Synthesis and characterization of novel intramolecularly base-stabilized boron halides. Molecular structures of 1-X2BOCR1R 2-2-NMe2C6H4 [R1 = R 2 = Ph, X = Cl or F; R<

Article abstract of DOI:10.1002/zaac.200400375

The lithium alkoxides [1-LiOCR¹R²-2-NMe ₂C₆H₄]₂ [R¹ = R ² = Ph (1), Cy (2)] react with BCl₃ or BF ₃(Et₂O) to give 1-X₂BOCR<

Full text of DOI:10.1002/zaac.200400375

Synthesis and Characterization of Novel Intramolecularly Base-stabilized Boron
Halides. Molecular Structures of 1-X2BOCR1R2-2-NMe2C6H4 [R1 ؍ R2 ؍ Ph,
X ؍ Cl or F; R1 ؍ R2 ؍ Cy, X ؍ Cl] and [1-LiN(Ph)C(H)Ph-2-NMe2C6H4]2
Harbi Tomah Al-Masria, Joachim Sielera, 1), Steffen Blaurocka, 1), Peter Lönneckea, 1), Peter C. Junkb, 1), and
Evamarie Hey-Hawkins*,a
a Leipzig, Institut für Anorganische Chemie der Universität
b Victoria / Australia, School of Chemistry, Monash University
Received August 16th, 2004.
Dedicated to Professor Arndt Simon on the Occasion of his 65th Birthday
Abstract. The lithium alkoxides [1-LiOCR1R2-2-NMe2C6H4]2 [R1ϭ
R2 ϭ Ph (1), Cy (2)] react with BCl3 or BF3(Et2O) to give 1-
X2BOCR1R2-2-NMe2C6H4 [R1ϭ R2 ϭ Ph, X ϭ Cl (4); R1ϭ R2 ϭ
Cy, X ϭ Cl (5); R1ϭ R2 ϭ Ph, X ϭ F (6); R1ϭ R2 ϭ Cy, X ϭ F
(7)]. The lithium amide [1-LiN(Ph)C(H)Ph-2-NMe2C6H4]2 (3) re-
acts with BCl3 to give 1-Cl2BN(Ph)C(H)Ph-2-NMe2C6H4 (8).
Compounds 4 Ϫ 8 were characterized spectroscopically (NMR, IR,
MS), and crystal structures were determined for 3 Ϫ 6.
Keywords: Lithium alkoxide; Lithium amide; BCl2 derivatives; BF2
derivatives; Molecular structures
Synthese und Charakterisierung neuartiger intramolekular basen-stabilisierter
Borhalogenide. Molekülstrukturen von 1-X2BOCR1R2-2-NMe2C6H4 [R1 ؍ R2 ؍ Ph,
X ؍ Cl, F; R1 ؍ R2 ؍ Cy, X ؍ Cl] und [1-LiN(Ph)C(H)Ph-2-NMe2C6H4]2
Inhaltsübersicht.
Die
Lithiumalkoxide
[1-LiOCR1R2-2-
2-NMe2C6H4]2 (3) setzt sich mit BCl3 zu 1-Cl2BN(Ph)C(H)Ph-2-
NMe2C6H4 (8) um. Die Verbindungen 4 Ϫ 8 wurden spektrosko-
pisch (NMR, IR, MS), 3 Ϫ 6 auch röntgenstrukturanalytisch cha-
rakterisiert.
NMe2C6H4]2 [R1ϭ R2 ϭ Ph (1), Cy (2)] reagieren mit BCl3 oder
BF3(Et2O) zu 1-X2BOCR1R2-2-NMe2C6H4 [R1ϭ R2 ϭ Ph, X ϭ
Cl (4); R1ϭ R2 ϭ Cy, X ϭ Cl (5); R1ϭ R2 ϭ Ph, X ϭ F (6);
R1ϭ R2 ϭ Cy, X ϭ F (7)]. Das Lithiumamid [1-LiN(Ph)C(H)Ph-
Introduction
reported the synthesis of B2Mes3Ph2Ϫ (Mes ϭ 2,4,6-
2-
Me3C6H2)
[3a],
B2Ph2(NMe2)2
[3b]
and
Boron reagents with reactive boronϪsubstituent bonds are
interesting starting materials for the preparation of tran-
sition metalϪboron complexes [1] or compounds with mul-
tiple bonds between boron and main group elements, es-
pecially boronϪboron bonds. Stable transition metal com-
plexes with MϪB bonds have been prepared with amido-
substituted boron compounds by Braunschweig et al. [1] and
Nöth et al. [2], while Power et al. [3] and Nöth et al. [4]
B2(NMe2)2(NRЈ2)22Ϫ (NRЈ2 ϭ pyrrolyl, indolyl, carbazolyl)
[4], which formally contain a boronϪboron double bond.
In our ongoing studies on the synthesis and solid-state
structures
of
boron
reagents
with
reactive
boronϪsubstituent bonds [5, 6], we previously reported sol-
vent-free chelated dimethylamino lithium alkoxide and lith-
ium arylamide dimers with six- and seven-membered che-
late rings [7, 8], which are obtained from the corresponding
alcohols or amines [9]. These lithium salts are suitable start-
ing materials for the synthesis of transition metal [10] or
main group element complexes [11] with intramolecularly
base-stabilized six- and seven-membered chelate rings
which are more labile than the corresponding five-mem-
bered rings.
* Prof. Dr. Evamarie Hey-Hawkins
Institut für Anorganische Chemie, Universität Leipzig
Johannisallee 29, D-04103 Leipzig, Germany
Tel.: ϩ49 (0) 341/9736151
Fax: ϩ49 (0) 341/9739319
E-mail: hey@rz.uni-leipzig.de
We now report the high-yield synthesis and spectroscopic
properties of the BCl2 and BF2 derivatives 1-X2BOCR1R2-
2-NMe2C6H4 [R1ϭ R2 ϭ Ph, X ϭ Cl (4); R1ϭ R2 ϭ Cy,
X ϭ Cl (5); R1ϭ R2 ϭ Ph, X ϭ F (6); R1ϭ R2 ϭ Cy, X ϭ
F (7)] and 1-Cl2BN(Ph)C(H)Ph-2-NMe2C6H4 (8). Com-
pounds 4 Ϫ 8 were characterized spectroscopically (NMR,
IR, MS), and crystal structures were determined for 4 Ϫ 6.
Dr. Peter Junk
School of Chemistry, Monash University
PO Box 23
Victoria 3800, Australia
ϩ61-3-9905-4597
E-mail: Peter.Junk@sci.monash.edu.au
1) Crystal structure determination
518
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Novel Intramolecularly Base-stabilized Boron Halides
and 49.0 ppm (8). Moreover, a singlet is observed for the
CH carbon atom at 58.0 (8). The CϪO carbon atoms ap-
pear as a singlet at 84.0 (4), 84.1 (5), 82.3 (6) and 82.4 ppm
(7). The signals of the aromatic rings and cyclohexyl carbon
atoms are in the expected range but slightly shifted com-
pared to the organic ligands [9].
The 19F NMR signal of the BF2 group appears as a
singlet at Ϫ156.9 (6) and Ϫ154.4 ppm (7).
11B NMR spectra
The 11B NMR spectra show that the 11B signal moves to
lower field in the BCl2 derivatives [δ ϭ 8.6 (4), 7.9 (5) and
9.8 ppm (8)] relative to the BF2 derivatives [δ ϭ 1.9 (6) and
1.3 ppm (7)]. These shifts appear in a region specific for an
sp3-coordinated boron atom (tetrahedral environment of
the 11B nucleus) [5, 6] with BϪN interaction and are at
higher field by ca. 69 ppm relative to three-coordinate boranes
(cf. 9-phenyl-9-BBN, 9-BBN ϭ 9-borabicyclo[3.3.1]nonyl;
80.4 ppm) [12]. It is of interest to note that the boron atom
in the six-membered BF2 chelate rings 6 and 7 are more
shielded than in the the six-membered BCl2 chelate rings 4
and 5, which can be understood by taking electronic and
steric factors into consideration. The F atom is more elec-
tronegative (more electron-withdrawing) and has a smaller
size (less steric) than the Cl atom, consequently, the BϪN
bond is expected to be stronger and the boron atom be-
comes more shielded. However, this result is not in agree-
ment with the BϪN bond distances obtained from X-ray
diffraction, the BϪN bond of the six-membered BF2 chelate
Scheme 1 Preparation of 4 Ϫ 8
Results and Discussion
Synthesis
˚
ring in 6 [1.642(2) A] being longer than those observed for
The intramolecularly base-stabilized boron compounds 4 Ϫ
8 were prepared from the lithium alkoxides [1-LiOCR1R2-
2-NMe2C6H4]2 [R1ϭ R2 ϭ Ph (1), Cy (2)] [7] or the lithium
amide [LiN(Ph)C(H)Ph-2-NMe2C6H4]2 (3) [8] and BCl3 or
BF3(Et2O) as shown in Scheme 1. The BCl2 and BF2 de-
rivatives 4 Ϫ 8 were obtained in 85-90 % yield; they are
colorless, mostly air-stable solids.
˚
the six-membered BCl2 chelate rings in 4 [1.630(4) A] and
˚
5 [1.626(2) A].
The corresponding tetracoordinate BH2 [δ ϭ Ϫ2.5 to 4.4]
[11a] derivatives with six- and seven-membered chelate rings
exhibit chemical shifts in the same range as the tetracoordi-
nate species in 4 Ϫ 8. In contrast, while the BEt2 derivatives
of 1 and 2 1-Et2BOCR2-2-NMe2C6H4 (R ϭ Ph, Cy), with
six-membered rings exhibit similar chemical shifts (7.6 and
6.9 ppm), two major signals with different intensities are
observed in the 11B NMR spectra of 1-Et2BOCPh2CH2-2-
NMe2C6H4 (7.9, 32.0 ppm, ca. 2:1), which demonstrates the
existence of an equilibrium between two types of boron
compounds, presumably in tricoordinate (sp2) and tetraco-
ordinate (sp3) environments [13], in this larger seven-mem-
bered heterocycle, which is derived from the organic com-
pound 1-HOCPh2CH2-2-NMe2C6H4 [9].
Spectroscopic Properties
1H NMR spectra
The N(CH3)2 protons appear as a singlet at 3.05 (4), 3.29
(5), 2.96 (6), 3.02 (7) and two singlets at 3.55 and 3.67 ppm
(8), i.e. shifted downfield in comparison with the parent or-
ganic ligands [9], which suggests coordination of nitrogen
to the boron atom. The CH proton appears as a singlet at
3.19 ppm (8). The resonances corresponding to the cyclo-
hexyl (1.0-2.1 ppm) and aromatic protons (6.9-7.5 ppm) for
each compound show the characteristic resonances in their
expected chemical shift regions similar to those observed
for the organic ligands [9].
Mass spectrometry
The mass spectra gave parent ion peaks at m/z ϭ 382.8 (4)
and 351.3 (6), or fragments due to the elimination of Cl
(359.9 [Mϩ-Cl] (5)), Cy (280.3 [Mϩ-Cy] (7)), or BCl2 (302.3
[Mϩ-BCl2] (8)), which agree with the calculated isotopic dis-
tribution pattern. There are many fragments, which are
either analogous or identical in these closely related com-
pounds (see experimental part).
13C and 19F NMR spectra
The 13C{1H} NMR signals of the N(CH3)2 carbon atoms
appear as a singlet at 51.0 (4), 52.7 (5), 47.9 (6), 49.5 (7)
Z. Anorg. Allg. Chem. 2005, 631, 518Ϫ523
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H. T. Al-Masri, J. Sieler, S. Blaurock, P. Lönnecke, P. C. Junk, E. Hey-Hawkins
Figure 1 Molecular structure of 3 (hydrogen atoms and toluene
omitted for clarity)
Figure 2 Molecular structure of 4 (toluene omitted for clarity)
˚
Table 1 Selected bond lengths /A and bond angles /deg. for 3
Li(1)-N(2)
Li(2)-N(4)
Li(1)-N(1)
Sum of angles at Li(1)
Li(1)-N(2)-Li(2)
N(2)-Li(2)-N(4)
1.975(8)
1.972(8)
2.053(8)
360.0
74.1(3)
107.1(3)
Li(2)-N(2)
Li(1)-N(4)
Li(2)-N(3)
Sum of angles at Li(2)
Li(2)-N(4)-Li(1)
N(4)-Li(1)-N(2)
1.986(7)
2.038(8)
2.034(8)
359.9
73.0(3)
105.0(3)
IR spectra
The infrared spectra of compounds 4 Ϫ 8 afford a means
of determining the BϪN stretching vibration, which usually
appears as one of the strongest bands of the spectra be-
tween 1500 and 1444 cmϪ1 [14]. For 4 Ϫ 7, the band which
appears in the range of 1445-1321 cmϪ1 is attributed to the
BϪO stretching frequency [15]. For 4, 5 and 8, the medium-
strong bands which appear in the range of 965-993 and 520-
570 cmϪ1 are tentatively assigned to the asymmetric and the
symmetric BCl2 stretching vibration, for 6 and 7, the strong
or medium bands which appear in the range of 1445 and
1260 cmϪ1 are tentatively assigned to the asymmetric and
the symmetric BF2 stretching vibration [16].
Figure 3 Molecular structure of 5
NMe2C6H4]2 [8]. The bond lengths and angles of the or-
ganic fragment are similar to those observed for the corre-
sponding organic compound [9].
A planar environment would be expected for the three-
coordinate lithium atoms, and the sums of bond angles are
indeed close to 360°. The anti arrangement of the two
NMe2 methyl groups with respect to the Li2N2 core is simi-
lar to the anti alignment of the two NMe2 methyl groups
with respect to the Li2O2 core in [1-LiOCCy2-2-
NMe2C6H4]2 and [1-LiOCPh2CH2-2-NMe2C6H4]2 [7]. The
Molecular Structures of 3 ؊ 6
Compound 3 was prepared as described previously [8]. Col-
orless crystals of 3 were obtained from toluene at 20 °C.
Compound 3 crystallizes in the triclinic space group P1.
¯
Compound 3 (Fig. 1, Table 1) forms a centrosymmetric
dimer in the solid state. Due to the presence of an inversion
center, only the meso isomer (R,S) is observed in the solid
state. The central four-membered Li2N2 ring is planar with
smaller Li-N-Li and larger N-Li-N bond angles. The di-
methylamino groups are coordinated to the lithium atoms
˚
Li-N amide bond lengths [Li(1)-N(2) 1.975(8) A; Li(1)-N(4)
˚
˚
˚
2.038(8) A; Li(2)-N(2) 1.986(7) A; Li(2)-N(4) 1.972(8) A]
are similar to other lithium amides, which also contain a
three-coordinate lithium atom [8].
Colorless crystals of 4 Ϫ 6 were obtained as described in
the experimental section. Selected bond lengths and angles
are collected in Table 2. The molecular structures are de-
picted in Figures 2-4.
˚
˚
[Li(1)-N(1) 2.053(8) A; Li(2)-N(3) 2.034(8) A]. The Li-
NMe2 bond lengths, Li-N-Li and N-Li-N angles are similar
to those reported previously for [1-LiNPhCHPhCH2-2-
520
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Novel Intramolecularly Base-stabilized Boron Halides
Me [18]). Thus, the C-B-N bond angles in the latter [94.7(2),
95.2(1) and 95.7(2)°] are much smaller than the O-B-N
bond angles of 4 Ϫ 6, while the O-B-N bond angles
[109.2(1) and 110.0(1)°] of the BOC3N six-membered rings
in BCl2{2-(NEt2CH2)OC6H4} and [BCl2{2-NHEt2CH2-6-
(NEt2CH2)OC6H3}]Cl [6] are larger than the O-B-N bond
angle of 6 and similar to those observed for 4 and 5.
The data of the six-membered BOC3N rings in 4 Ϫ 6 are,
however, similar with those of the BOC3N six-membered
rings in BCl2{2-(NEt2CH2)OC6H4} and [BCl2{2-
NHEt2CH2-6-(NEt2CH2)OC6H3}]Cl [6]. The C-O-B bond
angles [119.9(1) and 122.8(1)°] are smaller than those for 4
Ϫ 6, the bond angles about B(1) [bond angles range from
108.0(1) to 111.6(1) and from 106.4(1) to 112.1(1)°] are less
distorted than those observed for 4 Ϫ 6, the bond angle
about N(1) [bond angles range from 104.8(1) to 116.0(1)
and from 104.9(1) to 116.2(1)°] is more distorted than those
Figure 4 Molecular structure of 6
˚
observed for 4 Ϫ 6, and the BϪO [1.425(2) and 1.420(2) A]
˚
Table 2 Selected bond lengths /A and bond angles /deg. for 4 Ϫ 6
˚
and the BϪN bond lengths [1.633(2) and 1.627(2) A] are
similar to those observed for 4 Ϫ 6.
Other structurally characterized examples of intramol-
4
5
6
B(1)-O(1)
B(1)-N(1)
B(1)-Cl(or F)
1.394(3)
1.630(4)
1.881(3)
1.859(3)
1.493(3)
1.405(3)
1.540(3)
1.437(3)
124.0(2)
109.9(2)
114.6(2)
108.8(2)
118.4(2)
122.5(2)
110.4(2)
1.391(2)
1.626(2)
1.860(2)
1.891(2)
1.496(2)
1.401(2)
1.536(2)
1.438(2)
122.5(1)
109.2(1)
117.5(1)
107.8(1)
121.5(2)
124.0(1)
108.9(1)
1.409(2)
1.642(2)
1.389(2)
1.384(2)
1.484(2)
1.394(2)
1.537(2)
1.432(1)
122.73(9)
108.4(1)
115.8(1)
110.0(1)
118.9(1)
123.3(1)
111.41(9)
ecularly base-stabilized six-membered boron-containing
rings include B(cat){2-(NHPhCH2)OC6H4} (cat
O2C6H4) [19], BPh2{2-(CHO)OC6H4} [20]
ϭ
and
C(3)-N(1)
C(3)-C(8)
C(8)-C(9)
C(9)-O(1)
C(9)-O(1)-B(1)
O(1)-B(1)-N(1)
O(1)-B(1)-Cl(or F)
B(CF3)2NMe2CH(Me)CMeϭCHO [21]. Here, the NHPh
˚
or CϭO [BϪN 1.636(4); BϪO 1.496(4) or 1.45(1) A] group
is coordinated to the boron atom, which exhibits a distorted
tetrahedral environment [bond angles range from 106.0(2)
to 114.9(3)°] in the range found in 4 Ϫ 6, while the BϪO
bond is longer than those observed in 4 Ϫ 6 [1.394(3),
N(1)-C(3)-C(8)
C(3)-C(8)-C(9)
C(8)-C(9)-O(1)
˚
1.391(2) and 1.409(2) A].
The BϪN bond lengths of 4 Ϫ 6 are similar to those of
related dichloroboron derivatives [5] and those of dialkyl-
or dialkoxyboron compounds with BC3N rings [17, 18].
Also, the BϪN bond lengths in 4 Ϫ 6 are larger than those
The common feature of the molecular structures of 4 Ϫ
6 is the intramolecular stabilization of the boron com-
pounds by interaction with the dimethylamino group. The
structural data of the O-C-phenylene-NC2 fragments are
similar for 4 (Fig. 2, Table 2), 5 (Fig. 3, Table 2) and 6 (Fig.
4, Table 2). The coordination of the amino group results in
a puckered six-membered BOC3N ring in 4 Ϫ 6: the C(9)-
C(8)-C(3)-N(1) fragment is coplanar, and in 4 and 6, both
the boron and oxygen atom lie above this plane [4: B(1)
˚
of the adducts BCl3(NMe3) [BϪN 1.575(10) A] [22],
˚
BCl3(py) [BϪN 1.592(3) A] [23] and BCl3(NCMe) [BϪN
˚
1.562(8) A] [24].
The bond lengths and angles of the organic fragment of
4 Ϫ 6 are similar to those observed for the corresponding
organic compounds [9].
Experimental Section
˚
˚
˚
˚
0.995 A, O(1) 0.510 A; 6: B(1) 0.923 A, O(1) 0.351 A], while
˚
˚
in 5, B(1) lies 0.567 A below and O(1) lies 0.071 A above
this plane. This leads to a distorted tetrahedral environment
at B(1) [small O-B-N bite angle [4: 109.9(2); 5: 109.2(1); 6:
108.4(1)°], one large and one small O-B-X (X ϭ F, Cl) bond
angle [4: 114.6(2), 108.8(2); 5: 117.5(1), 107.8(1); 6:
115.8(1), 110.0(1)°].
The structural data of the O-B-N bond angles in 4 Ϫ 6
differ remarkably from those of the strained five-membered
BC3N rings in B(OCH2CPh2O){2,6-(NMe2CH2)2C6H3}
General Remarks: All experiments were carried out under purified
dry nitrogen. Solvents were dried and freshly distilled under nitro-
gen. The NMR spectra were recorded in CDCl3 with an AVANCE
1
DRX 400 spectrometer (Bruker): H (400.1 MHz) and 13C NMR
(100.6 MHz) with tetramethylsilane as external standard; 11B
NMR spectra (128.4 MHz) with BF3(Et2O) as external standard;
19F NMR spectra (228.3 MHz) with CFCl3 as external standard.
Infrared spectra were recorded with a Perkin-Elmer System 2000
FT-IR spectrometer between 4000 and 400 cmϪ1 using KBr disks.
Elemental analyses were determined with a VARIO EL (Heraeus).
Melting points (Gallenkamp) are uncorrected. Mass spectra were
recorded with a MAT-8230 (EI-MS, 70 eV). BCl3 and BF3(Et2O)
were used as purchased. 1 Ϫ 3 were prepared according to the
literature [7, 8].
[17],
BCl2{2,6-(NEt2CH2)2C6H3}
and
and
BCl2{2-
BX2{2-
N(BCl3)Et2CH2-6-(NEt2CH2)C6H3}
(NR2CH2)C6H4} (X ϭ Cl, R ϭ Me [5]; BX2 ϭ 9-borabicy-
clo[3.3.1]nonane [18], R ϭ Me, Et; X2 ϭ OCH2CPh2O, R ϭ
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H. T. Al-Masri, J. Sieler, S. Blaurock, P. Lönnecke, P. C. Junk, E. Hey-Hawkins
s, C in C6H11), 49.3 (s, C1 in C6H11), 52.7 (s, N(CH3)2), 84.1 (s, CO), 120.7
2-(Dimethylaminophenyl)diphenylmethanolatoborondichloride (4): A
(s, C6 in C6H4), 127.7 (s, C4 in C6H4), 128.7 (s, C3 in C6H4), 128.9 (s, C5 in
C6H4), 141.2 (s, C2 in C6H4), 143.8 (C1 in C6H4). 11B NMR (δ/ppm): 7.9 (s).
IR (KBr): 3019 m, 2985 m-s, 2919 vs, 2852 vs, 2669 w, 1488 vs, 1467 vs,
1447 vs, 1404 vs, 1328 m, 1308 m-s, 1278 m, 1233 m, 1205 m-s, 1168 vs,
1154 vs, 1130 vs, 1049 m, 1084 m, 1075 m, 1048 m-s, 987 s, 961 m-s, 951 m,
914 vs, 895 m-s, 871 m-s, 822 s, 789 vs, 767 vs, 745 m-s, 722 s, 701 vs, 677 m,
647 m-s, 608 s, 564 m-s, 558 m-s, 519 m cmϪ1. MS found: m/z 359.9 (10 %,
MϩϪCl), 311.9 (100 %, MϩϪCy), 275.9 (28 %, MϩϪCyϪCl), 232.0 (18 %,
MϩϪCyϪClϪN(CH3)2), 213.9 (30 %, MϩϪCyϪOBCl2), 83.0 (30 %,
C6H11ϩ), 55.1 (80 %, C4H7ϩ), calc. for C21H32BCl2NO: M ϭ 396.2. Found:
C 63.50; H 9.28; N 3.59 %. Calc. for C21H32BCl2NO: C 63.66; H 8.14; N
3.54 %.
100 ml Schlenk flask containing 1 (6.64 g, 10.7 mmol) was cooled
to Ϫ78 °C and 50 ml of toluene was added. BCl3 in pentane (1 M
solution, 21.4 ml, 21.4 mmol) was added dropwise to this solution
while stirring. The reaction mixture was stirred at r.t. for 4 h. The
resulting suspension was filtered through celite to remove LiCl, the
filtrate was concentrated to about 20 ml and cooled to Ϫ30 °C giv-
ing the product as colorless crystals in 90 % yield (3.69 g). Mp
170-175 °C.
1H NMR (δ/ppm): 3.05 (s, 6H, N(CH3)2), 7.17-7.31 (m, 14H, C6H4 and
C6H5). 13C{1H} NMR (δ/ppm): 51.0 (s, N(CH3)2), 84.0 (s, CO), 119.9 (s, C6
in C6H4), 128.1 (s, C4 in C6H4), 128.6 (s, C3 in C6H4), 128.9 (s, C5 in C6H4),
129.1 (s, p-C in C6H5), 129.8 (s, o-C in C6H5), 132.4 (s, m-C in C6H5), 136.9
(s, C2 in C6H4), 143.8 (s, C1 in C6H4), 147.2 (s, ipso-C in C6H5). 11B NMR
(δ/ppm): 8.6 (s). IR (KBr): 3053 w, 1603 m, 1583 m, 1491 s, 1470 s, 1445 s,
1430 m, 1207 m, 1171 vs, 1150 vs, 1130 vs, 1107 m, 1093 m, 1084 m, 1060 m,
1035 m, 1007 m, 993 m, 955 m, 930 m, 922 m-s, 897 m-s, 812 s, 789 vs, 761 vs,
742 s, 704 vs, 645 m, 637 s, 612 s, 599 m, 554 m cmϪ1. MS found: m/z 382.8
(12 %, Mϩ), 347.9 (100 %, MϩϪCl), 305.8 (15 %, MϩϪPh), 285.9 (68 %,
MϩϪOBCl2), 255.8 (18 %, MϩϪBCl2ϪN(CH3)2), 207.8 (35 %,
MϩϪOBCl2ϪPh), 164.8 (23 %, MϩϪOBCl2ϪPhϪN(CH3)2), 90.9 (93 %,
C7H7ϩ), 76.9 (28 %, C6H5ϩ), 55.1 (18 %, C4H7ϩ), calc. for C21H20BCl2NO:
2-(Dimethylaminophenyl)diphenylmethanolatoborondifluoride (6): A
100 ml Schlenk flask containing 1 (6.64 g, 10.7 mmol) was cooled
to Ϫ78 °C and 50 ml of toluene was added. BF3(Et2O) in diethyl
ether (1 M solution, 21.4 ml, 21.4 mmol) was added dropwise to
this solution. The reaction mixture was stirred at room temperature
for 2 h. The resulting suspension was filtered through celite to re-
move LiF, the resulting filtrate was concentrated to about 20 ml
and cooled to Ϫ20 °C to give the product as colorless crystals in
85 % yield (3.19 g). Mp 190-192 °C.
M
ϭ
383.1. Found:
C
62.40;
H
5.37;
N
2.69 %. Calc. for
1H NMR (δ/ppm): 2.96 (s, 6H, N(CH3)2), 7.14-7.50 (m, 14, C6H4 and C6H5).
13C{1H} NMR (δ/ppm): 47.9 (s, N(CH3)2), 82.4 (CO), 119.7 (s, C6 in C6H4),
127.1 (s, C4 in C6H4), 127.7 (s, C3 in C6H4), 128.1 (s, C5 in C6H4), 128.6 (s,
p-C in C6H5), 129.3 (s, o-C in C6H5), 132.0 (s, m-C in C6H5), 137.0 (s, C2 in
C6H4), 144.6 (s, C1 in C6H4), 147.8 (s, ipso-C in C6H5). 11B NMR (δ/ppm):
1.9 (s). 19F NMR (δ/ppm): Ϫ156.9 (s). IR (KBr): 3033 w, 1583 m, 1488 m-s,
1474 s, 1445 s, 1283 w, 1260 m, 1203 vs, 1176 vs, 1124 vs, 1101 vs, 1086 s,
1060 m, 1047 m-s, 1034 m, 1004 m, 960 m-s, 926 m, 906 vs, 881 vs, 863 s,
785 vs, 778 vs, 770 vs, 746 m-s, 726 vs, 703 vs, 664 m, 651 w, 639 s, 566 w
cmϪ1. MS found: m/z 351.3 (10 %, Mϩ), 303.2 (55 %, MϩϪBF2), 287.2
C
21H20BCl2NO·H2O: C 62.72; H 5.51; N 3.48 %.
Phenyl ring numbering scheme:
(15 %,
MϩϪOBF2),
274.1
(25 %,
MϩϪPh),
258.1
(15 %,
MϩϪBF2ϪN(CH3)2), 226.1 (58 %, MϩϪBF2ϪPh), 210.1 (72 %,
MϩϪOBF2ϪPh), 180.0 (18 %, MϩϪBF2ϪPhϪN(CH3)2), 91.0 (100 %,
C7H7ϩ), 77.0 (80 %, C6H5ϩ), 55.1 (45 %, C4H7ϩ), calc. for C21H20BF2NO:
M ϭ 351.2. Found: C 71.00; H 4.99; N 3.70 %. Calc. for C21H20BF2NO: C
71.82; H 5.74; N 3.99 %.
2-(Dimethylaminophenyl)dicyclohexylmethanolatoborondichloride
(5): The reaction was carried out as described for 4 except that 2
(6.88 g, 10.7 mmol) was used instead of 1. Colorless crystals were
obtained from diethyl ether at Ϫ10 °C in 90 % yield (3.81 g). Mp
180-185 °C.
2-(Dimethylaminophenyl)dicyclohexylmethanolatoborondifluoride
(7): The reaction was carried out as described for 6 except that 2
(6.88 g, 10.7 mmol) was used instead of 1. Colorless crystals were
1H NMR (δ/ppm): 1.08-2.11 (m, 22H, C6H11), 3.29 (s, 6H, N(CH3)2), 7.34-
7.48 (m, 4H, C6H4). 13C{1H} NMR (δ/ppm): 27.2, 28.0, 28.3, 29.2, 30.8 (all
Table 3 Crystal data and structure refinement for 3 Ϫ 6
3
4
5
6
formula
Mr
C42H42Li2N4·C7H8
708.81
208(2)
C21H20BCl2NO·0.5 C6H5CH3
430.16
220(2)
monoclinic
P21/n
8.6297(9)
13.376(1)
18.878(2)
90
95.781(2)
90
2168.1(4)
4
1.318
900
C21H32BCl2NO
396.19
223(2)
monoclinic
P21/c
7.328(2)
13.090(3)
21.199(5)
90
90.46(1)
90
C21H20BF2NO
351.19
210(2)
orthorhombic
P212121
9.482(1)
10.065(1)
18.212(2)
90
90
90
1738.1(3)
4
1.342
temp /K
crystal system
space group
triclinic
¯
P1
˚
a /A
12.253(2)
12.366(2)
14.593(2)
78.285(4)
86.969(3)
67.467(3)
1998.9(5)
2
˚
b /A
˚
c /A
Ͱ /°
β /°
γ /°
3
˚
V /A
2033.5(8)
4
1.294
Z
dcalcd. Mg mϪ3
F(000)
1.178
756
848
736
crystal size /mm
abs coeff /mmϪ1
no. of rflns collec.
no. of indep rflns
Rint
0.20 x 0.20 x 0.05
0.068
13288
8158
0.0651
696
0.0786
0.2029
0.216/Ϫ0.231
0.50 x 0.40 x 0.30
0.316
13348
4736
0.0413
300
0.0451
0.1204
0.345/Ϫ0.267
0.40 x 0.30 x 0.30
0.33
13032
4833
0.0351
237
0.0431
0.106
0.292/Ϫ0.274
0.80 x 0.40 x 0.20
0.096
10721
4102
0.0205
315
0.0297
0.0648
0.117/Ϫ0.219
no. of params
R1 (I > 2σ(I))
wR2 (all data)
Ϫ3
˚
(∆/ρ)min/max /e A
522
© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
zaac.wiley-vch.de
Z. Anorg. Allg. Chem. 2005, 631, 518Ϫ523

Novel Intramolecularly Base-stabilized Boron Halides
obtained from diethyl ether at Ϫ10 °C in 90 % yield (3.49 g). Mp
178-180 °C.
gew. Chem. Int. Ed. 1998, 37, 1786. (c) Review: G. J. Irvine,
M. J. G. Lesley, T. B. Marder, N. C. Norman, C. R. Rice, E.
G. Robins, W. R. Roper, G. R. Whittell, L. J. Wright, Chem.
Rev. 1998, 98, 2685. (d) H. Braunschweig, C. Kollann, K. W.
Klinkhammer, Europ. J. Inorg. Chem. 1999, 1523.
[2] I. Krossing, H. Nöth, W. Ponikwar, J. Knizek, Eur. J. Inorg.
Chem. 1998, 505.
[3] (a) A. Moezzi, M. M. Olmstead, P. P. Power, J. Am. Chem.
Soc. 1992, 114, 2715. (b) A. Moezzi, R. A. Bartlett, P. P. Power,
Angew. Chem. 1992, 104, 1075; Angew. Chem. Int. Ed. 1992,
31, 1082.
1H NMR (δ/ppm): 1.11-2.04 (m, 22H, C6H11), 3.02 (s, 6H, N(CH3)2), 7.26-
7.42 (m, 4H, C6H4). 13C{1H} NMR (δ/ppm): 26.5, 27.2, 27.6, 28.2, 29.2 (all
s, C in C6H11), 49.1 (s, C1 in C6H11), 49.5 (s, N(CH3)2), 82.3 (s, CO), 120.2
(s, C6 in C6H4), 127.2 (s, C4 in C6H4), 127.4 (s, C3 in C6H4), 128.1 (s, C5 in
C6H4), 139.2 (s, C2 in C6H4), 144.7 (s, C1 in C6H4). 11B NMR (δ/ppm): 1.3
(s). 19F NMR (δ/ppm): Ϫ154.4 (s). IR (KBr): 2935 vs, 2855 vs, 2748 m-s,
2531 m, 1615 m, 1583 m, 1445-1370 vs, br., 1306 s, 1279 m, 1264 m, 1244 m-
s, 1228 m-s, 1196 vs, 1172 m, 1125 m, 1097 m, 1085 m, 1074 m, 1046 m-s,
990 s, 947 m, 893 m, 817 s, 765 vs, 731 s, 677 s, 652 m, 584 w, 557 m-s, 547 m-
s, 519 m-s, 482 m cmϪ1. MS found: m/z 280.3 (100 %, MϩϪC6H11), 260.3
(5 %, MϩϪFϪC6H11), 214.2 (15 %, MϩϪOBF2ϪC6H11), 132.1 (35 %,
MϩϪOBF2Ϫ2C6H11), 91.1 (15 %, C7H7ϩ), 83.0 (30 %, C6H11ϩ), 77.1 (15 %,
C6H5ϩ), 55.1 (80 %, C4H7ϩ), calc. for C21H32BF2NO: M ϭ 363.0. Found: C
64.40; H 7.32; N 3.17 %. Calc. for C21H32BF2NO·H2O: C 66.15; H 8.99;
N 3.67 %.
[4] H. Nöth, J. Knizek, W. Ponikwar, Eur. J. Inorg. Chem. 1999,
1931.
[5] (a) R. Schlengermann, J. Sieler, S. Jelonek, E. Hey-Hawkins,
Chem. Commun. 1997, 197. (b) R. Schlengermann, J. Sieler, E.
Hey-Hawkins, Main Group Chem. 1997, 2, 141.
[6] (a) R. Papp, J. Sieler, E. Hey-Hawkins, Polyhedron 2001, 20,
1053. (b) R. Papp, F. B. Somoza, Jr., J. Sieler, S. Blaurock, E.
Hey-Hawkins, J. Organomet. Chem. 1999, 585, 127.
[7] H. T. Al-Masri, J. Sieler, E. Hey-Hawkins, Appl. Organomet.
Chem. 2003, 17, 63.
2-(Phenylamidoborondichloride-phenyl)methyl-dimethylamino-
benzene (8): The reaction was carried out as described for 4 except
that 3 (6.60 g, 10.7 mmol) was used instead of 1. The product was
obtained from toluene at 25 °C in 90 % yield (3.69 g). Mp 185-
195 °C.
1H NMR (δ/ppm): 3.19 (s, 1H, CH), 3.55 (br. s, 3H, N(CH3)2), 3.67 (s, 3H,
N(CH3)2), 6.92-7.55 (m, 14H, C6H4 and C6H5). 13C{1H} NMR (δ/ppm): 49.0
(s, N(CH3)2), 58.0 (s, CH), 115.0 (s, C6 in C6H4), 120.0 (s, C4 in C6H4),
127.8 (s, C3 in C6H4), 128.5 (s, C5 in C6H4), 128.9 (s, p-C in C6H5), 129.3
(s, o-C in C6H5), 129.7 (s, m-C in C6H5), 130.5 (s, C2 in C6H4), 131.8 (s, C1
in C6H4), 150.0 (s, ipso-C in C6H5). 11B NMR (δ/ppm): 9.8 (s). IR (KBr):
3064 w, 2922 vs, 2851 vs, 2671 w, 1633 m, 1582 w, 1490 m-s, 1475 s, 1447 vs,
1409 m, 1301 w, 1254 s, 1186 vs, 1146 vs, 1125 vs, 1093 vs, 1051 s, 965 m,
932 m, 895 s, 873 vs, 851 s, 802 m, 771 s, 760 s, 746 s, 702 m, 684 w, 661 w,
648 w, 612 m, 567 m, 547 w, 522 m cmϪ1. MS found: m/z 302.3 (35 %,
[8] H. T. Al-Masri, J. Sieler, E. Hey-Hawkins, Appl. Organomet.
Chem. 2003, 17, 641.
[9] H. T. Al-Masri, J. Sieler, P. Lönnecke, S. Blaurock, K. Doma-
sevitch, E. Hey-Hawkins, Tetrahedron 2004, 60, 333.
[10] H. T. Al-Masri, J. Sieler, E. Hey-Hawkins, Z. Anorg. Allg.
Chem. (in preparation)
[11] H. T. Al-Masri, J. Sieler, P. Lönnecke, P. Junk, E. Hey-Hawk-
ins, Inorg. Chem. 2004, 43, 7162. b) H. T. Al-Masri, J. Sieler,
P. Junk, K. Domasevitch, E. Hey-Hawkins, J. Organomet.
Chem. (in press).
MϩϪBCl2),
287.3
(10 %,
MϩϪBCl2ϪCH3),
210.2
(87 %,
MϩϪBCl2ϪCH3ϪPh), 195.0 (35 %, MϩϪBCl2Ϫ2CH3ϪPh), 91.1 (100 %,
C7H7ϩ), 77.1 (30 %, C6H5ϩ), 55.1 (80 %, C4H7ϩ), calc. for C21H21BCl2N2:
M ϭ 383.0. Found: C 65.90; H 5.46; N 6.88 %. Calc. for C21H21BCl2N2: C
65.84; H 5.53; N 7.31 %.
[12] E. Kalbarczyk, S. Pasynkiewicz, J. Organomet. Chem. 1985,
292, 119.
X-ray Crystallographic Study: Crystallographic data are given in
Table 3. Data [λ(MoKα) ϭ 0.71073 A] were collected with a Sie-
[13] R. Köster, A. Sporzynski, W. Schussler, D. Blaser, R. Boese,
˚
Chem. Ber. 1994, 127, 1191.
[14] G. E. Coates, J. G. Livingstone, J. Am. Chem. Soc. 1961, 93,
2909.
[15] W. M. Cummings, C. H. Cox, H. R. Snyder, J. Org. Chem.
mens CCD (SMART) diffractometer. Empirical absorption correc-
tion with SADABS [25]. The structure was solved by direct meth-
ods (SHELXTL PLUS [26]). H atoms were located by difference
maps and refined isotropically for compounds 3 and 6; for 4 and 5
the hydrogen atoms were placed in calculated positions and refined
isotropically in the riding mode.
1969, 34, 1673.
[16] H. K. Saha, J. Inorg. Nucl. Chem. 1994, 26, 1617.
[17] S. Toyota, T. Futawaka, M. Asakura, H. Ikeda, M. Oki, Or-
¯
ganometallics 1998, 17, 4155.
[18] S. Toyota, M. Oki, Bull. Chem. Soc. Jpn. 1992, 65, 1832.
[19] R. T. Baker, J. C. Calabrese, S. A. Westcott, J. Organomet.
Crystallographic data for the structural analysis have been de-
posited with the Cambridge Crystallographic Data Centre, CCDC
244737 for 3, CCDC 244738 for 4, CCDC 244739 for 5 and CCDC
244740 for 6. These data can be obtained free of charge via
www.ccdc.cam.ac.uk/conts/retrieving.html or from Cambridge
Crystallographic Data Centre, 12, Union Road, Cambridge CB2
1EZ, UK; fax: (internat.) ϩ44-1223/336-033; E-mail: deposit@-
ccdc.cam.ac.uk.
¯
Chem. 1995, 498, 109.
[20] S. Rettig, J. J. Trotter, Can. J. Chem. 1976, 54, 1168.
[21] A. Ansorge, D. J. Brauer, H. Bürger, F. Dörrenbach, T. Hagen,
G. Pawelke, W. Weuter, J. Organomet. Chem. 1990, 396, 253.
[22] H. Hess, Acta Crystallogr. 1969, 25B, 2338.
[23] K. Töpel, K. Hensen, M. Trömel, Acta Crystallogr. 1981,
37B, 969.
Acknowledgments. P.C. Junk thanks the DAAD for a guest pro-
[24] B. Swanson, D. F. Shriver, J. A. Ibers, Inorg. Chem. 1969, 8,
2182.
fessorship (A/00/18168-226/WS) at the University of Leipzig.
[25] G. M. Sheldrick, SADABS Ϫ a Program for Empirical Ab-
sorption Correction, Göttingen, 1998.
References
[26] SHELXTL PLUS, Siemens Analyt. X-ray Inst. Inc., 1990, XS:
Program for Crystal Structure Solution, XL: Program for
Crystal Structure Determination, XP: Interactiv Molecular
Graphics.
[1] (a) H. Braunschweig, C. Kollann, U. Englert, Angew. Chem.
1998, 110, 3355; Angew. Chem. Int. Ed. 1998, 37, 3179. (b)
Review: H. Braunschweig, Angew. Chem. 1998, 110, 1882; An-
Z. Anorg. Allg. Chem. 2005, 631, 518Ϫ523
zaac.wiley-vch.de
© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
523