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Bis(dihydro-1 2-azaborolyl)tinЧa Novel Boron-Nitrogen Stannocene.

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Table I . Spectroscopic and X-ray structural data of the 0x0-complexes 2 and 3 and some reference compounds.
IR[cm '1
I,(M -0 - M)
~
v(M=O)
'H
I.Sl[b]
2.07 [b]
910[a]
715
1.81[b]
908[a]
879
925[c]
90 1
930,92O[c]
898,850
755 (br)
I.97 [b]
NMR(6-values)
"C
M =O
10.2[b]
103.2
10.7[b]
107.3
10.2[b]
118.6
10.6[b]
121.7
710
770
-
909 [a]
878
930[a]
2.08 [el
634
614
X-ray structure analysis[pm]
M-0(-M)
M-M
159.4(3)
181.7(4)
181.3(5)
250.S( I)
169.5
170.2
170.2
193.2
194.8
194.8
260.2
164.l[d]
165. I
lSl(2), 192(2)[d]
182(3), 199(3)
193.7av.
256.9(4)
270.2(6)
to
290.0(6)
= 175131
10.2[fj
120.4
2.03 lgl
[a] KBr. [bl [DJacetone. [cl C4CLand N u i d mulls. [dl Cr=N and Cr-N(-Cr)
[g] CD,C12, 28°C
tion on the same side of the non-planar four-membered
ring. In the case of the molybdenum(v) cation 10 both the
cis- as well as the trans-form could be structurally characterized;'I3' the trans-isomer can be converted irreversibly
into the thermodynamically more stable ~is-isomer."~'
The
chromium-chromium distance and the Cr=O distances in
2 are remarkably short.
distances, see [12]. [el CDIC12, -80°C.
[fl CDCI,.
Energie Physik Mathematik, D-75 14 Eggenstein-Leopoldshafen2, on quoting the depository number CSD 51 445, the names of the authors, and
the full citation of the journal.
1121 N. Wiberg, H.-W. Haring, U. Schuhert, Z. Naturjorsch. B33 (1978)
1365.
[I31 K. Wieghardt, M. Hahn, W. Swiridoff, J. Weiss. Anyew. Chem. 95(1983)
499: Angew. Chem. Int. Ed. Engl. 22 (1983) 491; Angew. Chem. Suppl.
1983, 583.
1141 M. Hahn, K. Wieghardt, Inorg. Chem. 23 (1984) 3977.
Received: March II, 1985 [Z 1217 IE]
German version: Angew,. Chem 97 (1985) 603
CAS Registry numbers:
l a , 34808-36-1; l b , 51213-19-5; 2, 96689-32-6; 3, 96689-33-7; Cr, 7440-47-3.
[I] W. A. Herrmann, R. Serrano, H. Bock, Angew. Chem. 96 (1984) 364; Angew. Chem. I n / . Ed. Engl. 23 (1984) 383.
[2] W. A. Herrmann, R. Serrano, U. Kusthardt, M. L. Ziegler, E. Guggolz,
T. Zahn, Angew. ChPm. 96 (1984) 498: Angew. Chem. I n t . Ed. Engl. 23
(1984) 515.
131 W. A. Herrmann, R. Serrano, A. Schafer, U. Kiisthardt, M. L. Ziegler, E.
Guggolz, J. Organomei. Chem. 272 (1984) 55.
[4] A. H. Klahn-Oliva, D. Sutton, 0rganometallic.s 3 (1984) 1313.
IS] Procedures: 2 : A solution of l a (273 mg, I mmol) in 50 m L of toluene
(or ether) was saturated with 0,-gas and stirred in the presence of air for
2-4 h until the 1R spectra ( v ( C 0 )region) showed that no more l a was
present. The solution was evaporated to dryness at room temperature
and the brown residue was chromatographed o n silica gel TLC-plates
(Merck TLC 60 GF254,pentane/THF (I0 :2)). Recrystallization from
THFIpentane gave red crystals of 2, which are insoluble in H,O, sparingly soluble in pentane, but readily soluble in polar organic solvents.
The 02-saturated solution of l b
Yield: 90-110 mg (41-50%).-3:
(160 mg, 0.5 mmol) in toluene (30 mL), after five hours' stirring and subsequent thin-layer chromatography of the residue, furnished a yellow
powder that crystallized from pentane/THF at -30°C in the form of
yellow needles. Yield l l O m g (40%). FD-MS: m/z 542 (w.r.1. "Mo;
M+).
[6] E. 0. Fischer, K. Ulm, H.-P. Fritz, Chpm. Ber. 93 (1960) 2167.
[7] a) F. Bottomley, D. E. Paez, P. S. White, J. Am. Chem. Sot. 103 (1981)
5581; b) ibid. 104 (1982) 5651.
[8] F. Bottomley, F. Grein, Inorg. Chem. 21 (1982) 4170.
[9] M. Cousins, M. L. H. Green, J. Chem. Soc. 1964, 1567.
[lo] C . Couldwell, K. Prout, Acta C<v.md/ogr.834 (1978) 933.
[ I l l Pi, Z = I , a=827.0(2), b=857 5(2), c=927.5(4) pm, a=98.78(4),
b= lOX.14(2), y = 117.77(3)', V = 5 1 7 . 2 x lo6 pm3,p,,,= 1.41 (in CHBrJ
hexane), P ~ . ~=, .1.408 g/cm-3: Mo,, radiation, graphite monochromator
8/2Bscan: 1703 independent reflections (28<50") with />u(/);Lp- but
no absorption correction @ = 10.1 c n - ' ) ; H atoms not considered;
R = 0.067, R , ( F ) = 0.076. Further details of the crystal structure investigation are avaifable o n request from the Fachinformationszentrum
602
0 V C H Verlaqsgerellschafi mbH. 0.6940 Wemheim. 1985
Bis(dihydr0-1,Zazaborolyl)tina Novel Boron-Nitrogen Stannocene**
By Giinter Schmid,* Dagmar Zaika, and Roland Boese
Dihydro-1,2-azaborolyl ligands provide transition metals
with a more diverse range of electronic possibilities than
the isoelectronic cyclopentadienyl(Cp) systems. In addition to q5-coordination, q4- and $-coordination are observed."] Corresponding to its electron configuration, the
metal seeks stronger contact to the acceptor atom boron, to
the donor atom nitrogen, to the C3 ally1 moiety, or equally
to all five ring atoms. Interestingly, in the stannocenes that
have been synthesized and structurally investigated in the
last few years, relatively marked deviations from the q 5 arrangement of the Cp ligands have been found. Moreover,
the Cp rings are usually not coplanar but rather are at an
angle with respect to each other.
With the synthesis of bis( I-tert-butyl-2,3-dimethyldihydro- 1,2-azaborolyl)tin I , we have succeeded for the first
time in binding a main group metal to a dihydro-1,2-azaborolyl ligand (apart from Li in I-tert-butyl-2,3-dimethyl-
[*] Prof. Dr. G. Schmid, Dip1.-Chem. D. Zaika, Dr. R. Boese
lnstitut fur Anorganische Chemie der Universitat
Universitatsstrasse 5-7, D-4300 Essen I (FRG)
I**]
Azaborolinyl Complexes, Part 19. This work was supported by the
Fonds der Chemischen Industrie. Comment on the nomenclature: the
traditional name "azaborolinyl" has been replaced by "dihydroazaborolyl" according to IUPAC rule RB-1.2 (Pure Appl Chem. 55 (1983)
409).-Part 18: G. Schmid, G. Barbenheim, R. Boese, Z. Narurfmwh. B.
in press.
0S70-0833/85/0707-602 $ 02.50/0
Anyen,. Chem. Inl. Ed. Engl. 24 (198s) N o . 7
dihydro-1,2-azaborolyl, 2). 1 has enabled us to study the
behavior of the metal with respect to its preferred coordination site and to make comparisons with stannocenes.
The reaction of 2 with SnCI2 at - 45°C in tetrahydrofuran (THF) afforded orange-yellow 1 in 49% yield; 1 decomposes above - 20°C with formation of tin.['] The molecular structure of the BN/NB isomer[31 (Fig. 1) shows
"i
.jic7
Fig. I. Crystal structure of 1. Selected bond lengths [A]: Sn-C3 2.489(9),
Sn-C4 2.592(10), Sn-B2 2.742( lo), Sn-C5 2.810(10), Sn-NI 2.917(9),
NI-82 1.480(7), B2-C3 1.511(7), C3-C4 1.422(6), C4-C5 1.377(8), NI-C5
1.399(4).
planar rings lying at a n angle with respect to each other
and thus resembles most of the stannocenes studied so
far.[4-71Only in the sterically highly hindered [(Ph,Cs)zSn]
are the rings arranged in a coplanar fashion."] The molecule exhibits C, symmetry, which is due to the crystallographic axis in 0/Y/0.25.
The angle of aperture between the two rings in 1 is
46.5", thus lying between the corresponding angles in stannocene (55 0)[41 and decamethylstannocene (36").['] According to MO calculations, the angled structure is energetically favorable (energy minimum at 60") compared with
the coplanar geometry.[51Figure 2 shows the displacement
6
c8
c10
c9
Fig. 2. Displacement of the tin atom from the ring center in 1
A
of tin from the center of the ring by 0.48 in the direction
of the atoms C3 and C4. Accordingly, the Sn-CS and
Sn-NI distances, 2.810 and 2.917 A, respectively, are unusually long. This observation is in accord with the bonding
relationships in stannocenes o r stannocene-like complexes,
in which marked differences in the Sn-C bond angles also
exist: 2.56-2.85
in 3,[412.59-2.74A in 4J5] or 2.532.81 A in 5.16] In the boron-containing complexes 6191and
A
Anyew,. Chem. I n l . Ed. Engl. 24 (1985) No. 7
7"01 the tin atoms are clearly displaced from the center of
the ring in the direction of the boron atoms.
Whereas metal-boron bonds in transition-metal complexes result in upfield shifts of the "B-NMR signals compared with those in the free ligands, a shift downfield from
6=24.5 (in 2) to 6=31.5 is observed for 1. This i s due to
the reduced ability of main group metals to engage in
back-bonding because of a lack of available d electrons.
As is the case for the dihydro-l,2-azaborolyl complexes
with transition metals, the two expected diastereomers of 1
can be observed by 'H-NMR spectroscopy; their formation is due to the prochiral character of the rings. The proton signals of the diastereomers have an intensity ratio of
ca. 10 : 1. It is not yet known whether the enrichment of
one of the forms occurs only during the course of the
work-up, or, instead, whether one isomer is already formed
preferentially during the formation of the complexes. In
the case of the transition-metal complexes, an isomer ratio
of ca. 1 : 1 is usually found. Possibly, the special bonding
and structure relationships play a role in the example discussed here. The 'H-NMR signals lie in the expected
ranges, the ring protons H4 and H5 each appearing as a
doublet due to the mutual coupling.
Received: March I , 1985 [Z 1198 IE]
German version: Angew. Chern. 97 (1985) 581
CAS Registry numbers:
1, 96745-78-7; 2, 96706-55-7; 8 , 96706-56-8; I-rert-butyl-2-methyl- I H-2,3-dihydro-1,2-azaborolyllithium,84356-32- 1.
[ I ] G. Schmid, Cornm. Inorg. Chem.. in press.
(21 Experimental procedure: I-ferf-Butyl-2,3-dimethyl-lH-2,3-dihydroI ,2azaborole 8 : 1 -ferr-butyl-2-methyl- I H-2,3-dihydro- I ,2-azaborolyllithium
(8.55 g, 59.8 mmol) [ l I] was dissolved in 90 mL of T H F and treated
dropwise at -50°C with a solution of iodomethane (8.49 g, 59.8 mmol)
in pentane. The solution was warmed slowly to room temperature and
stirred for I h. LiI was separated by suction filtration through a sinteredglass filter. Distillation at 163- 165°C afforded 6.86 g (75.9%) of colorless 8. ' H NMR (200 MHz, [D,]benzene): S=0.69 (s, 3 H , BCH,), 1.15
(d, J = 7 - 8 Hz, 3 H , CCH,), 1.16 ( s , 9 H , C(CH,),), 1.78 (m,I H, H3),
5.41 (dd, J = 4 Hz, J = 2 Hz, 1 H, H4), 6.47 (dd, J = 4 Hz, J = 2 Hz, I H,
H5): "B NMR (200 MHz, [DJbenzene): 6=50.8+ I : "C('HJ NMR (200
MHz, [DJbenrene): 6=0.8 (br. s, BCH,), 13.01 ( s , CCH,), 31.35 (s,
C(CH,),), 35.6 (br. s, C 3 ) , 53.52 (s, C(CH,),), 118.21 (s, C4), 136.4 (s,
C 5). Correct C-H-N analysis. 2 : Similarly to the synthesis of other dihydroazaborolyllithium salts from lithium tetramethylpiperidide and 8
Ill]. Yield: 76.0°/o. 'H NMR (200 MHz, [D,JTHF): 6=0.47 ( s , 3 H ,
BCH,), 1.34 (s, 9 H , C(CH,),), 1.82 ( 5 , 3H, CCH,), 5.54 (d, J = 2 . 7 Hz,
I H, H4), 5.73 (d, 3=2.7 Hz, I H, H5); "B NMR (200 MHz, [DJTHF):
6=24.5?1; '3C('H) NMR (200 MHz, [D,]THF): 6=0.6 (br. s, BCH,),
15.25 (s, CCH,), 32.56 (s, C(CH,),), 53.64 (s, C(CH,),), 103.28 (s, C4),
113.31 ( s , C5). The signal for C3 cannot be observed due to the neighboring boron atom. Correct C-H-N-Li
analysis. I : Anhydrous SnCI,
(0.74 g, 3.9 mmol) in 25 m L of THF was slowly added dropwise to a solution of 2 (1.23 g, 7.8 mmol). After l h, the solvent was removed without heating. The residue was treated with 20 mL of cold pentane. Filtration through a sintered-glass filter cooled with dry ice afforded an
orange-yellow solution. The solvent was removed at - 20°C. Repeated
washing with pentane at -20°C and subsequent drying in vacuum
yielded 0.79 g (48.6%) of analytically pure 1 as a mixture of diastereomers, which was stored at -78°C. According to the ' H NMR spectrum,
the sample contains both diastereomers in a ratio of 10 ( a ) : 1 (b). Assignment of a and b to the BN/BN- or BN/NB isomer was not
achieved since a preparative separation was not possible. 'H NMR (200
MHz, [D8]toluene, -40°C): 6 = ( a ) 1.02, ( b ) covered by C(CH,),, ( s , 6 H,
BCH3), 1.10 (1.16) ( s , 18H, C(CH,),), 2.28 (2.42) (s, 6 H , CCH,), 5.39
(5.52) (d, J = 3 Hz, 2H, H4), 6.80 (6.70) (d, J = 3 Hz, 2 H , H5): "B NMR
0 VCH Verlagsgesellschaft rnbH, 0-6940 Weinheim.1985
0570-0833/85/0707-0603 $ 02.50/0
603
(200 MHz, [D,]toluene, -40°C): 6 = 3 1 . 5 f 1 (a = b); "C('H1 NMR (200
MHz, [Dx]toluene, -40°C): & = ( a ) 13.41 (s, CCHi), 31.22 (s, C(CH,),
54.22 (s, C(CH3)'), 103.89 (s, C4), 117.94 (s, C5). The signals for C3 and
C6 cannot be observed due to their position next to the boron atom.
Owing to the poor signal-to-noise ratio, the "C-NMR signals of b can
no longer be observed. Correct C-H-N-Sn
analysis.
[31 In the BN/NB isomer, the same sides of the rings are coordinated to tin:
in the BN/BN isomer, different sides. BN/NB 1 (-120°C): from pentane at low temperature: C2/c; 2 = 4 : a=20.972(4), b =9.266(2),
r=18.137(S)A; fl=144.01(1)"; V=2071.2(9)A3; pCalcd
=1.34 g/cm':
3 " 5 2 8 5 6 0 " (MoKn,d=0.71069
graphite monochromator), p = 12.4
c m - ' : 2469 independent intensities, 2320 with F23.5c~((F).Structure solution using Patterson and difference Fourier methods, refinement according to the block cascade method with SHELXTL. The hydrogen
atoms of the CH, groups were refined as "riding groups" and the ring
hydrogen atoms were obtained from a difference Fourier synthesis and
refined to R =0.066. Further details of the crystal structure investigation
are available on request from the Fachinformationszentrum Energie
Physik Mathematik, D-7514 Eggenstein-Leopoldshafen 2, by quoting
the depository number CSD 51413, the names of the authors, and the
journal citation.
[4] J. L. Atwood, W. E. Hunter, J . Chem. Soc. Chem. Commun. 1981, 925.
[S] P. Jutzi, F. Kohl, P. Hofmann, C. Kriiger, Y.-H. Tsay, Chem. Ber. 113
(1980) 757.
.[6] A. H. Cowley, J. G. Lasch, N. C. Norman, C. A. Steward, T. C. Wright,
OrganometaNics 2 (1983) 1691.
171 A. H. Cowley, P. Jutzi, F. X. Kohl, J. G. Lasch, N. C. Norman, E.
Schluter, Angew. Chem. 96 (1984) 603; Angew. Chem. f n t . Ed. Engl. 23
(1984) 616.
[S] M. J. Heeg, C. Janiak, J. J. Zuckerman, J . A m . Chem. SOC.106 (1984)
A,
We recently reported the synthesis and structure of rhenium complexes of type B,I4I while Cowley et al. have described the first phosphavinylidene complex 4.l5l In this
communication we present for the first time a phosphaalkenyl complex of iron, which represents a complex of type
A.
The synthetic strategy chosen here is an extension of
that developed by Berker for the synthesis of phosphaalkenes from disilylphosphanes and pivoloyl chloride[61to the
disilylphosphidoiron complex 1 ."I The complex 1 reacts
with pivaloyl chloride to give the brown title compound
3.[*]N o intermediate, such as, e.g., 2, could be detected in
the reaction between - 70°C and 22°C by 3'P-NMR spectroscopy.
[(q5-CsH5)(CO),FeP(SiMe3){C(0)tBu)]
--t
2
[(qS-CSHs)(CO)2FeP=C(OSiMe3)(fB~)]
3
4259.
[9] H. Wadepohl, H. Pritzkow, W. Siebert, Organometalks 2 (1983) 1899.
[lo] A. H. Cowley, P. Galow, N. S. Hosmane, P. Jutzi, N. C. Norman, J .
Chem. Soc. Chem. Commun. 1984, 1564.
(1 I ] G. Schmid, S. Amirkhalili, U. Hohner, D. Kampmann. R. Boese, Chem.
Ber. 115 (1982) 3830.
Z-[(q5-C5H,)(C0)2Fe-P= C(OSiMe&tBu)],
a Phosphaalkenyl-Complex with FeP Single Bond**
By Lothar Weber,* Klaus Reizig, Roland Boese. and
Michael Polk
Multiple-bond systems with elements of higher periods
(n 2 3) are of current interest, not only from the preparative
and the theoretical point of view,['] but also with regard to
the ligand properties of compounds containing such structural units.11er21
Thus, for example, q'- and $-complexes of
phosphaalkenes and phosphaalkynes have recently been
the subject of intensive studies ; phosphaalkenes can be
terminal or bridging ligands.l3I All phosphaalkene complexes reported so far contain an intact R'P=CR2R3 structural unit.
In principle, it should be possible to replace the R', R2
and R3 groups of a phosphaalkene by transition metalcomplex fragments to give complexes of the type A - E .
Ln',
.P=C
/
RZ
/ML,
R',
.*P=c\
\R3
L,M\
,M'L',
.P=C
\R3
D
4
The constitution and configuration of the isolated complex 3 were confirmed by elemental analysis and spectroscopic methods.lsl The Fe(CO),-group gives rise to two intense v ( C 0 ) bands in the IR spectrum. The characteristic
downfield shifts of the resonances of the (C=P) unit and
the M + ion in the masslspectrum are reconcilable with the
monomeric structure of the complex. The configuration at
the P=C bond was ascertained by analysis of the 'H- and
I3C-NMR spectra. The protons of the Me3Si0 unit gave
rise to a singlet at 6 = 0.44,while the resonances of the tertbutyl protons appear as a doublet due to coupling with the
phosphorus atom. The doublet at 6=4.15is assigned to the
c10
/ML,
Rl,
,P=C,
R3
B
A
[(q5-CsH,)(CO)2Mo=P=C(SiMe3)2]
M'L',
C
L,M~
/M'L',
.*P=C\
M'L",
eb
E
c7
[*] Priv.-Doz. Dr. L. Weber, Dip1:Chem. K. Reizig, Dr. R. Boese,
Dipl.-Chem. M. Polk
lnstitut fur Anorganische Chemie der Universitat
Universitatsstr. 5-7, D-4300 Essen I (FRG)
(**I This work was supported by the Fonds der Chemischen Industrie and
by the Deutsche Forschungsgemeinschaft.
604
0 VCH Verlagsgesellschaft mbH, 0-6940 Weinheim, 1985
Fig. 1. Crystal structure of 3. Selected bond lengths [pm] and angles ["I:
Fe-P 229.8(1), P-CI 170.1(4), CI-01 136.5(5), CI-C4 152.9(6), Fe-C2
175.3(5), Fe-C3 178.3(5), C2-02 l15.1(6), C3-03 110.8(7), Fe-C(ring)
21 1.2(3) to 21 1.9(3). C2-Fe-P
86.2(1), P-Fe-C3
88.8(2), C2-Fe-C3
96.5(2), Fe-P-CI
113.8(2), P-CI-01
123.9(3), P-CI-C4 120.5(3),
01-Cl-C4 115.3(4), CI-01-Si 144.70).
0570-0833/85/0707-0604 $ 02.50/0
Angew. Chem. Int. Ed. Engl. 24 (1985) No. 7
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dihydro, tinчa, azaborolyl, stannocene, nitrogen, bis, novem, boron
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