Reaction of C(PPh3)2 with MI2 Compounds (M = Zn, Cd) - Formation and Crystal Structures of [I2Zn{C(PPh 3)2}], [(I2Cd{C(PPh3) 2})2] and the Salt-Like Compounds (HC{PPh 3}2)[MI3(THF)] and (HC{PPh3} 2)2[ZnI4]

Article abstract of DOI:10.1002/ejic.201100646

The reaction of the carbodiphosphorane C(PPh₃)₂ (1) with group 12 MI₂ compounds in THF leads to the salts (HC{PPh ₃}₂)[MI₃(THF)] (M = Zn²⁺, 2; Cd ²⁺, 3) in good yields upon proton abstraction from the solvent. The salt-like complex (HC{PPh₃}₂)₂[ZnI₄] (4) formed upon reaction of ZnI₂ with 1 in toluene and subsequent heating of the resulting powder in 2-bromofluorobenzene. When this reaction was carried out in 2-bromofluorobenzene as the solvent, no proton transfer occurred, and the colorless addition compounds [I₂Zn←1] (5) and [I ₂C←1]₂ (6) were isolated. Compound 5 is monomeric, whereas in 6 the monomeric units are linked by bridging iodine ligands to produce a dimer. All compounds were characterized by X-ray analyses and ³¹P NMR and IR spectroscopy. The reaction of the C(PPh ₃)₂ with ZnI₂ in 2-bromofluorobenzene yields the monomeric adduct [I₂Zn(C{PPh₃}₂)], whereas with CdI₂ the dimeric complex [I₂Cd(C{PPh ₃}₂)]₂ is formed. For steric reasons, the change in ionic radius from Zn²⁺to Cd²⁺ allows dimerization only for the Cd complex. In THF or DME proton abstraction from the solvent gives rise to the salt-like compounds (HC{PPh₃) ₂)[(THF)MI₃] (M = Zn, Cd).

Full text of DOI:10.1002/ejic.201100646

FULL PAPER
DOI: 10.1002/ejic.201100646
Reaction of C(PPh3)2 with MI2 Compounds (M = Zn, Cd) – Formation and
Crystal Structures of [I2Zn{C(PPh3)2}], [(I2Cd{C(PPh3)2})2] and the Salt-Like
Compounds (HC{PPh3}2)[MI3(THF)] and (HC{PPh3}2)2[ZnI4]
Wolfgang Petz*[a] and Bernhard Neumüller*[a]
Keywords: Ylides / Zinc / Cadmium / Addition compounds / Carbodiphosphorane
The reaction of the carbodiphosphorane C(PPh3)2 (1) with
group 12 MI2 compounds in THF leads to the salts
(HC{PPh3}2)[MI3(THF)] (M = Zn2+, 2; Cd2+, 3) in good yields
upon proton abstraction from the solvent. The salt-like com-
plex (HC{PPh3}2)2[ZnI4] (4) formed upon reaction of ZnI2 with
1 in toluene and subsequent heating of the resulting powder
in 2-bromofluorobenzene. When this reaction was carried out
in 2-bromofluorobenzene as the solvent, no proton transfer
occurred, and the colorless addition compounds [I2Znǟ1] (5)
and [I2Cdǟ1]2 (6) were isolated. Compound 5 is monomeric,
whereas in 6 the monomeric units are linked by bridging io-
dine ligands to produce a dimer. All compounds were charac-
terized by X-ray analyses and 31P NMR and IR spectroscopy.
or two phenyl rings of 1 with the formation of a C,C,C
pincer ligand;[9] similar results have been found with Rh[10]
and Pd compounds.[11] Further addition compounds of the
type Mǟ1 have been prepared and characterized for main-
group Lewis acids with M = S, Se,[12] I+,[13,14] H+, Cl+, and
the molecules InMe3 and AlBr3.[15] We have recently re-
ported the coordination of 1 to two boron atoms.[16] The
coordination chemistry of ylides has been summarized in
several reviews.[17,18,19] We have recently isolated the first
complex with two molecules of 1 in a linear arrangement
in the cationic complex [1ǞAgǟ1]+.[20] We found that CuI
and HgI2 react similarly to produce the related cationic
compounds [1ǞCuǟ1]+ and [1ǞHgǟ1]2+, respectively.[21]
These results prompted us to extend our studies to homo-
logues with group 12 elements. Here we report the outcome
of reactions of 1 with ZnI2 and CdI2 in various solvents.
1. Introduction
The double ylide C(PPh3)2 (1) can be considered as a
carbon atom stabilized by two phosphane ligands. Com-
pound 1 has a bent structure and belongs to a series of CL2
compounds, in which a carbon(0) atom attains eight valence
electrons by the coordination of two neutral donor mole-
cules, L. L stands for various donors such as PR3, N-het-
erocyclic carbenes (NHCs), and others with a free pair of
electrons. This newly recognized class of compounds,[1] for
which the name carbones has been proposed,[2] possesses
one σ- and one π-type lone pair orbital [highest occupied
molecular orbital (HOMO) and HOMO–1] at the carbon
atom. We have recently reported a compilation of transition
metal complexes of carbones accompanied by theoretical
calculations.[3]
2. Results and Discussion
Transition metal complexes with 1 are rare and concen-
trate on a few examples. Thus, addition compounds are de-
scribed and confirmed by X-ray analyses, in which a mole-
cule of 1 coordinates with the carbon atom at the electron
Although the reaction of 1 with HgI2 in tetrahydrofuran
(THF) generates the cationic complex [1ǞHgǟ1]2+, under
the same conditions the homologous MI2 compounds (M
= Zn, Cd) prefer a reaction pathway that we have frequently
observed with main-group Lewis acids,[15] [Co2(CO)8],[22]
and [Mn2(CO)10][23] in THF, which leads to proton abstrac-
tion from the solvent forming the salts (HC{PPh3}2)-
[MI3(THF)] (M = Zn 2, M = Cd, 3). Both compounds were
obtained from THF as large colorless crystals as the only
crystalline products. The reaction with ZnI2 was also per-
formed in dimethoxyethane (DME) with nearly the same
results; the insoluble colorless powder indicates the forma-
tion of (HC{PPh3}2)+, which was identified by IR and 31P
deficient transition metal fragments Ni(CO)n (n = 2, 3),[4]
+ [5]
ReO3
,
CuCl,[6] and CuCp*.[7] A Au complex has also
been described, in which 1 bridges a Au–Au bond.[8] Coor-
dination to Pt is accompanied by orthometallation of one
[a] Fachbereich Chemie der Universität
35032 Marburg, Germany
Fax: +49-6421-2825653
E-mail: petz@staff.uni-marburg.de
neumuell@chemie.uni-marburg.de
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201100646.
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NMR spectroscopy. Although the cation bears a free pair colorless crystals of 6. In contrast with 5, 6 is dimeric and
of electrons, the nucleophilicity is apparently too weak to the monomeric units are connected by two bridging I
replace the coordinated THF molecule in the anions of 2 atoms. It is interesting to note that cadmium complexes
and 3. However, in the absence of coordinating anions the with NHCs or other carbenes have not been reported to
cation can act as a ligand as shown in the complex [(PPh3)2- date.
HCǞAgǟHC(PPh3)2]3+ [1]
.
We have also reacted ZnI2 with
The 31P NMR spectrum of 5 exhibits singlets at
1 in toluene. A pale yellow insoluble precipitate formed 17.8 ppm in 2-bromofluorobenzene and 19.0 ppm in
whose IR spectrum does not indicate the presence of DMSO. However, after several hours in DMSO the signal
(HC{PPh3}2)+. The insoluble material dissolves in dimeth- disappears and is replaced by that of (HC{PPh3}2)+ at
ylsulfoxide (DMSO) and the 31P NMR spectrum exhibits a 20.6 ppm. The crystals dissolve slightly in THF but only
singlet at 19.6 ppm, which was identified as that of the signal of the cation was detected in the 31P NMR spec-
(HC{PPh3}2)+; addition of small amounts of (HC{PPh3}2) trum. The spectrum of 6 shows a 31P NMR signal at
I to this solution gave no new signal. Thus, the initially 18.5 ppm in 2-bromofluorobenzene and only that of
formed adduct between 1 and ZnI2 deprotonates in DMSO (HC{PPh3}2)+ in DMSO. Thus, both compounds easily ab-
as well as THF. The precipitate from the reaction of ZnI2 stract protons similar to many main group addition com-
in toluene was heated in 2-bromofluorobenzene. Upon pounds of 1.
cooling, colorless crystals separated, which were the salt-
like complex (HC{PPh3}2)2[ZnI4] (4). The different path-
ways within the group 12 iodides shown in Scheme 1 may
3. Crystal Structures
be explained by the less covalent nature of these compounds
To gain an insight into the nature of the complexes and
relative to HgI2 and their proximity to main-group Lewis
the bonding situation, X-ray analyses of 2–6 were per-
acids.
formed. The structures of 2, 4, 5, and 6 are shown in Fig-
ures 1–4; crystallographic data are collected in Table 5, and
selected distances and angles are presented in Tables 1–4.
3.1 Crystal Structures of (HC{PPh3}2)[MI3(THF)]
(M = Zn, 2; Cd, 3)
The structural parameters of the cations are close to
those found in related salts based on the data from about
30 examples of (HC{PPh3}2)X salts.[15,25] The molecular
Scheme 1. Reaction pathways of 1 with MI2 (M = Zn, Cd) in THF,
toluene, and 2-bromofluorobenzene.
Alternatively, 1 was allowed to react with ZnI2 and CdI2
directly in 2-bromofluorobenzene. With ZnI2, a colorless
precipitate formed, which dissolved upon heating to give a
brownish solution. On cooling, large colorless crystals sepa-
rated in high yield, which were the addition compound 5.
2-Bromofluorobenzene is more polar than toluene but the
proton abstraction that occurs in THF is suppressed. Com-
plex 5 is the first addition compound of a carbone and a
Zn2+ compound; even Zn2+ complexes with NHCs are
rare.[24] However, to the best of our knowledge, no carbene
Figure 1. Molecular structure of 2 showing the atomic numbering
complexes with ZnI2 have been reported to date. The reac-
tion of CdI2 under the same conditions led to a clear, pale
beige solution and, on cooling to room temperature, all ma-
terial remained in solution. Layering with n-pentane gave for clarity.
scheme. Compound 3 is isostructural (Supporting Information).
The ellipsoids are drawn at 40% probability. The phenyl groups
and THF are represented as thin lines, and the H atoms are omitted
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Reaction of C(PPh3)2 with MI2 Compounds (M = Zn, Cd)
Table 1. Selected bond lengths [Å] and angles [°] of 2 and 3.
M = Zn/Cd
M(1)–O(1)
M(1)–I(2)
C(1)–P(2)
C(1)–H(1)
P(1)–C(8)
P(2)–C(20)
P(2)–C(32)
O(1)–M(1)–I(3)
I(3)–M(1)–I(2)
I(3)–M(1)–I(1)
P(1)–C(1)–P(2)
2.071(2)/2.314(2)
2.5649(5)/2.7263(3)
1.692(3)/1.699(2)
0.077(4)/0.081(3)
1.811(3)/1.807(2)
1.805(3)/1.807(2)
1.813(3)/1.817(2)
102.37(6)/99.17(4)
115.59(2)/115.341(9)
114.81(2)/119.890(9)
130.2(2)/128.0(2)
M(1)–I(3)
M(1)–I(1)
C(1)–P(1)
P(1)–C(2)
P(1)–C(14)
P(2)–C(26)
2.5589(4)/2.7247(3)
2.5830(4)/2.7384(3)
1.706(3)/1.703(3)
1.796(3)/1.801(2)
1.814(3)/1.817(2)
1.803(3)/1.804(2)
O(1)–M(1)–I(2)
O(1)–M(1)–I(1)
I(2)–M(1)–I(1)
103.73(8)/107.28(5)
103.04(8)/99.08(5)
114.78(2)/112.625(9)
structure of 2 is depicted in Figure 1. The cations and
anions are connected by hydrogen bridges with C(1)–I(1)
distances of 4.087(2) Å in 2 and 4.149(3) Å in 3, which
cause the related M–I(1) bond lengths to be slightly elon-
gated relative to the two other M–I bonds (Table 1). No
uncoordinated solvent molecules are incorporated in the
unit cell. The central transition metals of the anions are in
a distorted tetrahedral environment with small O–M–I and
large I–M–I angles. To the best of our knowledge, only two
other compounds with the anions [MI3(THF)]– (M = Zn,
Cd) have been reported to date in [(THF)5NdI2][MI3-
(THF)]; here, the anions have no contacts to the cations
leading to more balanced M–I distances.[26] The molecular
structure of 3 can be found in the Supporting Information.
3.2 Crystal Structure of (HC{PPh3}2)2[ZnI4] (4)
Figure 3. Unit cell of 4 viewed down [001].
The molecular structure of 4 is shown in Figure 2. There
are no remarkable contacts between the ions. The anions
are stacked along [001] and the gaps are filled by the cat-
ions; the unit cell is shown in Figure 3. The mean Zn–I
bond length is 2.6356(9) Å, which is appreciably longer than
3.3 Crystal Structure of [I2Zn{C(PPh3)2}] (5)
Complex 5 crystallizes with two independent molecules
that in 2 (Table 2). Only one of the six I–Zn–I angles corre- in the unit cell, not including solvent molecules, and the
sponds to the ideal tetrahedral angle of 109.5°; the angles structure of one molecule is shown in Figure 4. Compound
range between 107° and 112°.
5 represents a rare example of three-coordination at the Zn
Figure 2. Molecular structure of 4 showing the atomic numbering scheme. The ellipsoids are drawn at 40% probability. The phenyl groups
are represented as thin lines, and the H atoms are omitted for clarity.
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W. Petz, B. Neumüller
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Table 2. Selected bond lengths [Å] and angles [°] of 4.
Zn(1)–I(4)
Zn(1)–I(2)
2.6278(9)
2.6328(9)
Zn(1)–I(3)
Zn(1)–I(1)
2.6365(8)
2.6452(8)
C(1)–P(2)/C(38)–P(4)
C(1)–H(11)/C(38)–H(381)
P(1)–C(8)/P(3)–C(45)
P(2)–C(20)/P(4)–C(57)
P(2)–C(32)/P(4)–C(69)
I(4)–Zn(1)–I(2)
1.716(6)/1.701(7)
0.95/ 0.95
1.811(8)/1.808(7)
1.815(6)/1.826(7)
1.804(7)/1.809(7)
112.14(3)
C(1)–P(1)/C(38)–P(3)
P(1)–C(2)/P(3)–C(39)
P(1)–C(14)/P(3)–C(51)
P(2)–C(26)/P(4)–C(63)
1.700(6)/1.709(7)
1.809(6)/1.807(6)
1.792(6)/1.807(6)
1.812(7)/1.811(7)
I(4)–Zn(1)–I(3)
I(4)–Zn(1)–I(1)
I(3)–Zn(1)–I(1)
109.56(3)
106.62(3)
111.40(3)
I(2)–Zn(1)–I(3)
I(2)–Zn(1)–I(1)
106.87(3)
110.30(3)
P(1)–C(1)–P(2)/P(3)–C(38)–P(4)
128.9(4)/127.7(5)
atom; the bulky phenyl groups of the ligand and the small bridging iodine atoms. Two molecules of the solvent are
ionic radius of Zn2+ (0.74 Å) prevent dimerization. The Zn included in the unit cell but have no near contacts to the
atom and the coordinating C(1) atom are in planar environ- centrosymmetric dimer. The larger ionic radius of cadmium
ments, which indicates sp2 hybridization; the I2Zn and P2C (0.92 Å) allows a dimeric arrangement, such that the fa-
planes form a dihedral angle of 67°. The large angle is prob- vored coordination number of four is achieved with 18 elec-
ably caused by steric repulsion between the iodine atoms trons for the Cd ion. The plane of the four membered Cd2I2
and the phenyl rings. The Zn–C(1) bond length (Table 3) is ring forms an angle of 95° with the P(1)–C(1)–P(2) plane.
appreciably shorter than that in most of the addition com- A distorted tetrahedral environment with angles ranging
pounds between Zn2+ species and various NHCs[24] and between 91° and 120° for the Cd ion is recorded; the small-
slightly longer than that in the dimeric ArZnI complex [Ar est being the I–Cd–I angle in the four membered ring.
= 2,6-bis(2,6-diisopropylphenyl)phenyl].[27]
For C(1), sp2 hybridization is achieved but the sum of
the angles amounts to 357.6(6), indicating slight pyrami-
dalization; the C atom is located about 0.16 Å out of the
P(1)–Cd–P(2) plane. The Cd(1)–C(1) bond length is larger
[2.25(1) Å, Table 4] than that in the dimeric ArCdI complex
[2.15 Å; Ar = 2,6-bis(2,6-diisopropylphenyl)phenyl].[27]
4. Conclusion and Outlook
Linearly dicoordinated complexes with carbones are rep-
resented by a few examples based on Cu+, Ag+, and Hg2+
exclusively with 1 as a ligand to date. Extending the series
to include Zn2+ and Cd2+ could not be realized. During our
experiments with Lewis acid adducts of 1, we have fre-
quently observed that reactions with solvents such as THF,
DME, DMSO, and halogenated hydrocarbons occur with
transformation of H+ to 1 to produce (HC{PPh3}2)+ or
(H2C{PPh3}2)2+ especially with main-group Lewis acids.
The first and second group 12 iodides follow this route in
THF and DMSO solution. The use of 2-bromofluoroben-
zene as the solvent apparently combines some polarity with
the lack of proton abstraction ability, which enables the iso-
lation of 5 and 6. However, dissolution of 5 and 6 in DMSO
generates (HC{PPh3}2)+ as shown by 31P NMR spec-
troscopy.
Figure 4. Molecular structure of 5 showing the atomic numbering
scheme. The ellipsoids are drawn at 40% probability. The phenyl
groups are represented as thin lines, and the H atoms are omitted
for clarity.
Table 3. Selected bond lengths [Å] and angles [°] of one indepen-
dent molecule of 5.
Zn(1)–C(1)
Zn(1)–I(2)
C(1)–P(2)
P(1)–C(1)–P(2)
C(1)–Zn(1)–I(2)
P(1)–C(1)–Zn(1)
2.000(9)
2.556(1)
1.703(8)
128.3(6)
123.9(2)
116.7(4)
Zn(1)–I(1)
C(1)–P(1)
2.577(1)
1.691(9)
As an alternative to the sp2-hybridized carbon atom
shown in A (Scheme 2) and an electron pair of π symmetry,
pyramidalization to give a σ-type electron pair may occur
as shown in B (Scheme 2); this means that the occupied p
orbital gains some sp contribution. The resulting B form is
probably more basic and able to abstract a proton from an
appropriate solvent such as THF. A bent array as shown in
B apparently plays a role in compounds where M represents
group 12 (Hg) and group 13 (BH3) Lewis acids, and slight
C(1)–Zn(1)–I(1)
I(2)–Zn(1)–I(1)
P(2)–C(1)–Zn(1)
121.0(2)
115.16(5)
113.9(4)
3.4 Crystal Structure of
[({Ph3P}2C)CdI(µ-I)2ICd(C{PPh3}2)]·2(1-Br-2-F-C6H4) (6)
The molecular structure of 6 is depicted in Figure 5. In pyramidalization at the related carbon atoms was recorded,
contrast to 5, 6 consists of two I2Cdǟ1 units linked by two similar to 6. It is interesting to note that the pyramidalized
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Reaction of C(PPh3)2 with MI2 Compounds (M = Zn, Cd)
Figure 5. Molecular structure of 6 showing the atomic numbering scheme. The ellipsoids are drawn at 40% probability. The phenyl groups
are represented as thin lines, and the H atoms are omitted for clarity.
Table 4. Selected bond lengths [Å] and angles [°] of 6.
Does a partial double bond between Zn and the carbon
atom in 5 exist? In this arrangement the three-coordinate
Zn atom has only 16 valence electrons as in [(CO)2Niǟ1].
However, the relatively short P–C bond length of about
1.700 Å is indicative of a single bond, and the doubly occu-
pied p orbital at the carbon atom is mainly involved in some
P–CPh σ* negative hyperconjugation. Long P–C bonds and
additionally increased C–C double bond character were
found in the related CS2 and CO2 addition compounds,
where π donation into the vacant p orbital at the carbon
atoms seems reliable. A C–Re double bond is proposed in
the cation [O3Reǟ1]+ where the mean P–C bond length is
1.771 Å;[5] for comparison, the mean P–C bond lengths in
other X3Eǟ1 adducts are in the range between 1.685 and
1.718 Å, similar to those in 5 and 6, indicating single bonds.
Cd(1)–C(1)
Cd(1)–I(1A)
C(1)–P(1)
P(1)–C(1)–P(2)
C(1)–Cd(1)–I(2)
C(1)–Cd(1)–I(1A)
I(1)–Cd(1)–I(1A)
P(2)–C(1)–P(1)
P(1)–C(1)–Cd(1)
2.25(1)
Cd(1)–I(1)
Cd(1)–I(2)
C(1)–P(2)
C(1)–Cd(1)–I(1)
I(2)–Cd(1)–I(1)
I(2)–Cd(1)–I(1A)
Cd(1)–I(1)–Cd(1A) 88.89(3)
P(2)–C(1)–Cd(1) 115.1(5)
2.886(1)
2.782(1)
1.68(1)
117.1(2)
106.26(4)
100.80(3)
2.924(1)
1.700(9)
124.8(7)
120.7(2)
116.0(3)
91.11(3)
124.8(7)
117.7(6)
HOMO p orbital in 6 is in the plane with the terminal Cd–
I(2) bond, which the P atoms are bent away from. For the
addition compound 1ǟBH3, pyramidalization has been
predicted theoretically,[28] which means that this phenome-
non is electronic rather than steric in origin.
Experimental Section
General: All operations were carried out under an argon atmo-
sphere in dry degassed solvents using Schlenk techniques. The sol-
vents were thoroughly dried and freshly distilled prior to use. The
IR spectra were run with a Nicolet 510 spectrometer. Elemental
analyses were performed by the analytical service of our depart-
ment. 31P NMR spectra were measured with a Bruker AC 300 in-
strument. Compound 1 was prepared according to a modified lit-
erature procedure.[30] Commercially available ZnI2 and CdI2 were
dried in vacuo prior to use. 2-Bromofluorobenzene from ACROS
was dried with P2O5.
Scheme 2. Possible coordination modes of carbones with Lewis ac-
ids (M).
One reason for the different behavior of group 12 ions
may be that the Hg–C bond is more covalent, which pre-
vents proton abstraction from the solvent. The shape of 5
is of the X2Eǟ1-type and resembles that of the addition
compounds [(CO)2Niǟ1],[4] [S2Cǟ1], and [O2Cǟ1].[29] To
date, Lewis acids M have been found to be of the types XE,
X2E, and X3E. For the following X2Eǟ1 compounds the
bonding parameters, mean P–C bond length and dihedral
angles [Å/°] have been recorded: ZnI2, 1.697(8)/67;
Ni(CO)2, 1.677(3)/9; CS2, 1.751(2)/20; CO2, 1.723(3)/10.
For electron deficient X2Eǟ1 compounds with X =
halogen, dimerization is optional to attain electron satura-
tion. In going from Zn2+ in 5 to Cd2+ in 6, this step is
achieved by the increase of the ionic radius by 0.18 Å (and
increase of the M–C bond length by 0.25 Å), which allows
the steric repulsion to be minimized.
(HC{PPh3}2)[MI3(THF)] (M = Zn, 2; Cd, 3): A mixture of 1
(0.27 g, 0.50 mmol) and CdI2 (0.27 g, 0.75 mol) in THF (4 mL) was
treated for 10 min in an ultrasonic bath. The clear solution was
separated from small amounts of precipitate by filtration. The 31P
NMR spectrum of the solution showed two signals at 20.6 and
17.0 ppm in a 1:0.3 ratio. The signal at 20.6 ppm was assigned to
[Hǟ1]+. Layering with n-pentane produced large colorless crystals
of 3. IR (Nujol mull): ν = 1586 (w), 1480 (m), 1435 (s), 1337 (w),
˜
1312 (w), 1213 (s), 1181 (s), 1161 (w), 1099 (s), 1074 (m), 1036 (m),
1028 (m), 1007 (m), 988 (s), 877 (m), 808 (m), 760 (m), 747 (s), 719
(s), 692 (s), 557 (s), 529 (s), 515 (s), 500 (s), 488 (m) cm–1.
A similar procedure with 1 (0.30 g, 0.56 mmol) and ZnI2 (0.27 g,
0.84 mmol) in THF (ca. 4 mL) gave a pale yellow solution. The 31
P
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NMR spectrum of the solution showed a singlet at 20.6 ppm due
perature in about 70% yield. 31P NMR (2-bromofluorobenzene): δ
to the formation of [Hǟ1]+. The work up procedure gave colorless
= 17.8 (s) ppm. IR (Nujol mull): ν = 1481 (s), 1135 (s), 1310 (m),
˜
crystals of 2 in high yield. IR (Nujol mull): ν = 1586 (w), 1480 (m),
1261 (w), 1237 (w), 1184 (m), 1122 (s), 1026 (m), 997 (m), 812 (s),
˜
1435 (s), 1339 (w), 1314 (w), 1213 (s), 1181 (s), 1161 (w), 1099 (s), 798 (s), 741 (s), 714 (s), 693 (s), 576 (w), 530 (s), 500 (s), 450 (w)
1074 (m), 1028 (m), 1007 (m), 986 (s), 874 (m), 808 (m), 760 (m), cm–1. C37H30I2P2Zn (855.73): calcd. C 51.93, H 3.53; found C
747 (s), 720 (s), 696 (s), 557 (s), 530 (s), 515 (s), 498 (s), 488 (m) 51.88, H 3.54.
cm–1.
[({Ph3P}2C)CdI(µ-I)2ICd(C{PPh3}2)]·2(1-Br-2-F-C6H4) (6): In
a
When the reaction was carried out in DME, a colorless precipitate
formed. The supernatant solution showed two signals at 21.2 and
20.8 ppm in a 1:0.4 ratio. The IR spectrum of the precipitate is
identical to that of 3 from THF.
similar procedure to that described for 5, a mixture of 1 (0.17 g,
0.32 mmol) and CdI2 (0.13 g, 0.37 mmol) was reacted in 2-bromo-
fluorobenzene (2 mL). No crystals formed upon cooling the clear
tan-colored solution to room temperature. Layering the solution
with n-pentane gave colorless crystals of 6 in about 80% yield. 31P
NMR (2-bromofluorobenzene): δ = 18.5 (s) ppm. IR (Nujol mull):
(HC{PPh3}2)2[ZnI4] (4): The reaction described above was also car-
ried out in toluene resulting in the formation of insoluble material.
ν = 1478 (s), 1136 (s), 1310 (w), 1262 (w), 1236 (w), 1104 (vs), 1081
˜
IR (Nujol mull): ν = 1588 (w), 1481 (m), 1437 (s), 1333 (w), 1310
˜
(s), 1026 (m), 997 (m), 793 (s), 750 (s), 713 (s), 694 (s), 654 (w), 564
(w), 526 (s), 501 (s) cm–1. C86H68Br2Cd2F2I4P4 (2155.50): calcd. C
47.92, H 3.18; found C 47.02, H 3.21%.
(w), 1233 (w), 1184 (w), 1159 (w), 1123 (vs), 1099 (vs), 1090 (m),
1071 (w), 1026 (w), 1010 (w), 997 (m), 990 (m), 812 (s), 799 (s), 741
(vs), 714 (vs), 692 (vs), 530 (vs), 522 (s), 517 (s), 500 (s) cm–1.
For details on the X-ray crystal structure determinations see Table
5.
[I2Zn{C(PPh3)2}] (5): A mixture of 1 (0.20 g, 0.34 mmol) and ZnI2
(0.12 g, 0.37 mmol) in 2-bromofluorobenzene (2 mL) was treated
in an ultrasonic bath for about 5 min. The resulting suspension was
heated for about 2 min, and a clear tan solution was obtained from
which colorless crystals of 5 separated upon cooling to room tem-
CCDC-793477 (for 2), -793478 (for 3), -827706 (for 4), -827707 (for
5), and -827708 (for 6) contain the supplementary crystallographic
data for this paper. These data can be obtained free of charge from
Table 5. Crystal data for 2–6.
2
3
4
5
6
Formula
MW
Crystal system
Space group
a [Å]
b [Å]
c [Å]
C41H39I3OP2Zn
1055.73
C41H39CdI3OP2
1102.76
C74H62I4P4Zn
1648.09
monoclinic
P21/n (No. 14)
14.077(1)
16.945(1)
28.707(1)
90
C37H30I2P2Zn
855.72
C86H68Br2Cd2F2I4P4
2155.5
I2/a (No. 15)
31.825(1)
10.221(1)
25.157(1)
90
P21/n (No. 14)
17.138(1)
14.526(1)
18.064(1)
90
Cc (No. 9)
11.013(1)
18.077(1)
34.213(2)
90
P21/n (No. 14)
11.051(1)
17.221(1)
21.031(1)
90
α [°]
β [°]
γ [°]
94.05(1)
90
8162.7(9)
8
1.718
100
116.98(1)
90
4007.5(4)
4
1.828
100
102.34(1)
90
6689.4(7)
4
1.636
100
97.78(1)
90
6748.5(8)
8
1.684
100
100.21(1)
90
3939.0(5)
2
1.817
100
Volume [Å3]
Z
dcalcd. [gcm–3]
Temperature [K]
μ [cm–1]
29.79
29.66
23.51
26.77
32.52
2θmax [°]
Radiation
Diffractometer
Crystal size [mm]
51.90
51.84
56.84
51.82
51.92
Mo-Kα
IPDS II (Stoe)
0.11ϫ 0.11ϫ 0.06
0.17ϫ 0.16ϫ 0.07
0.25ϫ 0.21ϫ 0.16
0.14ϫ 0.11ϫ
0.05
0.17ϫ 0.04ϫ 0.03
Index range
–39 Ն h Ն 39
–12 Ն k Ն 12
–30 Ն l Ն 30
–14 Ն h Ն 14
–17 Ն k Ն 17
–25 Ն l Ն 25
55737
–18 Ն h Ն 18
–19 Ն k Ն 22
–25 Ն l Ն 28
35348
–10 Ն h Ն 13
–22 Ն k Ն 19
–41 Ն l Ն 41
13549
–13 Ն h Ն 13
–19 Ն k Ն 21
–20 Ն l Ն 25
16077
Reflections collected 56241
Independent reflec- 7941 (0.0559)
tions (Rint
7798 (0.0411)
16625 (0.1132)
10624 (0.0412)
7569 (0.095)
)
Observed reflections 5782
[Fo Ͼ 4σ(Fo)]
6059
6839
6541
3018
Refinement against
SHELXL-97[31]
F2
Parameters
Structure solution
438
438
749
758
452
direct methods, Sir-
92[34]
Patterson method,
SHELXTL-Plus
direct methods,
direct methods, Sir-92 direct methods,
SHELXS-97[33]
SHELXS-97[33]
[32]
[34]
H atoms
calculated positions with common displacement parameter; H(1) was
refined freely
calculated positions with common dis-
placement parameter
Flack parameter
R1
wR2 (all data)
–
–
–
0.09(2)
0.0285
0.0443
0.392
–
0.0234
0.0425
0.0176
0.0329
0.698
0.0444
0.0724
0.94
0.0477
0.0896
1.066
Max. resid. electron 0.665
density [eÅ–3]
4894
www.eurjic.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2011, 4889–4895

Reaction of C(PPh3)2 with MI2 Compounds (M = Zn, Cd)
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[18]
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Received: June 24, 2011
Published Online: September 23, 2011
Eur. J. Inorg. Chem. 2011, 4889–4895
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
4895