Synthesis and properties of 1, 3-Bis(2, 6-diisopropylphenyl)-2-(trimethylstannyl)-2, 3-dihydro-1H-1, 3, 2-diazaborole

Article abstract of DOI:10.1515/znb-2017-0122

The diazaborole Me₃Sn-B{N(Dipp)CH}₂ (1; B{N(Dipp)CH}₂ = N,N′-bis(2, 6-diisopropylphenyl)-2, 3-dihydro-1H-1, 3, 2-diazaborolyl) was prepared by the reaction of Me₃SnCl with one equivalent of Li[B{N(Dipp) CH}

Full text of DOI:10.1515/znb-2017-0122

Z. Naturforsch. 2017; 72(10)b: 747–752
Frauke Schödel, Jens M. Breunig, Vasco Thiel, Michael Bolte, Matthias Wagner
and Hans-Wolfram Lerner*
Synthesis and properties of 1,3-Bis(2,6-
diisopropylphenyl)-2-(trimethylstannyl)-
2
,3-dihydro-1H-1,3,2-diazaborole
https://doi.org/10.1515/znb-2017-0122
firstly described in 2006 by Nozaki and coauthors [1].
Received July 20, 2017; accepted August 9, 2017
Very recently, Li[B{N(Dipp)CH} ] has been utilized as a
2
nucleophilic source of the boryl fragment in the synthesis
of novel low-valent and low-coordinate main-group com-
pounds (e.g. M[B{N(Dipp)CH} ] , Mꢀ=ꢀGa, In, Tl see Fig. 1
Abstract: The diazaborole Me Sn–B{N(Dipp)CH} (1;
3
2
B{N(Dipp)CH} ꢀ=ꢀN,N′-bis(2,6-diisopropylphenyl)-2,3-
2
2
2
dihydro-1H-1,3,2-diazaborolyl) was prepared by the reac-
and Ref. [5]).
tion of Me SnCl with one equivalent of Li[B{N(Dipp)
3
Despite its broad usefulness, the availability of
CH} ]. Single crystals of 1 were obtained from hexane
2
Li[B{N(Dipp)CH} ] is more or less unreliable due to its
2
̅
(
triclinic space group P1). The diazaborole 1 was mono-
extreme sensitivity towards water and oxygen. In order
to prevent unwanted side reactions, in particular oxida-
tive and hydrolytic degradation, we decided to prepare
the diazaborole Me Sn–B{N(Dipp)CH} as an alternative,
deprotonated at the heterocycle upon treatment with
Li[Me] to give product 2. In contrast to Li[B{N(Dipp)CH} ]
2
which reacted with P to give the tetraphosphenediide
4
3
2
Li [{HC(Dipp)N} B–P(1)P(2)P(3)P(4)–B{N(Dipp)CH} ] (3;
2
2
2
boron-containing building block.
1
1
δ ꢀ=ꢀ364.5, –29.4; J
ꢀ=ꢀ–509.8 Hz, JP(1),P(2)ꢀ=ꢀ–434.3 Hz,
P
P(2),P(3)
In this context it should be also noticed that the B–Sn
bond can be activated by strong nucleophiles. Recently,
Kleeberg has reported that the borolidene derivative
2
3
JP(1),P(3)ꢀ=ꢀ–3.7 Hz, JP(1),P(4)ꢀ=ꢀ178.9 Hz) and the triphosphenide
Li[{HC(Dipp)N} B–PPP–B{N(Dipp)CH} ] (δ ꢀ=ꢀ665.1, 175.4;
2
2
P
1
J ꢀ=ꢀ500 Hz), the stannyl derivative 1 did not activate
P, P
Me Sn–B{N(iPr)CH }
(1,3-diisopropyl-1,3,2-diazaboro-
3
2 2
white phosphorus. The reaction of 1 with GaCl yielded
3
lidinyl)trimethylstannane) reacts with K[OtBu] to give
K[SnMe ] and tBuO–B{N(iPr)CH } [6]. In considering these
either Me ClSn–B{N(Dipp)CH} (4) or MeCl Sn–B{N(Dipp)
2
2
2
3
2 2
CH} (5) depending on the molar ratio of the reactants. The
2
facts we asked ourselves: Is it possible to cleave the B–Sn
monochlorinated diazaborole Me ClSn–B{N(Dipp)CH}
2
2
bond by treatment of the diazaborole Me Sn–B{N(Dipp)
3
was also obtained by the reaction of 1 with AsCl3.
CH} with strong nucleophiles and if it does, which anion
2
Keywords: boryl anion; diazaborole; X-ray structure – the B-centered diazaborolyl anion or the stannyl anion
−
analysis.
[SnMe ] – will be formed?
3
The purpose of this paper is to describe the synthesis
and properties of diazaborole 1. In particular we exam-
ined the reactions of 1 with Li[Me], P , GaCl , and AsCl .
4
3
3
1
Introduction
Finally the solid-state structure of the diazaborole 1 is
reported herein.
Compounds with negatively charged boron centers have
attracted considerable interest in the last decades [1–4].
The most prominent example of this class of substances
is diazaborolyl lithium Li[B{N(Dipp)CH} ] which was 2 Results and discussion
2
At first we synthesized the diazaborolyl lithium
*
Corresponding author: Hans-Wolfram Lerner, Institut für
Li[B{N(Dipp)CH} ]fromBr–B{N(Dipp)CH} andlithiumbya
2
2
Anorganische Chemie, Goethe-Universität Frankfurt am Main,
Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany,
Fax: +49-69-79829260, E-mail: lerner@chemie.uni-frankfurt.de
Frauke Schödel, Jens M. Breunig, Vasco Thiel, Michael Bolte
and Matthias Wagner: Institut für Anorganische Chemie,
Goethe-Universität Frankfurt am Main, 60438 Frankfurt am Main,
Germany
literature-known procedure [1]. As shown in Scheme 1, the
reaction of Me SnCl with one equivalent of Li[B{N(Dipp)
3
CH} ] at −30°C gave the diazaborole 1 in decent yield. Sub-
2
−3
limation of the crude product at 90°C/10 mbar yielded
the analytically pure diazaborole 1 which could be recrys-
tallized from hexane.
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48ꢀꢀꢀꢀꢁꢀF. Schödel et al.: Diazaborole
Dipp
Dipp
N
E
N
B
B
N
N
Dipp Dipp
Fig. 1:ꢀE[B{N(Dipp)CH} ] (Eꢁ=ꢁGa, In, Tl); see Ref. [5].
2
2
Li
B
SnMe3
B
Dipp
(i)
Dipp
Dipp
Dipp
N
N
N
N
1
Scheme 1:ꢀSynthesis of the stannylated diazaborole 1. (i) +Me SnCl,
3
–LiCl; thf, –30°C.
The diazaborole 1 crystallizes in the triclinic space
̅
group P1 with two crystallographically independent mole-
cules in the asymmetric unit (Figs. 2 and 3). Since most
structural parameters of both molecules are very similar,
only the molecular structure of one molecule is shown in
Fig. 2 (selected bond lengths and angles are given in the
figure caption).
Fig. 3:ꢀPacking diagram of 1.
The structure of 1 displays an almost planar BN C
2
2
heterocycle. The phenyl rings of the Dipp substituents are
nearly perpendicular to the plane of this heterocycle (cf.
Fig. 3). The conformation of the trimethylstannyl group
shows that one of the methyl groups is located in the
plane of the heterocycle whereas the remaining two are
located above and below this plane. The B–N distances in
1
are quite short (1.419(6) and 1.430(6) Å), suggesting an
additional πꢀ−ꢀinteraction between the B and N atoms. All
other structural parameters of 1 are within the expected
range.
1
1
1
The B{ H} NMR spectrum of 1 is characterized by a
broad resonance (δ ꢀ=ꢀ29.6 ppm). Compound 1 exhibits
1
1B
only one singlet proton resonance for the diazaborolyl
1
H nuclei but two doublets for the diastereotopic methyl
protons of the isopropyl substituents. Due to the coupling
between the tin nuclei and the trimethylstannyl protons
Fig. 2:ꢀSolid-state structure of the diazaborole 1. Hydrogen atoms
2
2
(
J1H,119Snꢀ=ꢀ50 Hz, J1H,117Snꢀ=ꢀ48 Hz), satellites of the signal
are omitted for clarity. Selected bond lengths (Å), and bond angles
at δꢀ=ꢀ–0.17 ppm are present. Therefore this resonance
(
deg): Sn(1)–C(3) 2.144(6), Sn(1)–C(5) 2.149(5), Sn(1)–C(4) 2.150(7),
can unambiguously be assigned to the Me Sn group.
3
Sn(1)–B(1) 2.252(5), B(1)–N(1) 1.419(6), B(1)–N(2) 1.430(6), N(1)–C(1)
1
19
1
The Sn{ H} NMR spectrum of 1 displays a quartet at
1
1
.401(5), N(1)–C(11) 1.437(5), N(2)–C(2) 1.395(6), N(2)–C(31)
.443(6), C(1)–C(2) 1.325(6), C(3)–Sn(1)–C(5) 106.6(2), C(3)–Sn(1)–
1
–148.3 ppm ( J
ꢀ=ꢀ984 Hz), as shown in Fig. 4.
1
19Sn,11B
C(4) 105.5(3), C(5)–Sn(1)–C(4) 106.0(3), C(3)–Sn(1)–B(1) 115.0(2),
C(5)–Sn(1)–B(1) 111.9(2), C(4)–Sn(1)–B(1) 111.3(2), N(1)–B(1)–N(2)
At first we investigated the reaction of diazaborole
1
with Li[Me]. Surprisingly, treatment of 1 with 1 equiva-
1
04.9(4), N(1)–B(1)–Sn(1) 127.2(3), N(2)–B(1)–Sn(1) 127.7(4),
C(1)–N(1)–B(1) 108.2(3), C(1)–N(1)–C(11) 122.9(4), B(1)–N(1)–C(11)
28.8(3), C(2)–N(2)–B(1) 107.9(4), C(2)–N(2)–C(31) 122.9(3),
B(1)–N(2)–C(31) 128.9(4), C(2)–C(1)–N(1) 109.3(4), C(1)–C(2)–N(2)
09.7(4).
lent of Li[Me] in thf afforded the lithiated diazaborole 2,
as shown in Scheme 2. In this context it should be noted
that treatment of 2 with an excess of water resulted in an
immediate reaction and the resonances of the diazaborole
1
1
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F. Schödel et al.: Diazaboroleꢂꢁꢀꢀꢀꢂ749
Fig. 4:ꢀ119Sn{ H} NMR spectrum of Me Sn–B{N(Dipp)CH} (1) in C D . Chemical shift and coupling constant of 1: δꢁꢁ=ꢁꢁ–148.3 ppm; J119Sn,11Bꢁ=ꢁ984 Hz.
1
1
3
2
6
6
SnMe3
B
SnMe3
B
Dipp
Dipp
Dipp
N
(i)
ii)
Dipp
Dipp
Dipp
Dipp
N
B
N
P
P
Li
N
N
N
N
Li
N
B
N
P
P
B
2
+
P
P
N
(
thf
P
P
Li
H
Li
Dipp
1
2
Dipp
Dipp
3
Scheme 2:ꢀDeprotonation of the stannylated diazaborole 1. (i)
Li[Me], –CH ; thf, r.t. (no reaction took place either between 1 and
+
4
Scheme 3:ꢀReaction of two equivalents of Li[B{N(Dipp)CH} ] with P .
2
4
Li[tBu] or 1 and Na[SitBu ]); (ii) +H O, –LiOH; thf, r.t.
3
2
SnMe2Cl
B
1
were monitored by NMR spectroscopy (Scheme 2). Addi-
tionally, we also investigated the behavior of 1 towards the
bulky reagent Li[tBu] and the sterically crowded silanide
(
i)
Dipp
Dipp
Dipp
N
N
N
SnMe3
B
4
Na[SitBu ] (supersilyl sodium) [7]. Due to steric hindrance, Dipp N
Dipp
3
N
however, no reactions took place. In summary, the chemi-
cal behavior of 1 towards bases is in stark contrast to that
of Me Sn–B{N(iPr)CH } . As already mentioned, the reac-
SnMeCl2
B
1
(
ii)
Dipp
N
3
2 2
tion of Me Sn–B{N(iPr)CH } with K[OtBu] led to the cleav-
age of the B–Sn bond.
3
2 2
5
Furthermore we examined the nucleophilic proper- Scheme 4:ꢀReaction of the stannylated diazaborole 1 with one or
ties of 1. At first the chemical behavior of 1 towards white two equivalents of GaCl . (i) +GaCl , –MeGaCl ; benzene, r. t.; (ii) +2
3
3
2
GaCl , –2 MeGaCl ; benzene, r. t.
phosphorus was investigated. In contrast to Li[B{N(Dipp)
3
2
1
CH} ] which reacted with P (cf. Scheme 3 ), no reaction
2
4
occurred when P was treated with the stannylated diaz-
4
depending on the ratio between the diazaborole 1 and GaCl .
3
aborole 1 neither at room nor at elevated temperature.
The monochlorinated diazaborole Me ClSn–B{N(Dipp)CH}
2
2
The reaction of 1 with Lewis-acidic GaCl was also inves-
3
was also obtained by the reaction of 1 with AsCl3.
tigated. As shown in Scheme 4, these reactions yielded
either Me ClSn–B{N(Dipp)CH} or MeCl Sn–B{N(Dipp)CH}
2
2
2
2
3
Experimental section
1
ꢁThe analogous, silylated products were isolated from the 1:2 and 1:3
reaction of P with M[SitBu ] (Mꢀ=ꢀLi, Na, K) [7] and Na[SiPhtBu ] [8];
4
3
2
The solvents thf, [D ]thf, Et O, benzene, and C D were
stirred over sodium/benzophenone and distilled prior
cf. Table 1 and Refs. [7, 9–13]. For the properties of the related diphos-
phene, [{HC(Dipp)N} B–Pꢀ=ꢀP–B{N(Dipp)CH} , see Ref. [14].
8
2
6
6
2
2
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50ꢀꢀꢀꢀꢁꢀF. Schödel et al.: Diazaborole
to use. Br–B{N(Dipp)CH} [1], Li[B{N(Dipp)CH} ] [1], and 0.1 mL H O to the reaction mixture, signals appeared in the
2
2
2
1
13
11
119
Na[SitBu ] [15] were prepared according to published H/ C/ B/ Sn NMR spectra of the solution which could be
3
procedures. All other starting materials were purchased assigned to the diazaborole 1.
1
from commercial sources and used without further puri-
2: H NMR (500 MHz, [D ]thf): δꢀ=ꢀ–0.59 (s, 9H, SnMe ),
8
3
3
3
fication. The NMR spectra were recorded on Bruker AM 1.15 (d, 12H, J ꢀ=ꢀ6.9 Hz, CHMe ), 1.16 (d, 12H, J ꢀ=ꢀ6.9 Hz,
H,H
2
H,H
3
2
5
50, DPX 250, Avance 300, Avance 400, and Avance CHMe ), 3.08 (sept, 4H, J ꢀ=ꢀ6.9 Hz, CHMe ), 5.82 (s,
2 H,H 2
13
1
00 spectrometers. NMR chemical shifts are reported in 1H, N–CHꢀ=ꢀCLi–N); 7.05–7.30 (m, 6H, ph-H). – C{ H}
ppm. Abbreviations: sꢀ=ꢀsinglet; dꢀ=ꢀdoublet; tꢀ=ꢀtriplet; NMR (126 MHz, [D ]thf): δꢀ=ꢀ–11.4 (Sn(CH ) ), 22.7/23.0
8
3 3
septꢀ=ꢀseptet; mꢀ=ꢀmultiplet; brꢀ=ꢀbroad. Mass spectrometry (CH(CH ) ), 24.4/24.6 (CH(CH ) ), 27.6/27.7 (CH(CH ) ),
3
2
3
2
3 2
was performed with a Fisons VG Platform II instrument. 121.5/121.9 (N–CHꢀ=ꢀCLi–N), 123.9/124.1 (ph-CH), 127.3/128.8
Elemental analyses were carried out by the Microanalyti- (ph-CH), 142.6 (ph-CN), 145.8/146.0 (ph-CC), 149.1 (ph-CN).
1
1
1
119
1
cal Laboratory of the Goethe University Frankfurt.
– B{ H} NMR (160 MHz, [D ]thf): δꢀ=ꢀ26.9. – Sn{ H} NMR
8
1
(
187 MHz, [D ]thf): δꢀ=ꢀ–143.8 (q, J119Sn,11Bꢀ=ꢀ1031 Hz).
8
Note 1: An NMR tube was charged with [D ]thf (0.5 mL)
8
3
.1 Synthesis of 1,3-bis(2,6-diisopropyl-
and the diazaborole 1 (0.05 mmol). To this solution
0
.1 mL of a 1.8 ꢂ solution of Li[Me] (0.18 mmol) in Et O
phenyl)-2-(trimethylstannyl)-
2
was added at room temperature. The NMR spectra of the
2
,3-dihydro-1H-1,3,2-diazaborole (1)
reaction solution revealed the signals of 2, methane, and
A solution of Li[B{N(Dipp)CH} ] (2.50 mmol) in thf (25 mL) the diazaborole 1. Additionally, signals of the products of
2
was added dropwise to a cooled (–30°C) solution of a side reaction between Li[Me] and Et O appeared in the
2
1
13
Me SnCl (0.50 g, 2.50 mmol) in thf (20 mL). The resulting H and C NMR spectra which can be assigned to ethene
3
mixture was stirred at –30°C for 1 h and slowly warmed (δH,[D8]thfꢀ=ꢀ5.34) and Li[OEt] (δH,[D8]thfꢀ=ꢀ1.23(t), 3.78(q)).
up to room temperature. After removal of all volatile
Note 2: A solution of 1 (0.05 mmol) and Li[tBu]
compounds in vacuo, the yellow residue was extracted (0.19 mmol) in 0.5 mL [D ]thf was kept for 3 day at room
8
1
13
11
119
into hexane. Filtering from LiCl and evaporation of temperature. The H/ C/ B/ Sn NMR spectra revealed
the solvents gave the diazaborole 1 as a yellow solid, exclusively the signals of 1 and Li[tBu].
which was purified by sublimation (90°C/10−3 mbar).
Note 3: A solution of 1 (0.05 mmol) and Na[SitBu ] [15]
3
Single crystals of 1 were obtained by recrystallization (0.1 mmol) in 0.5 mL [D ]thf was kept for 3 day at room
8
1
1
13
11
29
119
from hexane (yield: 0.56 g, 41%). – H NMR (300 MHz, temperature. The H/ C/ B/ Si/ Sn NMR spectra revealed
3
C D ): δꢀ=ꢀ–0.17 (s, 9H, SnMe ), 1.17 (d, 12H, JH,Hꢀ=ꢀ6.9 Hz, exclusively the signals of 1 and Na[SitBu ] [15].
6
6
3
3
3
CHMe ), 1.28 (d, 12H, J ꢀ=ꢀ6.9 Hz, CHMe ), 3.19 (sept, 4H,
JH,Hꢀ=ꢀ6.9 Hz, CHMe ), 6.37 (s, 2H, N–CHꢀ=ꢀCH–N); 7.12–7.26
2
H,H
2
3
2
1
3
(
m, 6H, 7.73–7.71, ph-H). – C{H} NMR (126 MHz, C D ): 3.3 Reaction of Li[B{N(Dipp)CH} ] with P
6
6
2
4
δꢀ=ꢀ–10.8 (Sn(CH ) ), 23.9 (CH(CH ) ), 25.9 (CH(CH ) ), 29.1
3
3
3
2
3 2
(
CH(CH ) ), 122.5 (N–CHꢀ=ꢀCH–N), 123.9 (ph-CH), 127.8 A solution of Li[B{N(Dipp)CH} ] (0.03 g, 0.08 mmol) in
3
2
2
1
1
1
(
ph-CH), 140.4 (ph-CC), 146.5 (ph-CN). – B{ H} NMR thf (0.8 mL) was added to a cooled solution (–78°C) of P4
1
19
1
(
96 MHz, C D ): δꢀ=ꢀ29.6 (h ꢀ=ꢀ350 Hz). – Sn{ H} NMR (0.04 mmol) in thf (0.3 mL). After 45 min at –78°C, the solu-
6 6 1/2
1
(
112 MHz, C D ): δꢀ=ꢀ–148.3 (q, J119Sn,11Bꢀ=ꢀ984 Hz; cf. Fig. 3). tion was allowed to reach room temperature. All volatiles
6
6
+
+
–
MS (ESI ): m/z (%)ꢀ=ꢀ552 [M] . – Anal. for C H BN Sn were removed in vacuo and [D ]thf (0.5 mL) was added.
2
9
4
5
2
8
31
(
8
551.2): calcd. C 63.19, H 8.23, B, N 5.08; found C 63.34, H According to the P NMR spectrum (Fig. 5) the tetraphos-
.18, N 4.47.
phenediide Li [{HC(Dipp)N} B–PPPP–B{N(Dipp)CH} ] (3)
2
2
2
was formed as the main product (60% P) and the triphos-
phide Li[{HC(Dipp)N} B–PPP–B{N(Dipp)CH} ] (δ ꢀ=ꢀ665.1,
2
2
P
1
3.2 Reaction of 1 with Li[Me]
175.4 ppm; J ꢀ=ꢀ500 Hz) as a side product (10% P) of this
PP
reaction (cf. the analogous reaction behavior of M[SitBu3]
A solution of Li[Me] (0.36 mmol) in 0.2 mL Et O and 1 mL thf (Mꢀ=ꢀLi, Na, K) [7] and Na[SiPhtBu ] [8] towards P ; see
2
2
4
was added to a solution of the diazaborole 1 (0.36 mmol) Table 1 and Refs. [7, 9–13]).
1
in 5 mL thf at –78°C. The resulting mixture was slowly
Selected data for 3: H NMR (250 MHz, [D ]thf): δꢀ=ꢀ1.12
8
1
13
11
119
3
3
warmed up to room temperature. The H/ C/ B/ Sn NMR (d, 12H, J ꢀ=ꢀ7 Hz, CH(CH ) ), 1.17 (d, 12H, J ꢀ=ꢀ7 Hz,
H,H
3
2
H,H
3
spectra of the reaction solution revealed exclusively the CH(CH ) ), 3.02 (sept, 4H, J ꢀ=ꢀ7 Hz, CH(CH ) ), 6.27 (s,
3
2
H,H
3 2
3
1
1
signals of 2 and methane (δH,[D8]thfꢀ=ꢀ0.16). After addition of 2H, (N)HCꢀ=ꢀCH(N), 7.13–7.26 (6H, m, ph-H). – P{ H} NMR
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F. Schödel et al.: Diazaboroleꢂꢁꢀꢀꢀꢂ751
Fig. 5:ꢀAA′ part of the 31P{ H} NMR spectrum of Li [{HC(Dipp)N} B–P(1)P(2)P(3)P(4)–B{N(Dipp)CH} ] (3) in [D ]thf. Chemical shifts and coupling
1
2
2
2
8
1
1
2
3
constants of 3: δꢁ=ꢁ364.5, –29.4 ppm; J
ꢁ=ꢁ–509.8, J
ꢁ=ꢁ–434.3, J
ꢁ=ꢁ–3.7, J
ꢁ=ꢁ178.9 Hz [16].
P(2),P(3)
P(1),P(2)
P(1),P(3)
P(1),P(4)
3
1
Table 1:ꢀ P NMR data of the tetraphosphenediides M [RP –P ꢁ=ꢁP –P R] (chemical shifts δ in ppm, coupling constants J in Hz).
2
1
2
3
4
ꢁJ
ꢃJ
P(ꢂ),P(ꢄ)
δP
P(ꢂ),P(ꢃ)
Li [{HC(Dipp)N} BPPPPB{N(Dipp)CH} ]
ꢄꢅꢆ.ꢇ, –ꢃꢈ.ꢆ
ꢄꢈꢆ.ꢃ, –ꢇꢃ.ꢈ
ꢄꢈꢉ.ꢆ, –ꢆꢆ.ꢄ
ꢆꢌꢌ.ꢌ, –ꢆꢇ.ꢃ
ꢄꢈꢌ.ꢊ, –ꢄꢆ.ꢉ
ꢆꢌꢋ.ꢄ, –ꢇ.ꢊ
–ꢄ.ꢉ
ꢊꢉꢋ.ꢈ
ꢊꢈꢋ.ꢄ
ꢊꢋꢇ.ꢆ
ꢊꢋꢇ.ꢆ
ꢊꢃꢅ.ꢉ
ꢊꢃꢊ.ꢃ
ꢃ
ꢃ
ꢃ
Li [tBu SiPPPPSitBu ] [ꢈ]
–ꢃꢈ.ꢋ
–ꢄꢆ.ꢃ
–ꢄꢆ.ꢃ
–ꢃꢋ.ꢉ
–ꢄꢄ.ꢈ
ꢃ
ꢄ
ꢄ
Na [tBu PhSiPPPPSiPhtBu ] [ꢊꢌ]
ꢃ
ꢃ
ꢃ
Na [tBu SiPPPPSitBu ] [ꢊꢊ]
ꢃ
ꢄ
ꢄ
[
Na(ꢊꢋ-crown-ꢅ)(thf) ][tBu SiPPPPSitBu ] [ꢊꢊ]
ꢃ ꢄ ꢄ
K [tBu SiPPPPSitBu ] [ꢊꢃ]
ꢃ
ꢄ
ꢄ
1
1
1
3
(
(
101.25 MHz, [D ]thf) see Fig. 5 and Table 1. – B{ H} NMR CHMe ), 3.18 (sept, 4H, J ꢀ=ꢀ6.8 Hz, CHMe ), 6.35 (s, 2H,
8
2
H,H
2
4
80.25 MHz, [D ]thf): δꢀ=ꢀ22.0.
J
ꢀ=ꢀ13.5 Hz, N–CHꢀ=ꢀCH–N), 7.11–7.26 (m, 6H, ph-H).
B{ H} NMR (96 MHz, C D ): δꢀ=ꢀ28.9 ( JSnBꢀ=ꢀ1095 Hz,
8
119Sn,H
1
1
1
1
Note: A solution of the diazaborole 1 (0.10 mmol) in
–
6
6
1
19
1
0
.5 mL [D ]thf was added to a solution of P (0.04 mmol) h ꢀ=ꢀ220 Hz). – Sn{ H} NMR (112 MHz, C D ): δꢀ=ꢀ84.7 (q,
8
4
1
/
2
6
6
1
in thf (0.3 mL). After 1 d at room temperature the J119Sn,11Bꢀ=ꢀ1095 Hz). – Anal. for C H BClN Sn (571.6): calcd.
28
42
2
1
13
11
31 119
H/ C/ B/ P/ Sn NMR spectra of the solution revealed C 58.83, H 7.41, N 4.90; found C 58.64, H 7.58, N 4.72.
the signals of 1 and P4.
Note: AsCl (0.22 g, 1.19 mmol) was added to a solution
3
of 1 (0.01 g, 0.01 mmol) in C D (0.5 mL). After 1 d at room
6
6
1
13
11
119
temperature the H/ C/ B/ Sn NMR spectra of the solu-
3
.4 Synthesis of 1,3-bis(2,6-diisopropyl-
phenyl)-2-(chlorodimethylstannyl)-
tion revealed the signals of 4.
2
,3-dihydro-1H-1,3,2-diazaborole (4)
3
.5 Synthesis of 1,3-bis(2,6-diisopropyl-
GaCl (0.10 g, 0.60 mmol) was added to a solution of
3
phenyl)-2-(dichloromethylstannyl)-
1
(0.31 g, 0.57 mmol) in benzene (10 mL). The result-
2
,3-dihydro-1H-1,3,2-diazaborole (5)
ing mixture was stirred for 1.5 h at room temperature.
After removal of all volatile compounds in vacuo, 4 was GaCl (0.12 g, 0.68 mmol) was added to a solution of
3
−
3
obtained by sublimation (100°C/10 mbar) as a color- 1 (0.18 g, 0.32 mmol) in benzene (10 mL). The result-
1
less solid (yield: 0.19 g, 60%). – H NMR (300 MHz, ing mixture was stirred for 1.5 h at room temperature.
2
C D ): δꢀ=ꢀ0.10 (s, 6H, J
1
ꢀ=ꢀ49 Hz, SnClMe ), 1.17 (d, After removal of all volatile compounds in vacuo, 5
6
6
119Sn,H
2
3
3
−3
2H, J ꢀ=ꢀ6.8 Hz, CHMe ), 1.29 (d, 12H, JH,Hꢀ=ꢀ6.8 Hz, was obtained by sublimation (100°C/10 mbar) as a
H,H 2
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7
52ꢀꢀꢀꢀꢁꢀF. Schödel et al.: Diazaborole
Table 2:ꢀCrystal data and structure refinement of 1.
Three isopropyl groups are disordered over two posi-
tions with site occupation factors of 0.61(1), 0.54(3) and
0.58(3) for the major occupied site. Bond lengths and
angles in the disordered groups were restrained to have
the same values as in a non-disordered group. All disor-
dered atoms were isotropically refined.
CCDC 1530547 (1) contains the supplementary crystal-
lographic 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.
Formula
Mr
C H BN Sn
ꢃꢈ ꢆꢇ ꢃ
ꢇꢇꢊ.ꢊꢉ
Crystal size, mmꢄ
Crystal system
Space group
a, Å
ꢌ.ꢊꢋꢁ×ꢁꢌ.ꢊꢄꢁ×ꢁꢌ.ꢌꢄ
triclinic
Pꢊ
̅
ꢈ.ꢆꢆꢃꢇ(ꢇ)
ꢊꢃ.ꢅꢋꢈꢊ(ꢉ)
ꢃꢇ.ꢇꢋꢄꢄ(ꢊꢆ)
ꢋꢋ.ꢇꢃꢃ(ꢆ)
ꢋꢃ.ꢈꢅꢈ(ꢆ)
ꢋꢆ.ꢆꢄꢉ(ꢆ)
ꢄꢌꢃꢉ.ꢅ(ꢄ)
ꢆ
b, Å
c, Å
α, deg
β, deg
γ, deg
V, Åꢄ
Z
Dcalcd., g cm−ꢄ
References
[1] Y. Segawa, M. Yamashita, K. Nozaki, Science 2006, 314, 113.
[2] Y. Segawa, Y. Suzuki, M. Yamashita, K. Nozaki, J. Am. Chem.
Soc. 2008, 130, 16069.
[3] T. Kajiwara, T. Terabayashi, M. Yamashita, K. Nozaki, Angew.
Chem. Int. Ed. 2008, 47, 6606.
[4] M. Yamashita, Y. Suzuki, Y. Segawa, K. Nozaki, J. Am. Chem.
Soc. 2007, 129, 9570.
[5] A. V. Protchenko, D. Dange, J. R. Harmer, C. Y. Tang,
A. D. Schwartz, M. J. Kelly, N. Phillips, R. Tirfoin,
K. H. Birjkumar, C. Jones, N. Kaltsoyannis, P. Mountford,
S. Aldridge, Nat. Chem. 2014, 6, 315.
[6] C. Kleeberg, J. Grunenberg, X. Xie, Inorg. Chem. 2014, 53,
4400.
ꢊ.ꢃꢊ
−
ꢊ
μ(MoK ), mm
ꢌ.ꢈ
α
F(ꢌꢌꢌ), e
hkl range
ꢊꢊꢇꢃ
±ꢊꢊ, ±ꢊꢇ, ±ꢄꢌ
ꢌ.ꢇꢈꢇ
−
(
(sinθ)/λ)max, Å ꢊ
Refl. measured
Refl. unique/Rint
Param. refined
ꢄꢄ ꢈꢌꢋ
ꢊꢌ ꢅꢅꢉ/ꢌ.ꢌꢈꢉꢅ
ꢇꢈꢄ
ꢌ.ꢌꢈꢄꢅ/ꢌ.ꢌꢉꢈꢊ
ꢌ.ꢉꢈꢋ
ꢌ.ꢆꢄ/–ꢌ.ꢆꢆ
ꢀ
a,b
Rꢊ (F)/wRꢃ (F ) (all refls.)
ꢃ
c
GoF (F )
−
ꢄ
Δρ (max/min), e Å
fin
a
R1ꢁ=ꢁΣꢁ|ꢁ|ꢁF ꢁ|ꢁ–ꢁ|ꢁF ꢁ|ꢁ|ꢁ/Σꢁ|ꢁF ꢁ|; wR2ꢁ=[Σw(F ꢁ–ꢁF ) /Σw(F ) ]1/2,
b
2
2
2
2 2
o
c
o
o
c
o
2
2
2
−1
2
2
wꢁ=[σ (F )ꢁ+ꢁ(aP) ꢁ+ꢁbP] , where Pꢁ=(Max(F , 0)ꢁ+ꢁ2F )/3;
o
o
c
c
2
2
2
1/2
GoFꢁ=ꢁSꢁ=ꢁ[Σw(F ꢁ–ꢁF ) /(nobsꢁ–ꢁnparam)]
.
o
c
[
[
7] H.-W. Lerner, Coord. Chem. Rev. 2005, 249, 781.
8] H.-W. Lerner, S. Scholz, M. Bolte, M. Wagner, Z. Anorg. Allg.
Chem. 2004, 630, 443.
1
colorless solid (yield: 0.09 g, 45%). – H NMR (300 MHz,
2
C D ): δꢀ=ꢀ0.41 (s, 3H, J
ꢀ=ꢀ53 Hz, SnCl Me), 1.10 (d,
[9] H.-W. Lerner, M. Wagner, M. Bolte, Chem. Commun. 2003, 990.
[10] A. Lorbach, S. Breitung, I. Sänger, F. Schödel, M. Bolte, M. Wag-
ner, H.-W. Lerner, Inorg. Chim. Acta 2011, 378, 1.
11] A. Lorbach, A. Nadj, S. Tüllmann, F. Dornhaus, F. Schödel,
I. Sänger, G. Margraf, J. W. Bats, M. Bolte, M. C. Holthausen,
M. Wagner, H.-W. Lerner, Inorg. Chem. 2009, 48, 1005.
6
6
119Sn,H
2
3
3
1
2H, J ꢀ=ꢀ6.9 Hz, CHMe ), 1.31 (d, 12H, JH,Hꢀ=ꢀ6.9 Hz,
H,H
2
3
CHMe ), 3.06 (sept, 4H, J ꢀ=ꢀ6.9 Hz, CHMe ), 6.27 (s, 2H,
2
H,H
2
[
4
J1
19Sn,H
1
ꢀ=ꢀ20 Hz, N–CHꢀ=ꢀCH–N), 7.07–7.20 (m, 6H, ph-H).
– 11
B{ H} NMR (96 MHz, C D ): δꢀ=ꢀ27.2 ( J119Sn,11Bꢀ=ꢀ1380 Hz,
1
6
6
119
1
h ꢀ=ꢀ160 Hz). – Sn{ H} NMR (112 MHz, C D ): δꢀ=ꢀ106.3 [12] H.-W. Lerner, M. Bolte, K. Karaghiosoff, M. Wagner,
1
/2
6
6
1
Organometallics 2004, 23, 6073.
(
q, J1
ꢀ=ꢀ1380 Hz). – Anal. for C H BCl N Sn (592.0):
19Sn,11B 27 39 2 2
[
[
[
13] N. Wiberg, A. Wörner, K. Karaghiosoff, D. Fenske, Chem. Ber.
calcd. C 54.77, H 6.64, N 4.73; found C 53.94, H 6.38, N 4.67.
1997, 130, 135.
14] S. Asami, M. Okamoto, K. Suzuki, M. Yamashita, Angew. Chem.
Int. Ed. 2016, 55, 12827.
15] N. Wiberg, K. Amelunxen, H.-W. Lerner, H. Schuster, H. Nöth,
I. Krossing, M. Schmidt-Amelunxen, T. Seifert, J. Organomet.
Chem. 1997, 542, 1.
3
.6 Crystal structure determinations
Data for 1 (Table 2) were collected on a STOE IPDS II two- [16] Iterative optimization of the simulated spectrum with the
circle diffractometer with graphite-monochromatized
MoKα radiation (λꢀ=ꢀ0.71073 Å) [17] and corrected for
absorption using the program Pꢃꢄꢅꢆꢇ [18]. The structure
software ꢍꢎꢏꢐꢑꢒꢓꢔꢍ 2.5.5 (K. Marat, Sꢎꢏꢐꢑꢒꢓꢔꢍ, University
of Manitoba, Winnipeg, MB, 2006) yields the shown coupling
constants.
[
[
17] X-Aꢓꢕꢖ, Diffractometer control program system, STOE & Cie
GmbH, Darmstadt (Germany) 2002.
18] A. L. Spek, J. Appl. Crystallogr. 2003, 36, 7.
[19] G. M. Sheldrick, Acta Crystallogr. 2008, A64, 112.
was solved by Direct Methods using the program ꢈꢉꢊꢃꢋꢈ
2
[
17] and refined against F with full-matrix least-squares
techniques using the program ꢈꢉꢊꢃꢋꢃ [19].
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