Prototypical arsine-triel adducts (R3AsEX3 for E = B, Al, and Ga)

Article abstract of DOI:10.1139/V10-029

Complexes of arsine ligands (R₃As, R = Me, Et, Ph) and Lewis acids of group-13 elements of the form EX₃ (E = B, X = Ph, C ₆F₅; E = Al, X = Cl, Br, I; E = Ga, X = Cl) have been isolated and characterized by X-ray

Full text of DOI:10.1139/V10-029

797
Prototypical arsine–triel adducts (R3AsEX3 for
E = B, Al, and Ga)
Eamonn Conrad, Janet Pickup, Neil Burford, Robert McDonald, and
Michael J. Ferguson
Abstract: Complexes of arsine ligands (R3As, R = Me, Et, Ph) and Lewis acids of group-13 elements of the form EX3
(E = B, X = Ph, C6F5; E = Al, X = Cl, Br, I; E = Ga, X = Cl) have been isolated and characterized by X-ray crystallogra-
1
phy, infrared spectroscopy, H, 13C{1H}, 11B{1H}, and 27Al NMR spectroscopy. The compounds are compared with rare
arsine–triel adducts.
Key words: arsine–triel (boron, aluminum, gallium) Lewis adducts.
´
´
´
´
´ ´
Resume : Les complexes des ligands d’arsine (R3As, R = Me, Et, Ph) et des acides de Lewis du groupe des elements 13
´ ´
´
´
´
de la forme EX3 (E = B, X = Ph, C6F5; E = Al, X = Cl, Br, I; E = Ga, X = Cl) ont ete isoles et caracterises par la cristal-
1
lographie aux rayons-X, la spectroscopie infrarouge, et la spectroscopie RMN de H, 13C{1H}, 11B{1H} et 27Al. Les com-
´
´
poses sont compares aux adduits rares d’arsine–triel.
´
Mots-cles : adduits de Lewis d’arsine–triel (bore, aluminium, gallium).
´
[Traduit par la Redaction]
Introduction
Results and discussion
Compounds involving bonds between tetracoordinate
group-13 elements and tetracoordinate group-15 elements
represent prototypical examples of Lewis acid–base adducts
and are well-known for compounds involving nitrogen or
phosphorus donors. In contrast, examples of adducts involv-
ing arsine ligands on Lewis acids of group-13 elements are
rare despite the importance of arsenic in the development of
semiconducting materials such as gallium arsenide.
Compounds containing a coordinatively unsaturated ar-
senic center bound to a coordinatively unsaturated boron cen-
ter are known,1 but adducts of tetracoordinate arsenic bound
to tetracoordinate boron have not been reported. Moreover,
although examples of complexes of arsines with alanes,2–4
gallanes,5–7 or indanes7,8 have been spectroscopically or crys-
tallographically characterized, there are limited data available
and few acyclic complexes are known that represent proto-
typical examples of arsines with Lewis acids of group-13
elements and provide fundamental data for the As–E bonds.
Prompted by the recent use of arsine ligands to stabilize
pnictogenium cations (PnR2+)9 and diphosphenium dications
(RPPR2+),10 we report crystallographic and NMR spectro-
scopic data for compounds of the form R3AsEX3 for E = B,
Al, and Ga. Comparisons are made with the rare examples
that have been previously reported.
Reaction mixtures containing an alkyl- or aryl-arsine
(R3As, R = Me, Et, Ph) and an arylborane (BX3, X = Ph,
C6F5) in CH2Cl2 exhibit a single signal in the 11B{1H}
NMR spectra (Table 1). The chemical shifts are consistent
with those observed for the corresponding solids that are
isolated from reaction mixtures and redissolved in CD2Cl2
(or CD3CN). Derivatives containing X = C6F5 have chemical
shifts in the range observed for those compounds involving
B(C6F5)3 moieties.11 Reaction mixtures of arsines (R3As, R =
Me, Et, Ph) with haloalanes (AlX3, X = Cl, Br, I) in CH2Cl2
show a single chemical shift in the 27Al NMR spectra
(Table 1) with chemical shifts that are in the range of tetra-
coordinate aluminum centers.12
Crystalline samples of Me3AsBPh3, Et3AsB(C6F5)3,
Ph3AsAlCl3, and Ph3AsAlI3 have been isolated from the
reaction mixtures described above and Ph3AsGaCl3 was isolated
from the reaction of Ph3As and GaCl3. The compounds have
been crystallographically characterized as adducts of arsine
ligands on group-13 Lewis acids. The structures all involve
slightly distorted tetrahedral geometries at the arsenic and
group-13 element centers, as illustrated in Figs. 1–5. There are
no significant intermolecular interactions in any of the structures.
Selected bond distances and angles are presented in Table 2
and torsional angles are available as Supplementary data.
Received 24 January 2010. Accepted 16 February 2010. Published on the NRC Research Press Web site at canjchem.nrc.ca on 27 May
2010.
This article is part of a Special Issue dedicated to Professor R. J. Boyd.
E. Conrad, J. Pickup, and N. Burford.1 Department of Chemistry, Dalhousie University, Halifax, NS, B3H 4J3, Canada.
R. McDonald and M.J. Ferguson. X-ray Crystallography Laboratory, Department of Chemistry, University of Alberta, Edmonton, AB
T6G 2G2, Canada.
1Corresponding author (e-mail: Neil.Burford@dal.ca).
Can. J. Chem. 88: 797–803 (2010)
doi:10.1139/V10-029
Published by NRC Research Press

798
Can. J. Chem. Vol. 88, 2010
Table 1. 11B{1H} NMR and 27Al NMR chemical
shifts (ppm) in reaction mixtures of R3As with
EX3 and for crystalline samples of adducts redis-
solved.
Fig. 2. Crystallographic view of Et3AsB(C6F5)3. Nonhydrogen
atoms are represented by Gaussian ellipsoids at the 50% probability
level.
Compound
Me3AsBPh3
Et3AsBPh3
11B{1H} or 27Al (d, ppm)
53.6 (s)
36.3 (s)
Ph3AsBPh3
Me3AsB(C6F5)3
Et3AsB(C6F5)3
Ph3AsB(C6F5)3
Me3AsAlCl3
Et3AsAlCl3
Ph3AsAlCl3
Me3AsAlBr3
Et3AsAlBr3
Ph3AsAlBr3
Me3AsAlI3
Et3AsAlI3
67.8 (s)
–11.0 (s)
–11.8 (s)
–11.6 (s)
104.3 (s)
110.3 (s)
104.1 (s)
112.9 (s)
104.8 (s)
108.4 (s)
110.5 (s)
111.2 (s)
103.8 (s)
Ph3AsAlI3
Fig. 1. Crystallographic view of Me3AsBPh3. Nonhydrogen atoms
are represented by Gaussian ellipsoids at the 50% probability level.
Fig. 3. Crystallographic view of the Ph3AsAlCl3 molecule showing
the atom labelling scheme. Nonhydrogen atoms are represented by
Gaussian ellipsoids at the 50% probability level. Hydrogen atoms
are shown with arbitrarily small thermal parameters.
˚
The As–B bond lengths in Me3AsBPh3 (2.148(3) A) and
˚
Et3AsB(C6F5)3 (2.1905(18) A) are longer than the sum of
˚
the covalent radii for arsenic and boron (2.09 A). Both
adducts adopt a close to eclipsed conformation (smallest
C–As–B–C torsion angle in Me3AsBPh3 = 24.03(8)8, in
Et3AsB(C6F5)3 = 9.89(13)8), which compares with the con-
formation observed in the phosphine–borane analogue,
Et3PB(C6F5)3 (smallest C–P–B–C torsion angle = 15.7(3)8).11
Adducts Ph3AsAlCl3 and Ph3AsAlI3 are isomorphous with
both Ph3PGaI3 and Ph3AsGaI3.7 As for the arsine–borane ad-
to the lower steric repulsion in the organoalane derivatives
and the inductive influence of the halogens on the Lewis acid-
ity of the alane in the haloalane. The alane adducts Ph3AsAlCl3
and Ph3AsAlI3 adopt a more staggered conformation about
the As–Al bond axis (smallest C–As–Al–C torsion angle in
Ph3AsAlCl3 = 32.58(6)8, in Ph3AsAlI3 = 38.83(6)8) than the
borane adducts Me3AsBPh3 and Et3AsB(C6F5)3.
˚
ducts, the As–Al bond lengths (Ph3AsAlCl3, 2.5191(9) A;
Crystals of Ph3AsGaCl3 are isomorphous with both
7
˚
Ph3AsAlI3, 2.517 A) are slightly longer than the sum of the co-
Ph3PGaI3 and Ph3AsGaI3 and there are two crystallographi-
˚
valent radii for aluminum and arsenic (2.47 A). Nevertheless,
cally independent molecules in the unit cell (Fig. 5). The
˚
˚
the As–Al bonds are shorter than those in i-Pr3AsAl-t-Bu3
As–Ga bond lengths (2.540(6) A and 2.449(6) A) are close
to the sum of the covalent radii for arsenic and gallium
3
˚
˚
(2.839(1) A) and TMS3AsAl-t-Bu3 (2.654(2) A), likely due
Published by NRC Research Press

Conrad et al.
799
Fig. 4. Crystallographic views of Ph3AsAlI3. Nonhydrogen atoms
are represented by Gaussian ellipsoids at the 50% probability level.
transferring an aliquot of sample in an appropriate deuterated
solvent into a 5 mm sample tube. The tubes were capped and
sealed with Parafilm prior to removal from the inert atmos-
phere. IR spectra were obtained from powdered and crystal-
line samples dissolved in CH2Cl2 and spotted on CsI plates.
Data collection was on a Bruker Vertex FTIR spectrometer.
Peaks are reported in wavenumbers (cm–1) with ranked in-
tensities in parenthesis beside the value, where a value of
one is indicative of the most intense peak in the spectrum.
Melting points were recorded on an Electrothermal melting
point apparatus in sealed capillary tubes under N2.
Caution
All arsines are known carcinogens and must be handled
using appropriate procedures.
Preparation of Me3AsBPh3
A solution of Me3As (52.0 mL, 0.50 mmol) in CH2Cl2
was added to a solution of BPh3 (121.0 mg, 0.50 mmol) in
CH2Cl2 and the mixture was stirred for 30 min. The solution
was layered with hexanes and stored at –25 8C overnight. A
white precipitate was isolated and washed with hexanes
(3 ꢀ 3 mL). Crystals were obtained by CD3CN/ether diffu-
sion at –25 8C over 48 h. Yield: 65%, 117 mg; mp 144–
146 8C. FTIR (CsI plates, ranked intensities, cm–1): 3058
(1), 2917 (3), 2849 (4), 1590 (12), 1430 (13), 1261 (11),
1238 (10), 1096 (9), 1020 (8), 802 (5), 746 (6), 696 (2),
7
˚
(2.47 A), and to that in Ph3AsGaI3. The torsion angles
about the As–Ga bond (smallest C–As–Ga–Cl torsion angles
for molecule A = 29.9(3)8, for molecule B = –53.4(3)8) are
more staggered than in the arsine–borane adducts.
Summary
1
636 (7). H NMR (CD2Cl2, 273 K, 500 MHz, ppm) d: 1.23
(s, 9H), 7.52–7.57 (m, 6H), 7.58–7.63 (m, 3H), 7.65–7.70
(m, 6H). 13C{1H} NMR (CD2Cl2, 273K, 125.76 MHz) d:
8.4 (s), 128.0 (s), 130.6 (s), 138.3 (s). 11B{1H} NMR
(CD2Cl2, 273 K, 160.42 MHz) d: 53.6 (s).
Prototypical examples of compounds containing As ? B,
As ? Al, and As ? Ga coordinate bonds have been iso-
lated from reaction mixtures of an arsine Lewis base with a
triel Lewis acid. The compounds provide fundamental spec-
troscopic and structural data. While bond length trends are
as expected, As ? B < As ? Al < As ? Ga, the torsion
angles are generally smaller for As ? B complexes than
for the As ? Al and As ? Ga complexes.
Preparation of Me3AsB(C6F5)3
A solution of Me3As (52.0 mL, 0.50 mmol) in CH2Cl2
was added to a solution of B(C6F5)3 (256.0 mg, 0.50 mmol)
in CH2Cl2 and stirred for 30 min. A white precipitate
formed immediately. The solid was isolated and washed
with ether (3 ꢀ 3 mL) and has poor solubility. Crystals
were obtained by CD3CN/ether diffusion at –25 8C over
48 h. Yield: 78%, 236 mg; mp 257–259 8C. FTIR (CsI
plates, ranked intensities, cm–1): 2917 (1), 2703 (14), 1644
(10), 1516 (4), 1446 (1), 1370 (6), 1163 (16), 1117 (15),
1087 (5), 979 (3), 960 (2), 780 (9), 770 (8), 730 (17), 667
Experimental procedures
Reactions were carried out in an MBraun glovebox under
atmosphere of dry N2. Solvents were dried on an MBraun
˚
solvent purification system and stored over 4 A molecular
sieves. Deuterated solvents were purchased from Sigma-
Aldrich and were used as received. Experimental details
relating to the single crystal X-ray diffraction studies are
summarized in Table 3. X-ray diffraction data were col-
lected on a Bruker APEX II CCD area detector/D8 diffrac-
tometer. Crystals were coated with Paratone-N oil, mounted
on glass fibres, and placed in a cold stream of N2. Structures
were solved by direct methods (SHELXS-97) 14 or Patterson
search/structure expansion (DIRDIF-2008), 15 and refined us-
ing full-matrix least-squares on F2 (SHELXL-97).14 Hydro-
gen atom positions were calculated from the sp2 or sp3
hybridization geometries of their attached atoms. NMR
spectra were obtained at room temperature, unless otherwise
1
(7), 617 (11). H NMR (CD3CN, 273 K, 500 MHz, ppm) d:
0.96 (s, 9H). 11B{1H} NMR (CD3CN, 273 K, 160.42 MHz)
d: –11.0 (s).
Preparation of Et3AsBPh3
A solution of Et3As (70.5 mL, 0.50 mmol) in CH2Cl2 was
added to a solution of BPh3 (121.0 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. The solution was layered
with ether and stored at –25 8C overnight. Clear colourless
crystals were obtained by CD3CN/ether diffusion at –25 8C
over 48 h and were isolated and washed with ether (3 ꢀ
3 mL). Yield: 66%, 133 mg; mp 86–88 8C. FTIR (CsI
plates, ranked intensities, cm–1): 3666 (14), 3061 (1), 2425
(4), 1953 (13), 1642 (2), 1554 (12), 1462 (11), 1453 (10),
1
stated, on a Bruker AVANCE 500 H (500.13 MHz, 11.7 T)
and Bruker/Tecmag AC250 1H (250.06 MHz, 5.9 T).
13C{1H} NMR (125.76 MHz) chemical shifts were refer-
enced to dTMS = 0.00, as were 11B{1H} NMR (160.42 MHz)
and 27Al-NMR (130.29 MHz). Chemical shifts (d) are re-
ported in ppm. NMR spectra of samples were obtained by
1
1260 (5), 1098 (7), 1020 (6), 847 (3), 699 (9), 613 (8). H
3
NMR (CD2Cl2, 273 K, 500 MHz, ppm) d: 1.17 (t, JHH
=
3
7.0 Hz, 9H), 1.68 (q, JHH = 7.0 Hz, 6H), 7.48–7.54 (m,
Published by NRC Research Press

800
Can. J. Chem. Vol. 88, 2010
Fig. 5. Crystallographic views of the two crystallographically independent conformers (a and b) of the disordered structure of Ph3AsGaCl3.
Nonhydrogen atoms are represented by Gaussian ellipsoids at the 50% probability level.
˚
Table 2. Selected bond lengths (A) and angles (8) in Ph3BAsMe3,
Preparation of Et3AsB(C6F5)3
Et3AsB(C6F5)3, Ph3AsAlCl3, Ph3AsAlI3, Ph3AsGaCl3, and related
compounds.
A solution of Et3As (70.5 mL, 0.50 mmol) in CH2Cl2 was
added to a solution of B(C6F5)3 (256.0 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. A white precipitate formed
immediately. The solid was redissolved in CH3CN and crys-
talline material was obtained by CH3CN/ether diffusion
at –25 8C over 48 h. Yield: 44%, 142 mg; mp 204–206 8C.
FTIR (CsI plates, ranked intensities, cm–1): 2918 (12), 1645
(7), 1518 (4), 1460 (1), 1374 (6), 1283 (8), 1100 (5), 979
(2), 965 (3), 772 (11), 731 (10), 669 (9). 1H NMR d:
˚
Compound
E—As (A)
C–As–E (8) X–E–As (8)
Me3AsBPh3
Et3AsB(C6F5)3
2.148(3)
115.80(6)
114.70(7)
112.75(8)
117.02(7)
106.9(2)
104.83(10)
103.35(10)
107.52(10)
104.56(11)
124.3(5)
101.76(4)
108.76(4)
102.48(2)
106.29(16)
107.40(16)
102.97(2)
—
111.5(2)
121.8(1)
110.2(1)
C–Al–As
106.0(2)
102.9(2)
104.2(2)
C–Al–As
112.5(2)
114.7(2)
110.3(2)
112.5(2)
C–Ga–As
103.3(2)
104.6(2)
105.3(2)
2.1905(18)
{(t-Bu)2As}2BPh1
2.064(5)
a
Ph3AsAlCl3
2.5191(9)
114.17(5)
3
(CD3CN, 273 K, 500 MHz, ppm) d: 1.19 (t, JHH = 7.5 Hz,
3
9H), 1.86 (q, JHH = 7.5 Hz, 6H). 11B{1H} NMR (CD3CN,
Ph3AsAlI3
Ph3AsGaCl3
2.5140(10)
2.540(6)
2.449(6)
2.490(1)
2.509
113.78(6)
113.1(2)
113.4(2)
113.21(7)
—
106.3(1)
100.5(1)
105.4(1)
Si–As–Al
113.5(1)
113.3(1)
113.2(1)
Si–As–Al
114.10(6)
114.79(6)
273 K, 160.42 MHz, ppm) d: –11.8 (s).
b
Preparation of Ph3AsBPh3
7
Ph3AsGaI3
13
A solution of Ph3As (151.5 mg, 0.50 mmol) in CH2Cl2
was added to a solution of BPh3 (121.0 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. The solution was layered
with hexanes and stored at –25 8C overnight. A white pow-
der was isolated and washed with ether (3 ꢀ 3 mL). Yield:
55%, 150 mg; decomposes above 100 8C. FTIR (CsI plates,
ranked intensities, cm–1): 3059 (1), 2429 (10), 2283 (11),
1980 (12), 1642 (2), 1260 (7), 1097 (6), 1019 (5), 910 (4),
804 (3), 734 (9), 694 (8). 1H NMR (CD2Cl2, 273 K,
500 MHz, ppm) d: 7.28–8.27 (m, 30H). 13C{1H} NMR
(CD2Cl2, 273 K, 125.76 MHz, ppm) d: 128.2 (s), 129.4 (s),
132.1 (s), 134.4 (s), 136.4 (s), 139.2 (s), 140.5 (s), 143.9 (s).
11B{1H} NMR (CD2Cl2, 273 K, 160.42 MHz, ppm) d: 67.8
(s).
TMS3AsGaI3
3
i-Pr3AsAl-t-Bu3
2.839(1)
3
TMS3AsAlEt3
2.654(2)
2.539(2)
4
[TMS2AsAlEt2]2
6
TMS3AsGaPh3
2.671(1)
Si–As–Ga
114.45(7)
110.74(7)
113.98(7)
Preparation of Ph3AsB(C6F5)3
A solution of Ph3As (151.5 mg, 0.50 mmol) in CH2Cl2
was added to a solution of B(C6F5)3 (256.0 mg, 0.50 mmol)
in CH2Cl2 and stirred for 30 min. A white precipitate
formed immediately. The solid was redissolved in CH3CN
and then precipitated by ether diffusion at –25 8C over
48 h. The solid was washed with ether (3 ꢀ 3 mL). Yield:
51%, 201 mg; mp 155–157 8C. FTIR (CsI plates, ranked in-
tensities, cm–1): 3001 (1), 2342 (17), 1895 (16), 1645 (12),
1464 (2), 1389 (4), 1366 (3), 1260 (9), 1230 (6), 1011 (11),
1020 (10), 950 (7), 923 (8), 888 (15), 850 (14), 802 (13),
aDisorder in structure.
bTwo crystallographically independent molecules in the asymmetric unit.
8H), 7.60–7.65 (m, 7H). 13C{1H} NMR (CD2Cl2, 273 K,
125.76 MHz, ppm) d: 10.2 (s), 16.1 (s), 127.9 (s), 129.1 (s), 137.8
(s), 136.3 (s). 11B{1H} NMR (CD2Cl2, 273 K, 160.42 MHz, ppm)
d: 36.3 (s).
Published by NRC Research Press

Table 3. Crystallographic data for Ph3BAsMe3, Et3AsB(C6F5)3, and Ph3AsEX3 (E = Al and Ga; X = Cl and I).
Compound
Formula
Ph3BAsMe3
C21H24AsB
Et3AsB(C6F5)3
C24H15AsBF15
Ph3AsAlCl3
C18H15AlAsCl3
Ph3AsAlI3
C18H15AlAsI3
Ph3AsGaCl3
C18H15AsCl3Ga
Formula weight
Crystal system
Space group
362.13
674.09
Monoclinic
P21/n
12.5167 (4)
10.5712 (3)
18.2940 (5)
90
439.55
713.90
482.29
Trigonal
Trigonal
Trigonal
Trigonal
ꢀ
ꢀ
ꢀ
ꢀ
P3 (No. 147)
R3 (No. 148)
R3 (No. 148)
R3 (No. 148)
˚
a (A)
11.3230 (6)
11.3230 (6)
8.1329 (4)
90
13.9920 (12)
13.9920 (12)
16.8498 (14)
90
14.8705 (6)
14.8705 (6)
16.7263 (6)
90
14.0065 (7)
14.0065 (7)
16.8497 (9)
90
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
90
120
90.2369 (3)
90
90
120
90
120
90
120
Crystal size (mm3)
Reflections collected
Independent reflections (R(int))
GoFa
0.43 ꢀ 0.21 ꢀ 0.19
0.32 ꢀ 0.29 ꢀ 0.28
0.67 ꢀ 0.60 ꢀ 0.34
0.49 ꢀ 0.41 ꢀ 0.31
0.48 ꢀ 0.36 ꢀ 0.29
7754
19 870
7861
9448
8386
1387 (Rint = 0.0219)
1.106
2
903.02 (8)
1.332
0.0199
0.0534
5564 (Rint = 0.0178)
1.046
4
2420.58 (12)
1.850
0.0256
1452 (Rint = 0.0196)
1.072
6
2856.8 (4)
1.533
0.0196
0.0508
1644 (Rint = 0.0162)
1.119
6
3203.2 (2)
2.221
0.0147
0.0358
1470 (Rint = 0.0152)
1.158
6
2862.7 (3)
1.679
0.0171
0.0509
Z
3
˚
V (A )
rcalcd (mg m–3)
R1
wR2
0.0683
P
w
aS ¼ ½
ðFo2 ꢁ Fc2Þ =ðn ꢁ pÞꢂ (n = number of data; p = number of parameters varied; w ¼ ½s2ðFo2Þ þ ð0:0259PÞ þ 0:3085Pꢂꢁ1, where P ¼ ½MaxðFo2; 0Þ þ 2Fc2ꢂ=3).
2
1=2
2

802
Can. J. Chem. Vol. 88, 2010
1
729 (5). H NMR d: (CD3CN, 273 K, 500 MHz, ppm) d:
7.34–7.41 (m, 15H). 11B{1H} NMR (CD3CN, 273 K,
160.42 MHz, ppm) d: –11.6 (s).
(s), 13.6 (s). 27Al NMR (CD2Cl2, 273 K, 130.29 MHz, ppm)
d: 110.3 (s).
Preparation of Et3AsAlBr3
Preparation of Me3AsAlCl3
A solution of Et3As (70.5 mL, 0.50 mmol) in CH2Cl2 was
added to a solution of AlBr3 (133.5 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. The solution was layered
with hexanes and stored at –25 8C overnight. A white pow-
der formed and was isolated and washed with ether (3 ꢀ
3 mL) and solvents removed in vacuo. Yield: 62%, 133 mg.
FTIR (CsI plates, ranked intensities, cm–1): 2973 (1), 2940
(2), 2880 (3), 2849 (8), 2431 (16), 1640 (14), 1459 (4),
1416 (12), 1389 (13), 1240 (11), 1093 (15), 1022 (9), 923
A solution of Me3As (52.0 mL, 0.50 mmol) in CH2Cl2
was added to a solution of AlCl3 (61.5 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. The solution was layered
with hexanes and stored at –25 8C overnight. A white pow-
der formed and was isolated and washed with ether (3 ꢀ
3 mL). Yield: 70%, 89 mg; mp 143–145 8C. FTIR (CsI
plates, ranked intensities, cm–1): 3094 (1), 2921 (2), 2850
(3), 2432 (12), 2361 (11), 1642 (5), 1462 (14), 1412 (10),
1
1
1261 (9), 1100 (13), 1018 (8), 925 (4), 848 (7), 651 (6). H
(17), 793 (3), 744 (10), 706 (5), 678 (5). H NMR (CD2Cl2,
NMR (CD2Cl2, 273 K, 500 MHz, ppm) d: 2.21 (s, 9H).
13C{1H} NMR (CD2Cl2, 273 K, 125.76 MHz, ppm) d: 7.9
(s). 27Al NMR (CD2Cl2, 273 K, 130.29 MHz, ppm) d: 104.3
(s).
3
273 K, 500 MHz, ppm) d: 1.59 (t, JHH = 9.0 Hz, 9H), 3.07
3
(q, JHH = 9.0 Hz, 6H). 13C{1H} NMR (CD2Cl2, 273 K,
125.76 MHz, ppm) d: 8.7 (s), 26.3 (s). 27Al NMR (CD2Cl2,
273 K, 130.29 MHz, ppm) d: 104.8 (s).
Preparation of Me3AsAlBr3
Preparation of Et3AsAlI3
A solution of Me3As (52.0 mL, 0.50 mmol) in CH2Cl2
was added to a solution of AlBr3 (133.5 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. The solution was layered
with hexanes and stored at –25 8C overnight. A white pow-
der formed and was isolated and washed with ether (3 ꢀ
3 mL). Yield: 71%, 137 mg. FTIR (CsI Plates, ranked inten-
sities, cm–1): 3016 (7), 2918 (8), 2848 (9), 1414 (4), 1269
(10), 1011 (11), 989 (12), 962 (13), 921 (1), 835 (6), 790
A solution of Et3As (70.5 mL, 0.50 mmol) in CH2Cl2 was
added to a solution of AlI3 (204.0 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. The solution was layered
with hexanes and stored at –25 8C overnight. A pale brown
1
oil was obtained and washed with ether (3 ꢀ 3 mL). H
3
NMR (CD2Cl2, 273 K, 500 MHz, ppm) d: 1.36 (t, JHH
=
7.95 Hz, 9H), 2.06 (q, JHH = 7.90 Hz, 6H). 13C{1H} NMR
(CD2Cl2, 273 K, 125.76 MHz, ppm) d: 9.3 (s), 13.4 (s). 27Al
NMR (CD2Cl2, 273 K, 130.29 MHz, ppm) d: 111.2 (s).
3
1
(2), 698 (3), 626 (5). H NMR (CD2Cl2, 273 K, 500 MHz,
ppm) d: 1.59 (s, 9H). 13C{1H} NMR (CD2Cl2, 273 K,
125.76 MHz, ppm) d: 6.9 (s). 27Al NMR (CD2Cl2, 273 K,
130.29 MHz, ppm) d: 112.9 (s).
Preparation of Ph3AsAlCl3
A solution of Ph3As (151.5 mg, 0.50 mmol) in CH2Cl2
was added to a solution of AlCl3 (61.5 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. The solution was layered
with hexanes and stored at –25 8C overnight. A white pow-
der formed and was isolated and washed with ether (3 ꢀ
3 mL). Crystals were obtained by CH2Cl2/pentane layering
at –25 8C over 48 h. Yield: 65%, 142 mg; mp 57–59 8C.
FTIR (CsI plates, ranked intensities, cm–1): 3064 (1), 2432
(14), 1886 (20), 1642 (5), 1578 (11), 1480 (6), 1433 (4),
1336 (18), 1305 (16), 1261 (17), 1184 (14), 1156 (15),
1083 (8), 1074 (9), 1023 (13), 998 (11), 844 (10), 735 (2),
Preparation of Me3AsAlI3
A solution of Me3As (52.0 mL, 0.50 mmol) in CH2Cl2
was added to a solution of AlI3 (204.0 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. Upon completion, the solu-
tion was layered with hexanes and allowed to sit at –25 8C
overnight. White powder was obtained and washed with
ether (3 ꢀ 3 mL) and solvents removed in vacuo. Yield:
69%, 184 mg; mp 138–140 8C. FTIR (CsI plates, ranked in-
tensities, cm–1): 3000 (1), 2918 (2), 2849 (3), 1641 (9), 1462
(4), 1389 (8), 1365 (7), 1261 (15), 1230 (10), 1094 (14),
1
692 (3), 613 (2). H NMR (CD2Cl2, 273 K, 500 MHz, ppm)
1
1019 (11), 923 (12), 802 (13), 729 (5), 719 (6). H NMR
d: 7.69–7.75 (m, 6H), 7.73–7.83 (m, 6H), 7.86–7.91 (m,
3H). 13C{1H} NMR (CD2Cl2, 273 K, 125.76 MHz, ppm) d:
131.6 (s), 133.1 (s), 133.7 (s), 135.4 (s). 27Al NMR (CD2Cl2,
273 K, 130.29 MHz, ppm) d: 104.1 (s).
(CD2Cl2, 273 K, 500 MHz, ppm) d: 1.57 (bs, 9H). 13C{1H}
NMR (CD2Cl2, 273 K, 125.76 MHz, ppm) d: 7.1 (s). 27Al
NMR (CD2Cl2, 273 K, 130.29 MHz, ppm) d: 110.5 (s).
Preparation of Et3AsAlCl3
Preparation of Ph3AsAlBr3
A solution of Et3As (70.5 mL, 0.50 mmol) in CH2Cl2 was
added to a solution of AlCl3 (61.5 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. The solution was layered
with hexanes and stored at –25 8C overnight. A white pow-
der formed and was isolated and washed with ether (3 ꢀ
3 mL). Yield: 65%, 96 mg; mp 160–162 8C. FTIR (CsI
plates, ranked intensities, cm–1): 3341 (14), 2972 (4), 2938
(6), 2879 (7), 2304 (13), 2197 (14), 1459 (3), 1416 (9),
1387 (10), 1238 (8), 954 (2), 876 (16), 794 (12), 696 (1),
A solution of Ph3As (151.5 mg, 0.50 mmol) in CH2Cl2
was added to a solution of AlBr3 (133.5 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. The solution was layered
with hexanes and stored at –25 8C overnight. Yellow glassy
material was obtained and washed with ether (3 ꢀ 3 mL).
Yield: 60%, 171 mg. FTIR (CsI plates, ranked intensities,
cm–1): 3060 (1), 2905 (2), 2870 (3), 2427 (10), 1642 (4),
1515 (13), 1451 (12), 1260 (8), 1097 (7), 1019 (6), 845 (5),
730 (9), 696 (11). 1H NMR (CD2Cl2, 273 K, 500 MHz,
ppm) d: 7.76–7.77 (m, 6H), 7.83–7.87 (m, 6H), 7.93–7.98
(m, 3H). 13C{1H} NMR (CD2Cl2, 273 K, 125.76 MHz,
1
678 (5). H NMR (CD2Cl2, 273 K, 500 MHz, ppm) d: 1.36
3
3
(t, JHH = 7.85 Hz, 9H), 2.06 (q, JHH = 7.85 Hz, 6H).
13C{1H} NMR (CD2Cl2, 273 K, 125.76 MHz, ppm) d: 9.3
Published by NRC Research Press

Conrad et al.
803
ppm) d: 131.8 (s), 133.3 (s), 133.5 (s), 135.8 (s). 27Al NMR
(CD2Cl2, 273 K, 130.29 MHz, ppm) d: 108.4 (s).
doi:10.1021/ja00061a021.; (b) Rivard, E.; Merrill, W. A.;
Fettinger, J. C.; Power, P. P. Chem. Commun. (Camb.)
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Koschmieder, S. U.; Nunn, C. M.; Atwood, J. L.; Bott, S. G.
Organometallics 1993, 12 (1), 24. doi:10.1021/om00025a010.;
(b) Yablokov, V. A.; Dozorov, A. V.; Mitrofanova, S. V.;
Yavich, B. S. Russ. J. Gen. Chem. 1990, 60, 574.
Preparation of Ph3AsAlI3
A solution of Ph3As (151.5 mg, 0.50 mmol) in CH2Cl2
was added to a solution of AlI3 (204.0 mg, 0.50 mmol) in
CH2Cl2 and stirred for 30 min. The solution was layered
with hexanes and stored at –25 8C overnight. Small yellow
crystals were obtained and were washed with ether (3 ꢀ
3 mL). Yield: 50%, 179 mg; mp 86–88 8C. FTIR (CsI
plates, ranked intensities, cm–1): 3052 (11), 2994 (10), 2917
(9), 2849 (8), 1578 (12), 1481 (4), 1433 (3), 1365 (17), 1261
(13), 1184 (14), 1158 (15), 1082 (5), 1022 (6), 997 (7), 799
(3) Wells, R. L.; McPhail, A. T.; Speer, T. M. Organometallics
1992, 11 (2), 960. doi:10.1021/om00038a070.
(4) Kuczkowski, A.; Schulz, S.; Nieger, M.; Schreiner, P. R. Or-
ganometallics 2002, 21 (7), 1408. doi:10.1021/om0200205.
(5) (a) Cheng, F.; Hector, A. L.; Levason, W.; Reid, G.; Web-
ster, M.; Zhang, W. Inorg. Chem. 2007, 46 (17), 7215.
doi:10.1021/ic700895r. PMID:17658877.; (b) Jouet, R. J.;
Wells, R. L.; Rheingold, A. L.; Incarvito, C. D. J. Organo-
met. Chem. 2000, 601 (1), 191. doi:10.1016/S0022-
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(24), 3187. doi:10.1139/v67-513.
1
(16), 735 (1), 694 (2). H NMR (CD2Cl2, 273 K, 500 MHz,
ppm) d: 7.69–7.72 (m, 2H), 7.81–7.85 (m, 2H), 7.93–7.97
(m, 1H). 13C{1H} NMR (CD2Cl2, 273 K, 125.76 MHz,
ppm) d: 130.9 (s), 132.2 (s), 134.4 (s), 135.6 (s). 27Al NMR
(CD2Cl2, 273 K, 130.29 MHz, ppm) d: 103.8 (s).
(6) Wells, R. L.; McPhail, A. T.; Jones, L. J., III; Self, M. F.;
Butcher, R. J. Organometallics 1992, 11 (7), 2694. doi:10.
1021/om00043a064.
(7) Baker, L.-J.; Kloo, L. A.; Rickard, C. E. F.; Taylor, M. J. J.
Organomet. Chem. 1997, 545–546 (1), 249. doi:10.1016/
S0022-328X(97)00221-0.
Preparation of Ph3AsGaCl3
The procedures were described by Reid and co-workers,5a
and the characterization data was consistent. Crystalline ma-
terial was obtained by CH2Cl2/pentane layering at –25 8C
over 48 h.
(8) Baker, L.-J.; Rickard, C. E. F.; Taylor, M. J. J. Organomet.
Chem. 1994, 464 (1), C4. doi:10.1016/0022-328X(94)87020-9.
(9) (a) Conrad, E.; Burford, N.; McDonald, R.; Ferguson, M. J.
J. Am. Chem. Soc. 2009, 131 (14), 5066. doi:10.1021/
ja900968j. PMID:19296681.; (b) Conrad, E.; Burford, N.;
McDonald, R.; Ferguson, M. J. Inorg. Chem. 2008, 47 (8),
2952. doi:10.1021/ic800287e. PMID:18345596.; (c) Kilah,
N. L.; Weir, M. L.; Wild, S. B. Dalton Trans. 2008, 2480.
doi:10.1039/b800965a. PMID:18461204.
Supplementary data
Supplementary data for this article are available on the
journal Web site (canjchem.nrc.ca). CCDCs 759512–759516
contain the X-ray data in CIF format for this manuscript.
These data can be obtained, free of charge, via www.ccdc.
cam.ac.uk/conts/retrieving.html (Or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge
CB2 1EZ, UK; fax +44 1223 336033; or deposit@ccdc.
cam.ac.uk).
(10) Conrad, E.; Burford, N.; McDonald, R.; Ferguson, M. J. J.
Am. Chem. Soc. 2009, 131 (46), 17000. doi:10.1021/
ja907613c. PMID:19886662.
Acknowledgements
(11) Welch, G. C.; Prieto, R.; Dureen, M. A.; Lough, A. J.; La-
¨
¨
beodan, O. A.; Holtrichter-Rossmann, T.; Stephan, D. W.
Dalton Trans. 2009, 1559. doi:10.1039/b814486a. PMID:
19421599.
We thank the Natural Sciences and Engineering Research
Council of Canada (NSERC), the Canada Research Chairs
Program, the Canada Foundation for Innovation (CFI), the
Walter C. Sumner Foundation, and the Nova Scotia
Research and Innovation Trust Fund for funding, and the
Atlantic Region Magnetic Resonance Centre for use of in-
strumentation. We thank Sara Vickers for assistance with
translations.
(12) Cowley, A. H.; Kemp, R. A. Chem. Rev. 1985, 85 (5), 367.
doi:10.1021/cr00069a002.
(13) Johansen, J. D.; McPhail, A. T.; Wells, R. L. Adv. Mater.
Opt. Electron. 1992, 1 (1), 29. doi:10.1002/amo.860010106.
(14) Sheldrick, G. M. Acta Crystallogr. 2008, A64, 112. doi:10.
1107/S0108767307043930.
(15) Beurskens, P. T.; Beurskens, G.; de Gelder, R.; Smits, J. M.
M.; Garcia-Granda, S.; Gould, R. O. The DIRDIF-2008 pro-
gram system; Crystallography Laboratory, Radboud Univer-
sity Nijmegen: The Netherlands, 2008.
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Published by NRC Research Press