Cyclopentadiene elimination reactions for the preparation of organoindium(III) derivatives. Crystal and molecular structures of Me2In(acac), (Me3CCH2)2In(acac), (Me)(Me3CCH2)In(acac), and [Me2InNH(t-Bu)]2

Article abstract of DOI:10.1021/om0304154

The compounds R₂InO(t-Bu), R₂In(acac), R₂InSSiPh₃, and R₂InPPh₂ (R = Me, CH₂CMe₃) and Me₂InNH(t-Bu) have been prepared in nearly quantitative yields by the cyclopentadiene elimination reaction between R₂In(C₅H₅) and the appropriate alcohol, thiol, phosphine or amine. All reactions except those of H₂N(t-Bu) occur readily at room temperature. Even though solutions of R₂In(C₅H₅) exist as equilibrium mixtures of R₂In(C₅H₅), RIn(C₅H₅)₂, In-(C₅H₅)₃, and InR₃, neither methane nor neopentane was observed as a product from the above reaction mixtures. A ligand redistribution reaction between Me₂In(C₅H₅) and (Me₃-CCH₂)₂In(C₅H₅) was used to prepare (Me) (Me₃CCH₂)In(C₅H₅) that, in turn, was reacted with H(acac) to form (Me)(Me₃CCH₂)In(acac), an indium compound with three different substituents. The compounds Me₂In(acac), (Me₃CCH₂)₂In(acac), and (Me)(Me₃CCH₂)In(acac) exist as centrosymmetric dimers in the solid state, but in benzene solution Me₂In(acac) is a monomer-dimer equilibrium mixture, whereas (Me₃CCH₂)₂In(acac) is a monomer. The thiolate Me₂InSSiPh₃ is an equilibrium mixture of dimers and trimers in benzene solution, but (Me₃CCH₂)₂InSSiPh₃ is a dimer. The phosphide Me₂InPPh₂ is an equilibrium mixture of monomers and dimers when dissolved in benzene. The tert-butylamide Me₂InNH(t-Bu), when dissolved in benzene, is a mixture of monomers and dimers with both cis and trans configurations, but only a dimer with the trans configuration exists in the solid state.

Full text of DOI:10.1021/om0304154

Organometallics 2003, 22, 3991-4000
3991
Cyclop en ta d ien e Elim in a tion Rea ction s for th e
P r ep a r a tion of Or ga n oin d iu m (III) Der iva tives. Cr ysta l
a n d Molecu la r Str u ctu r es of Me2In (a ca c),
(Me3CCH2)2In (a ca c), (Me)(Me3CCH2)In (a ca c), a n d
[Me2In NH(t-Bu )]2
O. T. Beachley, J r.,* David J . MacRae, Melvyn Rowen Churchill,
Andrey Yu. Kovalevsky, and Eric S. Robirds
Department of Chemistry, University at Buffalo, The State University of New York,
Buffalo, New York 14260
Received J une 3, 2003
The compounds R2InO(t-Bu), R2In(acac), R2InSSiPh3, and R2InPPh2 (R ) Me, CH2CMe3)
and Me2InNH(t-Bu) have been prepared in nearly quantitative yields by the cyclopentadiene
elimination reaction between R2In(C5H5) and the appropriate alcohol, thiol, phosphine or
amine. All reactions except those of H2N(t-Bu) occur readily at room temperature. Even
though solutions of R2In(C5H5) exist as equilibrium mixtures of R2In(C5H5), RIn(C5H5)2, In-
(C5H5)3, and InR3, neither methane nor neopentane was observed as a product from the
above reaction mixtures. A ligand redistribution reaction between Me2In(C5H5) and (Me3-
CCH2)2In(C5H5) was used to prepare (Me)(Me3CCH2)In(C5H5) that, in turn, was reacted with
H(acac) to form (Me)(Me3CCH2)In(acac), an indium compound with three different substit-
uents. The compounds Me2In(acac), (Me3CCH2)2In(acac), and (Me)(Me3CCH2)In(acac) exist
as centrosymmetric dimers in the solid state, but in benzene solution Me2In(acac) is a
monomer-dimer equilibrium mixture, whereas (Me3CCH2)2In(acac) is a monomer. The
thiolate Me2InSSiPh3 is an equilibrium mixture of dimers and trimers in benzene solution,
but (Me3CCH2)2InSSiPh3 is a dimer. The phosphide Me2InPPh2 is an equilibrium mixture
of monomers and dimers when dissolved in benzene. The tert-butylamide Me2InNH(t-Bu),
when dissolved in benzene, is a mixture of monomers and dimers with both cis and trans
configurations, but only a dimer with the trans configuration exists in the solid state.
In tr od u ction
ature and produce gallium-containing products in nearly
quantitative yields and in excellent purity. Since organo-
indium cyclopentadienide derivatives exist as equilib-
rium mixtures of compounds such as the gallium
derivatives but InR3 is more reactive than GaR3 (R )
Me, CH2CMe3) to protonic reagents,8 we wanted to learn
more about the corresponding cyclopentadiene elimina-
tion reaction in organoindium chemistry. Thus, the
reactions of Me2In(C5H5)9 and (Me3CCH2)2In(C5H5)9a
with tert-butyl alcohol, acetylacetone (2,4-pentanedione),
triphenylsilanethiol, diphenylphosphine, and tert-butyl-
amine, a series of bases with protons of varying acidi-
ties, were investigated.
Even though solutions of R2GaCp (R ) Me,1,2 Et,3
CH2CMe3;4 Cp ) C5H5, C5H4Me, C5H4SiMe3) exist as
equilibrium mixtures of R2GaCp, RGaCp2, GaR3, and
GaCp3, reactions with HXR′ (X ) O, S; R′ ) organic
groups)5-7 and HYR′2 (Y ) N, P; R′ ) organic groups,
H)5-7 produce organogallium derivatives with the sim-
plest formulas R2GaXR′ and R2GaYR′2 and the cyclo-
pentadiene exclusively (eq 1). No methane, ethane, or
R2Ga(C5H5) + HYR′2 solvent8 1/2[R2GaYR′2]2 + C5H6
(1)
Resu lts a n d Discu ssion
neopentane is formed. These cyclopentadiene elimina-
tion reactions typically occur at or below room temper-
The cyclopentadiene elimination reaction is exceed-
ingly useful for the preparation of organoindium(III)
derivatives of oxygen-, sulfur-, nitrogen-, and phosphorus-
containing substituents. Products of the types R2InXR′
and R2InYR′2 (R ) Me, CH2CMe3; X ) O, S; Y ) N, P)
were formed in nearly quantitative yields and in excel-
lent purity. All reactions except those of the amine
occurred at room temperature or below. No reaction
between Me2In(C5H5) and H2N(t-Bu) was observed at
* Corresponding author.
(1) Beachley, O. T., J r.; Royster, T. L.; Arhar, J . R. J . Organomet.
Chem. 1992, 434, 11.
(2) Beachley, O. T., J r.; Mosscrop, M. T. Organometallics 2000, 19,
4550.
(3) Beachley, O. T., J r.; Rosenblum, D. B.; Churchill, M. R.; Lake,
C. H.; Krajkowski, L. M. Organometallics 1995, 14, 4402.
(4) Beachley, O. T., J r.; Maloney, J . P.; Rogers, R. D. Organometallics
1997, 16, 3267.
(5) Beachley, O. T., J r.; Royster, T. L.; Arhar, J . R.; Rheingold, A.
L. Organometallics 1993, 12, 1976.
(6) Beachley, O. T., J r.; Rosenblum, D. B.; Churchill, M. R.; Lake,
C. H.; Toomey, L. M. Organometallics 1996, 15, 3653.
(7) Beachley, O. T., J r.; Maloney, J . D.; Rogers, R. D. Organome-
tallics 1997, 16, 3267.
(8) Coates, G. E.; Green, M. L. H.; Wade, K. Organometallic
Compounds; Methuen: London, 1967; Vol. 1, p 343.
(9) (a) Beachley, O. T., J r.; MacRae, D. J .; Kovalevsky, A. Yu.; Zhang,
Y.; Li, X. Organometallics 2002, 21, 4632. (b) Beachley, O. T., J r.;
Robirds, E. S.; Atwood, D. A.; Wei, P. Organometallics 1999, 18, 2561.
10.1021/om0304154 CCC: $25.00 © 2003 American Chemical Society
Publication on Web 09/03/2003

3992 Organometallics, Vol. 22, No. 20, 2003
Beachley et al.
room temperature. Even though R2In(C5H5) incorpor-
ates two different organic ligands, only cyclopentadiene
(C5H6) is formed. The thermodynamically more stable
compound, CH4 or CMe4, is not a product of the reaction.
Thus, the course of the cyclopentadiene elimination
reaction must be controlled by kinetic rather than
thermodynamic factors.
The cyclopentadiene elimination reaction between
Me2In(C5H5) and t-BuOH in a 1:1 mole ratio at room
temperature provided [Me2InO(t-Bu)]2 in nearly quan-
titative yield. No methane was evolved during this
reaction, even though an ether solution of InMe3‚Et2O
reacts readily with t-BuOH at 25-35 °C.10 The indium-
containing product was initially isolated as a colorless
waxy solid after sublimation at 35 °C. However, when
Me2InO(t-Bu) was allowed to stand under vacuum at
room temperature for 4-5 days, the compound changed
from an opaque colorless film to individual crystals that
rotated the plane of polarized light. However, a single
crystal suitable for an X-ray structural study could not
be isolated. The crystals deformed during contact and
became waxy again. Cryoscopic molecular studies in
benzene solution indicated that Me2InO(t-Bu) is dimeric
over the concentration range of 0.03-0.09 m. The 1H
NMR spectrum in d6-benzene exhibited two sharp
resonances.
F igu r e 1. Molecular geometry and labeling of atoms for
Me2In(acac) (50% probability ellipsoids for non-hydrogen
atoms; hydrogen atoms are omitted for clarity).
Ta ble 1. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for Me2In (a ca c)a
Bond Distances
In(1)-C(6)
In(1)-O(1)
In(1)-O(2)
O(1)-C(2)
O(2)-C(4)
C(2)-C(3)
C(4)-C(5)
2.129(2)
2.198(1)
2.256(1)
1.298(2)
1.258(2)
1.381(2)
1.505(2)
In(1)-C(7)
In(1)-O(1)
In(1)-O(1A)
O(1)-In(1A)
C(1)-C(2)
C(3)-C(4)
2.131(2)
2.198(1)
2.551(1)
2.551(1)
1.505(2)
1.416(2)
The new compound [(Me3CCH2)2InO(t-Bu)]2 was syn-
thesized from (Me3CCH2)2In(C5H5) and t-BuOH at room
temperature in high yield. Neopentane was not ob-
served. The compound was dimeric in benzene solution
according to cryoscopic molecular studies in the con-
centration range of 0.02-0.05 m. A molecular weight
determination was also attempted at the higher con-
centration of 0.078 m, but crystals formed as the
solution was cooled. Thus, [(Me3CCH2)2InO(t-Bu)]2 has
limited solubility in benzene and trace solubility in
pentane but is readily soluble in Et2O and THF. The
1H NMR spectrum in d6-benzene exhibited three sharp
singlets.
Bond Angles
C(6)-In(1)-C(7)
C(7)-In(1)-O(1)
C(7)-In(1)-O(2)
C(6)-In(1)-O(1A)
O(1)-In(1)-O(1A)
C(2)-O(1)-In(1)
145.81(9) C(6)-In(1)-O(1)
105.67(7) C(6)-In(1)-O(2)
97.41(6) O(1)-In(1)-O(2)
90.62(6) C(7)-In(1)-O(1A)
107.22(6)
95.64(6)
82.87(5)
90.97(6)
71.70(4) O(2)-In(1)-O(1A) 154.52(4)
128.7(1) C(2)-O(1)-In(1A) 123.0(1)
In(1)-O(1)-In(1A) 108.30(4) C(4)-O(2)-In(1)
128.7(1)
115.2(1)
127.6(2)
116.8(2)
O(1)-C(2)-C(3)
C(3)-C(2)-C(1)
O(2)-C(4)-C(3)
C(3)-C(4)-C(5)
126.5(2)
118.3(2)
125.6(2)
117.6(2)
O(1)-C(2)-C(1)
C(2)-C(3)-C(4)
O(2)-C(4)-C(5)
a
Symmetry transformations used to generate equivalent at-
oms: -x, 1 - y, 1 - z.
The derivative Me2In(acac) was prepared by methane
elimination between InMe3 and Hacac in the absence
of solvent, as had been done previously.11 The analyti-
cally pure compound was isolated as colorless crystals,
but its melting point (136.9-137.8 °C with decomposi-
tion at ∼200 °C) was different from that reported in the
literature11 (118 °C dec). Cryoscopic molecular weight
studies in benzene solution suggest that the compound
exists as an equilibrium mixture of species, because the
degree of association decreased from 1.23 to 1.09 as the
solution was diluted from 0.068 to 0.010 m. Thus, di-
methylindium acaetylacetonate is very different from
Me2Ga(acac),12a Et2Ga(acac),12a (mesityl)2Ga(acac),12a R2-
Ga(bdk)12a (R ) Me, Et, mesityl; bdk ) tfac, hfac, tmhd),
and other gallium(III) â-diketonate derivatives.12b All
of these gallium compounds are monomeric in the solid
hibited only sharp single resonances whose chemical
shifts were independent of concentration in the range
studied.
An X-ray structural study of Me2In(acac) revealed the
compound to be a centrosymmetric dimer in the solid
state (Figure 1) with an inversion center interrelating
In(1) and In(1A). Bond distances and angles are col-
lected in Table 1. Each indium center is five-coordinate
with a distorted pseudo-trigonal-bipyramidal geometry.
The equatorial plane is defined by C(6), C(7), and O(1),
while O(2) and O(1A) occupy axial positions. The cor-
responding bond angles O(2)-In(1)-O(1A), C(6)-In(1)-
C(7), and O(1)-In(1)-C(6) are 154.52(4), 145.81(9), and
107.22(6)°, respectively.
One of the acetylacetonate oxygen atoms bridges two
indium atoms in an asymmetric manner. The In(1)-
O(1) bond length of 2.198(1) Å is considerably shorter
than the In(1)-O(1A) length of 2.551(1) Å. The In(1)-
O(2) bond is 2.256(1) Å, a distance which is in agreement
with it being in a pseudo-axial position. The In-O dis-
tances in In(acac)3 that involve six-coordinate indium
range from 2.118(5) to 2.138(4) Å.13 The bridging oxygen
O(1) in Me2In(acac) has a trigonal-planar configuration
in which the sum of the bond angles around it is 360.0-
1
state and in benzene solution. H NMR spectra of Me2-
In(acac) in both d6-benzene and d8-THF solutions ex-
(10) Schmidbauer, H.; Schindler, F. Chem. Ber. 1966, 99, 2178.
(11) (a) Coates, G. E.; Whitcombe, R. A. J . Chem. Soc. 1956, 3351.
(b) Clark, H. C.; Pickard, A. L. J . Organomet. Chem. 1976, 8, 427.
(12) (a) Beachley, O. T., J r.; Gardinier, J . R.; Churchill, M. R.;
Toomey, L. M. Organometallics 1998, 17, 1101. (b) Beachley, O. T.,
J r.; Gardinier, J . R.; Churchill, M. R.; Churchill, D. G.; Keil, K. M.
Organometallics 2002, 21, 946.

Organoindium(III) Derivatives
Organometallics, Vol. 22, No. 20, 2003 3993
Ta ble 2. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for (Me3CCH2)2In (a ca c)a
Bond Distances
In(1)-C(6)
In(1)-O(1)
O(1)-C(1)
C(1)-C(2)
C(2)-C(3)
C(6)-C(7)
C(7)-C(9)
C(11)-C(12)
C(12)-C(13)
2.169(2)
2.195(1)
1.288(2)
1.395(3)
1.403(3)
1.539(3)
1.531(3)
1.535(3)
1.529(3)
In(1)-C(11)
In(1)-O(2)
O(2)-C(3)
C(1)-C(4)
C(3)-C(5)
C(7)-C(10)
C(7)-C(8)
C(12)-C(15)
C(12)-C(14)
2.169(2)
2.203(1)
1.263(2)
1.498(3)
1.506(3)
1.520(3)
1.532(3)
1.522(3)
1.536(3)
Bond Angles
C(6)-In(1)-C(11)
C(11)-In(1)-O(1)
C(11)-In(1)-O(2)
C(1)-O(1)-In(1)
O(1)-C(1)-C(2)
C(2)-C(1)-C(4)
O(2)-C(3)-C(2)
C(2)-C(3)-C(5)
C(10)-C(7)-C(9)
C(9)-C(7)-C(8)
C(9)-C(7)-C(6)
137.12(8) C(6)-In(1)-O(1)
106.42(7) C(6)-In(1)-O(2)
103.53(7) O(1)-In(1)-O(2)
109.23(7)
103.36(7)
83.63(5)
129.1(1)
115.8(2)
127.1(2)
115.5(2)
121.4(1)
108.5(2)
111.0(2)
108.4(2)
127.9(1)
126.4(2)
117.8(2)
125.6(2)
118.9(2)
109.7(2)
108.5(2)
110.7(2)
C(3)-O(2)-In(1)
O(1)-C(1)-C(4)
C(1)-C(2)-C(3)
O(2)-C(3)-C(5)
C(7)-C(6)-In(1)
C(10)-C(7)-C(8)
C(10)-C(7)-C(6)
C(8)-C(7)-C(6)
F igu r e 2. Molecular geometry and labeling of atoms for
(Me3CCH2)2In(acac) (50% probability ellipsoids for non-
hydrogen atoms; hydrogen atoms are omitted for clarity).
(2)°; thus, it can be considered sp2-hybridized. The
acetylacetonate ligand is planar, but the π-system is not
completely delocalized. The bond distance O(1)-C(2)
(1.298(2) Å) is significantly longer than the bond dis-
tance for O(2)-C(4) (1.258(2) Å). Thus, the C-O bond
(1.298(2) Å) between the bridging oxygen atom and the
indium atom has a lower bond order than the C-O bond
(1.258(2) Å) between the indium and the nonbridging
oxygen.
C(12)-C(11)-In(1) 121.2(1)
C(15)-C(12)-C(11) 111.1(2)
C(15)-C(12)-C(14) 108.4(2)
C(11)-C(12)-C(14) 108.5(2)
C(15)-C(12)-C(13) 110.1(2)
C(13)-C(12)-C(11) 110.3(2)
C(13)-C(12)-C(14) 108.4(2)
a
Symmetry transformations used to generate equivalent at-
oms: 1 - x, 1 - y, 1 - z.
produced a hard, dry powder that “melted” sharply at
92.4-94.2 °C. Even though the powder “melted” sharply,
many observations suggest that the product is a mixture
of possibly (Me)(Me3CCH2)In(C5H5), Me2In(C5H5), (Me3-
CCH2)2In(C5H5), InMe3, and/or In(CH2CMe3)3. First, the
isolated product was exceedingly soluble in benzene,
pentane, THF, and diethyl ether. All other organoin-
dium(III) cyclopentadienide derivatives are insoluble in
diethyl ether, benzene, and pentane but soluble only in
a strongly coordinating solvent such as THF.9 Attempts
to recrystallize the product by slow cooling of a pentane
solution resulted in the formation of a gelatinous
material that became a rigid foam after solvent removal.
Likewise, attempted crystal growth by slow sublimation
resulted in the formation of an amorphous material that
resembled liquid droplets with no evidence of crystal-
linity, according to observations with a polarizing
Cyclopentadiene elimination reactions were used to
prepare (Me3CCH2)2In(acac) and Me2In(acac). Neither
neopentane nor methane was formed, even though
InMe3 and In(CH2CMe3)3 have been observed to react
readily with H(acac) at room temperature. Experimental
observations indicate that the cyclopentadiene elimina-
tion reaction between Me2In(C5H5) and Hacac is faster
than the methane elimination reaction between InMe3
and Hacac. Several properties of (Me3CCH2)2In(acac)
are very different from those of Me2In(acac). The neo-
pentyl derivative melted at a lower temperature and
was monomeric in benzene solution in the concentration
range of 0.04-0.08 m according to cryoscopic molecular
studies. However, an X-ray structural study of (Me3-
CCH2)2In(acac) indicated that the compound was a
centrosymmetric dimer with an inversion center be-
tween In(1) and In(1A) and short van der Waals contacts
between O(1) and In(1A) (2.759 Å) (Figure 2 and Table
2). The configuration about indium is irregular, due to
the acetylacetonate ligand, with the angle O(1)-In(1)-
O(2) being 83.63(5)°. The other bond angles about
indium are C(6)-In(1)-C(11) at 137.12(8)°, C(6)-In(1)-
O(1) at 109.23(7)°, and C(11)-In(1)-O(2) at 103.53(7)°.
The short van der Waals contacts result in the inequal-
ity of the O(1)-C(1) and O(2)-C(3) bond lengths. The
acetylacetonate ligand is planar.
1
microscope. H NMR spectra in both d8-THF and d6-
benzene exhibited more resonances than would be
expected for (Me)(Me3CCH2)In(C5H5), but these obser-
vations are consistent with organoindium(III) cyclopen-
tadienide chemistry. Many of the resonances in the d8-
THF solution could be identified with species formed
by multiple ligand redistribution reactions.9 When d6-
benzene was the solvent, the resonances were extremely
broad. No specific assignments could be made for these
resonances, as no other indium cyclopentadienide de-
rivative has been sufficiently soluble in benzene for
A ligand redistribution reaction between Me2In(C5H5)
and (Me3CCH2)2In(C5H5) in a 1:1 mole ratio in THF
solution was investigated in order to determine whether
a compound with three different organic ligands, (Me)-
(Me3CCH2)In(C5H5), could be prepared, isolated, and
characterized as a pure compound in a specific phase.
The product of the redistribution reaction was purified
by heating to 90 °C, during which a colorless glass
“sublimed” to the coldfinger. Scrapping of the coldfinger
characterization by H NMR spectroscopy.9
1
As there was no readily available method to deter-
mine the purity or existence of (Me)(Me3CCH2)In(C5H5)
as a single compound in the condensed state, a sample
that might be the proposed compound was reacted with
acetylacetone in pentane in an attempt to prepare (Me)-
(Me3CCH2)In(acac) by a cyclopentadiene elimination
reaction. The chelated acetylacetonate ligand might be
expected to hinder ligand redistribution reactions12 and
enable the isolation of (Me)(Me3CCH2)In(acac) as a pure
(13) Palenik, G. J .; Dymock, K. R. Acta Crystallogr. 1980, B36, 2059.

3994 Organometallics, Vol. 22, No. 20, 2003
Beachley et al.
Ta ble 3. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for (Me)(Me3CCH2)In (a ca c)a
Bond Distances
In(1)-C(6)
In(1)-O(1)
In(1)-O(1A)
O(1)-In(1A)
C(1)-C(2)
C(3)-C(4)
C(7)-C(8)
C(8)-C(11)
2.141(2)
2.206(2)
2.569(2)
2.569(2)
1.509(3)
1.413(3)
1.535(3)
1.535(3)
In(1)-C(7)
In(1)-O(2)
O(1)-C(2)
O(2)-C(4)
C(2)-C(3)
C(4)-C(5)
C(8)-C(9)
C(8)-C(10)
2.155(2)
2.262(2)
1.300(3)
1.257(3)
1.387(3)
1.511(3)
1.528(3)
1.535(4)
Bond Angles
C(6)-In(1)-C(7)
C(7)-In(1)-O(1)
C(7)-In(1)-O(2)
C(6)-In(1)-O(1A)
O(1)-In(1)-O(1A)
C(2)-O(1)-In(1)
In(1)-O(1)-In(1A)
O(1)-C(2)-C(3)
C(3)-C(2)-C(1)
O(2)-C(4)-C(3)
C(3)-C(4)-C(5)
C(9)-C(8)-C(7)
C(7)-C(8)-C(11)
C(7)-C(8)-C(10)
150.1(1)
101.15(8)
99.36(8)
91.57(8)
72.32(6)
127.9(1)
107.68(6)
126.7(2)
118.0(2)
125.0(2)
118.1(2)
110.2(2)
110.5(2)
109.6(2)
C(6)-In(1)-O(1)
C(6)-In(1)-O(2)
O(1)-In(1)-O(2)
C(7)-In(1)-O(1A)
O(2)-In(1)-O(1A)
C(2)-O(1)-In(1A)
C(4)-O(2)-In(1)
O(1)-C(2)-C(1)
C(2)-C(3)-C(4)
O(2)-C(4)-C(5)
C(8)-C(7)-In(1)
C(9)-C(8)-C(11)
C(9)-C(8)-C(10)
C(11)-C(8)-C(10)
107.38(8)
93.12(8)
82.36(6)
88.70(7)
154.49(6)
123.8(1)
128.4(2)
115.3(2)
127.6(2)
116.9(2)
120.3(2)
109.4(2)
108.8(2)
108.2(2)
F igu r e 3. Molecular geometry and labeling of atoms for
(Me)(Me3CCH2)In(acac) (50% probability ellipsoids for non-
hydrogen atoms; hydrogen atoms are omitted for clarity).
solid. An X-ray structural study of a single crystal
isolated from the recrystallized bulk product obtained
from the cyclopentadiene elimination reaction identified
the presence of (Me)(Me3CCH2)In(acac) (see the follow-
ing paragraph). The melting point of the solid was sharp
(52.7-53.5 °C), but an elemental analysis suggested the
bulk sample was impure, as the percentages of carbon
and hydrogen were low. The 1H NMR spectra of d6-
benzene and d8-THF solutions of the bulk material
indicated the product changed with time. Thus, these
data suggest that (Me)(Me3CCH2)In(acac), when in
solution, undergoes ligand redistribution reactions. It
is noteworthy that d6-benzene solutions of Me2In(acac)
and of (Me3CCH2)2In(acac) alone do not appear to
undergo ligand redistribution reactions. However, when
Me2In(acac) and (Me3CCH2)2In(acac) were mixed in a
1:1 mole ratio in d6-benzene in an NMR tube, reso-
a
Symmetry transformations used to generate equivalent at-
oms: 1 - x, 1 - y, 1 - z.
(2) Å). The In(1)-O(2) bond has a length of 2.262(2) Å,
which is in agreement with the fact that it is a pseudo-
axial bond. The bridging oxygen (O(1)) is in a trigonal-
planar configuration, with the sum of the bond angles
around it being 359.5(3)°; thus, it can be considered to
be sp2-hybridized.
Although the acetylacetonate ligand is planar, the
indium center (In(1)) is displaced from the acetylaceto-
nate plane by -0.306 Å in the direction of the neopentyl
ligand and the fused-ring system in the dimer has a
zigzag conformation. The acetylacetonate ligand shows
a high degree of π-delocalization, but the carbon-oxygen
bonds are not equal. The O(1)-C(2) bond (1.300(3) Å)
is longer than O(2)-C(4) (1.257(3) Å), indicating more
single-bond character than for the latter.
The availability of X-ray structural data for Me2In-
(acac), Me2In(hfac),15 (Me3CCH2)2In(acac), and (Me)-
(Me3CCH2)In(acac) permits a comparison of their many
features and with those of other oxygen-bridged indium-
containing dimers. All of these acetylacetonate deriva-
tives exist as centrosymmetric dimers with an inversion
center located between the five-coordinate indium at-
oms. The In(1)‚‚‚O(1A) distances are 2.551(1) and 2.569-
(2) Å for Me2In(acac) and (Me)(Me3CCH2)In(acac), re-
spectively, whereas the corresponding distances for
Me2In(hfac)15 and (Me3CCH2)2In(acac) at 2.869(2) and
2.759(3) Å, respectively, are significantly longer. These
distances are much longer than the bridging distances
in other simple four-coordinate indium oxygen dimers
such as [(C5H5)2InO(t-Bu)]2 at 2.129 Å (average),14 {[(t-
Bu)O]2InO(t-Bu)}2 at 2.111 Å16 (average), and [MeCl-
InO(t-Bu)]2 at 2.116 Å (average).17 This difference in
bond lengths in the â-diketonate derivatives may indi-
cate a considerably higher degree of bonding interac-
tions between the indium and bridging oxygen atoms
in Me2In(acac) and (Me)(Me3CCH2)In(acac) than in Me2-
In(hfac)15 and (Me3CCH2)2In(acac), but steric and/or
14
nances for In(acac)3 were observed after a few days.
In contrast, a mixture of In(acac)3 and Me2In(acac) did
not undergo ligand redistribution at room temperature
or after heating at 75 °C for 6 days. Even though no
example of a gallium â-diketonate derivative bearing
two different organic ligands has been characterized as
a pure compound, other derivatives with multiple sub-
stituents such as (Me)(Cl)Ga(acac),12b (Et)(Cl)Ga(acac),12b
(Mes)(Cl)Ga(acac),12b and [N(SiMe3)2](Cl)Ga(acac)12b ex-
ist as single compounds.
The X-ray structural study of the single crystal
isolated from the product of the reaction of (Me)(Me3-
CCH2)In(C5H5) with acetylacetone revealed (Me)(Me3-
CCH2)In(acac) to be a centrosymmetric dimer with the
inversion center located between In(1) and In(1A)
(Figure 3 and Table 3). Each indium center is five-
coordinate with highly distorted pseudo-trigonal-bipy-
ramidal geometry. The equatorial plane is formed by
C(6), C(7), and O(1), while O(2) and O(1A) occupy the
axial positions. The corresponding bond angles O(2)-
In(1)-O(1A), C(6)-In(1)-C(7), and O(1)-In(1)-C(6) are
154.49(6), 150.1(1), and 107.38(8)°, respectively (Table
3). One of the acetylacetonate oxygen atoms (O(1))
bridges two indium atoms, but the associated indium-
oxygen bonds are different, with In(1)-O(1) (2.206(2)
Å) being considerably shorter than In(1)-O(1A) (2.569-
(15) Chongying, X.; Baum, T. H.; Guzei, I.; Rheingold, A. L. Inorg.
Chem. 2000, 39, 2009.
(14) Beachley, O. T., J r.; MacRae, D. J .; Kovalevsky, A. Y. Organo-
metallics 2003, 22, 1690.
(16) Suh, S.; Hoffman, D. M. J . Am. Chem. Soc. 2000, 122, 9396.
(17) Veith, M.; Hill, S.; Huch, V. Eur. J . Inorg. Chem. 1999, 8, 1343.

Organoindium(III) Derivatives
Organometallics, Vol. 22, No. 20, 2003 3995
pound did not form an isolable adduct with Et2O, THF,
1
PPh3, or pyridine. The H NMR spectrum of a d6-ben-
zene solution of (t-Bu)2In(acac) exhibited three sharp
resonances.
The cyclopentadiene elimination reaction is an ef-
ficient method for the preparation of Me2InSSiPh319 and
(Me3CCH2)2InSSiPh3. The compound Me2InSSiPh3 was
previously prepared by the methane elimination reac-
tion between InMe3 and HSSiPh3 in toluene solution at
room temperature.19 The sample of the compound pre-
pared in the present study did not melt but decomposed
at 159.2-162.3 °C. The earlier work described a melting
point of 160 °C with no mention of decomposition.19
A
benzene solution of Me2InSSiPh3 exists as an equilib-
rium mixture of species, probably dimers and trimers,
in the concentration range of 0.01-0.03 m. The degree
of association decreased from 2.46 to 2.37 as the solution
was diluted from 0.0304 to 0.0175 m. Limited solubility
prevented molecular weight measurements at higher
concentrations. Although Me2InSSiPh3 is a mixture of
dimers and trimers in benzene solution according to the
1
molecular weight study, only three H NMR resonances
were observed for a d6-benzene solution. The derivative
Me2InSSiPh3 is trimeric in the solid state.19 The closely
related compound (Me3CCH2)2InSSiPh3 is similar to
Me2InSSiPh3, as it decomposed rather than melted upon
heating. The compound is dimeric in benzene solution
in the concentration range of 0.02 to 0.10 m.
The cyclopentadiene elimination reaction is also an
excellent synthetic method for the preparation of Me2-
InPPh220 and (Me3CCH2)2InPPh2.21 In contrast, HPPh2
reacted with In(C5H5)3 to reduce indium(III) to indium-
(I) to form indium(I) cyclopentadienide (In(C5H5)) and
P2Ph4 as final products.14 The reaction between Me2In-
(C5H5) and HPPh2 in a benzene solution at room temp-
erature produced a colorless powder that did not melt
but decomposed at 188.9-192.4 °C. Even though Me2-
InPPh2 has been described in three previous papers,20
characterization data were inconsistent. The compound
has been described as melting at either 243 °C20a or 245
°C20c but with decomposition beginning at either 140
°C20c or 185 °C.20c It should be noted that (Me3CCH2)2-
InPPh2 undergoes thermal decomposition rather than
melting.21 1H and 31P NMR spectra of Me2InPPh2 are
also different from those reported in the previous
studies, but the current spectra are consistent with the
spectral data for (Me3CCH2)2InPPh2.21 The 1H NMR
spectrum of Me2InPPh2 in d6-benzene exhibited two
singlets for the protons of the methyl groups bonded to
indium and two broad resonances for the protons
associated with the phenyl groups. Previous workers20
described only one resonance each for the protons of the
methyl groups and of the phenyl groups. Similarly, the
31P NMR spectrum in d6-benzene solution had two
F igu r e 4. Views of indium acetylacetonate derivatives
that show conformations of the chelate rings.
electronic effects associated with the substituents on the
metal center or the â-diketonate ligand may be signifi-
cant also. The steric bulkiness of the neopentyl ligand
in (Me3CCH2)2In(acac) or the strong electron-withdraw-
ing nature of the trifluoromethyl groups on the hexaflu-
oroacetylacetonate ligand in Me2In(hfac)15 may be re-
sponsible for the deviation in the bonding interactions
between the individual R2In(â-diketonate) units. The
six-membered InO2C3 rings in Me2In(acac), Me2In-
(hfac),15 and (Me3CCH2)2In(acac) are planar, whereas
the corresponding ring in (Me)(Me3CCH2)In(acac) is
nonplanar, with the indium being displaced from the
plane of the O2C3 ring by -0.306 Å in the direction of
the neopentyl ligand (Figure 4). This distortion of the
metallacyclic ring from planarity may be due to the
inequality in steric bulkiness of the methyl and neo-
pentyl ligands.
The compound (t-Bu)2In(acac) was prepared by a
metathetical reaction between (t-Bu)2InCl18 and Na-
(acac), rather than by a cyclopentadiene elimination
reaction. It is of interest that the chelating acetylaceto-
nate ligand was not able to stabilize (t-Bu)2In(acac)
sufficiently for complete characterization at room tem-
perature. A gray material believed to be indium metal
became apparent after approximately 1 week of storage
in the drybox. Even though the compound decomposed,
most likely by a â-hydride elimination reaction, the com-
(19) Rahbarnoohi, H.; Taghiof, M.; Heeg, M. J .; Dick, D. G.; Oliver,
J . P. Inorg. Chem. 1994, 33, 6307.
(20) (a) Burns, J . A.; Dillingham, M. D. B.; Hill, J . B.; Gripper, K.
D.; Pennington, W. T.; Robinson, G. H. Organometallics 1994, 13, 1514.
(b) Arif, A. M.; Barron, A. R. Polyhedron 1988, 7, 2091. (c) Aitchison,
K. A.; Backer-Dirks, J . D.; Bradley, D. C.; Faktor, M. M.; Frigo, D. M.;
Hursthouse, M. B.; Hussain, B.; Short, R. L. J . Organomet. Chem.
1989, 366, 11.
(21) (a) Banks, M. A.; Beachley, O. T., J r.; Buttrey, L. A.; Churchill,
M. R.; Fettinger, J . C. Organometallics 1991, 10, 1901. (b) Beachley,
O. T., J r.; Chao, S.-H. L. Organometallics 2000, 19, 2820. (c) Beachley,
O. T., J r.; Kopasz, J . P.; Hunter, W. E.; Atwood, J . L. J . Organomet.
Chem. 1987, 325, 69.
(18) Bradley, D. C.; Frigo, D. M.; Hursthouse, M. B.; Hussain, B.
Organometallics 1998, 7, 1112.

3996 Organometallics, Vol. 22, No. 20, 2003
Beachley et al.
resonances, one at -24.8 ppm and the other at -52.8
ppm, whereas only one had been reported previously.20
The current NMR spectral data suggest the existence
of an equilibrium between two species, possibly mono-
mers and dimers, because the chemical shifts of the 31P
NMR resonances for Me2InPPh2 are similar to those
observed for the monomer/dimer equilibrium reported
21
for (Me3CCH2)2InPPh2 (-30.8 ppm, monomer; -49.4
ppm, dimer). Thus, the physical properties, NMR spec-
tra, and structures of Me2InPPh2 and (Me3CCH2)2-
InPPh2 are now comparable and are in complete agree-
ment. Both compounds are trimers in the solid state and
equilibrium mixtures of monomers and dimers in solu-
tion. The closely related compounds (i-Pr)2InPPh2 and
(PhCH2)2InPPh2 also exist as trimers in the solid state
and as equilibrium mixtures of monomers and dimers
in benzene solution, according to cryoscopic molecular
weight studies.22
F igu r e 5. Molecular geometry and labeling of atoms for
[Me2InNH(t-Bu)]2 (30% probability ellipsoids for non-
hydrogen atoms; hydrogen atoms are artificially reduced).
Ta ble 4. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) for [Me2In NH(t-Bu )]2
The reaction of Me2In(C5H5) with H2N(t-Bu) is sig-
nificantly slower than the corresponding reactions of
any of the other reagents described in this paper and
with the corresponding reactions of R2Ga(C5H5) (R )
Me, Et)5-7 with amines, but the elimination of C5H6 is
faster than the elimination of methane from InMe3 with
the primary amines H2N(i-Pr) (∼120 °C)23 and H2N-
(C6F5) (∼110 °C).24 Heating of a benzene solution of Me2-
In(C5H5) and H2N(t-Bu) in a 75 °C oil bath for at least
2 days was required to achieve complete reaction for the
isolation of Me2InNH(t-Bu) in ∼92% yield. Even though
the trans isomer of the dimer [Me2InNH(t-Bu)]2 was
observed in the solid state by an X-ray structural study
(see below), cryoscopic molecular weight studies in
Bond Distances
In(1)-N(1)
In(1A)-N(1)
In(1)-C(2)
N(1)-C(3)
2.230(3)
2.220(3)
2.157(4)
1.495(4)
In(1)-N(1A)
In(1)-C(1)
In(1)‚‚‚In(1A)
N(1)-H(1)
2.220(3)
2.160(4)
3.335(2)
0.81(3)
Bond Angles
N(1)-In(1)-C(1)
C(1)-In(1)-C(2)
106.6(1)
121.5(2)
119.2(1)
82.9(1)
107.0(1)
97(2)
N(1)-In(1)-C(2)
116.1(1)
41.3(1)
119.3(1)
116.5(1)
41.6(1)
122.6(2)
97.1(1)
123.9(2)
N(1)-In(1)‚‚‚In(1A)
C(2)-In(1)-In(1A)
C(1)-In(1)-N(1A)
In(1A)‚‚‚In(1)-N(1A)
In(1)-N(1)-C(3)
C(1)-In(1)-In(1A)
N(1)-In(1)-N(1A)
C(2)-In(1)-N(1A)
In(1)-N(1)-H(1A)
H(1A)-N(1)-C(3)
H(1A)-N(1)-In(1A)
108(2)
104(2)
In(1)-N(1)-In(1A)
C(3)-N(1)-In(1A)
contain both cis and trans isomers, a most unusual ob-
servation. A review of the chemistry of amido deriva-
tives of gallium and indium25 suggests that many com-
pounds of this type exist as the two geometrical isomers
1
benzene solutions as well as H NMR spectra of d8-THF
and d6-benzene solutions suggest that the compound
exists as a mixture of monomers and dimers with both
cis and trans configurations. The resonances assigned
to the monomeric species disappeared as the concentra-
tion of Me2InNH(t-Bu) in each solvent was increased.
The observed percentage of monomer for the most dilute
solutions in both solvents was approximately 7%,
whereas the ratio of cis and trans isomers was 45/55
for d6-benzene and 41/59 for d8-THF.
23
in solution but only [Me2InNH(i-Pr)]2 exists as both
isomers in the solid state, whereas Me2InNH(t-Bu) is
the only indium amido derivative to our knowledge that
has been observed by NMR spectroscopy to exist as an
equilibrium mixture of monomers and dimers in ben-
zene solution and to be a dimer in the solid state.
1
Both synthetic scale reactions and H NMR spectral
The compound [Me2InNH(t-Bu)]2 crystallizes in the
centrosymmetric space group P21/n with Z ) 2 (Figure
5 and Table 4). The molecule lies on a crystallographic
inversion center and has precise Ci symmetry. This sym-
metry requires the two NH(t-Bu) ligands associated
with sp3-hybridized nitrogen atoms to be in a mutually
trans configuration, with one t-Bu group above the plane
of the In2N2 ring and the other below it. The In2N2 ring
is precisely planar, with In(1)-N(1) ) In(1A)-N(1A) )
2.230(3) Å and In(1)-N(1A) ) In(1A)-N(1) ) 2.220(3)
Å. The internal angle at the indium atom is acute
(N(1)-In(1)-N(1A) ) 82.9(1)°, while that at nitrogen
is obtuse (In(1)-N(1)-In(1A) ) 97.1(1)°). The In(1)‚‚‚
In(1A) distance is 3.335(2) Å. The two independent
indium-methyl bond lengths are In(1)-C(1) ) 2.160-
(4) Å and In(1)-C(2) ) 2.157(4) Å with an interligand
angle of C(1)-In(1)-C(2) ) 121.5(2)°. It is of interest
that an X-ray structural study of the closely related
studies (see the Supporting Information) have been used
to elucidate the reasons for the cyclopentadiene elimi-
nation reaction between Me2In(C5H5) and H2N(t-Bu)
being slow in comparison with others in this study.
Three of the four equations that describe the overall
process (eqs 2-5) are specifically shown as equilibria,
Me2In(C5H5) + H2N(t-Bu) h
Me2(C5H5)In-NH2(t-Bu) (2)
Me2(C5H5)In-NH2(t-Bu) h Me2InNH(t-Bu) + C5H6
(3)
Me2InNH(t-Bu) h 1/2[Me2InNH(t-Bu)]2
C5H6 f C10H12
(4)
(5)
23
compound [Me2InNH(i-Pr)]2 revealed the crystal to
because both the forward and reverse reactions have
been observed experimentally. The experimental data
support the following conclusions. (1) The cyclopenta-
(22) Werner, B.; Neumu¨ller, B. Organometallics 1996, 15, 4258.
(23) Neumu¨ller, B. Chem. Ber. 1989, 122, 2283.
(24) Belgradt, T.; Roesky, H. W.; Noltemeyer, M.; Schmidt, H.-G.
Angew. Chem., Int. Ed. 1993, 32, 1056.
(25) Carmalt, C. J . Coord. Chem. Rev. 2001, 223, 217.

Organoindium(III) Derivatives
Organometallics, Vol. 22, No. 20, 2003 3997
storage tubes after drying. All solvents were carefully dried
by using conventional procedures. Elemental analyses were
performed by Oneida Research Services, Whitesboro, NY.
Melting points were determined with a Mel-Temp by using
flame-sealed capillaries filled with argon and are uncorrected.
1H NMR spectra were recorded with either a Varian Unity-
Nova 400 or a 500 spectrometer (400 and 500 MHz, respec-
tively), whereas 31P NMR (161.9 MHz) spectra were recorded
with the Varian Unity-Nova 500 spectrometer. Proton chemi-
cal shifts are reported in δ (ppm) units and are referenced to
SiMe4 at δ 0.00 ppm with C6D5H at δ 7.15 ppm or the proton
impurities in d8-THF at δ 1.73 ppm. Phosphorus chemical
shifts are referenced to 85% H3PO4 at δ 0.00 ppm. All samples
for NMR spectra were contained in flame-sealed NMR tubes.
The deuterated solvents d6-benzene and d8-THF were pur-
chased from either Aldrich Chemical Co. or Cambridge Iso-
topes, Inc., were dried with P4O10, and then were vacuum-
distilled into tubes coated with sodium mirrors. Infrared
spectra of samples as Nujol mulls between CsI plates were
recorded by using a Perkin-Elmer 683 spectrometer. Molecular
weights were measured cryoscopically in benzene solution by
using an instrument similar to that described by Shriver and
Drezdon.26
Syn th esis of Me2In O(t-Bu ).10 A tube that contained 0.522
g (7.04 mmol) of t-BuOH dissolved in 4 mL of Et2O was
connected to a flask charged with 1.48 g (7.04 mmol) of Me2-
In(C5H5) dissolved in approximately 10 mL of Et2O and
equipped with a magnetic stir bar. The t-BuOH/Et2O solution
was added to the Me2In(C5H5) at room temperature. The
initially insoluble Me2In(C5H5) dissolved after 5 min of stirring.
The reaction mixture was stirred for 1 h, and all material
volatile at room temperature was removed by vacuum distil-
lation. Flask-to-flask sublimation at 35 °C produced 1.51 g
(6.92 mmol, 98.3% based on Me2In(C5H5)) of Me2InO(t-Bu)10
as a colorless waxy solid.
diene elimination reaction (eq 3) is faster in benzene
than in THF solution, but both solutions must be heated
to achieve complete reaction. There was no apparent
reaction when a solution of Me2In(C5H5) and H2N(t-Bu)
in benzene was maintained at room temperature for 30
days. (2) Removal of the volatile products from the
reaction mixture enhanced the rate of formation of Me2-
InNH(t-Bu). (3) The absence of solvent did not accelerate
significantly the rate of formation of Me2InNH(t-Bu).
(4) The reaction between Me2InNH(t-Bu) and C5H6 (the
reverse of eq 3) is faster in THF than in d6-benzene.
These data suggest that the occurrence of a significant
reaction between Me2In(C5H5) and H2N(t-Bu) to form
Me2InNH(t-Bu) requires dimerization of the indium
amide monomer (eq 4) and/or the removal or dimeriza-
tion of cyclopentadiene (eq 5). As the relative rates of
the reactions depend on the characteristics of the
solvent, reaction may proceed by the initial formation
of a Lewis acid/base adduct (eq 2), which is then followed
by proton transfer from the coordinated Lewis base to
the cyclopentadienide ligand (eq 3). The monomeric
amide can either dimerize to form the observed product
(eq 4) or be protonated by cyclopentadiene to reform the
Lewis acid/base adduct. A strongly coordinating solvent
such as THF can displace the amine from Me2In(C5H5)‚
NH2(t-Bu), thereby reducing the concentration of adduct
and slowing the overall rate of the cyclopentadiene
elimination reaction. However, THF can also stabilize
Me2InNH(t-Bu) as the monomer by forming an adduct
and, in turn, facilitate its protonation by cyclopentadi-
ene. Removal of C5H6 either physically by vacuum
distillation or chemically by a Diels-Alder dimerization
provides an alternative way to shift the equilibria and
enhance the formation of product.
Me2InO(t-Bu): mp 84.3-87.6 °C (appeared to shrink in tube,
possible glass transition), 90.2-91.5 °C (melted) (lit.10 mp 90
1
°C); H NMR (d6-benzene, δ) 0.89 (s, InCH3, 6.0 H), 1.09 (s,
The characterization data for compounds of the types
R2InXR′ and R2InYR′2 (R ) Me, CH2CMe3; X ) O, S; Y
) N, P; R′ ) organic groups) have established that the
degree of association depends on the physical state of
the compound. Molecules as solids frequently exhibit
degrees of association different from those of species in
solution. Thus, thermodynamic parameters contribute
significantly to the detailed nature of these types of
compounds. An X-ray structural study of a specific
organoindium(III) compound cannot be used to define
the nature of the compound in solution. Dissociative
reactions as well as ligand redistribution reactions play
significant roles in group 13 chemistry.
OC(CH3)3, 9.0 H). Cryoscopic molecular weight, benzene solu-
tion, formula weight 218.00 (observed molality, observed mol
wt, association): 0.0936, 435, 2.00; 0.0516, 433, 1.99; 0.0301,
443, 2.03. Soluble in THF, Et2O, C6H6, and C5H12
.
Syn th esis of (Me3CCH2)2In O(t-Bu ). The reagents, 1.478
g (7.040 mmol) of (Me3CCH2)2In(C5H5) dispersed in 10 mL of
Et2O and 0.522 g (7.04 mmol) of t-BuOH dissolved in 4 mL of
Et2O, were combined as described for the previous reaction.
The initially insoluble (Me3CCH2)2In(C5H5) dissolved after 5
min of stirring at room temperature. After the reaction mixture
was stirred for 1 h, all material volatile at room temperature
was removed by vacuum distillation. A fine-porosity frit
attached to a round-bottom flask was fitted to the Schlenk
flask, and the product was isolated by recrystallization from
2 × 20 mL of Et2O at -40 °C. After the resulting crystals were
washed with pentane at 0 °C, 1.51 g (6.92 mmol, 98.3% based
on (Me3CCH2)2In(C5H5)) of (Me3CCH2)2InO(t-Bu) was isolated
as a colorless solid.
(Me3CCH2)2InO(t-Bu): mp 120.5-130.2 °C dec; 1H NMR (d6-
benzene, δ) 1.25 (s, CH2CCH3, 18.00 H), 1.35 (s, OC(CH3)3, 9.0
H), 1.37 (s, InCH2, 4.0 H). Anal. Calcd for C14H31InO: C, 50.92;
H, 9.46. Found: C, 50.48; H, 9.29. Cryoscopic molecular weight,
benzene solution, formula weight 330.21 (observed molality,
observed mol wt, association): 0.0449 m, precipitate formed
as solution cooled; 0.0495, 683, 2.07; 0.0220, 672, 2.04. Soluble
in THF and Et2O, slightly soluble in C6H6, and trace solubility
Exp er im en ta l Section
All compounds described in this investigation were sensitive
to oxygen and moisture and were manipulated either under a
purified argon atmosphere in a Vacuum Atmospheres drybox
or by using standard vacuum line techniques. The indium-
(III) derivative In(C5H5)3 was prepared in THF solution8a and
used within 2 weeks of its preparation. The starting materials
Me2In(C5H5),9 (Me3CCH2)2In(C5H5),9a (t-Bu)2InCl,18 and In-
14
(acac)3 were prepared by literature methods, whereas t-
BuOH, Hacac, HPPh2, H2N(t-Bu), and InCl3 were purchased
from either Strem Chemicals, Inc. or Aldrich Chemical Co. tert-
Butyl alcohol was dried by stirring with CaH2 for 8 h and then
vacuum-distilled, whereas acetylacetone was dried over K2-
CO3 and distilled prior to use. The phosphine was distilled
under dynamic vacuum at ∼100 °C, whereas tert-butylamine
was dried with KOH. Indium(III) chloride was used as
received. All volatile reagents were vacuum-distilled into
in C5H12
.
Syn th esis of Me2In (a ca c)11 fr om In Me3 a n d Ha ca c.
After a Schlenk flask was charged with 0.251 g (1.57 mmol)
of InMe3, 0.165 g (1.65 mmol) of Hacac was vacuum-distilled
(26) Shriver, D. F.; Drezdon, M. A. The Manipulation of Air-Sensitive
Compounds; Wiley: New York, 1986; p 38.

3998 Organometallics, Vol. 22, No. 20, 2003
Beachley et al.
onto the InMe3. The reactants were slowly warmed to room
temperature, and bubbling occurred. After 4 h at 20 °C,
bubbling ceased and CH4 and excess Hacac were removed by
vacuum distillation. Sublimation of the resulting product at
40 °C produced 0.334 g (1.37 mmol, 87.5% based on InMe3) of
Me2In(acac) as a colorless solid. Crystals suitable for an X-ray
structural study were grown by slow sublimation in a sealed
tube placed above a 150 °C drying oven.
additional 3 h. The resulting colorless material was sublimed
at 90 °C to produce 0.891 g of (Me)(Me3CCH2)In(C5H5) (3.35
mmol, 91.4% yield, if pure).
(Me)(Me3CCH2)In(C5H5): mp 92.4-94.2 °C; 1H NMR (d8-
THF, δ): -1.10 (s, MeIn(C5H5)2, 0.22 H), -0.52 (s, Me2In(C5H5),
5.78 H), 0.37 (s, (Me3CCH2)In(C5H5)2, 1.77 H), 0.61 (s, (Me3-
CCH2)2In(C5H5), 0.19 H), 0.83 (s, Me3CCH2)In(C5H5)2, 7.87 H),
0.99 (s, (Me3CCH2)2In(C5H5), 0.91 H), 1.10 (s, (Me3CCH2)3In,
0.11 H), 6.04 (s, C5H5, 5.00H). Soluble in THF, Et2O, C6H6,
Me2In(acac): mp 136.9-137.8 °C; dec pt ∼200 °C (lit.11a mp
118 °C dec); 1H NMR (d8-THF, δ) -0.28 (s, InCH3, 6.01 H),
and C5H12
.
1
5.94), 1.83 (s, acac CH3, 6.01 H), 5.20 (s, acac H, 0.98 H); H
Attem p ted Syn th esis of (Me)(Me3CCH2)In (a ca c) fr om
(Me)(Me3CCH2)-In (C5H5) a n d Ha ca c. A Schlenk flask was
charged with 0.520 g (1.96 mmol) of (Me)(Me3CCH2)In(C5H5),
approximately 15 mL of C5H12, and a magnetic stir bar. After
the mixture was stirred for 10 min, 0.200 g (2.00 mmol) of
Hacac was added by vacuum distillation. The reaction mixture
was warmed to room temperature, and the clear, colorless
solution was stirred for 15 min. Then, the volatile components
were removed by vacuum distillation. Recrystallization of the
product from pentane at -30 °C produced 0.547 g of colorless
crystals (1.90 mmol of (Me)(Me3CCH2)In(acac), if pure, 96.9%
yield based on (Me)(Me3CCH2)In(C5H5)).
(Me)(Me3CCH2)In(acac): mp 52.7-53.5 °C; 1H NMR (d6-
benzene, δ) initial spectrum 0.02 (s, InCH3, 4.9 H), 0.13 (s,
InCH3, 11.7 H), 1.07 (s, CH2CCH3, 39.2 H), 1.11 (s, CH2CMe3,
8.6 H), 1.72 (s, acac CH3, 30.7 H), 5.04 (s, acac H, 4.2 H),
spectrum after 24 h at room temperature 0.02 (s, InCH3, 7.0
H), 0.13 (s, InCH3, 10.4), 1.06 (s, CH2CCH3, 31.6 H), 1.11 (s,
CH2CMe3, 6.9 H), 1.13 (s, CH2CCMe3, 6.5 H), 1.16 (s, CH2CMe3,
1.5 H), 1.72 (s, acac CH3, 6.0 H), 5.04 (s, acac H, 1.0 H),
spectrum after 6 months at room temperature 0.03 (s, InCH3,
2.5 H), 0.14 (s, InCH3, 3.2 H), 0.91 (s, CH2CMe3, 1.8 H), 1.07
(s, CH2CMe3, 5.5 H), 1.12 (s, CH2CMe3, 3.1 H), 1.14 (s,
CH2CMe3, 5.0 H), 1.17 (s, CH2CMe3, 2.6 H), 1.21 (s, CH2CMe3,
3.0 H), 1.73 (s, acac CH3, 6.5 H), 1.74 (s, acac CH3, 5.0 H),
5.03 (s, acac H, 0.2 H), 5.05 (s, acac H, 0.9 H), 5.07 (s, acac H,
0.6 H), 5.12 (s, acac H, 0.2 H). Anal. Calcd for C11H21InO2: C,
44.02; H, 7.05. Found: C, 42.83; H, 6.81. Soluble in THF, Et2O,
NMR (C6D6, δ) 0.11 (s, InCH3, 5.94 H), 1.71 (s, acac CH3, 6.07
H), 4.98 (s, acac H, 0.99 H); 13C NMR (d6-benzene, δ) -4.67
(s, InCH3), 28.08 (s, acac CH3), 100.27 (s, acac -C-C-), 192.28
(s, acac C-O); IR 1597 cm-1 (m, C-O). Anal. Calcd for C7H13
-
InO2: C, 34.46; H, 5.37. Found: C, 34.39; H, 5.27. Cryoscopic
molecular weight, benzene solution, formula weight 243.99
(observed molality, observed mol wt, association): 0.0678, 299,
1.23; 0.0549, 283, 1.16; 0.0480, 278, 1.138; 0.0420, 275, 1.13;
0.0244, 270, 1.11; 0.0099, 266, 1.09 (lit.10b 302). Soluble in THF,
Et2O, C6H6, and C5H12
.
Syn th esis of Me2In (a ca c). A Schlenk flask was charged
with 0.344 g (1.64 mmol) of Me2In(C5H5), approximately 25
mL of C5H12, and a magnetic stir bar. After the mixture was
cooled to -196 °C, 0.160 g (1.60 mmol) of Hacac was added by
vacuum distillation. The reaction mixture was slowly warmed
to room temperature and stirred vigorously. After 10 min the
mixture was clear and colorless, but after 30 min the solution
was yellow. Then, all material volatile at 20 °C was removed
by vacuum distillation. Sublimation at 40 °C produced 0.200
g (0.820 mmol, 87.5% based on Me2In(C5H5)) of Me2In(acac)
as a colorless solid.
1
Me2In(acac): mp 137.9-138.4 °C; H NMR spectrum was
identical with that observed for a sample of Me2In(acac)
prepared by the methane elimination reaction.
Syn th esis of (Me3CCH2)2In (a ca c). A Schlenk flask was
charged with 0.554 g (1.72 mmol) of (Me3CCH2)2In(C5H5), 0.173
g (1.72 mmol) of Hacac, and 30 mL of C6H6 and stirred at room
temperature with a magnetic stir bar. Then, C6H6, C5H6, and
unreacted Hacac were removed by vacuum distillation. Re-
crystallization of the product from pentane at -30 °C produced
0.559 g (1.57 mmol, 91.3% based on (Me3CCH2)2In(C5H5)) of
(Me3CCH2)2In(acac) as a colorless crystalline solid. Sublimation
at 40 °C in a sealed tube produced crystallographic quality
crystals.
C6H6, and C5H12
.
Syn th esis of (t-Bu )2In (a ca c). A Schlenk flask charged
with 0.993 g (3.75 mmol) of (t-Bu)2InCl18 was fitted with a
sidearm dumper that contained 0.468 g (3.84 mmol) of Na-
(acac) and a 90° elbow fitted to a another Schlenk flask. The
apparatus was evacuated, and 50 mL of diethyl ether was
distilled onto the (t-Bu)2InCl. Na(acac) was added to the (t-
Bu)2InCl over 1 h. After the solution was stirred for an
additional 4 h, the ether was removed by vacuum distillation.
(Me3CCH2)2In(acac): mp 44.6-45.8 °C; 1H NMR (d6-
benzene, δ) 1.13 (s, Me3CCH2, 18 H), 1.16 (s, Me3CCH2, 4 H),
1.73 (s, acac CH3, 6 H), 5.06 (s, acac H, 1 H). Anal. Calcd for
The (t-Bu)2In(acac) was then vacuum-distilled at 40 °C through
C
15H29InO2: C, 50.58; H, 8.21. Found: C, 50.75; H, 8.18.
the elbow to give 1.02 g (3.10 mmol, 82.7% based on (t-
Bu)
Cryoscopic molecular weight, benzene solution, formula weight
356.21 (observed molality, observed mol wt, association):
0.0787, 353, 0.99; 0.0594, 364, 1.02; 0.0458, 352, 0.99. Soluble
2InCl) of (t-Bu)2In(acac) as a colorless liquid that decom-
posed to a black solid in the drybox.
1
(t-Bu)2In(acac): mp ∼-8 °C; H NMR (d6-benzene, δ) 1.36
in THF, Et2O, C6H6, and C5H12
.
(s, C(CH3)3, 18.1 H), 1.75 (s, acac-CH3, 6.0 H), 5.04 (s, acac H,
0.92 H); 13C NMR (d6-benzene) δ 31.68 (s, t-Bu CH3), 35.75 (s,
t-Bu C), 28.03 (s, acac CH3), 100.27 (s, acac -C-C-), 193.06
(s, acac C-O); IR 1583 cm-1 (m, C-O). Soluble in THF, Et2O,
C6H6, and C5H12. The compound did not form an isolable
adduct with OEt2, THF, pyridine, or PPh3 and was insuf-
ficiently stable to obtain an elemental analysis from an
external laboratory.
Syn th esis of (Me3CCH2)2In (a ca c) fr om In (CH2CMe3)3
a n d Ha ca c. The reagents, 0.3021 g (0.9203 mmol) of In(CH2-
CMe3)3, 0.101 g (1.01 mmol) of Hacac, and benzene, were
combined as described in the previous experiment. The
product, 0.301 g (0.846 mmol, 91.9% based on In(CH2CMe3)3)
of (Me3CCH2)2In(acac), was isolated as colorless blocks after
recrystallization from 2 × 20 mL of pentane at -30 °C.
(Me3CCH2)2In(acac): characterization data were identical
Syn th esis of Me2In SSiP h 3.19 A flask was charged with
0.977 g (4.65 mmol) of Me2In(C5H5), ∼20 mL of C6H6, and a
magnetic stir bar while a sidearm dumper contained 1.24 g
(4.25 mmol) of HSSiPh3. After ∼15 min after the addition of
the thiol, most of the Me2In(C5H5) had dissolved but a cloudy
colorless suspension remained. The suspension was stirred for
a total of 4 h, and then the C6H6 was removed by vacuum
distillation. The product was isolated by extraction with 3 ×
30 mL of C5H12 through a medium-porosity frit followed by
cooling to -30 °C to give 1.56 g (3.58 mmol, 84.3% based on
HSSiPh3) of Me2InSSiPh3 as colorless crystals.
with those obtained for
prepared by the cyclopentadiene elimination reaction.
a sample of (Me3CCH2)2In(acac)
Attem p ted Syn th esis of (Me)(Me3CCH2)In (C5H5) fr om
Me2In (C5H5) a n d (Me3CCH2)2In (C5H5). A reaction mixture
was prepared by dissolving 0.590 g (1.83 mmol) of (Me3CCH2)2-
In(C5H5) and 0.385 g (1.83 mmol) of Me2In(C5H5) in ∼10 mL
of THF. After the resulting light yellow solution was stirred
with a magnetic stir bar at room temperature for 1.5 h, the
THF was removed by vacuum distillation to leave a colorless,
rigid foam. The flask was dynamically evacuated for an

Organoindium(III) Derivatives
Organometallics, Vol. 22, No. 20, 2003 3999
Ta ble 5. Da ta for X-r a y Cr ysta llogr a p h ic Stu d ies
of Me2In (a ca c), (Me3CCH2)2In (a ca c), a n d
(Me)(Me3CCH2)In (a ca c)
Me2InSSiPh3: mp 159.2-162.3 °C (dec as indicated by a
color change to a yellow solid and then to a tan liquid (lit.19
mp 160 °C); 1H NMR (d6-benzene, δ) -0.01 (s, CH3, 6 H), 7.09
(m, C6H5, 9 H), 7.78 (m, C6H5, 6 H), (lit.18 1H NMR (d6-benzene)
δ 0.00 (s, CH3, 6 H)), 7.10 (m, C6H5, 9 H), 7.79 (m, C6H5, 6 H).
Cryoscopic molecular weight, benzene solution, formula weight
436.35 (observed molality, observed mol wt, association):
0.0304, 1072, 2.46; 0.0175, 1034, 2.37.
(Me3CCH2)2-
In(acac)
(Me)(Me3CCH2)-
In(acac)
Me2In(acac)
14H26In2O4
mol formula
Mr
C
C
30H58In2O4
C22H42In2O4
487.99
712.52
600.20
cryst shape
colorless
parallelepiped
colorless
parallelepiped
colorless
parallelepiped
Syn th esis of (Me3CCH2)2In SSiP h 3. The reagents, 1.033
g (3.206 mmol) of (Me3CCH2)2In(C5H5) and 0.849 g (2.903
mmol) of HSSiPh3, were reacted in ∼20 mL of C6H6 as
described for the synthesis of Me2InSSiPh3. After ∼20 min
most of the (Me3CCH2)2In(C5H5) had dissolved but a cloudy
colorless suspension remained. The suspension was stirred for
4 h, and then the C6H6 was removed by vacuum distillation.
The crude product was isolated by extraction with 3 × 20 mL
of benzene through a medium-porosity frit as a colorless goo
with a suspended solid. The crude product was recrystallized
from 3 × 30 mL of pentane followed by cooling to -30 °C to
give 1.39 g (2.53 mmol, 87.1% based on HSSiPh3) of (Me3-
CCH2)2InSSiPh3 as colorless crystals.
cryst syst
space group
a, Å
b, Å
c, Å
triclinic
P1h
triclinic
P1h
monoclinic
P21/n
11.112(2)
7.265(2)
16.555(3)
90
102.43(3)
90
1305.1(5)
1.527
7.7868(3)
8.3327(4)
8.5418(4)
101.719(1)
112.587(1)
107.314(1)
455.76(4)
1.778
9.5246(8)
9.5363(8)
9.8629(8)
102.705(2)
91.902(2)
104.773(2)
841.2(1)
1.406
R, deg
â, deg
γ, deg
V, Å3
D
Z
calcd, g/cm3
1
1
2
µ(Mo KR),
2.538
1.399
1.788
mm-1
T (K)
90(1)
60.0
90.0(1)
59.2
90.0(1)
75.5
max 2θ, deg
abs cor method SADABS27
SADABS27
7724
SADABS27
19 386
(Me3CCH2)2InSSiPh3: mp 135.9 °C began to turn tan,
142.7-150.2 °C glass transition, continually became darker
brown until 198.2-200.7 °C, when all material appeared to
melt; 1H NMR: (d6-benzene, δ) 1.04 (s, Me3CCH2, 18 H), 1.23
(s, Me3CCH2, 4 H), 7.19 (m, C6H5, 9 H), 7.78 (m, C6H5, 6 H).
Anal. Calcd for C28H37InSSi: C, 61.31; H, 6.80. Found: C,
61.24; H, 6.65. Cryoscopic molecular weight, benzene solution,
formula weight 548.56 (observed molality, observed mol wt,
association): 0.0968, 1079, 1.97; 0.0547, 1080, 1.97; 0.0236,
1109, 2.02.
no. of rflns
measd
no. of unique
rflns (Rint
7993
2651(0.027)
3826 (0.017)
3447
5618 (0.045)
4106
)
no. of rflns with 2537
I > 4σ(I)
no. of refined
131
279
134
params
R1 (I > 2σ(I))
wR2
goodness of fit 1.097
0.019
0.045
0.021
0.050
1.07
0.033
0.077
0.991
0.0059(4)
extinction coeff 0.033(2)
none
Syn th esis of Me2In P P h 2.20 The reagents, 0.502 g (2.39
mmol) of Me2In(C5H5) and 0.423 g (2.27 mmol) of HPPh2
dissolved in ∼2 mL of C6H6, were combined in ∼20 mL of C6H6.
After ∼5 min most of the Me2In(C5H5) had dissolved but a
cloudy, colorless suspension remained. The suspension was
stirred for 4 h, and then the C6H6 was removed by vacuum
distillation. The product was isolated by extraction with 2 ×
30 mL of C5H12 through a medium-porosity frit and then
recrystallized by cooling to -30 °C to give 0.708 g (2.14 mmol,
94.3% based on HPPh2) of Me2InPPh2 as colorless crystals.
Me2InPPh2: mp 188.9-192.4 °C dec (lit. 243 °C melting,20a
140 °C began to decompose,20c 185 °C darkened slightly,20c 245
°C melting20c); 1H NMR (d6-benzene, δ) 0.19 (s, Me2InPPh2
dimer, 6.0 H), 0.30 (s, Me2InPPh2 monomer, 0.60 H), 7.39 (br,
PC6H5, 4.2 H); 31P{1H} NMR (d6-benzene, δ) -24.8 (s, mono-
mer, 5.3 P), -52.8 (s, dimer, 94.7 P). (lit.20a 1H NMR (d6-
benzene, δ) 0.182 (d of t, 18 H, InMe), 6.93-7.39 (mult, 30 H,
PC6H5); lit.20a 31P{1H} NMR (CDCl3, δ) -54.23 (s); lit.20b 1H
NMR (d6-benzene, δ) 0.17 (s, 6 H, InMe), 7.39 (m, 4 H, PC6H5),
6.95 (m, 6 H, PC6H5); lit.20b 31P{1H} NMR (d6-benzene, δ) -56.6
(s); lit.20c 1H NMR (d6-benzene, δ) 0.18, s, InMe, 6.8-7.7, m,
PC6H5); lit.20c 31P{1H} NMR (d6-benzene) -53.1 (s)).
Syn th esis of (Me3CCH2)2In P P h 2.21 A flask was charged
with 0.723 g (2.24 mmol) of (Me3CCH2)2In(C5H5) and ∼20 mL
of C6H6, whereas an addition tube contained 0.400 g (2.15
mmol) of HPPh2 and ∼2 mL of C6H6. The reagents were
combined, and ∼5 min after mixing most of the (Me3CCH2)2-
In(C5H5) had dissolved, but a cloudy colorless suspension
remained. The suspension was stirred for 4 h, and then the
volatile material was removed by vacuum distillation. The
product was isolated by extraction with 2 × 20 mL of C5H12
through a medium-porosity frit and recrystallized by cooling
to -30 °C to give 0.867 g (1.96 mmol, 91.2% based on HPPh2)
of (Me3CCH2)2InPPh2 as colorless crystals.
(m, PC6H5, 5.0 H), 7.60 (m, PC6H5, 5.2 H); 31P{1H} NMR (d6-
benzene, δ) -29.14 (s, monomer, 85.5 P), -48.64 (s, dimer, 14.5
P).
Syn th esis of Me2In NH(t-Bu ). A tube equipped with a
Teflon valve was charged with 0.579 g (2.76 mmol) of Me2In-
(C5H5), 0.200 g (2.70 mmol) of H2N(t-Bu), and ∼5 mL of
benzene and heated to 75 °C with an oil bath for 3 days. The
material volatile at room temperature was removed by vacuum
distillation. The solid remaining in the tube was sublimed at
45 °C to a coldfinger, and 0.543 g (2.50 mmol, 91.6% yield
based on H2N(t-Bu)) of Me2InNH(t-Bu) as a colorless powder
was obtained.
Me2InNH(t-Bu): mp 48-50 °C phase transition, 60.7-62.9
1
°C melting; H NMR (d6-benzene, δ) -0.11 (s, InCH3 cis, 7.6
H), -0.05 (s, InCH3 monomer, 0.9 H), 0.03 (s, InCH3 trans,
19.9 H), 0.17 (s, InCH3 cis, 7.7 H), 0.77 (s, NH, 5.7 H), 0.87 (s,
t-Bu monomer, 3.5 H), 0.96 (s, t-Bu trans, 30.4 H), 0.99 (s,
t-Bu cis, 24.4 H); 1H NMR (d8-THF, δ) -0.52 (s, InCH3
monomer, 0.88 H), -0.40 (s, In-CH3 cis, 6.8 H), -0.23 (s, In-
CH3 trans, 21.7 H), -0.05 (s, In-CH3 cis, 6.8 H), 1.09 (s, t-Bu
monomer, 4.4 H), 1.14 (s, t-Bu trans, 32.3 H), 1.15 (s, t-Bu cis,
22.1 H), 1.38 (br, N-H, 2.1 H), 1.43 (br, N-H, 3.0 H). Anal.
Calcd for C6H16InN: C, 33.21; H, 7.43; N, 6.45. Found: C,
33.27; H, 7.58; N, 6.34. Cryoscopic molecular weight, benzene
solution, formula weight 217.02 (observed molality, observed
mol wt, association): 0.0689, 456, 2.10; 0.0545, 443, 2.04;
0.0342, 415, 1.91.
Collection of X-r a y Diffr a ction Da ta a n d Str u ctu r a l
Solu tion s for Me2In (a ca c), (Me3CCH2)2In (a ca c), (Me)-
(Me3CCH2)In (a ca c) a n d [Me2In NH(t-Bu )]2: Gen er a l F ea -
tu r es. (a) A well-defined crystal of each of the acetylacetonate
derivatives were covered with Infineum V8512 oil (Infineum
USA LP, 1900 East Linden Ave., Linden, NJ 07036) and
mounted on
a Bruker SMART1000 CCD diffractometer
(Me3CCH2)2InPPh2: mp 138.3-139.1 °C phase transition,
142.7-148.9 °C dec (lit.22a mp 143.5-150 °C dec); 1H NMR (d6-
benzene, δ) 1.03 (s, (CH3)3CCH2, 3.1 H), 1.08 (s, (CH3)3CCH2,
18.0 H), 1.48 (s, Me3CCH2, 4.8 H), 7.01 (m, PC6H5, 3.2 H), 7.06
equipped with the rotating anode (Mo KR radiation, λ )
0.710 73 Å). X-ray diffraction data were collected at 90 K.
Details for these compounds are provided in Table 5. Data
collection for each compound involved 4 sets of frames (600

4000 Organometallics, Vol. 22, No. 20, 2003
Beachley et al.
Ta ble 6. Da ta for X-r a y Cr ysta llogr a p h ic Stu d ies
of [Me2In NH(t-Bu )]2
atoms were subsequently refined as idealized CH3 groups with
Uiso ) 1.5Ueq and by using the riding model with Uiso ) 1.2Ueq
of the preceding carbon atom for (Me3CCH2)2In(acac) and Me-
(Me3CCH2)In(acac). The positions of the hydrogen atom in the
case of Me2In(acac) were refined with Uiso ) 1.5Ueq for CH3
and with Uiso ) 1.2Ueq for the other hydrogen atoms. Data were
corrected for absorption by using the Bruker AXS SADABS
program that is a part of the SAINTPLUS package.27
mol formula
Mr
cryst syst
space group
a, Å
b, Å
c, Å
C12H32In2N2
434.0
monoclinic
P21/n (No. 14)
7.005(3)
12.109(4)
11.114(5)
90
94.16(3)
90
940.3(7)
1.533
R, deg
â, deg
γ, deg
V, Å3
(b) A crystal of size 0.9 × 0.3 × 0.13 mm of [Me2InNH(t-
Bu)]2 was sealed in a thin-walled glass capillary and mounted
on a Siemens R3m/V diffractometer. Unit cell parameters were
obtained from a least-squares analysis of 50 automatically
centered reflections.29 The Laue symmetry (C2h) indicated the
monoclinic system, and the systematic absences established
the space group as P21/n (No. 14). A complete sphere of data
was collected for 2θ ) 6.0-50.0°. Data were corrected for the
effects of absorption (T ) 0.3532-0.5501) and for Lp factors.
The 6624 reflections thus collected were reduced to a unique
set of 1660 independent reflections with Rint ) 1.73% for the
four equivalent forms. Details are given in Table 6. All
crystallographic calculations were carried out by use of the
SHELXPLUS (release 4.11 (VMS)) program package.30 The
analytical scattering factors for neutral atoms were corrected
for ∆f ′ and ∆f ′′ components of anomalous dispersion.31 The
structure was solved with a Patterson map and a difference
Fourier synthesis and was refined to R ) 2.27% for those 1381
reflections with Fo > 6σ(Fo) and R ) 2.83% for all 1660
independent reflections.
D
Z
calcd, g/cm3
2
µ(Mo KR), mm-1
2.402
295
T (K)
F(000)
2θ range, deg
h
k
l
432
6.0-50.0
-8 to +8
-14 to +14
-13 to +13
6624
1660 (Rint ) 1.73%)
1381 (>6σ)
σ2(F) + 0.0014F2
0.0045(4)
0.5501/0.3532
80
no. of rflns collected
no. of indep rflns
no. of rflns for refinement
weighting scheme, w-1
ø (secondary extinction)
T
max/Tmin
no. of refined params
final R indicesa (obsd data), %
R
Rw
2.27
3.57
final R indicesa (all data), %
R
2.83
Rw
4.53
goodness of fit
largest, mean ∆/σ
data to param ratio
largest diff peak, e Å-3
largest diff hole, e Å-3
0.88
Ack n ow led gm en t. Purchase of the Siemens R3m/V
diffractometer was made possible by Grant No. 89-
13733 from the Chemical Instrumentation Program of
the National Science Foundation (M.R.C.).
0.002, 0.000
17.3:1
0.91
-0.56
a
R indices are defined as follows: R (%) ) 100∑||Fo| - |Fc||/
Su p p or tin g In for m a tion Ava ila ble: Complete tables of
positional parameters, interatomic distances and angles,
anisotropic thermal parameters, and positions for hydrogen
atoms and packing diagrams for the four compounds studied
∑|Fo|; Rw (%) ) 100[∑w(|Fo| - |Fc|)2/∑w|Fo| ]1/2
.
2
frames in each set) and covered half-reciprocal space using the
ω-scan technique (0.3° frame width) with different æ angles.
Reflection intensities were integrated by using the SAINT-
PLUS program.27 The solution and refinement of the struc-
tures were performed by use of the SHELXTL program
package.28 The structures were refined by full-matrix least
squares against F2. Non-hydrogen atoms were refined in the
anisotropic approximation. The hydrogen atoms were located
from difference electron density Fourier syntheses. Hydrogen
1
(these data are also available as CIF files) and text giving H
NMR spectral data for reactions between Me2In(C5H5) and
HPPh2, Me2In(C5H5) and H2N(t-Bu), Me2InNH(t-Bu) and C5H6,
Me2In(C5H5) and H(acac), Me2In(acac) and (Me3CCH2)2In(acac)
as well as for In(acac)3 and InMe3. This material is available
free of charge via the Internet at http://pubs.acs.org.
OM0304154
(29) Churchill, M. R.; Lashewycz, R. A.; Rotella, F. J . Inorg. Chem.
1977, 16, 265.
(27) SMART and SAINTPLUS, Area Detector Control and Integra-
tion Software, version 6.0.1; Bruker Analytical X-ray Systems, Madi-
son, WI, 1999.
(28) SHELXTL, an Integration System for Solving, Refining and
Displaying Crystal Structures from Diffraction Data, version 5.10;
Bruker Analytical X-ray Systems, Madison, WI, 1997.
(30) Sheldrick, G. M. SHELXTL PLUS, release 4.11 (VMS); Siemens
Analytical Instrument Corp., Madison, WI, 1989.
(31) (a) International Tables for X-ray Crystallography; Kynoch
Press: Birmingham, England, 1974; Vol. 4, pp 99-101. (b) Ibid., pp
149-150.