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Bis(dichloroboryl)silylamines and Tris(dichloroboryl)-amine.

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Ti7Cl16can be synthesized in several different ways, one
of the most convenient being, e.g., as follows: 400mg of Ti
foil and 50mg of NH4C1 are transferred to a cylindrical
ampoule. After purging with nitrogen, sufficient Al2CI6 (prepared from Al and CI2) is sublimed into the tube such that
the AlzC16-pressure at 375°C is ca. 5 atm; after further purging
with nitrogen lOOmg of TiClz (prepared according to the
method of Ehrlich et
is added and the ampoule sealed
under a high vacuum. After three days' heating black crystals
of Ti7ClI6(37.2 "/, Ti, 62.6 '% C1) are formed in the 350°C-zone
of the 400-350°C temperature gradient. The X-ray diagram
of this product differs from those of TiClz and TiCI,. The
new compound Ti7CIl6 is sensitive to hydrolysis and oxidation, but can be stored indefinitely in an inert atmosphere;
treatment with dilute acids leads to evolution of Hz and
formation of brown solutions.
Ti7Br16can be prepared by reaction of Br2 with an excess
of Ti in the presence of A12Br6 (conversion to TiBr3 at
350+ 250°C and then to Ti7BrI6at 300+250"C). This compound is also analytically pure.
Ti7ClI6,which according to Guinier photographs is isotypic
with Ti7Br16, forms orthorhombic crystals (a= 14.421,
b = 9.987, c= 6.890 A), space group Pnnm, Z = 2. The molecule
contains two sorts of Ti atoms, which we provisionally regard
as Ti" and Ti'". Trigonal Ti3C113 units consisting of Ti"CI6
octahedr: coupled edge-to-edge and containing Ti-Ti bonds
(2.954(2)A) are present [equilateral Ti3 triangles centered at
ca. '16 '13 ' 1 2 ; 'I3
'I6
,0; '16 '1, 'Iz and 'I3'I6 01. The Ti:'ClI3
groups are coupled three-dimensionally via octahedral edges
without Ti-Ti bonds (Ti.. .Ti > 3.80A) with one another and
with Ti"CI6 octahedra [in OOOand 'Iz
'/2 'I2]. This is consistent
(= "TiCI4
with the formula Ti'VC16;3[Ti~CII2/3(316/2]2
.6TiCI2"). The C1 atoms form a distorted cubic close packing
with layers parallel to (210).
A relationship is recognizable between the occurrence of
Ti3-units and the structures of Nb3Cl8, Nb3Br8, Nb318, and
ZnzMo308['I. Starting with an equal distribution of the Ti
valence electrons the additional electrons necessary for the
formation of the Ti3-groups are provided by the "isolated"
Ti.
Received: January 18, 1979 [Z 188 IE]
German version: Angew. Chem. 91. 343 (1979)
8.S. Samfeuson, G. E . MacWuod, J. Phys. Chem. 60, 316 (1956).
[2] E. H . Hall. .I.
M . Blocher, J. Phys. Chem. 63, 1525 (1959).
[3] M . Spirlie, H . A . b y e , Inorg. Chem. 1 7 , 2473 (1978).
[4] P. Ehulich, H . J . Hein, H . Kiihnl, Z . Anorg. Allg. Chem. 292, 139
( I 957).
[5] Cf. H . Schufer, H . G. D. Schnering, Angew. Chem. 76, 833 (1964); A.
Simon, H . G. u. Schnering, J . Less-Common Met. 11, 31 (1966).
[l]
Bis(dichloroboryl)silylarnines and Tris(dichlorobory1)amine
By The0 Gasparis, Heinrich Niith, and Wolfgang Starch"]
Dedicated to Professor Horst Pommer on the occasion of his
60th birthday
According to MO calculations, the D3,, molecule N(BF2),
should be stable[']; it was not examined, however, whether
the expected decomposition products BF, and BN are thermodynamically more stable. Nevertheless, N[B(CH3)z]3rz1 exhi-
[*I Prof. Dr. H. Noth, Dipl.-Chem. T. Gasparis, Dr. W. Storch
Institut fur Anorganische Chemie der Universitat
Meiserstrasse I , D-8000 Munchen 2 (Germany)
326
bits considerable thermal stability-in contrast to the diborylamines RN[B(CH3)2]2[31-suggesting that tris(dihalobory1)amines would also show little tendency to decompose. And
yet attempts to prepare N(BF2)3and N(BClZ), have hitherto
remained uns~ccessful[~~.
Although reaction of N[Si(CH3)3]3 with CH3BBr2 leads to
the B-halogenated diborylamine Br(CH3)2SiN[BCH3Br]2'51,
only methylation of the boron halides is observed with
BC13 or BBr3[61.In contrast, we have now found that Sn-N
cleavage according to (a) predominates in the reaction of BC13
with N[Sn(CH&], at low temperatures, while methylation
of the reactant BC13 or the product N(BC1z)3( I ) only occurs
at higher temperatures; an excess of BCI, prevents methylation
of ( I ). The bis(dichlorobory1)amines ( 2 ) - ( 5 ) are obtained
analogously, increasingly high reaction temperatures being
required along this series.
N[Sn(CH3b]3
+ 3BCL + N(BCI2), + 3(CH3)&CI
(4
(1i
Table 1. NMR data of the new dichloroborylamines ( 1 ) - ( 5 ) ;
B F 3 . 0 R z , NaNO,, TMS.
(1)
12)
(3
(4)
(5)
BC12
SiCI,
SiC12CH3
SiCl(CH,),
Si(CHd3
39 8
40.4
40.0
39.3
39.2
standards
-218
-
- 238
-
- 240
- 242
1.2
0.78
0.43
- 242
All the new compounds are water-clear liquids that are
extremely sensitive to hydrolysis. (1 ) exhibits remarkable thermal stability; it survives heating to 200°C for 2h. Nor do
( 2 ) - ( 5 ) decompose up to 100°C. We regard this observation
as further evidence that decomposition of the B-methylated
diborylamines is initiated by intermolecular BN coordination.
This step fails to occur with dichloroborylamines because
the basicity of the nitrogen is greatly reduced by the CllB
groups. The very low field 14N-NMR signals of a trigonalplanar nitrogen confirm the low electron density at this atom.
Accordingly, the boron atoms in ( I ) - ( 5 ) experience only
slightly greater shielding by BN-x interaction. The 6' 'B values
in the series (C13Si)2NBC12181
(43.6) > (2) > ( 2 ) indicate
that the C12B group of (1) is least twisted relative to the
NB3 -.Sin plane.
Synthesis qf trifdichlorobor~/)umine( I )
Trichloroborane (21.5 g, 183mrnol) is condensed at - 196°C
onto tris(trimethylstanny1)amine (I 5.2 g, 30 mmol) in n-pentane
(30 ml). The mixture is thawed with stirring to - 78 "C, warmed
to - 15°C after 1 h, and then cooled again to -78°C after
1.5 h. Insoluble material [(CH3)3SnCI and (CH3)2SnC12]is
filtered off, the filtrate is washed with cold pentane (- 78 "C),
and the solution evaporated down to 'I3 of its volume in
uacuo. After removal of the precipitate formed at -78"C,
all volatiles are stripped off at - 10°C/10 torr and the product
( I ) isolated at 27"C/1.5 torr (yield 3.4 g, 44 %).
Compounds ( 2 ) - ( 5 ) are prepared analogously. The reactions go to completion at 0-20°C with ( 2 ) - ( 4 ) , and at
35°C in the case of ( 5 ) . All compounds gave correct elemental
Aiigew. Chem. lnt. Ed.
0 Vcrlag 7hemie, GmbH, 6940 Weinheim,1979
Eiiyl.
I X ( I 979) No. 4
05 70-0833/79/0404-0326 S 02.50/0
A
analyses and showed the isotope pattern characteristic of the
molecular ion in the mass spectrum.
Received: March 6, 1979 [Z 192 IE]
German version: Angew. Chem. 91. 357 (1979)
[l] A . D. Buckingham. Proc. Chem. SOC.London 1962, 351.
[2] W Srorch. H . Niith, Angew. Chem. 88, 231 (1976); Angew. Chem. Int.
Ed. Engl. 15, 235 (1976); Chem. Ber. 110, 1636 (1977).
[3] H . Niith, H . Vahrmkamp, J. Organomet. Chem. 16, 357 (1969).
[4] R. A . Geanangel, J. lnorg. Nucl. Chem. 32, 3697 (1970); R. Storr, A .
N . Wriyh!, C . A. Widler. Can. J. Chem. 40, 1296 (1962).
[5] K . Burlos, H . Chrrsrl. If. Niith, Justus Liehigs Ann. Chem. 1976, 2272.
161 K . Budos, H . Nli'th, Chem. Ber. 110, 2783, 3460 (1977); W Huubold.
U . Kruatz, Z. Anorg. Allg. Chem. 421, 105 (1976).
171 H . W RoeAky, H . Wiezei, Chem. Ber. 107, 3186 (1974).
181 U . Wannagat, P . Schmidt, Inorg. Nucl. Chem. Lett. 4. 355 (1968).
Complex-StabilizedHydroxy(ptoly1)acetyleneby Reaction of trans-Chlorotetracarbonyl(toly1carbyne)tungsten
with Acetylacetone"'
By Ernst Otto Fischer and Peter Friedrich"]
Dedicated to Professor Horst Pommer on the occasion of his
60th birthday
The reaction of trans-halotetracarbonyl- or cyclopentadienyldicarbonyl-carbyne complexes with nucleophiles was
observed to involve not only substitution of halogen and
carbonyl but primarily specific transformations of the carbyne
ligand rCR['].
We have now discovered a new combined variant of the
reaction by photochemical interaction of trans-chlorotetracarbonyl(pto1ylcarbyne)tungsten (I )131 with acetylacetone. Fractional crystallization of the crude product yielded a dark
blue complex (1 : 1 adduct with diethyl ether) which is air
and temperature sensitive and readily soluble in polar solvents,
but only sparingly soluble in pentane. On the basis of the
analytical and spectroscopic data of the diamagnetic compound ( 2 ) , and the results of an X-ray structural analysis
(Fig. I), its formation can be envisaged as follows:
t r u n s - ( : I ( C O ) , W : C ~ C H ,+ Hacac
hu
EtzO, - 60 "C
(1)
C-OH
Fig. 1. Structure of the adduct (2).O(C2H& in the crystalline state. Crystal
data: monoclinic P2'/c, Z = 4 ; a=1069, b=1716, c=1547pm, /1=126.8",
~ . independent reflecV=2272 x 106pm3,p..Ic.= 1.697, pex,,= 1 . 6 4 g ~ m - 2423
tions. Syntex PZI four-circle diffractometer. Solution: Syntex XTL, conventional R I =0.042.
A very short contact distance between the oxygen atom
of the OH group in (2) and that in the solvate ether
[257(1)ppm, aC-O...O(Etz)= 125(1)"] indicates strong hydrogen bonding, which is characteristic of N H or OH acidic
systems such as carboxylic acids and
A 'H-NMR signal of (2) at 6=14.4 ([D6]acetone, rel.
to int. TMS, - S O T ) , whose chemical shift and half-width
are highly temperature dependent, is to be assigned to the
hydroxyl H atom; the chemical shift reveals the acidic character of the proton[']. The other signals (- 20°C) at 6 = 7.63
(M, 4 ; C6H4),5.78 (S, 1; CH(acac)["), 3.42 (Q, 4; CH2(Et20)),
2.49 (s, 3 ; C6H4<H3), 2.16 (S, 6; CH3(acac)), and 1.17
(T, 6 ; CH3(Et20))lie in the expected range.
The IR spectrum (KBr disc, room temperature) shows the
vco bands of the two cis carbonyl groups at 2060 (s) and
1960 cm-' (vs). Absorptions at 1590 (s) and 1517 cm-' (s)
are assigned to the stretching vibrations of the acetylacetonate
ligandlsl.Amedium strength band at 1675cm-' is attributable
in accord with other acetylenetungsten complexes[9] to the
C=C bond of the hydroxy(toly1)acetylene ligand which is
greatly weakened by coordination to the metal.
Procedure
Two cis carbonyl ligands have been substituted by the
acetylacetonate ion coordinated in (2) via the oxygen atoms.
One of the two C O groups is evolved as carbon monoxide,
whereas the second one combines with the tolylcarbyne ligand
and a H atom to give a new ligand, uiz. q2-hydroxy(p-toly1)acetylene, located trans to the halogen atom. I-Hydroxy-I-alkynes
were formerly regarded as incapable of existence, at least
in the free statec4].
As shown by the crystal structure analysis of (2), the two
acetylenic carbon atoms are coordinated entirely symmetrically to the central atom; the W-C distances are 204(2)pm
and thus, like the other bond lengths and angles in the TolC=C-O
fragment [dc...c= 130(2)pm, a C - C - C = 141(1y,
C r C - 0 = 138(1)"],closely resemble those in other qz-acetylenetungsten complexes['].
All preparative work is carried out under N2 and with
oxygen- and moisture-free solvents.-Compound (1 ) (304 mg,
0.7 mmol) and acetylacetone (900 mg, 9 mmol) are dissolved
in ether (250ml) at -60°C in a photochemical reactor fitted
with a cold finger (UV mercury high-pressure lamp, 150W,
Hanau) and irradiated at that temperature with stirring until
the evolution of CO has ceased. After stripping off the solvent
at - 20°C and the excess of acetylacetone at - 15°C (cold
finger), the violet residue is recrystallized several times from
ether at low temperature. Analytically pure ( 2 ) . 0 E t 2 is isolated, yield 77 mg (19 %).
Received: January 17, 1979 [Z 179 IE]
German version' Angew. Chem. 91. 345 (1979)
CAS Registry numbers:
( 1 ), 68480-95-5; (21,69631 -49-8; acetylacetone, 123-54-6
.-
[*] Prof. Dr. E. 0. Fischer, DipLChem. P. Friedrich
Anorganisch-chemisches Institut der Technischen Universitat Munchen
Lichtenhergstrasse 4, D-8046 Garching (Germany)
Angeu Chem
Iiir
[l] Transition-Metal Carhyne Complexes, Part 48 This work was supported
by the Deutsche Forschungsgemeinschaft. We are grateful to Ms B.
Zimmer-Gasser for measuring the low temperature 'H-NMR spectra.-
327
E d Engl 18 (1979) N o 4
0 Vrrlag Chemre, GmbH, 6940 Weinhelm, 1979
0570-0833179 0404-0327 $ 02 5010
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amin, dichloroboryl, bis, trish, silylamines
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