The new C-C bond formation in the reaction of o-amidophenolate indium(iii) complex with alkyl iodides

Article abstract of DOI:10.1039/c3dt50934f

The reaction of bis(4,6-di-tert-butyl-N-(2,6-di-iso-propylphenyl)-o- amidophenolato)indium(iii) anion with alkyl iodides is reported. This process includes oxidative addition of two RI (R = Me, Et) molecules to the non-transition metal complex and results

Full text of DOI:10.1039/c3dt50934f

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The new C–C bond formation in the reaction of
o-amidophenolate indium(III) complex with
alkyl iodides†
Cite this: Dalton Trans., 2013, 42, 10533
Alexandr V. Piskunov,* Irina N. Meshcheryakova, Georgy K. Fukin, Andrei S. Shavyrin,
Vladimir K. Cherkasov and Gleb A. Abakumov
The reaction of bis(4,6-di-tert-butyl-N-(2,6-di-iso-propylphenyl)-o-amidophenolato)indium(III) anion with
alkyl iodides is reported. This process includes oxidative addition of two RI (R = Me, Et) molecules to the
non-transition metal complex and results in an alkyl transfer to ring carbon atoms with the formation of
two new C–C bonds. The interaction proceeds at mild conditions and gives new indium(III) derivatives
containing iminocyclohexa-1,4-dienolate type ligands.
Received 9th April 2013,
Accepted 13th May 2013
DOI: 10.1039/c3dt50934f
www.rsc.org/dalton
each ligand and there is no change of metal oxidation state.
Moreover the complexes obtained (imSQ)2CoAlk (imSQ is
Introduction
The search for new highly selective reactions of C–C bond for- o-iminosemiquinone radical-anion ligand) are able to react with
mation is one of the primary goals in organic chemistry. In the organozinc halides. This leads to the regeneration of the
present time it is achieved quite effectively by using metal square planar starting cobalt anions and elimination of C–C
complex catalysis. The noble transition metal (Pd, Rh, Pt, etc.) coupling products. These transformations result in a complete
derivatives play a dominant role in catalytic carbon–carbon (or cycle for cobalt Negishi-like cross-coupling of alkyl halides
carbon–heteroatom) bond formation.1 This can be explained with organozinc reagents. The involvement of redox active
by the ability of such compounds to participate readily in one- ligands into the non-transition metal complexes allows the last
step two-electron transfer processes, which are the elementary ones to participate in the oxidative addition and reductive
steps of numerous transition metal catalyzed transformations. elimination reactions. To date some examples of unusual reac-
The complexes of the first-row transition metals are mostly tivity of such types of complexes were found.4 These include
characterized by one-electron transformations and have less the transformations of tin(IV)4a and gallium(III)4b o-amidopheno-
application in homogeneous catalysis. This is true for main late compounds in the reactions with dioxygen and sulfur
group metal compounds, for which the processes of electron and the unique ability of antimony(V) o-amidophenolate and
transfer are unusual at all. The problem of inactivity of these catecholate complexes to reversibly bind the dioxygen.4c,d The
elements in multiple electron transformations may be solved latest works devoted to the gallium and aluminum compounds
by means of the insertion of redox active ligands in their based on the redox active diiminoacenaphthene ligand (BIAN)
coordination sphere.2 Recently the excellent example of redox have demonstrated their outstanding ability to activate the
active ligand-mediated multielectron reactions for cross-coup- triple CuC bond.4e–g A rare example of the interaction of main
ling at square planar cobalt(III) complexes of the type [Co- group metal complexes with alkyl halides is the reaction of
(AP)2]− (AP is o-amidophenolate dianion ligand) was demon- BIANMg(THF)3 species with EtX (X = Cl, Br, I), which is
strated by J.D. Soper and coworkers.3 These compounds are accompanied by a one-electron transfer from the metal
strong nucleophiles and able to interact with alkyl halides complex to the alkyl halide molecule.5 The authors suggested
including CH2Cl2 under gentle conditions. The formal two- the subsequent recombination of two radicals in the solvent
electron transition consists of two one-electron oxidations of cell and the new C–C bond formation between the ethyl group
and the imine carbon atom of a diimine ligand. The present
work is the investigation of potential participation of non-tran-
G.A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences,
sition metal complexes containing redox active ligands in the
49 Tropinina Street, 603950 Nizhny Novgorod, Russia. E-mail: pial@iomc.ras.ru;
cross-coupling reactions, in particular the possibility of alkyl
Fax: (+7) 831-462-74-97
halides activation by such types of compound.
†CCDC 928221–928223. For crystallographic data in CIF or other electronic
format see DOI: 10.1039/c3dt50934f
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Scheme 1 The synthesis of the complex [In(AP)2]−[Na(DME)3]+ (1).
with three dimethoxyethane molecules. The indium atom in
the anion has a distorted tetrahedral ligand environment, the
Results and discussion
The object of the present investigation is the anionic indium(III) O and N atoms of both imQ ligands occupy the tetrahedron
complex containing two 4,6-di-tert-butyl-N-(2,6-di-iso-propyl- vertices. The dihedral angle between the C6H2O(1)N(1) and
phenyl)-o-amidophenolate dianion ligands [In(AP)2]−[Na- C6H2O(2)N(2) planes of the redox active ligands is 81.82°. On
(DME)3]+ (1), which is an analogue of the cobalt derivatives3 the contrary, the analogous cobalt(III) bis-o-amidophenolate
mentioned above. Compound 1 forms as the result of the reac- anions have a square planar geometry of the coordination
tion between indium(I) iodide and sodium o-iminobenzosemi- center.3 The C–O (1.355(3)–1.364(3) Å) and C–N (1.394(3)–
quinolate (imSQNa) (Scheme 1a). The interaction proceeds at 1.397(3) Å) distances lie in the range typical for the dianion form
−20 °C in the presence of N,N,N′,N′-tetramethylethylenedi- of the o-iminobenzoquinone ligand.8 The values of In–O (2.0633
amine (TMED) which increases the solubility of InI.6 During (15)–2.0646(17) Å) and In–N (2.057(2)–2.070(2) Å) bond lengths
this reaction the mixture color changes from bright blue to are less than the sum of the covalent radii of the corres-
pale yellow. This indicates the reduction of the o-iminosemi- ponding elements (2.16 Å for In–O9 and 2.17 Å for In–N9) and
quinolate ligand to the o-amidophenolate one and the for- are comparable with those values in known o-amidophenolate
mation of indium(III) species. The related process was recently indium compounds.10 The C6H2 rings of AP ligands contain
observed in the course of interaction of potassium 3,6-di-tert- equalized C–C distances (1.384(3)–1.432(3) Å) and have an aro-
butyl-o-semiquinolate with InI.7
The complex 1 can also be obtained by the exchange reac- redox active ligands in 1.
matic nature. All these facts point out the dianion nature of
tion between indium(III) iodide and disodium o-amidopheno-
Compound 1 was found to react readily with methyl and
late (APNa2) in the molar ratio 1 : 2 (Scheme 1b). This method ethyl iodides. The interaction with an excess of RI (R = Me, Et)
seems to be more convenient for the preparation of 1.
The structure of complex 1 was determined by X-ray diffrac- in boiling THF. The reaction mixture color changes from pale
tion analysis (Fig. 1). yellow to bright orange-yellow and the precipitation of NaI is
proceeds slowly at room temperature but completes in 4 hours
The compound 1 is the ate-complex containing a bis-(o-ami- observed. This process involves two equivalents of RI per one
dophenolato)indium(III) anion and sodium cation coordinated equivalent of complex 1 and results in the formation of the
diamagnetic products 2 and 3 (Scheme 2). On the contrary,
related cobalt(III) derivatives react with alkyl halides in molar
ratio 1 : 1 that leads to the oxidation of amidophenolate
ligands to the o-iminosemiquinolate ones and the formation
of a Co–alkyl bond.3
The structures of compounds 2 and 3 were confirmed by
X-ray diffraction analysis (Fig. 2 and 3). Selected bond lengths
and angles of the complexes are given in Table 1. The geo-
metry of the coordination polyhedra in 2 and 3 can be described
as distorted tetragonal pyramidal or a trigonal bipyramidal.
The N(1), N(2), O(1) and O(2) atoms form the tetragonal
pyramid base while the I(1) atom occupies the apical site. The
N(1), N(2) and I(1) atoms lie in equatorial positions and O(1)
and O(2) atoms are in apical sides in the case of the second
polyhedron. The univocal choice of the coordination poly-
hedron type is unclear. The authors11 propose to use the
Fig. 1 The molecule structure of the [In(AP)2]− anion of 1 with 50% thermal
probability ellipsoids. The H atoms and methyl groups of i-Pr substituents are
omitted for clarity.
10534 | Dalton Trans., 2013, 42, 10533–10539
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Scheme 2 The reaction of complex 1 with alkyl iodides.
Table 1 Selected bond lengths [Å] and angles [°] of complexes 1·0.5DME,
2 and 3
Bond lengths (Å)
1·0.5DME
2
3
In(1)–O(1)
In(1)–O(2)
In(1)–N(1)
In(1)–N(2)
In(1)–I(1)
N(1)–C(1)
N(2)–C(27)
O(1)–C(2)
O(2)–C(28)
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
2.0651(15)
2.0645(13)
2.0565(17)
2.0684(18)
—
2.083(3)
2.077(3)
2.214(4)
2.224(3)
2.7106(6)
1.308(5)
1.300(5)
1.354(6)
1.342(4)
1.474(7)
1.344(6)
1.526(8)
1.485(8)
1.317(6)
1.436(7)
1.472(5)
1.351(5)
1.517(5)
1.503(5)
1.337(5)
1.450(5)
1.623(8)
1.571(6)
—
2.0771(16)
2.0869(18)
2.2018(18)
2.2222(19)
2.7001(3)
1.308(3)
1.300(3)
1.332(3)
1.329(3)
1.477(3)
1.357(4)
1.507(3)
1.500(3)
1.343(4)
1.433(3)
1.472(4)
1.349(4)
1.523(4)
1.475(5)
1.325(4)
1.451(4)
1.584(4)
—
1.399(3)
1.392(2)
1.359(3)
1.358(3)
1.423(3)
1.404(3)
1.404(3)
1.387(3)
1.392(3)
1.394(3)
1.432(3)
1.398(3)
1.411(3)
1.390(3)
1.393(3)
1.400(3)
—
Fig. 2 The molecule structure of complex 2 with 50% thermal probability ellip-
soids. The H atoms and methyl groups of i-Pr substituents are omitted for clarity.
C(5)–C(6)
C(1)–C(6)
C(27)–C(28)
C(28)–C(29)
C(29)–C(30)
C(30)–C(31)
C(31)–C(32)
C(27)–C(32)
C(4)–C(53)
C(30)–C(54)
C(30)–C(55)
—
—
1.598(6)
Angles (°)
O(1)–In(1)–O(2)
O(1)–In(1)–N(1)
O(1)–In(1)–N(2)
N(1)–In(1)–N(2)
N(1)–In(1)–O(2)
O(2)–In(1)–N(2)
O(1)–In(1)–I(1)
N(1)–In(1)–I(1)
O(2)–In(1)–I(1)
N(2)–In(1)–I(1)
111.07(6)
82.00(6)
129.09(6)
131.30(7)
125.41(6)
81.99(6)
—
—
—
—
157.54(13)
76.50(13)
97.85(11)
126.28(13)
88.87(12)
76.99(11)
100.90(10)
115.64(9)
100.78(8)
117.85(9)
151.94(8)
77.14(7)
91.96(7)
135.37(7)
94.18(7)
75.42(7)
106.60(5)
114.35(5)
101.30(6)
110.25(5)
Fig. 3 The molecule structure of complex 3 with 50% thermal probability ellip-
soids. The H atoms and methyl groups of i-Pr substituents are omitted for clarity.
geometric parameter τ for the definition of coordination geo-
metry in five-coordinate complexes. τ is equal to zero for a per-
fectly tetragonal geometry, while it becomes one for a perfectly
trigonal-bipyramidal geometry. In the case of 3 (τ = 0.28) the
coordination geometry is probably better described as a trigon-
ally distorted tetragonal pyramid, while in the case of 2 the τ sum of the covalent radii of the corresponding elements
parameter has an intermediate value (0.52). The six-membered (2.17 Å)9 and close to those in an indium(III) complex contain-
carbon C(1)–C(6) and C(27)–C(32) cycles of both ligands in 2 ing the neutral form of the imQ ligand.12 These bonds
and 3 contain sp3-hybridized C(4) and C(30) atoms bonded have donor–acceptor nature. The C–O bond lengths (1.329(3)–
with methyl (ethyl) groups. The In–O bond lengths (2.077(3)– 1.354(6) Å) are comparable with these distances in complex 1
2.0869(18) Å) are comparable with those in complex 1 and and are single while the C–N bonds (1.300(5)–1.308(5) Å) are
typical for an In–O single bond in catecholate and o-amidophe- shorter than the corresponding distances in 1 and are double.
nolate indium complexes.7,10 On the other hand, the values of In the six-membered carbon cyclohexadiene rings the double
the In–N distances (2.2018(18)–2.224(3) Å) are more than the CvC bonds alternate with two single C–C bonds. Thus, both
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Scheme 3 The possible isomers of complexes 2 (R = Me) and 3 (R = Et).
ligands in the complexes obtained are iminocyclohexa-1,4-di- and doesn’t depend on NMR sample temperature. The sample
enolates. Such a type of ligand was recently described for a of complex 3 prepared from the solution of single crystals suit-
tin(IV) compound.4a It should be noted that alkyl groups bonded able for X-ray diffraction shows the presence of predominantly
with C(4) and C(30) atoms are located on the opposite sides of one isomer according to the NMR spectroscopy. ge-HSQC,
the basal plane of the complexes both in 2 and 3. Moreover, ge-HMBC, and ge-COSY were used for attributing the groups
the methyl groups of the ethyl substituents in complex 3 are of signals to the structure fragments and assignments of 1H
turned towards the six-membered C(1)–C(6) and C(27)–C(32) and 13C NMR spectra.
rings. Such a configuration was found for a Sn(IV) derivative
The authors3 proposed a nucleophilic substitution SN2
containing the same iminocyclohexa-1,4-dienolate ligand.4a nature of the interaction between square-planar Co(III) bis-o-
The calculation of the energy barrier of the Et-groups rotation amidophenolate and alkyl halides. It is likely that the reaction
shows that this rotation is hindered and two different orien- of the related tetrahedral indium anion proceeds by an
tations of these fragments are possible for the Sn(IV) complex. another mechanism. This is indicated by the basically
Only one of them is realized in the crystal.4a In the case of different reaction products and stoichiometry. The univocal
complex 3 one probable orientation of the Et-groups is realized choice of the mechanism of the reaction requires additional
too. It is necessary to note that the new C–C bonds are research and will be the subject of subsequent studies.
much longer (1.571(6)–1.623(8) Å) than the typical bonds
between sp3 hybridized carbon atoms (1.54 Å). It may cause
the lability of new C–C bonds and promote their chemical
Experimental
Experimental details
transformations.
The presence of two bidentate ligands containing sp3-hybri-
All reactants were purchased from Aldrich. Solvents were puri-
fied by standard methods.13 The following reactants sodium
o-iminosemiquinolate (imSQNa),12 disodium o-amidopheno-
late (APNa2),12 indium(III) iodide (InI3)14 and indium(I) iodide
(InI)14 were prepared according to known procedures. All
manipulations on complexes were performed in vacuum under
conditions in which oxygen and moisture were excluded.
The infrared spectra of complexes in the 4000–400 cm−1
range were recorded on a FSM 1201 Fourier-IR spectrometer in
nujol. NMR spectra were recorded in CDCl3 solution by using
a Bruker Avance III 400 MHz instrument with TMS as an
internal standard. The elemental analysis was performed on
an Elemental Analyzer Euro EA 3000 instrument.
dized carbon atoms in the five-coordinated complexes 2 and 3
should lead to the formation of isomeric molecules that vary
in the position of the Me(Et) groups relative to the basal plane.
Another type of isomerism was shown to be characteristic for
related five-coordinated o-iminoquinolate metal derivatives.4a,b,12
This was due to the different location of two o-iminoquinone
ligands about the metal–X bond (X is any substituent). These
types of isomerism can lead to the formation of six probable
isomers a–f (Scheme 3). Moreover, the possibility of formation
of conformers with a different orientation of Et substitutes
relatively to the cyclohexadiene rings should not be excluded
in the case of complex 3.
In accordance with X-ray diffraction analysis data, isomer b
is present in the crystal unit of both complexes 2 and 3 only.
However, the 1H and 13C NMR spectra of solutions prepared
using microcrystalline samples of 2 and 3 are typical for
systems containing several isomers/diastereomers mixtures.
Synthesis of [In(AP)2]−[Na(DME)3]+ (1)
Method 1. The solution of imSQNa (0.48 g, 1.19 mmol) in
THF (25 mL) was added to an InI dispersion (0.1438 g,
0.595 mmol) in the same solvent (5 mL). The TMED (0.5 mL)
was added to this solution. The reaction mixture was stirred
for 1 h at −20 °C till the complete disappearance of the InI pre-
cipitate. During this the reaction mixture color changed from
bright blue to pale yellow. THF was removed under reduced
pressure and the residue was dissolved in hexane (25 mL). The
1
Almost any signals observed in the H or 13C NMR spectra are
represented by groups of signals belonging to different
isomers. These signals are either separated or overlapping.
The ratio of isomers may be approximately determined by
comparing the intensities of resolved signals in the 13C NMR
spectra. This ratio depends on the recrystallization conditions
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NaI precipitate was removed by filtration. The DME (5 mL) was 1149 m, 1102 m, 1081 w, 1056 w, 1036 m, 1013 w, 1000 m,
added to the hexane solution. The dimethoxyethane solvated 980 m, 937 w, 888 m, 877 m, 820 w, 800 m, 786 m, 764 m,
complex 1 was obtained as fine crystalline nearly colorless 702 w, 688 w, 673 w, 643 w, 627 w, 615 w, 578 m, 537 w, 524 w,
product after cooling. Yield for 1·0.5DME: 0.587 g (81.4%). 508 w, 497 w cm−1
.
C66H109InN2NaO9: calcd C 65.38, H 9.06, In 9.47, Na 1.90;
found C 65.44, H 9.11, In 9.39, Na 1.85.
Complex 3. Yield: 0.272 g (77.8%). C56H84IInN2O2: calcd C
63.51, H 7.99, In 10.84, I 11.98; found C 63.56, H 8.05, In
1H NMR (CDCl3, J1HH/Hz, 20 °C): δ = 6.95–7.06 (m, 6H, 10.78, I 11.91.
H
anyl); 6.48 (d, J = 2.4, 2H, C–Harom); 5.93 (d, J = 2.4, 2H,
1H NMR (CDCl3, J1HH/Hz, 20 °C): δ = 7.16–7.25 (m, 4H, Hanyl);
C–Harom); 3.54 (s, 14H, CH2 (DME)), 3.31 (s, 21H, CH3 (DME)); 7.06–7.11 (m, 2H, Hanyl); 6.05–6.12 (s, 2H, H (C–H)); 3.68–3.77 (t,
2.7 (broad m, 4H, C–H (i-Pr)); 1.46, 1.06 (s, 36H, CH3 (t-Bu)); 2H, H(H–Csp3)); 3.06–3.30, 2.58–2.74 (sept, 4H, CH (i-Pr));
1.10, 0.10 (broad, CH3 (i-Pr)) ppm.
13C NMR (CDCl3, 20 °C): δ = 146.6, 146.5, 144.0, 143.6, 0.96–1.10, 0.93–1.11 (18H + 36H, CH3 (i-Pr), CH3 (t-Bu)) ppm.
137.9, 132.6 (Canyl); 124.9, 123.4 (broad, CHanyl); 109.2, 107.1
13C NMR (CDCl3, 20 °C): δ = 171.5–171.8 (vC-(t-Bu));
(CHarom); 71.5, 59.0 (DME); 34.7, 34.2 (C (t-Bu)); 31.7, 30.6 166.4–166.9 (CvN); 148.3–148.8 (C–O); 139.7–142.5 (vC-
(CH3 (t-Bu)); 31.6 (CH (i-Pr)); 23.7 (broad, CH3 (i-Pr)) ppm. (i-Pr)); 135.6–136.4 (vC-(t-Bu)); 125.9–126.2, 122.7–123.9
1.76–1.97 (m, 4H, CH2(Et–Csp3)); 1.28–1.35 (d, 6H, CH3 (i-Pr));
IR (Nujol): ν = 1582 w, 1551 m, 1445 s, 1415 s, 1359 m, 1332 (CHanyl); 117.2–117.9 (vCH); 42.6–43.6 (CH2CH3); 35.5–37.2
s, 1282 s, 1258 m, 1235 s, 1218 m, 1204 m, 1191 m, 1167 w, (C (t-Bu)); 30.2–30.5, 28.3–28.5 (CH3 (t-Bu)); 27.9–28.2 (CH
1159 w, 1122 s, 1115 m, 1084 s, 1042 w, 1030 w, 986 m, 936 w, (i-Pr)); 23.5–26.2 (CH3 (i-Pr)); 5.3–5.5 (CH2CH3) ppm.
1
920 w, 899 w, 882 w, 857 w, 840 w, 829 w, 817 w, 799 m, 765 w,
For the single crystal sample of complex 3 H NMR (CDCl3,
743 w, 714 w, 674 w, 654 w, 609 w, 579 w, 545 w, 530 w, 510 w, J1HH/Hz, 20 °C): δ = 7.20 (m, 4H, Hanyl), 7.09 (m, 2H, Hanyl),
499 w cm−1
6.08 (s, 2H, H (C–H)), 3.72 (t, 2H, H (H–Csp3)), 3.16 (sept, J =
.
Method 2. The solution of APNa2 (0.485 g, 1.14 mmol) in 6.64, 2H, CH (i-Pr)), 2.68 (sept, J = 6.64, 2H, CH (i-Pr)), 1.85 (m,
THF (25 mL) was added to the solution of InI3 (0.282 g, 4H, CH2 (Et–Csp3)), 1.31 (d, J = 6.64, 6H, CH3 (i-Pr)), 1.08 (d, J =
0.57 mmol) in the same solvent (5 mL). The reaction mixture 6.64, 6H, CH3 (i-Pr)), 1.05 (s, 18H, CH3 (t-Bu)), 1.04 (d, J = 6.64,
became pale yellow in a few minutes. The forming complex 6H, CH3 (i-Pr)), 1.02 (d, J = 6.64, 6H, CH3 (i-Pr)), 0.99 (s, 18H,
1·0.5DME was isolated according to the method 1. Yield: CH3 (t-Bu)), 0.46 (t, J = 7.16, CH3 (Et–Csp3)) ppm.
0.625 g (86.7%).
IR (Nujol): ν = 1626 s, 1592 m, 1567 s, 1533 s, 1450 s, 1399 s,
1395 s, 1355 s, 1350 s, 1332 m, 1311 s, 1257 s, 1235 s, 1223 s,
1187 s, 1164 m, 1148 m, 1094 m, 1039 w, 1027 w, 1018 w, 988 w,
The reaction of complex 1 with methyl and ethyl iodides
An excess of RI (1.65 mmol) was added to the solution of 970 w, 922 w, 891 m, 885 m, 879 m, 868 m, 838 w, 821 w, 808 w,
complex 1 (0.4 g, 0.33 mmol) in THF (30 mL). The reaction 792 w, 767 s, 744 w, 705 w, 682 w, 668 m, 635 w, 621 w, 568 w,
mixture was heated at the temperature of boiling solvent for 550 m, 539 m, 533 w, 494 w cm−1
4 h. The reaction was accompanied by the color change from
.
NMR investigation for 2 and 3
pale yellow to bright orange-yellow and precipitation of NaI.
1
The THF was removed under reduced pressure and the residue Almost all signals observed in H or 13C NMR spectra are rep-
was dissolved in hexane (25 mL). The NaI was removed by fil- resented by groups of signals belonging to different isomers.
tration. The hexane was replaced by acetonitrile (30 mL). The Some signals are separated and most are overlapped. Up to
complexes 2 and 3 were isolated as finely crystalline products.
four lines with an intensities ratio of 1 : 1.2 : 1.2 : 1.8 are
Complex 2. Yield: 0.277 g (81.4%). C54H80IInN2O2: calcd C observed in the 13C NMR spectrum for the signals of C–O,
62.91, H 7.82, In 11.14, I 12.31; found C 62.99, H 7.89, In C–(i-Pr) and some others. According to this ratio there are three
11.08, I 12.28.
isomers/diastereomers in a ratio of approximately 1 : 1.8 : 2.4
1H NMR (CDCl3, 20 °C): δ = 7.14–7.26 (m, 4H, Hanyl); or four isomers/diastereomers in a ratio of 1 : 1.2 : 1.2 : 1.8 in
7.04–7.11 (m, 2H, Hanyl); 5.86–5.92 (s, 2H, H (C–H)); 3.35–3.51 the mixture. This uncertainty is due to the presence of signals
(q, 2H, H(H–Csp3)); 3.10–3.35, 2.52–2.76 (sept, 4H, CH (i-Pr)); with equal intensity, which may be caused by two isomers with
1.27–1.40 (d, 6H, CH3 (i-Pr)); 1.11–1.25 (d, 6H, CH3 (Me–Csp3)); an equal ratio or one isomer with unsymmetrical fragments.
0.93–1.11 (18H + 36H, CH3 (i-Pr), CH3 (t-Bu)) ppm.
X-Ray crystallographic study of 1·0.5DME, 2 and 3
13C NMR (CDCl3, 20 °C): δ = 175.8–176.1 (vC-(t-Bu));
165.7–166.5 (CvN); 146.3–147.2 (C–O); 140.9–142.4 (vC- The single crystals suitable for X-ray diffraction analysis were
(i-Pr)); 140.9–141.5 (N–Canyl); 140.1–140.7 (vC-(t-Bu)); 125.9– obtained from DME (for 1·0.5DME), hexane (for 2) and aceto-
126.2, 123.2–123.9 (CHanyl); 114.4–115.2 (vCH); 38.1–38.4 nitrile (for 3). Intensity data were collected at 150 K (for
(Csp3); 36.8–37.0 (C (t-Bu)); 35.6–35.9 (CH3 (Me–Csp3)); 1·0.5DME) and 100 K (for 2 and 3) on a Smart Apex diffract-
30.1–30.3 (CH3 (t-Bu)); 28.3–28.7 (CH3 (t-Bu)); 28.0–28.6 (CH ometer with graphite monochromated Mo-Kα radiation (λ =
(i-Pr)); 23.5–27.1 (CH3 (i-Pr)) ppm.
0.71073 Å) in the φ–ω scan mode (ω = 0.3°, 10 s on each
IR (Nujol): ν = 1633 s, 1623 s, 1565 s, 1535 s, 1528 s, 1508 s, frame). The intensity data were integrated by the SAINT
1503 s, 1447 s, 1397 s, 1365 s, 1357 s, 1323 m, 1314 m, program.15 SADABS16 was used to perform area-detector
1260 m, 1254 m, 1247 m, 1236 s, 1223 s, 1212 s, 1185 m, scaling and absorption corrections. The structures 1·0.5DME,
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Table 2 Summary of crystal and refinement data for complexes 1·0.5DME, 2 and 3
Complex
1·0.5DME
66H109InN2NaO9
1212.36
150(2)
0.71073
Triclinic
ˉ
P1
2
3
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
C
C54H80IInN2O2
1030.92
100(2)
0.71073
Triclinic
C56H84IInN2O2
1058.97
100(2)
0.71073
Triclinic
ˉ
ˉ
Space group
P1
P1
Unit cell dimensions
a = 13.1453(5) Å
b = 16.6419(6) Å
c = 17.5596(6) Å
α = 65.2340(10)°
β = 85.4070(10)°
γ = 87.6900(10)°
3476.8(2)
a = 10.4639(19) Å
b = 12.638(2) Å
c = 22.385(4) Å
α = 74.287(3)°
β = 78.611(2)°
γ = 72.322(2)°
2693.6(8)
a = 11.1943(6) Å
b = 13.2672(7) Å
c = 20.1217(11) Å
α = 81.4470(10)°
β = 77.8950(10)°
γ = 71.0840(10)°
2753.6(3)
Volume (Å3)
Z
2
2
2
Density (calculated) (g cm−3
)
1.158
0.397
0.40 × 0.38 × 0.15
2.05 to 25.00
19 479
1.271
1.050
0.46 × 0.16 × 0.07
1.91 to 25.00
20 315
1.277
1.029
0.26 × 0.13 × 0.12
2.08 to 26.00
23 822
Absorption coefficient (mm−1
)
Crystal size (mm3)
Theta range for data collection, grad.
Reflections collected
Independent reflections (Rint
Completeness to theta max (%)
Absorption correction
Max. and min. transmission
Refinement method
Data/restraints/parameters
Final R indices [I > 2σ(I)]
)
12 168 (0.0199)
99.4
Semi-empirical from equivalents
0.9428 and 0.8573
Full-matrix least-squares on F2
12 168/98/745
R1 = 0.0481
9401 (0.0693)
99.1
Semi-empirical from equivalents
0.9302 and 0.6439
Full-matrix least-squares on F2
9401/10/569
R1 = 0.0600
10 757 (0.0229)
99.3
Semi-empirical from equivalents
0.8865 and 0.7758
Full-matrix least-squares on F2
10 757/13/605
R1 = 0.0398
wR2 = 0.1248
R1 = 0.0557
wR2 = 0.1301
1.072
wR2 = 0.1338
R1 = 0.1098
wR2 = 0.1471
0.943
wR2 = 0.0975
R1 = 0.0530
wR2 = 0.1027
1.053
R indices (all data)
Goodness-of-fit on F2
Largest diff. peak and hole (e Å−3
)
1.232 and −0.841
1.906 and −0.957
1.524 and −1.167
2 and 3 were solved by direct methods and were refined on F2
using all reflections with SHELXTL package.17 All non-hydro-
gen atoms were refined anisotropically. The hydrogen atoms
were placed in calculated positions and refined in the “riding-
model”. Selected bond lengths and angles of complexes
obtained are given in Table 1. Table 2 summarises the crystal
data and some details of the data collection and refinement.
Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic Data Centre,
CCDC no. 928221–928223 for compounds 1–3.
Notes and references
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In summary, new C–C bond formation was observed in the
course of the redox active ligand mediated reaction between
alkyl iodides and an indium(III) bis-o-amidophenolate anion.
The reaction proceeds at mild conditions and leads to new
indium(III) derivatives containing iminocyclohexa-1,4-dienolate
ligands.
Acknowledgements
We are grateful to the FSP “Scientific and Scientific-Pedagogi-
cal Cadres of Innovation Russia” for 2009–2013 years (GK
8465), Russian Foundation for Basic Research (grant 13-03-
97048-r_povolzh’e_a, 13-03-00891), Russian President Grants
(NSh-1113.2012.3) for financial support of this work.
10538 | Dalton Trans., 2013, 42, 10533–10539
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