Reactions of neopentylindium(III) derivatives with isopropylphosphorus compounds

Article abstract of DOI:10.1021/om0101902

A 1:1 mixture of In(CH₂CMe₃)₃ and HP(i-Pr)₂ at room temperature undergoes a very slow hydrocarbon elimination reaction to form [(Me₃CCH₂)₂InP(i-Pr)₂]₂ and neopentane. The indium phosphide [(Me₃CCH₂)₂InP(i-Pr)₂]₂ has also been prepared by reacting KIn(CH₂- CMe₃)₃H with ClP(i-Pr)₂ in pentane. When pentane solutions of these reagents were combined at -78°C and then maintained at ～20°C for 2 days, [(Me₃CCH₂)₂InP(i-Pr)₂]₂, (Me₃CCH₂)₃In·P(H)(i-Pr)₂, (Me₃CCH₂)₃In·P₂ (i-Pr)₄, (Me₃CCH₂)₃In·P (CH₂CMe₃)(i-Pr)₂, H₂, indium metal, and KCl were observed. The formation of all products is explained by a set of experimentally verified reactions. An X-ray structural study of [(Me₃CCH₂)₂InP(i-Pr)₂]₂ shows each molecule to have an unusual puckered four-membered In₂P₂ core.

Full text of DOI:10.1021/om0101902

4896
Organometallics 2001, 20, 4896-4902
Rea ction s of Neop en tylin d iu m (III) Der iva tives w ith
Isop r op ylp h osp h or u s Com p ou n d s
O. T. Beachley, J r.,* Sun-Hua L. Chao, Melvyn Rowen Churchill, and
Charles H. Lake
Department of Chemistry, University at Buffalo, The State University of New York,
Buffalo, New York 14260
Received March 9, 2001
A 1:1 mixture of In(CH2CMe3)3 and HP(i-Pr)2 at room temperature undergoes a very slow
hydrocarbon elimination reaction to form [(Me3CCH2)2InP(i-Pr)2]2 and neopentane. The
indium phosphide [(Me3CCH2)2InP(i-Pr)2]2 has also been prepared by reacting KIn(CH2-
CMe3)3H with ClP(i-Pr)2 in pentane. When pentane solutions of these reagents were combined
at -78 °C and then maintained at ∼20 °C for 2 days, [(Me3CCH2)2InP(i-Pr)2]2, (Me3CCH2)3-
In‚P(H)(i-Pr)2, (Me3CCH2)3In‚P2(i-Pr)4, (Me3CCH2)3In‚P(CH2CMe3)(i-Pr)2, H2, indium metal,
and KCl were observed. The formation of all products is explained by a set of experimentally
verified reactions. An X-ray structural study of [(Me3CCH2)2InP(i-Pr)2]2 shows each molecule
to have an unusual puckered four-membered In2P2 core.
In tr od u ction
Pr)2 system are described. The detailed chemistry was
different from the other two chlorophosphines as [(Me3-
CCH2)2InP(i-Pr)2]2, (Me3CCH2)3In‚P(H)(i-Pr)2, (Me3-
CCH2)3In‚P2(i-Pr)4, (Me3CCH2)3In‚P(CH2CMe3)(i-Pr)2,
and H2 were formed.
The simplest route to compounds of the type R2InPR′2
is the hydrocarbon elimination reaction (eq 1).1-3 As a
InR3 + HPR′2 hydrocarbon elimination8 R2LnPR′2 + RH (1)
reaction
Resu lts a n d Discu ssion
phosphine has an unpleasant odor and is typically toxic,
we have searched for a preparative route in which the
phosphine would be formed and then utilized in situ.
Thus, we investigated the reactions of KIn(CH2CMe3)3H
with a variety of chlorophosphines (eq 2). The reagent
The investigation of the chemistry of the KIn(CH2-
CMe3)3H-ClP(i-Pr)2 system was preceded by a study of
the reactions that occur between In(CH2CMe3)3 and HP-
(i-Pr)2. The initial product was the adduct (Me3CCH2)3-
1
In‚P(H)(i-Pr)2. Freezing point depression studies and H
n KIn(CH2CMe3)3H + n ClPR2 pentane8
and 31P NMR spectroscopy demonstrated that the
adduct is in equilibrium with the Lewis acid and base
(eq 3) in benzene solution. The equilibrium constant for
[(Me3CCH2)2InPR2]n + n KCl + n CMe4 (2)
ClP(t-Bu)2 produced [(Me3CCH2)2InP(t-Bu)2]2 in high
yield, and no side-reactions or -products were observed.4
However, when ClPPh2 was used, the products included
[(Me3CCH2)2InPPh2]n, (Me3CCH2)3In‚P(CH2CMe3)Ph2,
and H2.5 In the following paper the results of our
investigations of the reactions that occur in the ClP(i-
Kd
(Me3CCH2)3In‚P(H)(i-Pr)2 y\z
In(CH2CMe3)3 + HP(i-Pr)2 (3)
the dissociation of the adduct (Kd) as calculated from
the cryoscopic data had a value of (2.1 ( 0.2) × 10-3 at
∼5 °C. The 31P and 1H NMR spectroscopic data are
consistent with this equilibrium also and with the
occurrence of rapid exchange between components.
Consequently, the chemical shifts of the resonances and
the coupling constants depend on the concentrations of
the species as well as on the phosphorus-to-indium ratio.
Two resonances for the isopropyl methyl groups (P-C-
CH3) indicate that these methyl groups are not able to
rotate freely. In contrast, the methyl protons bonded to
the tertiary carbon of the tert-butyl group in the closely
related adduct (Me3CCH2)3In‚P(H)(t-Bu)2 rotate freely
at ambient temperature.4 The chemical shifts and
coupling constants for the different atoms for a pure
adduct (Me3CCH2)3In‚P(H)(i-Pr)2 were derived by ex-
trapolating the experimental data observed for various
mixtures of HP(i-Pr)2 and In(CH2CMe3)3 to a hypotheti-
(1) (a) Coates, G. E.; Graham, J . J . Chem. Soc. 1963, 233. (b)
Beachley, O. T., J r.; Coates, G. E. J . Chem. Soc. 1965, 3241. (c) Maury,
F.; Constant, G. Polyhedron 1984, 3, 581. (d) Aitchison, K. A.; Backer-
Dirks, J . D. J .; Bradley, D. C.; Faktor, M. M.; Fiegio, D. M.; Hursthouse,
M. B.; Hussain, B.; Short, R. L. J . Organomet. Chem. 1989, 366, 11.
(e) Alcock, N. W.; Degnan, I. E.; Wallbridge, M. G. H.; Powell, H. R.;
McPartlin, M.; Sheldrick, G. M. J . Organomet. Chem. 1989, 361, C3.
(f) Arif, A. M.; Benac, B. L.; Cowley, A. H.; J ones, R. A.; Kidd, K. B.;
Nunn, C. M. New J . Chem. 1988, 12, 553. (g) Dembowski, U.;
Noltemeyer, W.; Rockensu¨ss; Stuke, M.; Roesky, H. W. Chem. Ber.
1990, 123, 2335. (h) Burns, J . A.; Dillingham, J . B. H.; Gripper, K. D.;
Pennington, W. T.; Robinson, G. H.; (i) Beachley, O. T., J r.; Maloney,
J . D.; Banks, M. A. Rogers, R. D. Organometallics 1995, 14, 3448.
(2) Beachley, O. T., J r.; Kopasz, J . P.; Zhang, H.; Hunter, W. E.;
Atwood, J . L. J . Organomet. Chem. 1987, 325, 69.
(3) Banks, M. A.; Beachley, O. T., J r.; Buttrey, L. A.; Churchill, M.
R.; Fettinger, J . C. Organometallics 1991, 10, 1901.
(4) Beachley, O. T., J r.; Chao, S.-H. L.; Churchill, M. R.; Lake, C.
H. Organometallics 1993, 12, 3992.
(5) Beachley, O. T., J r.; Chao, S.-H. L. Organometallics 2000, 19,
2820.
10.1021/om0101902 CCC: $20.00 © 2001 American Chemical Society
Publication on Web 10/03/2001

Reactions of Neopentylindium(III) Derivatives
Organometallics, Vol. 20, No. 23, 2001 4897
cal ratio of HP(i-Pr)2 to In(CH2CMe3)3 of zero. The
nominal data for the “pure adduct” (Me3CCH2)3In‚P(H)-
(i-Pr)2 are 31P NMR (C6D6) δ -15.2 (d, J ) 272 Hz); 1H
NMR (C6D6) δ 0.89 (dd, PCCH3, J ) 13 Hz, 7 Hz), 0.92
(dd, PCCH3, J ) 17 Hz, 7 Hz), 1.16 (s, InCH2), 1.31 (s,
InCCCH3), 3.05 (d, In‚P(H)(i-Pr)2, J ) 272.2 Hz). The
equilibrium constant for the dissociation of the adduct
1
(eq 3) as calculated from the H and 31P NMR spectral
data in the special case when [HP(i-Pr)2] ) [In(CH2-
CMe3)3] ) 0.368 m had a value of 0.008 ( 0.007 at ∼20
°C, a number consistent with the constant from the
cryoscopic data.
The adduct (Me3CCH2)3In‚P(H)(i-Pr)2 undergoes an
elimination reaction (eq 1) to form [(Me3CCH2)2InP(i-
Pr)2]2 and neopentane. When the neat adduct was
maintained at ∼20 °C, reaction was complete in 6 days.
In contrast, a benzene solution eliminated neopentane
more slowly, as 45 days was required to convert slightly
more than half of the phosphine to the phosphide at ∼20
°C. When there was a 5-fold excess of In(CH2CMe3)3 over
the phosphine in a benzene solution, the elimination
reaction was complete in only 4 days at ∼20 °C.
Similarily, the addition of Ga(CH2CMe3)3 to a solution
that was equimolal in In(CH2CMe3)3 and HP(i-Pr)2 also
accelerated the rate of the elimination reaction, but no
[(Me3CCH2)2GaP(i-Pr)2]2 was formed. In contrast, a
5-fold excess of HP(i-Pr)2 slowed the rate of the elimina-
tion reaction, as only a trace of the indium phosphide
formed after 41 days at ∼20 °C. Analogous kinetic
observations have been made for the In(CH2CMe3)3-
HP(t-Bu)2 system.4 All of these experimental observa-
tions suggest that this elimination reaction is a reaction
of the simple four-coordinate adduct, (Me3CCH2)3In‚
P(H)R2 (eq 1). Excess phosphine might lead to the
formation of a five-coordinate adduct that does not
undergo elimination.
F igu r e 1. Labeling of atoms for the asymmetric unit and
for the core atoms, In(1a) and P(1a), of molecule 1 in
crystalline [(Me3CCH2)2InP(i-Pr)2]2. The 30% probability
envelopes are shown for the anisotropic vibration ellipsoids
of all non-hydrogen atoms. All hydrogen atoms have been
omitted for the sake of clarity. The crystallographic C2 axis
(along y, at x ) 0 and z ) 1/4) is vertical and bisects both
the In‚‚‚In(1a) and P(1)‚‚‚P(1a) vectors.
13)7 with Z ) 4. However, each molecule lies on a
crystallographic C2 axis (Wyckoff position e)7 and has
approximate C2v symmetry. The crystallographic asym-
metric unit consists of two independent half-molecules.
Molecule 1, based upon In(1), P(1), and the symmetry
related (-x, y, 1/2-z) In(1A) and P(1A), is depicted in
Figure 1. Molecule 2, based upon In(2) and P(2), has a
similar geometry. The two independent molecules are
separated by approximately one-half a unit cell along
the b-axis. Selected interatomic distances and angles
are collected in Table 1. The structure of [(Me3CCH2)2-
InP(i-Pr)2]2 is very unusual for a dimeric organoindium
phosphide, as the In2P2 cores are significantly puckered.
The fold angles about the In‚‚‚In axes are 22.7° for
molecule 1 and 21.5° for molecule 2. The fold angles
about the P‚‚‚P axes are 20.5° for molecule 1 and 19.6°
for molecule 2. The only other organoindium phosphide
with a puckered four-membered ring is [(Me3CCH2)2-
In[µ-P(SiMe3)2][µ-PH(SiMe3)]In(CH2CMe3)2.8 The fold-
ing of the ring allows the isopropyl groups to reduce the
crowding around the In2P2 four-membered ring. The
indium-phosphorus bond lengths average 2.651 Å and
are shorter by ∼0.05 Å than those observed for other
neopentylindium phosphides, i.e., 2.701 Å average for
[(Me3CCH2)2InP(t-Bu)2]2,4 2.632 Å average for [(Me3-
CCH2)2InPEt2]2,1i 2.637 Å average for [(Me3CCH2)2InP-
(H)(C6H11)2]3,1i and 2.699 Å for [(Me3CCH2)2InPPh2]3.3
Two neopentyl groups are associated with each in-
dium atom with indium-carbon distances averaging
2.220 Å. Inter-ligand angles around indium atoms are
C(10)-In(1)-C(15) ) 133.4(4)° and C(30)-In(2)-C(35)
) 136.1(6)°. These angles are much larger than those
The new compound [(Me3CCH2)2InP(i-Pr)2]2 exists as
dimers in benzene solution at all concentrations studied
according to the cryoscopic molecular weight and the
NMR spectral data. A single line at -1.9 ppm was
observed in the 31P NMR spectrum. The 1H NMR
spectrum was also appropriate for a dimer. The reso-
nance for the P-C-CH3 protons was an apparent
quartet due to an overlapping doublet of doublets of
doublets. This pattern indicates that these methyl
protons are coupled to the CH proton of the isopropyl
group, the attached phosphorus atom, and the second
phosphorus atom of the In2P2 ring. Similar coupling has
1
been noted for the H NMR spectra of [(Me3CCH2)2InP-
(t-Bu)2]2 and [Me2InP(i-Pr)2]2.6 The resonance for the
4
P-CH protons was a broad, relatively weak mutiplet
due to an overlapping septet of triplets. The presence
of only one set of resonances for each type of isopropyl
and neopentyl protons suggests that the organic sub-
stituents are magnetically equivalent. Thus, the In2P2
core might be planar in benzene solution. Alternatively,
if the ring is puckered, as identified in the X-ray
structural study of a crystal, the ring would have to
undergo either a rapid inversion or a rapid dissociation,
rotation, and re-formation.
4
within [(Me3CCH2)2InP(t-Bu)2]2 (112.7(2)-117.7(2)°).
The increase in the angles between similar substituents
might be related to the decrease in the size of the ring
(i.e., shorter In-P distances). The C-In-C planes are
The compound [(Me3CCH2)2InP(i-Pr)2]2 crystallizes in
the centrosymmetric monoclinic space group P2/n (No.
(7) International Tables for X-ray Crystallography; Kynoch Press:
Birmingham, England, 1965; Vol. 1, p 97.
(6) Cowley, A. H.; J ones, R. A.; Mardones, M. A.; Nunn, C. M.
Organometallics 1991, 10, 1635.
(8) Wells, R. L.; McPhail, A. T.; Self, M. F. Organometallics 1993,
12, 3363.

4898 Organometallics, Vol. 20, No. 23, 2001
Beachley et al.
Ta ble 1. Selected In ter a tom ic Dista n ces (Å) a n d
An gles (d eg) for [(Me3CCH2)2In P (i-P r )2]2
angle P(1)-In(1)-C(10) ) 117.3(2)° is closer to an
equatorial arrangement (120°), whereas P(1)-In(1)-
C(15) ) 102.9(2)° is closer to an axial arrangement (90°).
The same is observed for In(1)-P(1)-C(23) ) 115.8(3)°
and In(1)-P(1)-C(20) ) 108.4(3)° in molecule 1 and for
the analogous angles in molecule 2.
(A) Indium-Phosphorus Distances
In(1)-P(1)
In(1)-P(1A)
2.638(2)
2.664(2)
In(2)-P(2)
2.663(2)
2.631(3)
In(2)-P(2A)
(B) Indium-Carbon Distances
In(1)-C(10)
In(1)-C(15)
2.201(9)
2.248(9)
In(2)-C(30)
In(2)-C(35)
2.206(9)
2.222(20)
When KIn(CH2CMe3)3H and ClP(i-Pr)2 were allowed
to react in pentane, the major products were [(Me3-
CCH2)2InP(i-Pr)2]2, CMe4, and KCl. Even though the
overall reaction appears straightforward, the detailed
process is actually very complicated. The complete list
of conclusively identified indium-phosphorus products
include [(Me3CCH2)2InP(i-Pr)2]2, (Me3CCH2)3In‚P(H)(i-
Pr)2, (Me3CCH2)3In‚P2(i-Pr)4, and (Me3CCH2)3In‚P(CH2-
CMe3)(i-Pr)2 (and/or (Me3CCH2)P(i-Pr)2). Hydrogen gas
and indium metal were also observed. These products
were observed after KIn(CH2CMe3)3H and ClP(i-Pr)2
were mixed as pentane solutions at -78 °C and the
resulting mixture was stirred at ∼20 °C for 2 days. All
compounds were identified by comparing the resonances
in the 1H and 31P NMR spectra of the crude product with
the spectra for authentic, fully characterized samples
of the pure compounds. It should be noted that the
composition of this product mixture changed over time
at ∼20 °C. The first species to disappear was (Me3-
CCH2)3In‚P(H)(i-Pr)2, and it formed [(Me3CCH2)2InP(i-
Pr)2]2. The second species to undergo further reaction
was (Me3CCH2)3In‚P2(i-Pr)4. It was converted into [(Me3-
CCH2)2InP(i-Pr)2]2 and (Me3CCH2)P(i-Pr)2.
(C) Phosphorus-Carbon Distances
P(1)-C(20)
P(1)-C(23)
1.865(9)
1.853(9)
P(2)-C(40)
P(2)-C(43)
1.864(13)
1.846(10)
(D) Angles around Indium Atoms
P(1)-In(1)-P(1A)
P(1)-In(1)-C(10)
P(1)-In(1)-C(15)
83.6(1) P(2)-In(2)-P(2A)
117.3(2) P(2)-In(2)-C(30)
102.9(2) P(2)-In(2)-C(35)
83.3(1)
99.7(3)
104.7(5)
C(10)-In(1)-P(1A) 108.0(2) C(30)-In(2)-P(2A) 100.9(3)
C(15)-In(1)-P(1A)
C(10)-In(1)-C(15) 133.4(4) C(30)-In(2)-C(35) 136.1(6)
98.6(3) C(35)-In(2)-P(2A) 117.6(6)
(E) Angles around Phosphorus Atoms
In(1)-P(1)-In(1A)
In(1)-P(1)-C(20)
In(1)-P(1)-C(23)
94.6(1) In(2)-P(2)-In(2A)
108.4(3) In(2)-P(2)-C(40)
115.8(3) In(2)-P(2)-C(43)
94.7(1)
120.3(4)
110.1(3)
C(20)-P(1)-In(1A) 112.3(3) C(40)-P(2)-In(2A) 114.6(5)
C(23)-P(1)-In(1A) 118.5(3) C(43)-P(2)-In(2A) 108.8(3)
C(20)-P(1)-C(23)
106.7(4) C(40)-P(2)-C(43)
107.6(6)
(F) Selected Angles around Carbon Atoms
In(1)-C(10)-C(11) 123.8(6) In(2)-C(30)-C(31) 122.9(6)
In(1)-C(15)-C(16) 122.6(7) In(2)-C(35)-C(36) 129.2(17)
P(1)-C(20)-C(21)
P(1)-C(20)-C(22)
P(1)-C(23)-C(24)
P(1)-C(23)-C(25)
113.0(7) P(2)-C(40)-C(41)
115.1(7) P(2)-C(40)-C(42)
114.5(7) P(2)-C(43)-C(44)
110.0(6) P(2)-C(43)-C(45)
120.0(11)
111.1(11)
114.2(7)
116.4(6)
The new and unexpected compound (Me3CCH2)3In‚
P2(i-Pr)4 was isolated as low-melting, thermally un-
stable, long needlelike crystals that grew across the
flask as it sat at ∼20 °C, a very unusual observation.
NMR spectra and a preliminary X-ray structural study9
confirmed the compound as a diphosphine adduct. The
two phosphorus atoms in (Me3CCH2)3In‚P2(i-Pr)4 are
magnetically equivalent at ambient temperature, as
only one line in the 31P NMR spectrum is observed.
However, two resonances in the 1H NMR spectrum were
observed for the isopropyl methyl groups, but there was
only one rersonance for the PCH proton. Thus, the
splitting pattern for the PCCH3 protons was apparent
triplets that overlapped and for P-CH an apparent
septet of triplets. Similar couplings were observed for
the carbon atoms of the methyl groups for the isopropyl
substituents on the phosphorus atoms as doublets of
doublets overlapped to appear as triplets. The hetero-
nuclear correlation spectrum between the 13C and 1H
NMR spectra confirmed that the methyl groups of the
isopropyl ligands were different. Resonances for two
nonequivalent methyl carbon atoms but only one CH
carbon atom were observed. One possible process that
would exchange phosphorus atoms but would preserve
the relative positions of the atoms of the isopropyl
groups might involve a type of “rocking motion” during
which the bond between indium and one of the phos-
phorus atoms is broken and then the bond to the other
phosphorus atom is formed before the diphosphine can
dissociate from the indium.
Ta ble 2. Da ta for X-r a y Cr ysta llogr a p h ic Stu d ies
of [(Me3CCH2)2In P (i-P r )2]2
molec. formula
Mr
C32H72In2P2
748.5
cryst syst
space group
a, Å
b, Å
c, Å
monoclinic
P2/n (No. 13)
10.969(2)
18.581(2)
20.814(3)
104.920(10)
4099.2(11)
1.213
â, deg
V, Å3
D
calcd, g/cm3
Z
4
µ(Mo Ka), mm-1
1.201
298
T (K)
scan mode
2θ range, deg
h
2θ-θ
5.0-45.0
-11 to 0
0 to 20
k
l
-21 to +22
no. of reflns collected
no. of unique reflns
no. of reflns used for refinement
abs corr
5927
5392 (Rint ) 0.97%)
5392 (F > 0.3σ(F))
semiempirical
0.6364/0.7685
307
R ) 8.18%
Rw ) 7.30%
0.69
T
min/Tmax
no. of refined params
final R indices (all data)a
largest difference peak, e Å-3
largest difference hole, e Å-3
-0.57
a
R indices are defined as follows: R(%) ) 100∑||Fo| - |Fc||/∑|Fo|;
Rw(%) ) 100[∑w(|Fo| - |Fc|)2/∑w|Fo| ]1/2
.
2
almost perpendicular to the P-In-P planes with angles
of 87.7° and 89.8° and are more regular than those in
[(Me3CCH2)2InP(t-Bu)2]2 (83.9° and 97.8°).4
Equations 4 through 11 explain the formation of all
intermediates, the conversion of these species to isolable
(9) Two attempts were made to carry out a full X-ray diffraction
study on this compound. Each time the diffraction data were very poor
and the crystal appeared to decompose in the X-ray beam. The data
were sufficient to provide a “proof of structure” in the space group P31.
The neopentyl and isopropyl substituents are ar-
ranged in alternating pseudoaxial and pseudoequatorial
positions around the four-membered ring. The bond

Reactions of Neopentylindium(III) Derivatives
Organometallics, Vol. 20, No. 23, 2001 4899
products and the dependence of the products on the
reaction conditions in the KIn(CH2CMe3)3H-ClP(i-Pr)2
system.
Sch em e of Rea ction s for th e KIn (CH2CMe3)3H-
ClP (i-P r )2 System
CCH2)2InP(i-Pr)2]2 and (Me3CCH2)P(i-Pr)2 (eq 8); 28
days were necessary to give a yield of 60-70% at room
temperature. When no solvent was present, In(CH2-
CMe3)3 and P2(i-Pr)4 formed crystals of (Me3CCH2)3In‚
P2(i-Pr)4. If any In(CH2CMe3)3 and ClP(i-Pr)2 remained,
they reacted to form more tertiary phosphine (Me3-
CCH2)P(i-Pr)2 and In(CH2CMe3)2Cl (eq 9). This reaction
was complete in 1 day at ∼20 °C. The product In(CH2-
CMe3)2Cl is very important to the overall process
because it is a necessary reactant for the formation of
H2. The chloride In(CH2CMe3)2Cl reacted with KIn(CH2-
CMe3)3H to form In(CH2CMe3)2H, In(CH2CMe3)3, and
KCl (eq 10).10 The indium hydride In(CH2CMe3)2H was
unstable and rapidly decomposed10,11 to H2, indium
metal, and In(CH2CMe3)3 (eq 11). Thus, the source of
hydrogen gas and indium metal in the isopropyl phos-
phine system is the decomposition of In(CH2CMe3)2H.
To ensure that hydrogen gas was not a product of a
reaction between KIn(CH2CMe3)3H with HP(i-Pr)2 as in
the phenylphosphine system,5 the reagents were com-
bined as a benzene solution. No H2 was formed in 14
days at room temperature. Hydrogen gas was also not
observed when KIn(CH2CMe3)3H and HP(t-Bu)2 were
combined.4
2 [KIn(CH2CMe3)3H + ClP(i-Pr)2 f
In(CH2CMe3)3 + P(H)(i-Pr)2 + KCl] (4)
2 [In(CH2CMe3)3 + HP(i-Pr)2 h
(Me2CCH2)3In‚P(H)(i-Pr)2 (5)
2 [(Me3CCH2)3In‚P(H)(i-Pr)2 f
1/2 [(Me3CH2)2InP(i-Pr)2]2 + CMe4 (6)
(1-x) [1/2 [(Me3CCH2)2InP(i-Pr)2]2 +
ClP(i-Pr)2 ∼20 min8 P2(i-Pr)4 + In(CH2CMe3)2Cl] (7)
(1-x)[In(CH2CMe3)3 + P2(i-Pr)4 >30 days8
1/2 [(Me3CCH2)2InP(i-Pr)2]2 + (Me3CCH2)P(i-Pr)2]
(8)
x [In(CH2CMe3)3 + ClP(i-Pr)2 1 day8
Exp er im en ta l Section
In(CH2CMe3)2Cl + (Me3CCH2)P(i-Pr)2] (9)
All compounds described in this investigation were exceed-
ingly sensitive to oxygen and moisture and were manipulated
1 [KIn(CH2CMe3)3H + In(CH2CMe3)2Cl f
KCl + In(CH2CMe3)3 + In(CH2CMe3)2H] (10)
either under
a purified argon atmosphere in a Vacuum
Atmospheres drybox or by using standard vacuum line tech-
niques. All solvents were dried by conventional procedures.
The starting compounds In(CH2CMe3)3,12 KIn(CH2CMe3)3H,10
and Ga(CH2CMe3)313 were prepared by literature methods. The
reagent KH was obtained from Aldrich Chemical Co. and was
washed with pentane to remove oil prior to use. The chloro-
phosphine ClP(i-Pr)2 was purchased from Aldrich Chemical
Co. and was purified by vacuum distillation at ambient
temperature. The secondary phosphine HP(i-Pr)2 was prepared
from ClP(i-Pr)2 and LiAlH4. The characterization data agreed
with the literature.14 Elemental analyses were performed by
E&R Microanalytical Laboratory, Parsippany, NJ . Melting
points were determined with a Mel-Temp by using flame-
sealed capillaries filled with argon and are uncorrected.
Infrared spectra of samples as Nujol mulls or neat liquids
between CsI plates were recorded by using a Perkin-Elmer
683 spectrometer. 1H NMR spectra were recorded at 400 MHz
by means of a Varian VXR-400 S spectrometer or at 300 MHz
with a Varian Gemini-300 spectrometer. 13C NMR spectra
were recorded at 125.7 MHz) spectra with a Varian VXR-500
spectrometer. Phosphorus NMR spectra were recorded with a
Varian VXR-400 spectrometer operating at 161.9 MHz. All
chemical shifts are reported in δ (ppm) units. Proton chemical
shifts are referenced to SiMe4 at δ 0.00 ppm and either C6D5H
at δ 7.15 or the residual proton in the other deuterated
solvents, as appropriate. Abbreviations for thre appearance
of resonances include dd (doublet of doublets), dt (doublet of
triplets), hd (heptet of doublets), and ht (heptet of triplets).
Carbon-13 chemical shifts are referenced to SiMe4 at δ 0.00
ppm and to C6D6 at δ 128.39 ppm. The 31P NMR spectra are
1 [In(CH2CMe3)2H f
1/2 H2 + 1/3 In0 + 2/3 In(CH2CMe3)3 (11)
Over a ll Rea ction a s Su m of Above Step s
3 KIn(CH2CMe3)3H + 3 ClP(i-Pr)2 f
[(Me3CH2)2InP(i-Pr)2]2 + (Me3CCH2)P(i-Pr)2] +
2/3 In(CH2CMe3)3 + 2 CMe4 + 1/3 In0 +
1/2 H2 + 3 KCl (12)
Independent synthetic experiments, NMR spectral stud-
ies, and experimental observations identified and con-
firmed all compounds in this sequence. When solutions
of KIn(CH2CMe3)3H and ClP(i-Pr)2 were mixed, a color-
less precipitate of KCl was formed. The other products,
In(CH2CMe3)3 and HP(i-Pr)2 (eq 4), underwent an
elimination reaction (eq 6) to produce [(Me3CCH2)2InP-
(i-Pr)2]2 and CMe4. The products P2(i-Pr)4, (Me3CCH2)P-
(i-Pr)2, H2, and indium metal were observed only when
the initial reagents were mixed at -78 °C. Cooling
decreased the solubility of KIn(CH2Me3)3H and reduced
the rate of the initial reaction so that less KIn(CH2-
CMe3)3H reacted with ClP(i-Pr)2. Thus, some ClP(i-Pr)2
was available to react with [(Me3CCH2)2InP(i-Pr)2]2 and/
or with In(CH2CMe3)3 in later steps of the sequence.
When ClP(i-Pr)2 reacted with [(Me3CCH2)2InP(i-Pr)2]2,
the products were P2(i-Pr)4 and In(CH2CMe3)2Cl (eq 7).
This reaction was one of the fastest reactions in the
sequence, as it was complete in less than 20 min at room
temperature according to NMR spectroscopy. However,
P2(i-Pr)4 was not always an isolable product. It reacted
slowly in solution with In(CH2CMe3)3 to form [(Me3-
(10) Beachley, O. T., J r.; Chao, S.-H. L.; Churchill, M. R.; See, R. F.
Organometallics 1992, 11, 1486.
(11) Downs, A. J .; Pulham, C. R. Chem Soc. Rev. 1994, 175.
(12) Beachley, O. T., J r.; Spiegel, E. F.; Kopasz, J . P.; Rogers, R. D.
Organometallics 1989, 8, 1915.
(13) Beachley, O. T., J r.; Pazik, J . C. Organometallics 1988, 7, 1516.
(14) (a) Issleib, K.; Krech, F. J . Organomet. Chem. 1968, 13, 283.
(b) Kostyanovsky, R. G.; Plekhanov, V. G.; Elnatanov, Y. I.; Zagur-
skaya, L. M.; Voznesensky, V. N. Org. Mass Spectrom. 1972, 6, 1199.

4900 Organometallics, Vol. 20, No. 23, 2001
Beachley et al.
reported relative to 85% H3PO4 in D2O solution at 0.00 ppm
via an external standard. Negative chemical shifts are as-
signed to resonances upfield from the reference. All samples
for NMR spectra were contained in flame-sealed NMR tubes.
Complete NMR spectral data including data at intermediate
times for the various studies are available in the Supporting
Information. Freezing points of benzene solutions for calculat-
ing molecular weights and equilibrium constants for dissocia-
tion of adducts were observed by using an instrument similar
to that described by Shriver and Drezdzon.15
Syn th esis of [(Me3CCH2)2In P (i-P r )2]2 fr om In (CH2CMe3)3
a n d HP (i-P r )2. The reagents, HP(i-Pr)2 (0.403 g, 3.41 mmol)
and In(CH2CMe3)3 (1.121 g, 3.42 mmol), as pentane solutions
were combined at -78 °C, and the resulting solution was
allowed to stir at ambient temperature for 18 h. Then the
pentane was removed by vacuum distillation while holding the
solution at approximately -20 °C. The remaining colorless
liquid slowly converted at room temperature to a very volatile
liquid and a colorless solid. After 6 days the very volatile liquid
was removed by vacuum distillation and identified as CMe4,
whereas the remaining solid was [(Me3CCH2)2InP(i-Pr)2]2 (1.20
g, 3.21 mmol, 94.1% yield based on HP(i-Pr)2). The indium
phosphide may be sublimed under vacuum at 60-65 °C. X-ray
quality crystals of [(Me3CCH2)2InP(i-Pr)2]2 were grown by
recrystallization from a very small amount of pentane at -30
°C.
Solu tion by F r eezin g P oin t Dep r ession Mea su r em en ts.
Solutions of In(CH2CMe3)3, excess HP(i-Pr)2, and benzene were
prepared and then diluted with additional benzene. The
freezing point of each solution was measured three times. The
presence of excess phosphine in these solutions prevented the
formation of [(Me3CCH2)InP(i-Pr)2]2 and the elimination of
neopentane during the cryoscopic study. Thus, the observed
molalitiy of a solution indicated the total of the concentrations
of (Me3CCH2)3In‚P(H)(i-Pr)2, In(CH2CMe3)3, and HP(i-Pr)2. (a)
Reagents: In(CH2CMe3)3 (0.0601 g, 0.183 mmol), HP(i-Pr)2
(0.0452 g, 0.383 mmol), and benzene (4.7376 g); dilution with
additional benzene (1.6060 and 3.3300 g). The following results
for each of the three solutions include the calcd molality of
HP(i-Pr)2 prior to reaction with In(CH2CMe3)3, obsd molality
of solution, calcd dissociation constant of adduct (Kd): 0.0808,
0.0825, 2.1 × 10-3; 0.0603, 0.0620, 2.1 × 10-3; 0.0395, 0.0410,
1.9 × 10-3. (b) Reagents: In(CH2CMe3)3 (0.0365 g, 0.111
mmol), HP(i-Pr)2 (0.0272 g, 0.230 mmol), and benzene (4.6500
g); dilution with additional benzene (1.3970 g). The following
results for each of the solutions include the calcd molality of
HP(i-Pr)2 prior to reaction with In(CH2CMe3)3, obsd molality
of solution, calcd dissociation constant of adduct (Kd): 0.0413,
0.0419, 2.1 × 10-3; 0.0318, 0.0324, 2.3 × 10-3. The average
dissociation constant for the adduct (Me3CCH2)3In‚P(H)(i-Pr)2
calculated by using all data is (2.1 ( 0.2) × 10-3
.
Rea ction of KIn (CH2CMe3)3H w ith ClP (i-P r )2 a t -78
°C. The reagents, ClP(i-Pr)2 (0.906 g, 5.94 mmol) dissolved in
10 mL of pentane and KIn(CH2CMe3)3H (2.19 g, 5.95 mmol)
dissolved in 20 mL of pentane, were cooled to -78 °C and
combined. The resulting mixture was allowed to slowly warm
to room temperature and was stirred for 2 days. The noncon-
densable gas (H2) that formed during the reaction was
measured by using a Toepler pump/gas buret assembly, while
the pentane solution was maintained at -196 °C (1.06 mmol
H2, 35.5% yield based on KIn(CH2CMe3)3H). The pentane-
soluble products were separated from the precipitate by
extraction (8 times) through a medium-porosity frit to room
temperature. The solvent was removed by vacuum distillation
at 0 °C. The pentane-soluble crude products were identified
as [(Me3CCH2)2InP(i-Pr)2]2, (Me3CCH2)3In‚P(H)(i-Pr)2, and (Me3-
CCH2)3In‚P2(i-Pr)4 with a small amount of (Me3CCH2)P(i-Pr)2
after comparison of the 1H and/or 31P NMR spectrum of the
product with the spectra for authentic samples. As the flask
sat at room temperature in the drybox, long-needle crystals
slowly formed. These crystals were mechanically separated
and identified as (Me3CCH2)3In‚P2(i-Pr)4 (0.563 g, 1.00 mmol,
33.7% yield based on ClP(i-Pr)2) after comparison of their 1H
and 31P NMR spectra and melting point with those for an
authentic sample that had been the subject of an X-ray
structural study.
[(Me3CCH2)2In P (i-P r )2]2. Mp: 126.9-127.9 °C. 31P{1H}
NMR (C6D6): δ -1.9 (s). 31P NMR (C6D6): δ -1.9 (s). 1H NMR
(C6D6): δ 1.25 (dt, [(CHMe2)2]2, J ) 7 Hz, 7 Hz, 12 H), 1.29 (s,
[(Me3CCH2)2InP, 18 H), 1.35 (s, [(Me3CCH2)2InP, 4 H), 2.44
(ht, PCH, J ) 7 Hz, 2 H) (see Results and Discussion for
description of spectrum). Anal. Calcd for C16H36InP: C, 51.35;
H, 9.70. Found: C, 51.27; H, 9.12. Cryoscopic molecular weight,
benzene solution, fw 374 (molality, obsd mol wt, assoc): 0.0477,
771.5, 2.06; 0.0349, 790.9, 2.11; 0.0231, 790.7, 2.11.
Rea ction of HP (i-P r )2 w ith 1 Equ iv of In (CH2CMe3)3
a s F ollow ed by NMR Sp ectr oscop y. A benzene-d6 solution
of HP(i-Pr)2 (0.0943 g, 0.798 mmol, 0.368 m) was combined
with a benzene-d6 solution of In(CH2CMe3)3 (0.262 g, 0.798
mmol, 0.368 m) in a glovebox. After a portion of the solution
had been added to an NMR tube, the tube was flame-sealed.
The progress of the reaction was monitored by NMR spectros-
copy. The intensities of the phosphorus signals suggested that
slightly more than half of the phosphine had been converted
to the phosphide after 45 days. Experimental data are avail-
able with the Supporting Information.
Rea ction of HP (i-P r )2 w ith 5 Equ iv of In (CH2CMe3)3
a s F ollow ed by NMR Sp ectr oscop y. A benzene-d6 solution
of HP(i-Pr)2 (0.0154 g, 0.130 mmol, 0.140 m) was combined
with a benzene-d6 solution of In(CH2CMe3)3 (0.2141 g, 0.6523
mmol, 0.701 m) as described in the previous experiment, and
the progress of the reaction was monitored by NMR spectros-
copy. The initial spectrum observed within 30 min of warming
the sample to room temperature demonstrated that CMe4 had
been formed. The elimination reaction was complete within 4
days. Complete experimental data are available with the
Supporting Information.
Rea ction of In (CH2CMe3)3 w ith 5 Equ iv of HP (i-P r )2
a s F ollow ed by NMR Sp ectr oscop y. A benzene-d6 solution
of HP(i-Pr)2 (0.0724 g, 0.613 mmol, 0.691 m) was combined
with a benzene-d6 solution of In(CH2CMe3)3 (0.0402 g, 0.123
mmol, 0.138 m) as described in the previous experiment. The
progress of the reaction was monitored by NMR spectroscopy,
but very little reaction had occurred after 41 days from mixing
the reagents. Complete experimental data are available with
the Supporting Information.
Cr u d e P r od u ct Mixtu r e. 31P{1H} NMR (C6D6): δ -1.9 (s,
[(Me3CCH2)2In‚P(i-Pr)2]2), -9.1 (s, (Me3CCH2)3In‚P2(i-Pr)4),
-15.2 (s, (Me3CCH2)3In‚P(H)(i-Pr)2). 31P NMR (C6D6): δ, -1.9
(m, [(Me3CCH2)2InP(i-Pr)2]2), -9.1 (m, (Me3CCH2)3In‚P2(i-Pr)4),
-15.2 (d, (Me3CCH2)3In‚P(H)(i-Pr)2, trace). 1H NMR (C6D6): δ
0.91 (s, (Me3CCH2)P(i-Pr)2), 1.07 (s, In(CH2CMe3)3), 1.13 (dd,
(Me3CCH2)3In‚P2(CHMe2)4, 14 Hz, 7 Hz), 1.13 (s, InCH2CMe3),
1.25 (q, [(Me3CCH2)2InP(CHMe2)2]2, 7 Hz), 1.28 (s, [(Me3CCH2)2-
InP(i-Pr)2]2), 1.34 (br, [(Me3CCH2)2InP(i-Pr)2]2), 2.04 (st, (Me3-
CCH2)3In‚P2(CHMe2)4), 2.43 (st, [(Me3CCH2)2InP(CHMe2)2]2).
Lon g-Needle Cr ystals: (Me3CCH2)3In ‚P 2(i-P r )4. Mp: 30-
33 °C. 31P{1H} NMR (C6D6): δ -1.9 (br, trace, [(Me3CCH2)2-
InP(i-Pr)2]2), -6.64 (br, trace, (Me3CCH2)P(i-Pr)2), -9.40 (s,
(Me3CCH2)3In‚P2(i-Pr)4). 31P NMR (C6D6): δ -9.5 (m, (Me3-
1
CCH2)3In‚P2(i-Pr)4). H NMR (C6D6): δ 1.07 (br, InCH2), 1.13
(td, J ) 7 Hz, J ) 7 Hz, PCHMe2), 1.13 (s, InCH2CMe3), 1.14
(td, J ) 7 Hz, J ) 5 Hz, PCHMe2), 1.29 (s, [(Me3CCH2)2InP-
(i-Pr)2]2), 2.03 (st, J ) 7 Hz, PCHMe2) (see Results and
Discussion for description of spectrum). 13C{1H} NMR (C6D6):
δ 21.1 (t, PCHMe2, J ) 10 Hz), 21.1 (t, PCHMe2, J ) 6 Hz),
21.8 (t, PCHMe2, J ) 9 Hz), 33.0 (s, InCH2CMe3), 34.7 (s,
Deter m in a tion of th e Equ ilibr iu m Con sta n t for th e
Dissocia tion of (Me3CCH2)3In ‚P (H)(i-P r )2 in Ben zen e
(15) Shriver, D. F.; Drezdzon, M. A. The Manipulation of Air-
Sensitive Compounds; Wiley: New York, 1986; p 38.

Reactions of Neopentylindium(III) Derivatives
Organometallics, Vol. 20, No. 23, 2001 4901
InCH2CMe3), 45.1 (s, InCH2CMe3). 13C NMR (C6D6): δ 21.1
(qm, PCHMe2, J ) 126 Hz), 21.1 (dm, PCHMe2, J ) 126 Hz),
21.8 (qm, PCHMe2, J ) 126 Hz), 32.6 (m, InCH2CMe3), 34.8
(qm, InCH2CMe3, J ) 124 Hz), 45.4 (tm, InCH2CMe3, J ) 126
Hz). Assignments were verified by HETCOR spectroscopy.
P r ep a r a tion of P 2(i-P r )4. A solution of ClP(i-Pr)2 (1.32 g,
8.67 mmol) in 5 mL of toluene was added to an excess of
sodium sand (0.241 g, 10.5 mmol) dispersed in 15 mL of
toluene. The reaction mixture was refluxed and stirred for 1
day, and a dark blue solution formed. The solvent was removed
by vacuum distillation at ambient temperature. The remaining
viscous liquid was purified by dynamic vacuum distillation and
identified as P2(i-Pr)4 (0.8438 g, 3.60 mmol, 83.0% yield based
on ClP(i-Pr)2).
(CHMe2)2, J ) 11 Hz), 19.8 (d, (Me3CCH2)P(CHMe2)2, J ) 16
Hz), 23.6 (d, (Me3CCH2)P(CHMe2)2, J ) 14 Hz), 30.8 (d, (Me3-
CCH2)P(CHMe2)2, J ) 9 Hz), 36.4 (d, (Me3CCH2)P(CHMe2)2,
J ) 23 Hz).
Rea ction betw een In (CH2CMe3)3 a n d ClP (i-P r )2 a s
F ollow ed by NMR Sp ectr oscop y. A C6D6 solution of ClP-
(i-Pr)2 (0.0554 g, 0.363 mmol) was added to a C6D6 solution of
In(CH2CMe3)3 (0.120 g, 0.365 mmol) and transferred to an
NMR tube. The total amount of C6D6 was 0.770 g. After the
tube was evacuated and degassed at -196 °C on a vacuum
line, the tube was flame-sealed. NMR spectra were recorded.
The formation of (Me3CCH2)P(i-Pr)2 and In(CH2CMe3)2Cl10 was
complete after 1 day. Complete NMR spectral data are
available with the Supporting Information.
P 2(i-P r )4. 31P{1H} NMR (C6D6): δ -10.3 (s, P2(i-Pr)4) (lit.
-11.58,16 -12.517). 31P NMR (C6D6): δ -10.4 (m, P2(i-Pr)4). 1H
NMR (C6D6): δ 1.14 (dt, PCHMe2, J ) 7 Hz, 7 Hz, 3 H), 1.15
(dt, PCHMe2, J ) 7 Hz, 7 Hz, 3 H), 2.01 (st, PCHMe2, J ) 7
Hz, 4 Hz, 1 H) (lit. 1.03, 1.98;16 1.4-2.217).
Rea ction of In (CH2CMe3)3 a n d P 2(i-P r )4. A reaction tube
charged with P2(i-Pr)4 (0.331 g, 1.41 mmol) was connected to
a flask that contained In(CH2CMe3)3 (0.464 g, 1.41 mmol) in
a glovebox. The mixture was allowed to stand under vacuum
for 12 days. A small amount of pentane (10 mL) was then
added to the mixture, and the resulting solution was stirred
for 18 h. The pentane was subsequently removed by vacuum
distillation at a temperature less than -30 °C. A few long-
needle crystals, presumably (Me3CCH2)3In‚P2(i-Pr)4, appeared
1 day after the removal of pentane. The benzene-soluble
products were identified by their 31P{1H}, 31P, and 1H NMR
spectra as (Me3CCH2)3In‚P2(i-Pr)4 (43% calcd from integration
of 1H NMR spectrum), [(Me3CCH2)2InP(i-Pr)2]2 (29%), and
(Me3CCH2)P(i-Pr)2 (29%).
P r ep a r a tion of (Me3CCH2)P (i-P r )2. A solution of ClP(i-
Pr)2 (2.51 g, 16.5 mmol) in 5 mL of methylcyclohexane was
added slowly to a solution of Li(CH2CMe3) (1.93 g, 24.8 mmol)
in 30 mL of methylcyclohexane that had been cooled under
vacuum to -40 to -50 °C with a dry ice/2-propanol bath. The
resulting mixture was heated with a 70-75 °C oil bath for 1
day. After the soluble product was separated from the LiCl
by extraction through a medium-porosity frit, the methylcy-
clohexane was removed by vacuum distillation at low temper-
ature (<-30 °C) to leave a viscous yellow liquid. This crude
product was purified by vacuum distillation at ambient tem-
perature into a tube cooled to -196 °C. The pure product (Me3-
CCH2)P(i-Pr)2 (1.94 g, 10.3 mmol, 62.7% yield based on ClP(i-
Pr)2) was isolated as a colorless liquid.
P r od u cts. 31P{1H} NMR (C6D6): δ -1.9 (s, [(Me3CCH2)2-
InP(i-Pr)2]2), -5.2 (s, (Me3CCH2)P(i-Pr)2), -10.3 (s, (Me3CCH2)3-
In‚P2(i-Pr)4). 31P NMR (C6D6): δ -1.8 (m, [(Me3CCH2)2InP(i-
1
Pr)2]2), -10.3 (m, (Me3CCH2)3In‚P2(i-Pr)4). H NMR (C6D6): δ
0.90 (br, ∼1 H), 0.97 (dd, J ) 11 Hz, 7 Hz, (Me3CCH2)P-
(CHMe2)2, 4 H), 1.01 (dd, J ) 13 Hz, 7 Hz, (Me3CCH2)P-
(CHMe2)2, 4 H), 1.03 (s, (Me3CCH2)P(CHMe2)2, ∼3 H), 1.07 (s,
In(CH2CMe3)3, 6 H), 1.13 (dt, J ) 7 Hz, 7 Hz, (Me3CCH2)3In‚
P2(CHMe2)4, 12 H), 1.14 (dt, J ) 7 Hz, 7 Hz, (Me3CCH2)3In‚
P2(CHMe2)4, 12 H), 1.14 (s, In(CH2CMe3)3, 27 H), 1.25 (q, J )
7 Hz, [(Me3CCH2)2InP(CHMe2)2]2, 18 H), 1.29 (s, [(Me3CCH2)2-
InP(i-Pr)2]2, 23 H), 1.36 (br, [(Me3CCH2)2InP(i-Pr)2]2), 2.02 (ht,
J ) 7 Hz, 4 Hz, (Me3CCH2)3In‚P2(CHMe2)4, ∼3 H), 2.44 (ht, J
) 7 Hz, 2 Hz, [(Me3CCH2)2InP(CHMe2)2]2, 2 H).
(Me3CCH2)P (i-P r )2. 31P{1H} NMR (C6D6): δ -5.0 (s, (Me3-
CCH2)P(i-Pr)2). 31P NMR (C6D6): δ -5.1 (m, (Me3CCH2)P(i-
1
Pr)2). H NMR (C6D6): δ 0.97 (dd, (Me3CCH2)P(CHMe2)2, J )
11 Hz, 7 Hz, 6 H), 1.02 (dd, (Me3CCH2)P(CHMe2)2, J ) 13 Hz,
7 Hz, 6 H), 1.04 (s, (Me3CCH2)P(CHMe2)2, 9 H), 1.18 (d, (Me3-
CCH2)P(CHMe2)2, J ) 6 Hz, 2 H), 1.56 (hd, (Me3CCH2)P-
(CHMe2)2, J ) 7 Hz, 7 Hz, 2 H).). Anal. Calcd for C11H25P: C,
70.17; H, 13.38, P, 16.44. Found: C, 70.17; H, 13.01, P, 16.79.
Syn th etic Rea ction betw een In (CH2CMe3)3 a n d ClP -
(i-P r )2 to F or m In (CH2CMe3)2Cl a n d (Me3CCH2)P (i-P r )2.
The reagents, ClP(i-Pr)2 (0.411 g, 2.69 mmol) and In(CH2-
CMe3)3 (0.883 g, 2.69 mmol), were degassed at -196 °C on the
vacuum line and then combined without solvent. The initial
mixture was a liquid with only a faint trace of solid. Then after
18 h the mixture became a colorless solid. After 1 more day a
gelatinous material was observed. Subsequent recrystallization
of the product from pentane at low temperature yielded
crystals of In(CH2CMe3)2Cl (0.606 g, 2.07 mmol, 76.9% yield).
Removal of the pentane from the mother liquor by vacuum
distillation at ambient temperature provided a liquid that was
purified by distillation at 65-75 °C with a short-path still. The
distillate was identified as (Me3CCH2)P(i-Pr)2 (0.0955 g, 0.507
mmol, 18.8% yield).
NMR Sp ectr a l Stu d y of Rea ction betw een In (CH 2-
CMe3)3 a n d P 2(i-P r )4. A reaction tube containing P2(i-Pr)4
(0.0747 g, 0.319 mmol) and C6D6 (1.0 mL) was attached to an
apparatus charged with In(CH2CMe3)3 (0.1047 g, 0.3189 mmol)
in a glovebox. The assembled apparatus was degassed at -196
°C on a vacuum line. The solution of P2(i-Pr)4 was added to
the In(CH2CMe3)3, and the resulting solution was then poured
into the NMR tube sidearm. The NMR tube was flame-sealed
under vacuum. Complete NMR spectral data are available
with the Supporting Information.
NMR Spectr al Stu dy of Reaction between [(Me3CCH2)2-
In P (i-P r )2]2 a n d ClP (i-P r )2. A reaction tube containing ClP-
(i-Pr)2 (0.312 g, 0.205 mmol) and C6D6 (1.0 mL) was attached
to an apparatus charged with [(Me3CCH2)2InP(i-Pr)2]2 (0.765
g, 0.204 mmol monomer) in a glovebox. The assembled ap-
paratus was degassed at -196 °C on the vacuum line. The
solution of ClP(i-Pr)2 was poured onto the [(Me3CCH2)2InP(i-
Pr)2]2, and the resulting solution was then poured into the
NMR tube sidearm and flame-sealed under vacuum. The
initial spectra indicated the presence of only In(CH2CMe3)2Cl
and P2(i-Pr)4. All resonances for the starting materials had
disappeared. Thus, reaction was complete within the time
required to prepare the sample and record the spectrum,
approximately 30 min. Complete NMR spectral data are
available with the Supporting Information.
In (CH2CMe3)2Cl. Mp: 164.2-167.1 °C (lit.12 162-165 °C).
1H NMR (C6D6): δ 1.09 (s, In(CH2CMe3)2Cl, 18 H), 1.58 (s, In-
(CH2CMe3)2Cl, 4 H) (lit.12 1.09, 1.56). No 31P signals.
(Me3CCH2)P (i-P r )2. 31P{1H} NMR (C6D6): δ -5.1 (s, (Me3-
CCH2)P(i-Pr)2). 31P NMR (C6D6): δ -5.1 (m, (Me3CCH2)P(i-
1
Pr)2). H NMR (C6D6): δ 0.97 (dd, (Me3CCH2)P(CHMe2)2, J )
11 Hz, 7 Hz, 6 H), 1.01 (dd, (Me3CCH2)P(CHMe2)2, J ) 14 Hz,
7 Hz, 6 H), 1.03 (s, (Me3CCH2)P(i-Pr)2, 9 H), 1.18 (d, (Me3-
CCH2)P(CHMe2)2, 2 H), 1.56 (sd, (Me3CCH2)P(CHMe2)2, J )
7 Hz, 2 Hz, 2 H). 13C{1H} NMR (C6D6): δ 18.5 (d, (Me3CCH2)P-
NMR Sp ectr a l Stu d y of a Solu tion P r ep a r ed fr om KIn -
(CH2CMe3)3H, In (CH2CMe3)2Cl, a n d (Me3CCH2)P (i-P r )2.
An NMR tube was charged with (Me3CCH2)P(i-Pr)2 (0.0374 g,
0.199 mmol), In(CH2CMe3)2Cl (0.0571 g, 0.195 mmol), and KIn-
(16) Aime, S.; Harris, R. K.; McVicker, E. M.; Fild, M. J . Chem. Soc.,
Dalton Trans. 1976, 2144.
(17) DuMont, W.-W.; Kubiniok, S.; Severengiz, T. Z. Anorg. Allg.
Chem. 1985, 531, 21.

4902 Organometallics, Vol. 20, No. 23, 2001
Beachley et al.
(CH2CMe3)3H (0.0741 g, 0.201 mmol) in the glovebox. The tube
was degassed at -196 °C on the vacuum line, C6D6 (1.0 mL)
was added by vacuum distillation, and finally the tube was
flame-sealed under vacuum. Bubbling, most likely due to H2,
was observed upon warming the sample to room temperature,
whereas a large amount of a gray solid, probably indium metal,
was observed after 1 day. All observations suggest that KIn-
(CH2CMe3)3H reacted instantly with In(CH2CMe3)2Cl, whereas
(Me3CCH2)P(CHMe2)2 remained unchanged. Complete NMR
spectral data are available with the Supporting Information.
NMR Sp ectr a l Stu d y of Rea ction Mixtu r e P r ep a r ed
fr om KIn (CH2CMe3)3H, In (Me3CCH2)2Cl, a n d ClP (i-P r )2.
The reagents In(CH2CMe3)3 (0.161 g, 0.490 mmol) and ClP(i-
Pr)2 (0.0701 g, 0.459 mmol) were combined under vacuum in
benzene-d6 (0.8 mL) and stirred for 18 h. The products In-
(CH2CMe3)Cl and (Me3CCH2)P(i-Pr)2 were then combined with
0.7 mL of a benzene-d6 solution of KIn(CH2CMe3)3H (0.168 g,
0.457 mmol) at ambient temperature. The resulting solution
was stirred for 15 min, and part of the solution (0.9 mL) was
poured into the NMR tube sidearm. The products identified
by NMR spectroscopy were (Me3CCH2)3In‚P2(i-Pr)4 and HP(i-
Pr)2. In addition a large amount of a gray solid indicative of
indium metal was observed after 1 day. Complete NMR
spectral data are available with the Supporting Information.
Attem p ted Rea ction betw een KIn (CH 2CMe3)3H w ith
HP (i-P r )2. The reagents KIn(CH2CMe3)3H (1.74 g, 4.72 mmol)
and HP(i-Pr)2 (0.557 g, 4.72 mmol) were combined with 25 mL
of pentane at room temperature. No reaction occurred. No H2
formed in 14 days.
effects of absorption (via ψ-scans). The systematic absences,
h0l for l ) 2n + 1 (only), indicate that possible space groups
are the noncentrosymmetric Pc (No. 7) and the centrosym-
metric P2/c (No. 13). The latter was found to be appropriate
by the successful solution of the crystal structure in this
higher-symmetry space group.
Crystallographic calculations were carried out by use of the
SHELXTL PLUS (Release 4.11(VMS)) program package.19 The
structure was solved by direct methods and refined by a
combination of difference Fourier and least-squares refinement
techniques. The unit cell contains the expected four molecules,
but the crystallographic asymmetric unit consists of two
crystallographically independent “half-molecules” lying around
2-fold axes at (0, y, 1/4). Both molecule 1 and molecule 2
possess precise C2 site symmetry and approximate C2v molec-
ular symmetry. Hydrogen atoms were included in calculated
positions, based upon d(C-H) ) 0.96 Å.20 Their isotropic
thermal parameters were refined in blocks in earlier cycles
and then fixed at the end. The final discrepancy index was R
) 8.18% for all 5392 unique reflections (none omitted).
Ack n ow led gm en t. This work was supported in part
by the Office of Naval Research (O.T.B.). Purchase of
the Siemens R3m/V diffractometer was made possible
by Grant No. 89-13733 from the Chemical Instrumenta-
tion Program of the National Science Foundation.
Collection of X-r a y Diffr a ction Da ta a n d Str u ctu r e
Solu tion for [(Me3CCH2)2In P (i-P r )2]2. A colorless crystal of
approximate orthogonal dimensions 0.3 × 0.3 × 0.4 mm was
carefully sealed into a thin-walled glass capillary, then mounted
and aligned accurately on a Siemens R3m/V diffractometer.
The crystal’s Laue symmetry (2/m), crystal class (monoclinic),
orientation matrix, and cell dimensions were determined as
has been described in detail previously.18
Su p p or tin g In for m a tion Ava ila ble: (1) Complete tables
of positional parameters, interatomic distances and angles,
anisotropic thermal parameters and calculated positions for
hydrogen atoms for the compound studied. (2) Complete 1H
and 31P NMR spectral data for all spectral studies. This
material is available free of charge via the Internet at
http://pubs.acs.org.
OM0101902
The intensity data were collected by a coupled θ (crystal)-
2θ (counter) scan and were corrected for Lp factors and the
(19) Sheldrick, G. M. SHELXTL PLUS, Release 4.11 (VMS); Si-
emens Analytical Instrument Corp.; Madison, WI, 1989.
(20) Churchill, M. R. Inorg. Chem. 1973, 12, 1213.
(18) Churchill, M. R.; Lashewycz, R. A.; Rotella, F. J . Inorg. Chem.
1977, 16, 265.