1
56
Organometallics 1999, 18, 156-160
2
,6-Dip h en ylp h en yl-Ba sed Or ga n om eta llic Com p ou n d s of
†
Ga lliu m
R. Chad Crittendon, Brent C. Beck, J ianrui Su, Xiao-Wang Li, and
Gregory H. Robinson*
Department of Chemistry, The University of Georgia, Athens, Georgia 30602-2556
Received September 4, 1998
(
2,6-Diphenylphenyl)lithium-bis(diethyl ether), Ph
reaction of n-butyllithium with 2,6-diphenyl-1-iodobenzene in diethyl ether. Reaction of I
with group 13 metal halides, MX (M ) Ga, X ) Cl, I; M ) In, X ) Cl), affords bis(2,6-
diphenylphenyl)gallium iodide, (Ph GaI (II), bis(2,6-diphenylphenyl)indium chloride,
Ph InCl (III), and bis(diethyl ether)lithium trichloro-2,6-diphenylphenylgallate, [Li‚
Et GaCl ] (IV). Reaction of (2,4,6-triphenylphenyl)lithium with GaCl gives
diethyl ether)lithium trichloro(2,4,6-triphenylphenyl)gallate, [Li‚Et O][Ph GaCl ] (V).
2
C
6
H
3
Li‚2Et
2
O (I), was synthesized by
3
2
6 3 2
C H )
(
2
(
2 6 3 2
C H )
2
O][Ph
2
C
6
H
3
3
3
2
3
C
6
H
2
3
1
13
The group 13 metal aryls were characterized by H and C NMR spectroscopy, elemental
analyses, and single-crystal X-ray diffraction. The neutral lithium aryl (I) and arylgallium
halide species (II) exhibit trigonal-planar coordination, while the coordination of the gallium
atoms in anions IV and V assume distorted-tetrahedral conformations.
In tr od u ction
The organometallic chemistry of the heavier members
Braun Labmaster 130). Solvents were distilled under a
nitrogen atmosphere with sodium benzophenone. Nitrogen was
passed through copper-based purification and molecular sieve
drying columns prior to use. Gallium(III) chloride, gallium-
of group 13 has been of interest in this laboratory for
some time. Considerable effort has been directed toward
the preparation of low-coordination-number group 13
organometallic complexes as a function of ligand steric
loading. The synthesis and structure of such group 13
metal complexes have proven to be quite interesting.
In particular, the alkali-metal reduction of such com-
plexes has been shown to yield organometallic com-
(
III) iodide, indium(III) chloride, bromobenzene, 1,3,5-tri-
phenylbenzene, n-butyllithium, and bromine were purchased
from Aldrich Chemical Co. (Milwaukee, WI), while 2,6-dibro-
moaniline was purchased from Lancaster Synthesis Inc.
(
2 6 3
Windham, NH). 2,6-Diphenyl-1-iodobenzene, Ph C H I, was
6
prepared according to the published procedure. Elemental
analyses were performed by E + R Microanalytical Labora-
tories (Parsippany, NJ ). NMR spectra were recorded on a
Bruker AC-300 or Bruker AC-250 spectrometer. X-ray inten-
sity data were collected on a Siemens P4 diffractometer (50kV/
1
-5
pounds containing Ga-Ga bonds.
Herein, we report
the synthesis and structural characterization of (2,6-
diphenylphenyl)lithium-bis(diethyl ether), Ph2C6H3Li‚
Et2O (I), and its utilization in the syntheses of bis(2,6-
diphenylphenyl)gallium iodide, (Ph2C6H3)2GaI (II),
bis(2,6-diphenylphenyl)indium chloride, (Ph2C6H3)2InCl
III), and bis(diethyl ether)lithium trichloro(2,6-diphen-
ylphenyl)gallate, [Li‚2Et2O][Ph2C6H3GaCl3] (IV). The
synthesis and structure of (diethyl ether)lithium trichloro-
2,4,6-triphenylphenyl)gallate, [Li‚Et2O][Ph3C6H2GaCl3]
V), involving the closely related 2,4,6-triphenylphenyl
ligand, is also reported (Scheme 1).
4
0mA).
2
Syn th esis of P h
2
C
6
H
3
2
Li‚2Et O (I). To a suspension of 2,6-
diphenyl-1-iodobenzene (30 g, 86 mmol) in degassed hexane
(150 mL) was added n-butyllithium (60 mL of a 1.6 M solution
in hexanes) via syringe at room temperature over a period of
(
1
0 min. The inert nitrogen atmosphere was rigorously main-
tained throughout the procedure. The solution was stirred for
4 h, after which it was cooled to -78 °C for 3 h and filtered.
2
(
(
The remaining white powder was washed with another 150
mL portion of degassed hexane. The fine crude product was
then dried under vacuum and extracted with diethyl ether.
Cooling the ether solution to -25 °C afforded colorless rod-
shaped crystals (24.2 g, 63 mmol). X-ray-quality crystals were
grown from a saturated ether solution at room temperature,
undisturbed on the benchtop for 2 days. Yield: 73%. Mp: 181
Exp er im en ta l Section
Gen er a l Com m en ts. Standard Schlenk techniques were
employed in conjunction with an inert-atmosphere drybox (M
°
C. Anal. Calcd (found) for Ph
2
C
6
H
3
Li‚2Et
H, 8.78 (8.50). H NMR (300 MHz, 298 K, THF-d
2H), -OCH CH ; 3.33 (m, 8H), -OCH CH ; 6.93 (t, 2H), p′-
CH; 7.10 (t, 4H), m′-CH; 7.25 (d, 4H), o′-CH; 7.43 (t, 1H), p-CH;
2
O: C, 81.25 (80.69);
†
Dedicated to Prof. Dr. Peter J utzi on the ocassion of his 60th
1
8
): δ 1.13 (m,
birthday.
1
2
3
2
3
(
1) Li, X.-W.; Pennington, W. T.; Robinson, G. H. J . Am. Chem. Soc.
995, 117, 7578.
2) Li, X.-W.; Xie, Y.; Schreiner, P. R.; Gripper, K. D.; Crittendon,
1
(
13
7
1
.67 (d, 2H), m-CH. C NMR (300 MHz, 298 K, THF-d
8
): δ
R. C.; Campana, C. F.; Schaefer, H. F., III; Robinson, G. H. Organo-
metallics 1996, 15, 3798.
8.3, -OCH CH ; 68.5, -OCH CH ; 125.2, m-CH; 126.3, p′-
2
3
2
3
CH; 129.0, o′-CH; 130.5, m′-CH; 131.1, p-CH; 147.8, i′-C; 152.2,
o-C; 175.0, i-C.
Syn th esis of (P h
diphenylphenyl)lithium (2.36 g, 10 mmol) in diethyl ether (30
mL) was added to a solution of GaI (2.25 g, 5 mmol) in diethyl
(3) (a) Su, J .; Li, X.-W.; Crittendon, R. C.; Robinson, G. H. J . Am.
Chem. Soc. 1997, 119, 5471. (b) Xie, Y.; Grev, R. S.; Gu, J .; Schaefer,
H. F., III; Schleyer, P. v. R.; Su, J .; Li, X.-W.; Robinson, G. H. J . Am.
Chem. Soc. 1998, 120, 3773.
2 6 3 2
C H ) Ga I (II). A solution of (2,6-
(
4) Su, J .; Li, X.-W.; Crittendon, R. C.; Campana, C. F.; Robinson,
G. H. Organometallics 1997, 16, 4511.
5) Xie, Y.; Schreiner, P. R.; Schaefer, H. F., III; Li, X.-W.; Robinson,
G. H. J . Am. Chem. Soc. 1996, 118, 10635.
3
(
(6) Du, C. J . F.; Hart, H.; Ng, D. K. K. J . Org. Chem. 1986, 51, 3162.
1
0.1021/om980753i CCC: $18.00 © 1999 American Chemical Society
Publication on Web 12/18/1998