 994, 1064
(CH2Cl2): kmax, nm (
298(2.7), 337(1.8), 415(1.4), 457(3.1), 495(7.5), 527(1.6).
e
 10À3 molÀ1 L cmÀ1): 235(1.8), 261(7.5),
RBO3). IR (KBr)
1120m (B–O) +
1636, 1650sh
m
m
(B–F), 1573
m
(C@N–O), 1598
m(C@N–N),À1619m,
m
(C@C). MS (MALDI-TOF) m/z: 734 [MÀBF4 ]+. UV–
Vis (CH2Cl2): kmax, nm (
e
 10À3 molÀ1 L cmÀ1): 255(9.2), 272(10),
3.7. [FeDXO3(HCOC2H5)3(BCH@C(CH3)CH2CH@CH2)](BF4) (12)
302(5.8), 331(3.8), 456(3.3), 479(2.9), 495(9.9). 57Fe Mössbauer
spectrum (mm sÀ1): IS = 0.32, QS = 0.23.
This complex was synthesized like the previous one except that
the complex 7 (0.50 g, 0.9 mmol) was used instead of the complex
6. Yield: 0.14 g (22%). Anal. Calc. for C27H45N9O6B2FeF4: C, 43.52; H,
6.09; N, 16.92; Fe, 7.49. Found: C, 43.32; H, 5.99; N, 16.96; Fe,
7.69%. 1H NMR (CDCl3) d, ppm: 1.10 (br s, 9H, CH3(OEt)), 1.41 (s,
3H, CH3 (R)), 2.44, 2.51 (two s, 18H, CH3(DXO)), 3.10 (br s, 2H, –
CH2– (R)), 3.78 (br s, 6H, CH2(OEt)), 5.93–5.16, (m, 2H, @CH2 (R)),
5.48 (s, 1H, BCH (R)), 5.87 (m, 1H, @CH– (R)), 5.91 (c, 3H, HC).
13C{1H} NMR (CDCl3) d, ppm: 14.1, 14.9 (two s, CH3(DXO)), 18.5
(s, CH3(OEt)), 25.8 (s, CH3 (R)), 41.0 (s, –CH2– (R)), 65.9 (s, OCH2),
97.2 (s, HC), 115.4 (s, @CH2 (R)), 122.5 (br s, B–C (R)), 138.3 (s,
Table 1
Crystallographic data and refinement parameters for crystals of [7] (BF4) and [12]
(BF4) Á C6H6.
Parameter
[7] (BF4)
[12] (BF4)ÁC6H6
Empirical formula
Formula weight
Color, habit
Crystal dimensions (mm)
Crystal system
Space group
a (Å)
C18H33B2F4FeN9O3
577.00
C33H50B2F4FeN9O6
822.29
orange, prism
0.28 Â 0.12 Â 0.08
monoclinic
P21/n
dark-orange, prism
0.32 Â 0.18 Â 0.12
monoclinic
P21/n
@CH– (R)), 149.0 (s,
(R)), 151.6 (s, C@N–O), 170.0 (s, C@N–
C
Me
N). 11B{1H} NMR (CDCl3) d, ppm: À1.2 (s, BF4À), 5.9 (br s, RBO3).
8.3622(11)
40.368(5)
8.5590(12)
116.410(3)
2587.7(6)
4
11.9171(7)
13.6939(8)
23.4946(13)
90.6310(10)
3833.9(4)
4
IR (KBr)
m
/cmÀ1: 908m, 995, 1060
m
(N–O), 1102, 1123m
m(B–
b (Å)
c (Å)
O) + (B–F), 1575
m
m
(C@N–O), 1612 À
m(C@N–N), 1633, 1647 m(C@C).
MS (MALDI-TOF) m/z: 658 [MÀBF4 ]+. UV–Vis (CH2Cl2): kmax, nm
b (°)
Volume (Å3)
Z
(e
 10À3 molÀ1 L cmÀ1): 261(12), 297(6.7), 339(3.3), 399(1.2),
428(2.6), 466(6.6), 500(9.0), 515(3.7). 57Fe Mössbauer spectrum
(mm sÀ1): IS = 0.28, QS = 0.29.
Dcalc (g cmÀ3
)
1.481
1.425
l
(mmÀ1
)
0.65
0.47
F(0 0 0)
1200
1724
Tmin
Tmax
0.910
0.952
0.901
0.941
3.8. [FeDXO3(HCOC2H5)3(BCH@C(CH3)CH(CH3)CH@CH2)](BF4) (13)
Reflections collected
Independent reflection/Rint
Observed reflection
hmax (°)
12 524
6168/0.067
3885
28.0
0.060
0.107
6168
341
56 024
9242/0.091
5895
28.0
0.048
0.132
9242
491
This complex was obtained like the previous one except that the
complex 8 (0.50 g, 0.8 mmol) was used instead of the complex 7.
Yield: 0.17 g (26%). Anal. Calc. for C28H47N9O3B2FeF4: C, 44.30; H,
6.24; N, 16.60; Fe, 7.36. Found: C, 44.15; H, 6.16; N, 16.45; Fe,
7.43%. 1H NMR (CDCl3) d, ppm: 1.07–1.26 (m, 12H, CH3(OEt),
CH3CH (R)), 1.77 (s, 3H, CH3C@ (R)), 2.45, 2.53 (two s, 18H,
CH3(DXO)), 3.62–3.86 (m, 7H, CH2(OEt), CH3CH (R)), 5.04 (d, 1H,
@CH2 (R), J = 8.2), 5.04 (d, 1H, @CH2 (R), J = 8.2), 5.08 (d, 1H,
@CH2 (R), J = 9.8), 5.37 (s, 1H, BCH (R)), 5.98 (m, 1H, @CH (R))
6.17 (br s, 3H, HC). 13C{1H} NMR (CDCl3) d, ppm: 13.8, 14.9 (two
s, CH3(DXO)), 17.4, 18.8 (two s, CH3(OEt) + CH3CH (R)), 20.4 (s,
CH3C@ (R)), 41.8 (s, CH3CH (R)), 65.9 (s, OCH2), 97.3 (s, HC),
R[F2 > 2
wR(F2)
r
(F2)]
Number of reflections
Number of parameters
Weighting scheme
w = 1/[
r
2(F2o) +
w = 1/[r
2((F2o) +
(0.021P)2 + 1.9P],
(0.050P)2 + 4.5P],
P = ((F2o + 2(F2c )/3
<0.0001
P = ((F2o + 2(F2c )/3
0.001
(D/r)
max
D
qmax
,
D
qmin (e ÅÀ3
Goodness-of-fit (GOF)
)
0.47, À0.41
0.84, À0.75
1.01
1.02

398
Y.Z. Voloshin et al. / Inorganica Chimica Acta 363 (2010) 395–403
3.10. [FeDXO3(HCOC2H5)3(BCH@C(n-C3H7)CH(CH@CH2)2)](BF4) (15)
4. X-ray crystallography
This complex was obtained like the previous one except that the
complex 10 (0.16 g, 0.25 mmol) was used instead of the complex 9.
Yield: 0.09 g (39%). Anal. Calc. for C31H51N9O6B2FeF4: C, 49.97; H,
6.64; N, 14.57; Fe, 8.78. Found: C, 49.78; H, 6.58; N, 14.43; Fe,
8.71%. 1H NMR (CDCl3) d, ppm: 0.93 (t, 3H, CH3 (Pr), J = 7.2), 1.25
Single crystals of the [7](BF4) and [12](BF4) Á C6H6 complexes
were grown from chloroform–benzene 1:1 mixture at room tem-
perature. The intensities of reflections were measured at 100(2) K
with a Bruker Apex II CCD area detector using graphite monochro-
mated Mo Ka radiation (k = 0.71073 Å). Transmission coefficients
(br s, 9H, CH3(OEt)), 1.56 (m, 2H, b-CH2 (Pr)), 2.03 (t, 2H,
a-CH2
were determined using SADABS program [15]. The structures were
solved by the direct method and refined by full-matrix least
squares against F2. Non-hydrogen atoms were refined in aniso-
tropic approximation except that for the disordered C(26) and
C(27) atoms in the [7]+ cation: the vinyl C(26)H@C(27)H2 fragment
of this cation is equiprobably disordered over two positions and its
carbon atoms were refined isotropically. Positions of hydrogen
atoms of the N–H groups were obtained from the difference Fou-
rier synthesis; H(C) atoms were placed in their geometrically cal-
culated positions. Positions of other hydrogen atoms were
calculated and included in the refinement by the riding model with
Uiso(H) = nUeq(C), where n = 1.5 for methyl groups and 1.2 for the
other atoms. All calculations were made using the SHELXTL PLUS 5 pro-
gram package [16]. Parameters of data collection and refinement
are collected in Table 1.
(Pr), J = 8.0), 2.45, 2.51 (two s, 18H, CH3(DXO)), 3.76 (br s, 6H,
CH2(OEt)), 4.28 (br s, 1H, CH (R)), 5.09–5.14 (m, 4H, @CH2 (R)),
5.41 (s, 1H, BCH (R)), 5.88 (s, 3H, CH), 6.03 (ddd, 2H, @CH (R)
J = 17.6, 9.2, 6.3). 13C{1H} NMR (CDCl3) d, ppm: 14.3 (s, CH3(Pr)),
14.3, 15.0 (two s, CH3(DXO)), 17.5 (s, CH3(OEt)), 21.9, 35.6 (two s,
CH2 (Pr)), 52.4 (s, CH (R)), 66.1 (s, OCH2), 97.5 (s, CH), 115.1 (s,
@CH2 (R)), 123.1 (br s, B–C (R)), 140.6 (s, @CH (R)), 152.5 (s,
C
(R)), 153.4 (s, C@N–O), 159.6 (s, C@N–N). 11B{1H} NMR (CDCl3) d,
ppm: À1.2 (s, BF4À), 6.3 (br s, RBO3). IR (KBr)
m
/cmÀ1: 914, 995,
m(N–O), 1103–1120m m(B–O) + m(B–F), 1576 m(C@N–O),
1062
1627m
m
(C@C) +
m
(C@N–N). MS (MALDI-TOF) m/z: 712 [MÀBFÀ4 ]+.
UV–Vis (CH2Cl2): kmax
,
nm
(e
 10À3 molÀ1 L cmÀ1): 262(8.1),
283(3.8), 304(4.4), 338(1.9), 427(2.0), 468(2.9), 501(8.6). 57Fe
Mössbauer spectrum (mm sÀ1): IS = 0.32, QS = 0.24.
+
NH2 NH2
NH2
N
NH2
R1
N
N
N
R2
N(C2H5)3
CH3CN
R
Fe2+
Fe2+
3
N
N
O
N
N
O
B(Oiso-C3H7)2
O
OH
B
1
-
5
R
R1
H
H
CH3
H
R2
CH3
H
H
CH3
H
R2
R
R1
1,6,11
2,7,12
3,8,13
CH3
CH3
CH3
HC(OC2H5)3
H+
6
-
10
4,9,14 C6H5
5,10,15 n-C3H7 CH = CH2
CH3CN
+
H
H
H
OC2H5
OC2H5
N
N
N
N
OC2H5
N
N
Fe2+
N
O
N
N
O
O
B
R2
R
R1
11
-
15
Scheme 1.

Y.Z. Voloshin et al. / Inorganica Chimica Acta 363 (2010) 395–403
399
complexes 6–10 (Scheme 1) were obtained by template condensa-
tion of diacetylmonooxime hydrazone with 1,4-pentadienylboro-
nates 1–5 as Lewis acids on Fe2+ ion matrix in presence of
triethylamine for neutralization of H+ ions forming during reaction
and capable to protolytically cleavage of the reactive B–Cvinyl bond.
5. Results and discussion
Similarly to the boronates 1–4, diisopropyl ester of 1,4-penta-
dienylboronic acid 5 was synthesized from 1-pentyne and 2,4-pen-
tadienyl(dipropyl)borane
[17].
Semiclathrochelate
iron(II)
Fig. 1. Heteronuclear 1H–13C correlation NMR spectrum of the complex 10.

400
Y.Z. Voloshin et al. / Inorganica Chimica Acta 363 (2010) 395–403
Fig. 2. 57Fe Mössbauer spectrum of the complex 10.
H+-ion-catalyzed macrocyclization of these semiclathrochelate
precursors with excess of triethyl orthoformate resulted in oxi-
mehydrazonate clathrochelates 11–15 (Scheme 1).
1H and 13C{1H} NMR spectra of synthesized complexes 6–15
(see, for example, Fig. 1) contain signals of methyl substituents of
chelate oximehydrazonate fragments and characteristic signals of
1,4-pentadienyl groups. Number and position of signals in these
spectra, as well as the ratio of their integral intensities in the 1H
Fig. 4. ORTEP view of the [12] (BF4) molecule (the thermal ellipsoids are given with
50% probability level). The solvate benzene molecule is omitted for clarity. One
position of equiprobably disordered vinyl group is shown with a dashed line.
Fig. 3. ORTEP view of the [7] (BF4) molecule (the thermal ellipsoids are given with
50% probability level). Hydrogen bonds are shown with a dashed line.

Y.Z. Voloshin et al. / Inorganica Chimica Acta 363 (2010) 395–403
401
Table 3
NMR spectra, confirmed composition and C3 symmetry of the mol-
The characteristics of the hydrogen bonds in the crystal of [7] (BF4).
ecules. The single signals of methine groups of cross-linking frag-
ments and ethoxy substituents in 1H and 13C NMR spectra and
their chemical shift values, provide the evidence of formation of
syn,syn,syn-isomers of the corresponding clathrochelate com-
plexes. 11B{1H} NMR spectra of semiclathrochelate and clathroche-
late complexes contain the characteristic signals [18] of two types
of boron atoms (in tetrahedral apical capping O3BC fragments and
Fragment
d(D–H) (Å) d(HÁÁÁA) (Å) d(DÁÁÁA) (Å) \(DÁÁÁHÁÁÁA) (°)
N(3)–H(1)ÁÁÁF(1a) 0.88
N(3)–H(2)ÁÁÁF(1b) 0.88
2.401
2.421
2.441
2.462
2.162
2.061
2.150
3.028(3)
3.069(3)
3.030(4)
3.291(3)
3.027(3)
2.931(3)
2.962(4)
129
131
125
157
167
169
153
N(3)–H(2)ÁÁÁN(6)
N(6)–H(3)ÁÁÁF(4)
N(6)–H(4)ÁÁÁF(2c)
N(9)–H(5)ÁÁÁF(3)
N(9)–H(6)ÁÁÁN(3)
0.88
0.88
0.88
0.88
0.88
À
BF4 counter-ions).
IR spectra of obtained compounds contain the characteristic
bands of stretching vibrations of B–O and N–O bonds as well as
stretching vibrations bands of C@N ones in non-equivalent azome-
thine fragments of oximehydrazonate chelate cycles (oximate moi-
eties at approximately 1580 cmÀ1 and hydrazonate groups from
1590 to 1620 cmÀ1). The stretching vibrations bands of C@C bonds
in apical 1,4-pentadienyl substituents are observed in range of
Symmetry operations, which were used to generate the equivalent atoms: (a) xÀ1/2,
Ày + 1/2, z + 1/2; (b) xÀ1, y, z; (c) xÀ1/2, Ày + 1/2, zÀ1/2.
consistent with mean tabular values for corresponding ordinary
and double bonds. The coordination polyhedra of encapsulated ir-
on(II) ions in both cases have a distorted TP–TAP geometry. The
coordination Fe–N bonds are shorter from side of boron-capped
tripodal oximate fragment than those for the 1,3,5-triazacyclohex-
ane-capped group (Table 2). The shift of an encapsulated iron(II)
ion from center of FeN6-coordination polyhedron is stronger pro-
nounced in the case of semiclathrochelate [7]+ cation.
1619–1650 cmÀ1
The solution UV–Vis spectra of boron-containing iron(II) oxi-
.
mehydrazonates contain three bands of similar intensities (
e
ꢀ 1–
10 Â 103 molÀ1 L cmÀ1) in the range of 460–500 nm assigned to
the metal-to-ligand Fed ? Lp* charge transfer bands in the visible
region. The intensive bands in the UV region are caused by super-
position of the
ents and -diazomethine chelate fragments of highly
clathrochelate framework.
p–p
* transitions in 1,4-pentadienyl apical substitu-
-conjugated
a
p
Parameters of 57Fe Mössbauer spectra of obtained clathroche-
late complexes (see, for example Fig. 2), characterize them as
low-spin iron(II) complexes (as evident from isomeric shift (IS) val-
ues) with geometry that is intermediate between a TP (u = 0°) and
a TAP (u = 60°) (as evident from the quadrupole splitting (QS) val-
ues). The low-spin state of an encapsulated iron(II) ion can be ex-
plained by influence of high-field polyene macrobicyclic ligands
(so called ‘‘macrobicyclic effect”). These data are in a good agree-
ment with direct X-ray diffraction data for two synthesized
compounds.
The molecular structures of [7](BF4) and [12](BF4) complexes
are shown in Figs. 3 and 4; the main geometrical parameters of
their molecules are listed in Table 2. The C–C and C@C bond
lengths in the apical 1,4-pentadienyl substituents (Table 2) are
Table 2
The main geometrical parameters of the [7]+ and [12]+ cations.
Parameter
(Å)
[7]+
[12]+
Parameter
[7]+
[12]+
Fe(1)–N(1)
Fe(1)–N(2)
Fe(1)–N(4)
Fe(1)–N(5)
Fe(1)–N(7)
Fe(1)–N(8)
N(1)–C(2)
N(2)–C(3)
N(4)–C(6)
1.899(3) 1.900(2) N(4)–O(2)a (Å)
1.975(3) 1.933(2) N(7)–O(3)a (Å)
1.885(3) 1.901(2) N(2)–N(3) (Å)
1.982(3) 1.933(2) N(5)–N(6) (Å)
1.897(3) 1.903(2) N(8)–N(9) (Å)
1.959(3) 1.936(2) C(2)–C(3) (Å)
1.304(4) 1.311(3) C(6)–C(7) (Å)
1.381(3) 1.368(3)
1.387(3) 1.370(3)
1.381(3) 1.420(3)
1.397(3) 1.425(3)
1.378(4) 1.425(3)
1.442(5) 1.431(4)
1.461(4) 1.444(4)
1.304(4) 1.314(3) C(10)–C(11) (Å) 1.446(5) 1.436(4)
1.292(4) 1.310(3) C(13)–C(14)a
1.326(5) 1.329(4)
1.515(6) 1.505(5)
1.490(5) 1.504(6)
(Å)
1.313(4) 1.306(3) C(14)–C(16)a
(Å)
N(5)–C(7)
N(7)–C(10)
1.300(4) 1.309(3) C(16)–C(17)a
(Å)
N(8)–C(11)
B(1)–C(13)a
1.307(4) 1.312(3)
1.580(5) 1.575(4) C(17)–C(18)a
(Å)
1.502(5) 1.499(4)
1.503(4) 1.499(4) u (°)
1.512(6)
1.318(6) 1.308(6)
B(1)–O(1)a
B(1)–O(2)a
B(1)–O(3)a
N(1)–O(1)
1.309(6)
36.1
39.3
2.24
20.8
39.0
2.35
1.517(4) 1.501(4)
a (°)
1.369(3) 1.370(3) h (Å)
a
The O(2), O(3), C(13), C(14), C(16) and C(17) atoms of the [7]+ cation correspond
to the O(3), O(5), C(22), C(23), C(25) and C(27) atoms of the [12]+ macrobicycle
(Figs. 3 and 4). The bond distances in both the disordered C(26)–C(27) moieties are
given.
Fig. 5. Packing diagram of the [7] (BF4) molecules (view along the crystallographic
axis c). Hydrogen bonds are shown with a dashed line. Other hydrogen atoms are
omitted for clarity.

402
Y.Z. Voloshin et al. / Inorganica Chimica Acta 363 (2010) 395–403
Fig. 6. Packing diagram of the crystal of [12] (BF4) Á C6H6 (view along the crystallographic axis a). Hydrogen atoms are omitted for clarity.
Although the Fe–N (hydrazonate) bond lengths in the [7]+
the N–HÁÁÁF bonds with three semiclathrochelate cations and each
À
semiclathrochelate are longer than those in the 1,3,5-triazacyclo-
semiclathrochelate cation is bounded with four BF4 anions. As a
hexane-capped fragment of the [12]+ macrobicycle and the bite an-
result, the infinite H-bounded layers, which are perpendicular to
the crystallographical axis c (Fig. 5), are observed. These layers
are connected with each other by weak C(12)–HÁÁÁO(2) and
C(18)–HÁÁÁO(1) interactions with non-bonding CÁÁÁO and HÁÁÁO
distances equal to 3.293, 3.409 Å and 2.576, 2.557 Å, respectively,
and the C–HÁÁÁO angles approximately 130° and 149°. In the
crystal of [12](BF4) Á C6H6 (Fig. 4) only Coulombic and weak inter-
gles
a (half of the N–Fe–N angle in chelate cycle) are almost the
same in these cations, the height h of the TP–TAP coordination
polyhedron is smaller in the case of the semiclathrochelate com-
plex (2.24 and 2.35 Å for the [7]+ and [12]+ cations, respectively).
This fact may be explained by steric hindrances caused by macro-
cyclization of semiclathrochelate, which hinder distortion of the
coordination polyhedron around to C3-pseudoaxis that lies through
an encapsulated iron(II) ion and capping boron atoms. This hypoth-
esis is validated by the fact, that for semi- and clathrochelate [7]+
and [12]+ cations, the distortion angle u values are 36.1° and
20.8°, respectively. Moreover, the distortion of the FeN6-coordina-
tion polyhedron in the case of [7]+ also is valid for the second coor-
dination sphere of iron(II) ion: the rotation angle O(1)ÁO(2)ÁO(3)
relative to N(3)ÁN(6)ÁN(9) atoms (Fig. 3) is equal to 56.7°. Thus,
the whole semiclathrochelate [12]+ cation is more distorted around
to B(1)ÁÁÁFe(1) C3-pseudoaxis, which concludes that its macrocycli-
zation causes the translation-rotational elongation of the coordina-
tion polyhedron of an encapsulated iron(II) ion.
À
molecular contacts are observed. The BF4 anion is surrounded by
three clathrochelate cations andÀone solvate benzene molecule.
One of these cations and the BF4 anion forms the C(13)–HÁÁÁF(2)
and C(19)–HÁÁÁF(1) hydrogen bonds with non-bonding CÁÁÁF and
HÁÁÁF distances equal to 3.667, 3.336 Å and 2.687, 2.422 Å, respec-
tively. The C–HÁÁÁF angles between the hydrogen atoms of 1,3,5-
triazacyclohexane capping fragment and fluorine atoms of
this anion are equal to 167° and 152° (Fig. 6). Two other cations
are involved in the C–HÁÁÁF dipole–dipole interactions through
their methyl substituents. Each cation interacts with three
anions and a solvate benzene molecule through the C(9)–HÁÁÁ
p
contacts.
In agreement with X-ray diffraction data, ethoxy substituents in
the macrobicyclic [12]+ cation have the same orientation as its
semiclathrochelate fragment in relation to 1,3,5-triazacyclohexane
capping fragment (syn,syn,syn-isomer). This means that methine
hydrogen atoms in this moiety have anti,anti,anti-orientation in
relation to a semiclathrochelate fragment. Therefore, the sterical
effect of the apical 1,4-pentadienyl group in macrobicyclic [12]+
cation is not enough pronounced to result in anti-orientation of
any ethoxy substituent.
This work demonstrates that derivatives of 1,4-pentadienylbo-
ronic acids can be successfully used as cross-linking agents for syn-
thesis of oximehydrazonate d-metal clathrochelates with a single
apical 1,4-pentadienyl substituent that are precursors of the corre-
sponding metal-containing functionalized linear carbochain poly-
mers and co-polymers.
Acknowledgements
The ionic associates in the crystal of [7](BF4) are formed
(Fig. 3) both by the Coulombic interactions and by two strong
N–HÁÁÁF hydrogen bonds; geometrical parameters of these hydro-
gen bonds in this crystal are listed in Table 3. Each anion forms
The authors gratefully acknowledge support of the RFBR
(Grants 07-03-00765, 08-03-90441, 08-03-90107, 09-03-90454,
09-03-00928, and 09-03-00540), RAS (programmes 7 and 18),
and the President of RF (Grants MK-5074.2008.3 and

Y.Z. Voloshin et al. / Inorganica Chimica Acta 363 (2010) 395–403
403
[7] Y.Z. Voloshin, O.A. Varzatskii, S.V. Korobko, Y.A. Maletin, Inorg. Chem.
Commun. 1 (1998) 328.
[8] Y.Z. Voloshin, O.A. Varzatskii, N.G. Strizhakova, E.Y. Tkachenko, Inorg. Chim.
Acta 299 (2000) 104.
MK-966.2008.3). We also thank Marina Korisch for the editing of
English.
[9] Y.Z. Voloshin, O.A. Varzatskii, S.V. Korobko, M.Yu. Antipin, I.I. Vorontsov, K.A.
Lyssenko, D.I. Kochubey, S.G. Nikitenko, N.G. Strizhakova, Inorg. Chim. Acta
357 (2004) 3187.
[10] Y.Z. Voloshin, N.A. Kostromina, R. Krämer, Clathrochelates: Synthesis,
Structure and Properties, Elsevier, Amsterdam, 2002.
[11] Y.Z. Voloshin, S.Y. Erdyakov, I.G. Makarenko, E.G. Lebed, T.V. Potapova, S.V.
Svidlov, Z.A. Starikova, E.V. Polshin, M.E. Gurskii, Y.N. Bubnov, Russ. Chem.
Bull., Int. Ed. 56 (2007) 1787.
[12] M.O. Forster, B.B. Dey, J. Chem. Soc. 101 (1912) 2234.
[13] S.Y. Erdyakov, A.V. Ignatenko, T.V. Potapova, M.E. Gurskii, Y.N. Bubnov, in:
Abstr. XII Intern. Conf. on Boron Chemistry ‘‘Imeboron XII”, Japan, Sendai,
September 11–15, 2005, SP-B02.
Appendix A. Supplementary material
CCDC 708501 and 708502 contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif. Supplementary data associ-
ated with this article can be found, in the online version, at
doi:10.1016/j.ica.2009.11.005.
[14] Y.N. Bubnov, N.Y. Kuznetsov, F.V. Pastukhov, V.V. Kublitsky, Eur. J. Org. Chem.
2005 (2005) 4633.
References
[15] SADABS v.2.01, Bruker/Siemens Area Detector Absorption Correction Program,
Bruker AXS, Madison, WI, USA, 1999.
[16] SHELXTL v.5.10, Structure Determination Software Suite, Bruker AXS, Madison,
WI, USA, 1999.
[17] S.V. Svidlov, S.Y. Erdyakov, A.V. Ignatenko, M.E. Gurskii, Y.N. Bubnov,
Mendeleev Commun., 2010, in press.
[18] H. Nöth, B. Wrackmeyer, in: P. Diehl, E. Fluck, R. Kosfeld (Eds.), Nuclear
Magnetic Resonance Spectroscopy of Boron Compounds, NMR Basic Principles
and Progress, vol. 14, Springer, Berlin, 1978.
[1] J.A. Belinski, M.E. Squires, J.M. Kuchna, B.A. Bennet, J.J. Grzybowski, J. Coord.
Chem. 19 (1988) 159.
[2] J.N. Johnson, N.J. Rose, Inorg. Synth. 17 (1978) 139.
[3] V.L. Goedken, S.-M. Peng, Chem. Commun. (1973) 62.
[4] J.J. Grzybowski, R.D. Alien, J.A. Belinski, K.L. Bieda, T.A. Bish, P.A. Finnegan, M.L.
Hartenstein, G.S. Regitz, D.M. Ryalls, M.E. Squires, H.J. Thomas, Inorg. Chem. 32
(1993) 5266.
[5] K.L. Bieda, A.L. Kranitz, J.J. Grzybowski, Inorg. Chem. 32 (1993) 4209.
[6] Y.Z. Voloshin, A.I. Stash, O.A. Varzatskii, V.K. Belsky, Y.A. Maletin, N.G.
Strizhakova, Inorg. Chim. Acta 284 (1999) 180.