Cu(i) complexes based on cis, cis-1,3,5-tris(arylideneamino)cyclohexane ligands: Synthesis, structure and CO binding

Article abstract of DOI:10.1039/c0dt00986e

A new series of sterically bulky, facially coordinating N₃-donor tach-based ligands (tach; cis,cis-1,3,5-triaminocyclohexane) [2.1; cis,cis-1,3,5-tris(2,4-dimethylbenzylideneamino)cyclohexane, 4.1; cis,cis-1,3,5-tris(pentamethylbenzylideneamino)cyclohexane, 5.1; cis,cis-1,3,5-tris(2,6-dimethoxybenzylideneamino)cyclohexane, 6.1; cis,cis-1,3,5-tris(pentafluorobenzylideneamino)cyclohexane, 7.1; cis,cis-1,3,5-tris(3,5-bis(ditrifluoromethyl)benzylideneamino)cyclohexane, 8.1; cis,cis-1,3,5-tris(2-trifluoromethylbenzylideneamino)cyclohexane, 9.1; cis,cis-1,3,5-tris(2-methoxybenzylideneamino)cyclohexane] have been obtained from the condensation of tach with three equivalents of the appropriate substituted benzaldehyde. Reaction with [Cu(NCCH₃) ₄]PF₆ gives Cu(i) complexes of tach-based ligands {2.2-9.2, eg; 2.2; [Cu(2.1)(NCCH₃)]PF₆}. Displacement of the acetonitrile ligand by CO was achieved successfully for all the Cu(i) complexes of tach-based ligands and the resulting complexes have been shown to bind carbon monoxide {2.3-9.3, eg; 2.3; [Cu(2.1)(CO)]PF₆}. The X-ray single crystal structures of 5.1, 8.1, 9.1, 3.2, 7.2, 8.2, 9.2, 3.3, 5.3 and 6.3 have been determined. The Royal Society of Chemistry 2010.

Full text of DOI:10.1039/c0dt00986e

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www.rsc.org/dalton | Dalton Transactions
Cu(I) complexes based on cis, cis-1,3,5-tris(arylideneamino)cyclohexane
ligands: synthesis, structure and CO binding†
Parisa Ebrahimpour, Michael Cushion, Mairi F. Haddow, Andrew J. Hallett and Duncan F. Wass*
Received 9th August 2010, Accepted 6th September 2010
DOI: 10.1039/c0dt00986e
A new series of sterically bulky, facially coordinating N3-donor tach-based ligands (tach;
cis,cis-1,3,5-triaminocyclohexane) [2.1; cis,cis-1,3,5-tris(2,4-dimethylbenzylideneamino)cyclohexane,
4.1; cis,cis-1,3,5-tris(pentamethylbenzylideneamino)cyclohexane, 5.1; cis,cis-1,3,5-tris(2,6-
dimethoxybenzylideneamino)cyclohexane, 6.1; cis,cis-1,3,5-tris(pentafluorobenzylideneamino)-
cyclohexane, 7.1; cis,cis-1,3,5-tris(3,5-bis(ditrifluoromethyl)benzylideneamino)cyclohexane, 8.1;
cis,cis-1,3,5-tris(2-trifluoromethylbenzylideneamino)cyclohexane, 9.1; cis,cis-1,3,5-tris(2-
methoxybenzylideneamino)cyclohexane] have been obtained from the condensation of tach with three
equivalents of the appropriate substituted benzaldehyde. Reaction with [Cu(NCCH3)4]PF6 gives Cu(I)
complexes of tach-based ligands {2.2–9.2, eg; 2.2; [Cu(2.1)(NCCH3)]PF6}. Displacement of the
acetonitrile ligand by CO was achieved successfully for all the Cu(I) complexes of tach-based ligands
and the resulting complexes have been shown to bind carbon monoxide {2.3–9.3, eg; 2.3;
[Cu(2.1)(CO)]PF6}. The X-ray single crystal structures of 5.1, 8.1, 9.1, 3.2, 7.2, 8.2, 9.2, 3.3, 5.3 and 6.3
have been determined.
ands, their Cu(I) complexes and the propensity of such complexes
to bind CO.
Introduction
Ligands based on
a cis,cis-1,3,5-tris(arylamino)cyclohexane
framework have attracted attention as they provide a face-
capping N3-coordination environment around a metal centre
which is a versatile mimic for metalloenzyme active sites.1–5 More
generally, these ligands form a protected cavity around the metal
centre which has been exploited in biomimetic and catalysis
research.6–9 Several synthetic routes for the generation of cis,cis-
1,3,5-triaminocyclohexane (tach) ligands have been reported.10–12
A general disadvantage of these methods is the undesirable genera-
tion of cis and trans isomers, which are difficult to separate. Planalp
and co-workers discovered a synthetic route that almost exclusively
produces the cis-isomer of tach (1) from the commercially available
cis,cis-1,3,5-cyclohexanetricarboxylic acid; this route is key in
enabling the use of this ligand framework.13
Our interest in such ligands stems from the potential their
group 11 complexes to separate simple substrates (such as CO
and ethylene) from the mixture of waste gases that are common
in petrochemical plants and refining, by weakly binding to such
molecules.14 Moreover such complexes could also be used in
concentrating and delivering 11CO, an important development for
radiolabelling in positron emission tomography technology.15
We have previously communicated the synthesis and prelimi-
nary study of one derivative of tach-based ligands, namely cis,cis-
1,3,5-tris(mesitylideneamino)cyclohexane, its copper(I) complex
and the substrate binding selectivity of this complex.16 We report
here the syntheses and characterisation of a broader library of
novel non-fluorinated and fluorinated N3-donor tach-based lig-
Results and discussion
Synthesis and structural study of tach-based ligands
Cis,cis-1,3,5-tris(arylamino)cyclohexane ligands were prepared
by same the method we used to obtain cis,cis-1,3,5-
tris(mesitylideneamino)cyclohexane.16 Reaction of cis,cis-1,3,5-
triaminocyclohexane (tach) with three equivalents of the appro-
priate substituted benzaldehyde in toluene and removal of water
by azeotropic distillation over an 18–20 h period gave the relevant
1
tach-based ligands in 34 to 81% yield (see Scheme 1). The H
NMR spectrum of each ligand exhibited a characteristic broad
singlet around 8.50 ppm and a broad triplet of triplets around
3.50 ppm, corresponding to the amine protons (-N CHb-) and
cyclohexane protons ( N–CHa-) respectively. All the prepared
ligands are stable with respect to ambient conditions.
Scheme 1 General synthesis of tach-based ligands 2.1–9.1.
School of Chemistry, University of Bristol, Cantock’s Close, Bristol, UK
BS8 1TS. E-mail: duncan.wass@bristol.ac.uk
† CCDC reference numbers 788164–788173. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/c0dt00986e
Crystals of 5.1, 8.1 and 9.1 suitable for single crystal X-ray
analysis were obtained by slow evaporation of a CH2Cl2 solution
under ambient conditions. The structures of 5.1, 8.1 and 9.1
10910 | Dalton Trans., 2010, 39, 10910–10919
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◦
˚
Table 1 Selected bond lengths (A) and angles ( ) for 5.1·6(H2O), 8.1 and 9.1·CH2Cl2
5.1·6(H2O)
8.1
9.1·CH2Cl2
N1–C3
N1–C3–C4–C5
1.2712(16)
-147.88(13)
N1–C7
N2–C15
N3–C23
1.268(2)
1.270(2)
1.269(2)
N1–C7
N2–C15
N3–C23
1.269(2)
1.267(2)
1.272(2)
N1–C7–C8–C13
N2–C15–C16–C21
N3–C23–C24–C29
146.88(14)
-149.84(15)
177.04(14)
N1–C7–C8–C9
N2–C15–C16–C17
N3–C23–C24–C25
-166.70(18)
-173.19(19)
176.26(18)
Fig. 1 ORTEP representation of the molecular structures of 5.1·6(H2O), 8.1 and 9.1·CH2Cl2. For clarity all hydrogen atoms have been omitted as well
as a molecule of CH2Cl2 from 9.1 and six molecules of H2O from 5.1 molecular structures. Thermal ellipsoids are drawn at the 50% probability level.
are shown in Fig. 1 and selected bond and angles given in
Table 1.
Cu(I) complexes can be handled under ambient conditions for
approximately two weeks without any apparent decomposition;
polyfluorination of these ligands has been shown to increase
the thermal stability and the solubility in fluorocarbon solvents
of these metal complexes.17,18 Corresponding properties were
observed for the complexes 6.2 and 8.2, where an increased
degree of fluorination is present. Crystals containing 3.2, 7.2,
8.2 and 9.2 were grown from saturated dichloromethane–hexane
solutions. X-Ray crystallography data of 3.2·CH2Cl2, 7.2, 8.2 and
9.2·CH2Cl2 are given in Table 5. Molecular structures of 7.2, 8.2
and 9.2·CH2Cl2 (Fig. 2, with selected bond lengths and angles in
Table 2) show that the phenyl rings are arranged facially around
the copper centre, producing a cavity, in which one molecule of
acetonitrile can be accommodated (Scheme 1). The coordination
geometry around the Cu(I) centre is pseudo-tetrahedral, whereby
the Ntach–Cu–Ntach bond angles range between 86◦–102◦ and
the NMeCN–Cu–Ntach bond angles range between 114◦–129◦. A
slight shortening of the CMeCN –NMeCN bond length (1.132 to
Molecular structures of 5.1, 8.1 and 9.1 show the tach-based
ligand has three benzyl substituted imino arms that inherit the
cis,cis-stereochemistry. Each imine moiety adopts the sterically
favourable equatorial position, whereby the cyclohexane back-
bone is found in the chair conformation.
Synthesis and molecular structure of complexes
[Cu(NCMe)(2.1–9.1)]PF6 (2.2–9.2)
The Cu(I) complexes of tach-based ligands 2.2–9.2 were synthe-
sised in moderate to excellent yields (25–98%) by reaction with
the corresponding ligands 2.1–9.1 with [Cu(I)(NCCH3)4]PF6 in
CH2Cl2. The reaction between ligand and metal precursor was
monitored by 1H NMR spectroscopy. Observation of the Ha
protons provided an analytic NMR handle for the quantitative
assessment of the reaction progress. These cyclohexyl protons were
observed to resonate in the uncoordinated ligands 2.1–9.1 between
3.50–3.90 ppm (see Scheme 2). Upon coordination to Cu(I)-
NCMe fragments, these signals typically experience a downfield
shift to resonate between 4.10–4.40 ppm. Solid samples of these
˚
˚
1.143 A) in comparison with free acetonitrile (1.155 A) is
observed and it is expected upon coordination to a copper
centre.19
The Cu-complex of ligand 3.1 (compound 3.2) was obtained
from its reaction with [Cu(NCMe)4]PF6 in CH2Cl2, following
exactly the same method as other complexes. Surprisingly the 1H
NMR and elemental analysis obtained was not consistent with the
expected compound, analogous to other examples. This mystery
was illuminated by the X-ray crystal structure of 3.2 (Fig. 3),
showing co-crystallisation of the expected 3.2(A) with 3.2(B). The
molecular structure of 3.2(B) contains two 3.1 ligands in which the
phenyl arms of the two ligands are in equatorial position. Three
copper centres are coordinated to the nitrogen of each ligand
and adopt a linear geometry with an angle of 173.03◦. The Cu–
˚
N distance is 1.909 A on average and N C are approximately
Scheme 2 Reaction of tach-based ligands with [Cu(I)(NCCH3)4]PF6.
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◦
˚
Table 2 Selected bond lengths (A) and angles ( ) for 7.2, 8.2 and 9.2·CH2Cl2
7.2
8.2
9.2·CH2Cl2
N4–C1
N4–Cu1
N1–C9
N2–C27
1.137(4)
1.922(2)
1.275(4)
1.274(4)
1.283(4)
175.5(3)
-40.2(4)
-45.6(4)
157.4(3)
N2–C1
N2–Cu1
N1–C5
Cu1–N2–C1
N1–C5–C6–C7
1.138(5)
1.899(3)
1.269(3)
180.00(16)
-118.4(3)
N1–C1
N1–Cu1
N2–C9
N3–C17
1.143(4)
1.943(3)
1.283(4)
1.276(4)
1.273(4)
178.0(3)
162.0(3)
153.2(3)
37.5(4)
N3–C18
N4–C25
Cu1–N4–C1
N1–C9–C10–C15
N2–C27–C28–C33
N3–C18–C19–C20
Cu1–N1–C1
N2–C9–C10–C15
N3–C17–C18–C23
N4–C25–C26–C31
Fig. 2 ORTEP representation of the molecular structures of 7.2, 8.2 and 9.2·CH2Cl2. For clarity all hydrogen atoms and the [PF6]- counter ions have
been omitted as well as a molecule of CH2Cl2 from the molecular structure of 9.2. Thermal ellipsoids are drawn at the 50% probability level.
◦
˚
Table 3 Selected bond lengths (A) and angles ( ) for 3.2·CH2Cl2
3.2(A)
3.2(B)
Cu1–N1
Cu1–N2
Cu1–N3
Cu1–N4
N1–C9
N2–C16
N4–C7
2.105(7)
2.068(7)
2.063(7)
1.933(7)
1.283(10)
1.270(13)
1.132(10)
176.8(7)
Cu2–N9
Cu2–N5
Cu3–N6
Cu3–N10
Cu4–N7
Cu4–N8
N10–C77
N6–C43
N7–C50
N8–C63
N9–C70
N5–C36
N6–Cu3–N10
N6–Cu3–N10
N6–Cu3–N10
1.902(6)
1.922(6)
1.913(6)
1.906(6)
1.909(6)
1.907(6)
1.282(9)
1.269(9)
1.292(9)
1.291(9)
1.288(9)
1.265(9)
172.8(3)
172.4(3)
173.9(3)
Cu1–N4–C7
˚
1.281 A (see Table 3) whereby the other complex shows that the
Cu centre is four-coordinate and adopts a pseudo tetrahedral
geometry. The phenyl rings are arranged facially around the
coordinated acetonitrile. The coordinated acetonitrile is linear
Fig. 3 ORTEP representation of the molecular structure of 3.2·CH2Cl2.
For clarity all hydrogen atoms have been omitted as well as a molecule of
CH2Cl2 and the [PF6]- counter ions. Thermal ellipsoids are drawn at the
50% probability level.
˚
and the bond length of NMeCN–C7 is 1.132(10) A which is slightly
Reactivity of tach-based Cu(I) complexes with CO
˚
shorter than free acetonitrile (1.155 A). Other characterising data
(NMR spectra, elemental analysis) is consistent with this co-
crystalline product. Whilst the formation of 3.2(B) is certainly
unexpected, it is noteworthy that ligand 3.1 is the least sterically
bulky of those investigated, and therefore potentially the best able
to accommodate this structure.
Treatment of Cu(I) complexes (2.2–9.2) with CO in CH2Cl2 leads
to a marked colour change from intense yellow to much paler
yellow or colourless, and the complete replacement of acetonitrile
as monitored by 1H NMR. The IR spectra of these complexes show
the expected n(CO) between 2099–2073 cm-1 indicating minimal
10912 | Dalton Trans., 2010, 39, 10910–10919
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backbonding to the coordinated CO ligand.16,18 The trends in
n(CO) are very much as expected with complex 5.3, containing a
ligand with an electron-releasing 2,6-dimethoxy aryl substitution
pattern, appearing at 2073 cm-1, and complex 7.3, containing
an electron-withdrawing 3,5-ditrifluoromethyl aryl substitution
pattern, appearing at 2099 cm-1. As previously reported, cop-
per causes fast relaxation of proximal nuclei, and it was not
possible to observe the 13C NMR resonance for the coordinated
CO.16
Suitable crystals of 3.3, 5.3 and 6.3 for X-ray structure
determination were grown by slow diffusion of n-hexane into
CH2Cl2 solutions of these complexes. The molecular structures
are illustrated in Fig. 4, with selected bond lengths and angles
in Table 4. Crystals of 3.3, 5.3·CH2Cl2 and 6.3 form in the
¯
space groups C2/c, P213 and P3c1 respectively. Compound
6.3 has crystallographically-imposed threefold symmetry (as do
compounds 5.1 and 8.2). The copper complexes adopt a very
similar conformation to 3.2, 8.2 and 9.2, i.e. a pseudo tetrahedral
Fig. 4 ORTEP representation of the molecular structures of 3.3, 5.3·CH2Cl2and 6.3. For clarity all hydrogen atoms and the [PF6]- counter ions have
been omitted as well as a molecule of CH2Cl2 from the molecular structure of 5.3. Thermal ellipsoids are drawn at the 50% probability level.
◦
˚
Table 4 Selected bond lengths (A) and angles ( ) for 3.3, 5.3·CH2Cl2 and 6.3
3.3
5.3·CH2Cl2
6.3
C1–O1
Cu1–C1
N1–C8
N2–C15
1.150(6)
1.808(6)
1.294(6)
1.270(6)
1.294(6)
171.9(5)
44.9(8)
C1–O1
Cu1–C1
N1–C8
N2–C17
1.202(3)
1.938(2)
1.274(3)
1.227(3)
1.228(3)
179.4(2)
-50.4(3)
-55.7(3)
-48.0(3)
C1–O1
Cu1–C1
N1–C4
Cu1–C1–O1
N1–C4–C5–C6
1.117(9)
1.824(7)
1.273(5)
180.0
N3–C22
N3–C26
-46.5(5)
Cu1–C1–O1
N1–C8–C9–C14
N2–C15–C16–C21
N3–C22–C23–C24
Cu1–C1–O1
N1–C8–C9–C10
N2–C17–C18–C23
N3–C26–C27–C32
-45.2(7)
-31.2(8)
Table 5 X-Ray crystallography data of 5.1.6H2O, 7.1 and 9.1·CH2Cl2
Compound
5.1.6H2O
7.1
9.1·CH2Cl2
Colour, habit
Empirical formula
M
Yellow needle
C33H39N3O6.6(H2O)
681.77
Colourless plate
C30H24F9N3
597.52
Monoclinic
P21/n
14.9989(7)
8.0442(4)
23.7247(11)
90.00
102.2680(10)
90.00
2797.1(2)
4
0.126
Yellow block
C30H33N3O3·CH2Cl2
568.52
Crystal system
Trigonal
Monoclinic
P21/c
20.8117(17)
13.7364(10)
10.7141(7)
90.00
103.852(4)
90.00
2973.8(4)
4
¯
Space group
R3
˚
a/A
21.4700(7)
21.4700(7)
13.9509(10)
90.00
˚
b/A
˚
c/A
a (◦)
b (◦)
g (◦)
90.00
120.00
5569.3(5)
6
0.093
3
˚
V/A
Z
m/mm-1
0.254
100(2)
T/K
100(2)
100(2)
Reflections: (measured/unique/observed)
Rint
33104/4488/3081
0.0578
0.0565
24293/6481/4585
0.0370
0.0396
6951/6901/4459
—
0.0505
R1(observed reflection)[I ≥ 2 s (I)]
wR2(all reflection)
0.1769
0.1015
0.1162
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coordination for the Cu(I) centre. Notable is the significant
recorded on VG Analytical Quattro (ESI). Microanalyses were
carried out by the Microanalytical Laboratory of the School of
Chemistry at the University of Bristol.
˚
increase in the bond length of CO (1.20 A) in 5.3 compared with
20
˚
free CO (1.128 A). This is in contrast to the CO bond length of
˚
1.171 A in 6.3, and is consistent with the increased donor ability of
this methoxy-substituted derivative compared to the fluorinated
analogue.
Synthesis of ligands and complexes
Synthesis of tach-based ligands 2.1–9.1
One of the notable features of the complexes reported in our
preliminary communication is the preference for CO binding over
ethylene.16 Again with this wider set of derivatives, the facile
substitution of acetonitrile with CO is in contrast to the lack
of substitution reactivity of the same acetonitrile complexes with
olefins. Bubbling ethylene through dichloromethane solutions of
(2.2–9.2) gives no reaction. Only in the case of complex 8.2
when pressurised with 1–5 bar of ethylene in a high pressure
NMR tube, was the signal corresponding to coordinated ethylene
observed. Upon coordination of ethylene to the copper centre,
resonance for the olefinic protons was upfield shifted from
5.40 ppm for free ethylene to 5.23 ppm (-20 ◦C) for coordinated
The synthesis of tach-based ligands 2.1–9.1 will be described
in detail for cis,cis-1,3,5-tris(2,4-dimethylbenzylideneamino)-
cyclohexane (2.1) and is representative for the synthesis of ligands
3.1–9.1.
Synthesis of cis,cis-1,3,5-tris(2,4-dimethylbenzylideneamino)-
cyclohexane (2.1). Compound cis,cis-1,3,5-triaminocyclohexane
1 (0.50 g, 1.4 mmol) was dissolved in a solution of three equivalents
of sodium hydroxide (0.17 g, 4.2 mmol) in water (10 mL), followed
by addition of toluene (30 mL) and three equivalents of 2,4-
dimethylbenzaldehyde (0.56 g, 0.57 mL, 4.2 mmol). The reaction
2
ethylene in [(8.1)Cu(h -C2H4)]PF6.21 The moderate upfield shifting
◦
was heated to 150 C for 18–22 h, during which time water was
demonstrates a weak p-back donation from the copper centre
removed via azeotropic distillation with a Dean–Stark trap. The
solution was allowed to cool to ambient temperature, passed
through a short celite plug and the solvent was removed under
reduced pressure to leave a pale yellow solid. The crude product
was recrystallised from a minimal amount of hot diethylether and
dried in vacuo to give 2.1 as a white powder (0.31 g, 47% yield)
after purification.1H NMR (400.18 MHz, CD2Cl2): d 8.68 (s, 3H,
2
to ethylene.18,21,22 Compound [(8.1)Cu(h -C2H4)]PF6 was observed
to be stable under positive pressure of ethylene. However, it was
not possible to isolate the compound under ambient pressure,
suggesting a reversible complexation of ethylene to the copper
centre.
3
3
HC N), 7.78 (d, 3H, JHH 7.77 Hz, H5Ar), 7.07 (d, 3H, JHH
Conclusions
3
7.82 Hz, H6Ar), 7.04 (s, 3H, H3Ar), 3.58 (tt, 3H, JHH11.47 Hz,
3JHH 3.79 Hz, -CH-N ), 2.50 (s, 9H, ortho-ArCH3), 2.35 (s, 9H,
A set of novel non-fluorinated and fluorinated N3-donor tach-
based ligands (2.1–9.1) were synthesised and structurally charac-
terised. Cu-complexes of these ligands were obtained from their
reaction with [Cu(NCMe)4]PF6. The X-ray structures reveal a
sterically constrained cavity around the fourth coordination site
of the copper centre in which one molecule of acetonitrile can
be easily accommodated. In order to assess the ability of the
prepared Cu(I)–NCMe complexes of tach-based ligands (2.2–9.2)
to accommodate s-donating and p-accepting small molecules,
exchange reactions with CO were carried out. The reactions
were monitored by solution IR spectrometry and successful
displacement of the acetonitrile ligand by CO was observed for
all the Cu(I) complexes of tach-based ligands. By contrast, and in
line with our previous observations even for this broader library
of derivatives, ethylene is a poor ligand for such complexes.
3
para-ArCH3), 2.01 (q, br, 3H, JHH 11.93 Hz, trans-CHH-), 1.86
3
3
(dt, br, 3H, JHH11.73 Hz, JHH 3.79 Hz, cis-CHH-). 13C NMR
(100.6 MHz, CD2Cl2): d 157.7 (s, C N), 140.3 (s, Ar-C2), 137.6
(s, Ar-C4), 131.5 (s, Ar-C3), 127.4 (s, Ar-C6), 126.9 (s, Ar-C5), 123.5
(s, Ar-C1), 67.1 (s, cy-CH), 41.6 (s, cy-CH2), 21.1 (s, ortho-ArCH3)
and 19.1 (s, para-ArCH3). ESI mass spectrum: m/z = 500.30 [M +
Na]+, 478.322 [M+H]+. CI HR mass spectrum: m/z = 500.3042
[M +Na]+ (calcd 500.3036), 478.3223 [M +H]+ (calcd 478.3216).
Anal. calc. for C33H39N3: C, 82.97. H, 8.23. N, 8.80. Found: C,
83.00. H, 8.43. N, 8.71%.
Synthesis of cis,cis-1,3,5-tris(benzylideneamino)cyclohexane
(3.1). Sodium hydroxide (0.16 g, 4.2 mmol) in water (10 mL)
was added to compound 1 (0.5 g, 1.4 mmol), followed by toluene
(30 mL) and benzaldehyde (0.43 mL, 4.2 mmol). Yielded 3.1 as a
cream solid (0.4 g, 73%) after purification. 1H NMR (499.9 MHz,
CD2Cl2): d 8.30 (s, br, 3H, HC N), 7.66 (m, br, 6H, HAr), 7.33
Experimental
(m, br, 9H, HAr), 3.50 (tt, 3H, 3JHH 11.44 Hz, 3JHH 3.81 Hz, -CH-
3
General
N
), 1.89 (dd, 3H, JHH 11.60 Hz, trans-CHH-), 1.77 (m, 3H,
3JHH 11.90 Hz, 3JHH 3.97 Hz, cis-CHH-). 13C NMR (125.7 MHz,
CD2Cl2): d 158.5 (s, C N), 135.9 (s, Ar-Cipso), 129.7 (s, Ar-Cpara),
127.7 (s, Ar-Cortho), 127.3 (s, Ar-Cmeta), 65.6 (s, cy-CH), 40.3 (s,
cy-CH2).
All operations were carried out under an inert atmosphere of
argon or dinitrogen using standard Schlenk line techniques or
an MBraun glove box. Dry N2-saturated solvents were purified
using an anhydrous engineering Grubbs-type system.23 All other
chemicals were used as received unless otherwise stated. NMR
spectra were recorded using Varian VNMR S500, Jeol GX400,
Joel ECP (Eclipse) 400, Jeol ECP300 and Jeol Lambda 300
spectrometers. Compounds 1 and 3.1 were prepared as described
in the literature.13,24
Synthesis of cis,cis-1,3,5-tris(pentamethylbenzylideneamino)-
cyclohexane (4.1). Compound 1 (4.00 g, 10.75 mmol) was treated
by a solution of sodium hydroxide (1.29 g, 32.26 mmol) in water
(10 mL) followed by toluene (100 mL) and pentamethylbenzalde-
hyde (5.68 g, 32.26 mmol). The reaction was carried out under
the general reaction conditions for making tach-based-ligands.
The ligand 4.1 was obtained as a white/cream microcrystalline
IR solution spectra were recorded on a Perkin–Elmer 1600
series FTIR Spectrometer in dichloromethane. Mass spectra were
10914 | Dalton Trans., 2010, 39, 10910–10919
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solid (2.23 g, 34% yield). H NMR (300.5 MHz, CDCl3): d 8.75
801.14), CI HR mass spectrum: m/z = 824.1340 [M +Na]+ (calcd
824.1349), 802.1521 [M +H]+ (calcd 802.1509). Anal. calc. for
C33H21F18N3: C, 49.45. H, 2.64. N, 5.24. Found: C, 49.32, H, 2.83,
N, 5.18%.
1
3
3
(s, br, 3H, HC N), 3.70 (tt, 3H, JHH 11.30 Hz, JHH 3.80 Hz,
-CH-N ), 2.25 (s, 18H, ortho-CH3), 2.24 (s, 9H, para-CH3), 2.20
(s, 18H, meta-CH3), 2.02 (d, 3H, JHH 12.11 Hz, trans-CHH),
3
trans-CHH- obscured by ArCH3 signals. 13C NMR (100.6 MHz,
CD2Cl2): d 161.9 (s, C N), 140.1 (s, Ar-Cortho), 133.7 (Ar-Cmeta),
132.6 (Ar-Cpara), 131.4 (Ar-Cipso), 67.5 (cy-CH), 41.3 (cy-CH2),
17.4 (Ar–Cpara), 16.8 (Ar–Cmeta) and 15.9 (Ar-Cortho). ESI mass
spectrum: m/z = 626.44 [M + Na]+, 604.46 [M+H]+ (calcd 603.46).
CI HR mass spectrum: m/z = 626.4444 [M +Na]+ (calcd 626.4443),
604.4625 [M +H]+ (calcd 604.4625).
Synthesis of cis,cis-1,3,5-tris(2-trifluoromethylbenzylidene-
amino)cyclohexane (8.1). Sodium hydroxide (0.46 g, 12.09 mmol)
in water (10 mL) was added to 1 (1.50 g, 4.03 mmol), followed by
toluene (30 mL) and 2-(trifluoromethyl)benzaldehyde (1.59 mL,
2.11 g, 12.09 mmol). Yielded 8.1 as a white solid (1.94 g, 81%)
1
after purification. H NMR (299.9 MHz, CD2Cl2): d 8.73 (m,
3H, HC N), 8.22 (d, 3H, 3JHH 7.71 Hz, Hortho-Ar), 7.67 (m, 3H,
Hmeta(3)-Ar), 7.60 (m, 3H, Hmeta(5)-Ar), 7.51 (m, 3H, Hpara-Ar), 3.66
Synthesis of cis,cis-1,3,5-tris(2,6-dimethoxybenzylideneamino)-
cyclohexane (5.1). Treatment of compound 1 (0.74 g, 1.9 mmol)
in a solution of sodium hydroxide (0.15 g, 3.8 mmol) in water
(10 mL) and toluene (30 mL) with 2,6-dimethoxybenzaldehyde
(0.63 g, 3.8 mmol). Yielded 5.1 as a white solid (0.54 g, 47%). 1H
NMR (400.18 MHz, CD2Cl2): d 8.62 (s, 3H, HC N), 7.32 (t, 3H,
3JHH 8.42 Hz, HparaAr), 6.63 (d, 6H, 3JHH 8.43 Hz, HmetaAr), 3.85
(s,18H, -OCH3), 3.54 (tt, 3H, 3JHH 11.27 Hz, 3JHH 3.85 Hz, -CH-
3
3
(tt, 3H, JHH 11.40 Hz, JHH 4.0 Hz, -CH-N ), 2.03 (q, 3H,
3JHH 11.74 Hz, trans-CHH-), 1.85 (dt, 3H, JHH 11.74 Hz, JHH
3
3
4.12 Hz, cis-CHH-). 13C NMR (75.57 MHz, CD2Cl2): d 155.9 (s,
C
N), 134.6 (s, Ar-C5), 132.1 (s, Ar-C6), 130.1 (s, Ar-C4), 128.4
2
(q, JCF 32.31 Hz, Ar-C2), 128.4 (s, Ar-C1), 125.5 (s, Ar-Cmeta3),
124.4 (q, 1JCF 274.60 Hz -CF3), 66.5 (s, cy-CH), 40.6 (s, cy-CH2).
19F{ H} NMR (282.78 MHz, CD2Cl2): d -57.42 (s, -CF3). ESI
1
mass spectrum: m/z = 620.17 [M+Na]+, 598.19 [M+H]+. CI HR
mass spectrum: m/z = 620.1732 [M +Na]+ (calcd 620.1718),
598.1917 [M +H]+ (calcd 598.1899).
N
), 2.02 (q, br, 3H, 3JHH 11.61 Hz, trans-CHH-), 1.89 (m, 3H,
cis-CHH-). 13C NMR (100.6 MHz, CD2Cl2): d 159.5 (s, Ar-Cortho),
154.3 (s, C N), 130.8(s, Ar-Cpara), 104.3 (s, Ar-Cmeta), 103.7(s, Ar-
C
ipso), 68.3 (s, cy-CH), 56.1 (s, -OCH3), 41.5 (s, cy-CH2). ESI mass
Synthesis of cis,cis-1,3,5-tris(2-methoxybenzylideneamino)-
cyclohexane (9.1). Treatment of 1 (5.00 g, 13.44 mmol) in a
solution of sodium hydroxide (1.62 g, 40.35 mmol) in water
(10 mL) and toluene (100 mL) with three equivalents of 2-
methoxybenzaldehyde (4.87 mL, 5.49 g, 40.35 mmol). Yielded
spectrum: m/z = 574.29 [M+H]+. CI HR mass spectrum: m/z =
574.2930 [M +H]+ (calcd 574.2911).
Synthesis of cis,cis-1,3,5-tris(pentafluorobenzylideneamino)-
cyclohexane (6.1). Ligand 6.1 was obtained by addition of
sodium hydroxide (0.22 g, 3.6 mmol) in water (10 mL) to
compound 1 (0.70 g, 1.8 mmol) followed by toluene (30 mL)
and pentafluorobenzaldehyde (0.67 mL, 3.6 mmol), under general
reaction conditions. Yielded 6.1 (0.54 g, 44%) as a cream solid.
1H NMR (299.9 MHz, CD2Cl2): d 8.47 (s, 3H, HC N), 3.60
(tt, 3H, 3JHH 11.38 Hz, 3JHH 4.13 Hz, -CH-N ), 2.03 (q, br, 3H,
trans-CHH-), 1.88 (m, br, 3H, cis-CHH-). 13C NMR (125 MHz,
CD2Cl2): d 147.5 (s, C N), 145.2 (dm, 1JCF 256.27 Hz, Ar-Cortho),
1
9.1 as a cream solid (0.54.33 g, 67%). H NMR (400.18 MHz;
3
CD2Cl2): d 8.84 (s, br, 3H, HC N), 7.98 (dd, 3H, JHH 7.7 Hz,
4JHH 1.8 Hz, H6-Ar), 7.42 (ddd, 3H, 3JHH 8.3 Hz, 3JHH 7.2 Hz, H5-
Ar), 7.01 (t, 3H, 3JHH 7.50 Hz, H4-Ar), 6.98 (d, 3H, 3JHH 8.30 Hz,
3
3
H3-Ar), 3.90 (s, 9H, –O–CH3), 3.61 (tt, 3H, JHH 11.30 Hz, JHH
3
3.90 Hz, -CH-N ), 2.00 (q, 3H, JHH 11.80 Hz, trans-CHH-),
1.87 (dt, 3H, 3JHH 11.80 Hz, 3JHH 3.90 Hz, cis-CHH-). 13C NMR
(125.7 MHz, CD2Cl2): d 158.9 (s,Ar-C2), 155.2 (s, C N),131.8 (s,
Ar-C5), 127.3 (s, Ar-C6), 125.0 (s, Ar-C1), 120.7 (s, Ar-C4), 111.2
(s, Ar-C3), 66.9 (cy-CH), 55.6 (s, –O–CH3), 41.5 (cy-CH2). ESI
mass spectrum: m/z = 484.25 [M+H]+. CI HR mass spectrum:
m/z = 484.2575 [M +H]+ (calcd 484.2594).
1
1
141.3 (dm, JCF 256.27 Hz, Ar-Cpara), 136.9 (dm, JCF 253.36 Hz,
Ar-Cmeta), 110.6 (m br, Ar-Cipso), 66.8 (s, cy-CH), 39.3 (s, cy-CH2).
19F{ H} NMR (282 MHz, CD2Cl2): d -143.25 (m, 6F, Fortho-Ar),
1
3
-152.13 (t, 3F, JFF 20.56 Hz, Fpara-Ar), -166.80 (m, 6F, Fmeta
-
Ar). ESI mass spectrum: m/z = 664.09 [M+H]+, 686.07 [M+Na]+
(calcd 663.08).), CI HR mass spectrum: m/z = 686.0684 [M +Na]+
(calcd 686.0699), 664.0864 [M +H]+ (calcd 664.0864).
Synthesis of tach-based Cu(I)-NCMe complexes 2.2–9.2
The synthesis of tach-based Cu(I)-NCMe complexes 2.2–9.2 will
be described in detail for [Cu(I)(2.1)(NCMe)][PF6] (2.2) and is
representative for the synthesis of complexes 3.2–9.2.
Synthesis
benzylideneamino)cyclohexane (7.1). Treatment of 1 (1.0 g,
2.0 mmol) in solution of sodium hydroxide (0.25 g,
6.00 mmol) in water (10 mL) and toluene (30 mL) with 3,5-
bis(trifluoromethyl)benzaldehyde (1.00 mL, 1.45 g, 6.00 mmol).
Yielded 7.1 as a white solid (0.85 g, 53%). 1H NMR (299.9 MHz,
CD2Cl2): d 8.46 (s, 3H, HC N), 8.23 (br s, 6H, Hortho-Ar), 7.93
of
cis,cis-1,3,5-tris(3,5-bis(ditrifluoromethyl)-
a
Synthesis of [Cu(I)(2.1)(NCMe)][PF6] (2.2). Compound 2.1
(0.1 g, 0.2 mmol) was dissolved in CH2Cl2 (5 mL) and treated
with the dropwise addition of a solution of an equivalent amount
of [Cu(CH3CN)4]PF6 (0.07 g, 0.2 mmol) in CH2Cl2 (5 mL). The
1
2
mixture of the reaction was stirred for h at ambient condition.
3
3
(ms, 3H, Hpara-Ar), 3.69 (tt, 3H, JHH 11.3 Hz, JHH 4.0 Hz,
Product was precipitated by addition of n-hexane, collected by
filtration and dried in vacuo to obtain bright white powder of
2.2 (0.09 g, 64%).1H NMR (400.18 MHz; CD2Cl2): d 9.07 (s,
-CH-N ), 2.05 (q, 3H, 3JHH 11.6 Hz, trans-CHH-), 1.89 (dt, 3H,
3JHH 11.93 Hz, JHH 3.7 Hz, cis-CHH-). 13C NMR (75.57 MHz,
3
2
3
CD2Cl2): d 156.6 (s, C N), 138.5 (s, Ar-Cipso), 131.9 (q, JCF
34.04 Hz, Ar-Cmeta), 128.1 (s, Ar-Cpara), 123.9 (s, Ar-Cortho), 123.3
3H, HC N), 7.43 (d, 3H, JHH 7.82 Hz, H5Ar), 7.07 (s, 3H,
3
3
H3Ar), 6.28 (d, 3H, JHH 7.82 Hz, H6Ar), 4.39 (tt, br, 3H, JHH
11.24 Hz, 3JHH 4.40 Hz, -CH-N ), 2.92 (tt, br 3H, 3JHH 12.46 Hz,
trans-CHH-), 2.77 (q, br, 3H, 3JHH 12.46 Hz, cis-CHH-). 2.49 (s,
9H, ortho-ArCH3), 2.19 (t, br, 9H, para-ArCH3), 1.95 (m, 3H,
1
(q, JCF 272.87 Hz, -CF3), 66.0 (s, cy-CH), 40.4 (s, cy-CH2).
19F{ H} NMR (282.78 MHz, CD2Cl2): d -63.23 (m, -CF3). ESI
1
mass spectrum: m/z = 802.16 [M+H]+, 824.14 [M+Na]+ (calcd
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3JHH 12.46 Hz, cis-CHH-) and 1.46 (s, 3H, –NCCH3). 13C NMR
(100.6 MHz, CD2Cl2): d 171.2 (s, C N), 144.6 (s, Ar-C2), 139.8 (s,
Ar-C4), 131.7 (s, Ar-C3), 129.5 (s, Ar-C6), 127.2 (s, Ar-C5), 125.6
(s, Ar-C1), 65.5 (s, cy-CH), 42.9 (s, cy-CH2), 21.3 (s, ortho-ArCH3),
18.7 (s, para-ArCH3) and 2.2 (s, -NCCH3).
CD2Cl2): d -72.06 (s, 3F, BF6), -74.57 (s, 3F, BF6), -139.19 (d, 6F,
3JFF 16.24 Hz, Fortho-Ar), -150.43 (t, 3F, 3JFF 20.56 Hz, Fpara-Ar),
-162.06 (m, 6F, Fmeta-Ar). ESI mass spectrum: m/z; 726.01 [M-
(-NCCH3, PF6)]+ (calcd 726.01). CI HR mass spectrum: m/z =
726.0082 [M-(-NCCH3, PF6)]+ (calcd 726.0111).
Synthesis of [Cu(I)(7.1)(NCMe)][PF6] (7.2). Compound 7.1
(0.20 g, 0.24 mmol) was dissolved in CH2Cl2 (5 mL) and a solution
of [Cu(CH3CN)4]PF6 (0.09 g, 0.24 mmol) in CH2Cl2 (5 mL)
was added. A bright yellow precipitate of 7.2 (0.23 g, 92%) was
obtained after purification. 1H NMR (299.9 MHz, CD2Cl2): d 8.63
(s, 3H, HC N), 8.07 (br s, 6H, Hortho-Ar), 7.98 (s, 3H, Hpara-Ar),
Synthesis of [Cu(I)(3.1)(NCMe)][PF6] (3.2). Compound 3.2
was obtained by reaction of 3.1 (0.10 g, 0.25 mmol) in CH2Cl2
(5 mL) and a solution of [Cu(CH3CN)4]PF6 (0.09 g, 0.25 mmol)
in CH2Cl2 (5 mL). The bright yellow powder of 3.2 was obtained.
Yield (0.04 g, 25%). 1H NMR (400.18 MHz, CD2Cl2): d 8.49 (s, 3H,
HC N), 7.80 (m, br, 6H, HAr), 7.46 (m, br, 9H, HAr), 4.22 (s,
3
3
3
4.28 (s, 3H, -CH-N ), 2.51 (dt, 3H, JHH 15.4 Hz, JHH 3.9 Hz,
3H, -CH-N ), 2.47 (tt, 3H, JHH 11.90 Hz, JHH 4.15 Hz, trans-
3
3
CHH-) and 2.16 (d, 3H, JHH 11.90 Hz, cis-CHH-). 13C NMR
trans-CHH-), 2.24 (d, 3H, JHH 15.23 Hz, cis-CHH-) and 1.22
(br s, 3H,-NCCH3). 13C NMR (75.57 MHz, CD2Cl2): d161.8 (s,
(100.6 MHz, CD2Cl2): d 162.5 (s, C N), 132.9 (s, Ar-Cipso), 131.8
(s, Ar-Cpara), 128.9 (s, Ar-Cortho), 128.3 (s, Ar-Cmeta), 66.3 (s, cy-
CH), 37.5 (s, cy-CH2). Anal. calc. for C29H30CuN3. C54H54Cu3N6.
4PF6: C, 48.52. H, 4.07. N, 6.82. Found: C, 48.26, H, 4.07, N,
6.43%. ESI mass spectrum: m/z; 456.15 [M-(-NCCH3, PF6)]+. CI
HR mass spectrum: m/z = 456.1495 [M-(-NCCH3, PF6)]+ (calcd
456.1502).
C
N), 136.0 (s, Ar-Cipso), 131.8 (q, 2JCF 34.04 Hz, Ar-Cmeta), 128.9
1
(s, Ar-Cpara), 124.8 (s, Ar-Cortho), 122.9 (q, JCF 272.87 Hz, -CF3),
66.5 (s, cy-CH), 36.8 (s, cy-CH2). 19F{ H} NMR (282.78 MHz,
1
CD2Cl2): d -63.35 (m, 18F, -CF3), -71.32 (s, 3F, PF6), -73.84 (s,
3F, PF6). Anal. calc. for C35H24CuF18N4.PF6: C, 39.99, H, 2.30, N,
5.33. Found: C, 40.26, H, 2.54, N, 5.76%.
Synthesis of [Cu(I)(8.1)(NCMe)][PF6] (8.2). Compound 8.1
(0.51 g, 0.84 mmol) was dissolved in CH2Cl2 (5 mL) and a solution
of [Cu(CH3CN)4]PF6 (0.32 g, 0.84 mmol) in CH2Cl2 (5 mL) was
added. A deep yellow precipitate of 8.2 (0.62 g, 92%) was obtained
after purification. 1H NMR (400.2 MHz, CD2Cl2): d 8.74 (q, 3H,
Synthesis of [Cu(I)(4.1)(NCMe)][PF6] (4.2). Compound 4.1
(0.26 g, 0.33 mmol) was dissolved in CH2Cl2 (5 mL) and a solution
of [Cu(CH3CN)4]PF6 (0.12 g, 0.33 mmol) in CH2Cl2 (5 mL) was
added. The green cream precipitate of 4.2 was obtained. Yield
(0.10 g, 28%). 1H NMR (399.8 MHz, CDCl3): d 8.49 (s, 3H,
3
3
J 2.69 Hz, HC N), 7.71 (d, 3H, JHH 7.71 Hz, Hortho-Ar), 7.59
HC N), 4.12 (s, 3H, -CH-N ), 2.02 (dt, 3H, JHH 14.70 Hz,
3JHH 3.90 Hz, trans-CHH), 2.08 (s, 9H, para-CH3), 1.99 (d, 3H,
3JHH 14.70 Hz, cis-CHH-), 1.92 (s, 18H, meta-CH3), 1.83 (s, 18H,
ortho-CH3) and 0.78 (s, 3H, –NCCH3). 13C NMR (100.6 MHz,
CD2Cl2): d 164.9 (s, C N), 135.3 (s, Ar-Cortho), 132.4 (s, Ar-Cmeta),
132.0 (s, Ar-Cpara), 131.3 (s, Ar-Cipso), 65.8 (s, cy-CH), 37.6 (s, cy-
CH2), 17.1 (Ar–Cmeta), 16.6 (s, Ar–Cortho), 15.5 (Ar-Cortho) and 2.19
(s, -NCCH3).
(m, 3H, Hpara-Ar), 7.46 (m, 6H, Hmeta-Ar), 4.24 (br s, 3H, -CH-
3
3
N
), 2.49 (dt, 3H, JHH 15.03 Hz, JHH 4.09 Hz, trans-CHH-),
2.15 (d, 3H, 3JHH 14.9 Hz, cis-CHH-), 1.19 (br s, 3H, -NCCH3). 13
C NMR (100.62 MHz, CD2Cl2): d 161.1 (s, C N), 133.2 (s, Ar-
C5), 131.6 (s, Ar-C6), 130.7 (s, Ar-C4), 129.9 (s, Ar-C1), 128.3 (q,
2JCF 32.31 Hz, Ar-C2), 125.8 (s, Ar-C2), 123.9 (q, 1JCF 273.66 Hz,
Ar-CF3), 65.6 (s, cy-CH), 37.0 (s, cy-CH2). ESI mass spectrum:
m/z; 660.11 [M-(-NCCH3, PF6)]+, CI HR mass spectrum: m/z =
660.1117 [M-(-NCCH3, PF6)]+ (calcd 660.1121).
Synthesis of [Cu(I)(5.1)(NCMe)][PF6] (5.2). Treatment of a
CH2Cl2 (5 mL) solution of 5.1 (0.10 g, 0.17 mmol) with a solution
of [Cu(CH3CN)4]PF6 (0.07 g, 0.17 mmol) in CH2Cl2 (5 mL) led to
a bright green yellow powder which was collected by slow diffusion
of n-hexane into the CH2Cl2 solution of 5.2 at -18 ◦C. 1H NMR
Synthesis of [Cu(I)(9.1)(NCMe)][PF6] (9.2). Treatment of a
CH2Cl2 (5 mL) solution of 9.1 (0.50 g, 1.03 mmol) with a solution
of [Cu(CH3CN)4]PF6 (0.39 g, 1.03 mmol) in CH2Cl2 (5 mL) led
to a bright yellow solution which was precipitated by addition of
3
(499.9 MHz, CD2Cl2): d 8.94 (s, 3H, HC N), 7.38 (t, 3H, JHH
1
8.54 Hz, HparaAr), 6.52 (d, 3JHH 8.55 Hz, 6H, HmetaAr), 4.11 (m, br,
3H, -CH-N ), 3.54 (s, br, 18H, -OCH3), 2.74 (m, br, 3H, trans-
CHH-), 2.43 (m, br, 3H, cis-CHH-), 1.18 (s, 3H, NCCH3). 13C
NMR (125 MHz, CD2Cl2): d 164.2 and 161.3 (Ar-Cortho), 158.5
(C N), 134.9 and 134.5 (Ar-Cpara), 109.1 (Ar-Cmeta), 103.9 and
103.15 (Ar-Cipso), 66.3 (cy-CH), 55.2 (-OCH3), 41.0 (cy-CH2) and
10.9 (-NCCH3).
n-hexane to give 9.2 (0.74 g, 98%) as yellow powder. H NMR
(400.18 MHz; CD2Cl2): d 8.68 (s, br, 3H, HC N), 7.77 (d, 3H,
3JHH 7.3 Hz, H6-Ar), 7.48 (t, 3H, 3JHH 7.8 Hz, H5-Ar), 6.99 (d, 3H,
3JHH 8.3 Hz, H4-Ar), 6.87 (d, 3H, 3JHH 7.5 Hz, H3-Ar), 4.17 (s, 3H,
3
-CH-N ), 3.88 (s, 9H, –O–CH3), 2.43 (br d, 3H, JHH 14.7 Hz,
3
trans-CHH-), 2.12 (d, 3H, JHH 14.7 Hz, cis-CHH-), 1.54(s, 3H,
-NC–CH3). 13 C NMR (125.7 MHz, CD2Cl2): d 159.4 (s, C N),
159.0 (s,Ar-C2), 133.0 (s, Ar-C5), 129.5 (s, Ar-C6), 123.2 (s, Ar-C1),
119.5 (s, Ar-C3), 111.2 (s, Ar-C4), 66.3 (cy-CH), 55.8 (s, –O–CH3),
37.8 (cy-CH2), 1.89 (s, -NCCH3). ESI mass spectrum: m/z 546.18
[M-(-NCCH3, PF6)]+, CI HR mass spectrum: m/z = 546.1812 [M-
(-NCCH3, PF6)]+ (calcd 546.1829).
Synthesis of [Cu(I)(6.1)(NCMe)][PF6] (6.2). Compound 6.1
(0.06 g, 0.09 mmol) in CH2Cl2 (5 mL) was treated by a solution
of [Cu(CH3CN)4]PF6 (0.033 g, 0.09 mmol) in CH2Cl2 (5 mL) to
1
give a deep yellow precipitate of 6.2 (0.052 g, 63%). H NMR
(299.9 MHz, CD2Cl2): d 8.37 (s, 3H, HC N), 4.29 (s, 3H, -CH-
3
3
N
), 2.52 (tt, JHH 15.20 Hz, JHH 4.03 Hz 3H, trans-CHH-),
Synthesis of tach-based Cu(I)–CO complexes 2.3–9.3
1.88 (d, 3JHH 15.20 Hz, 3H, cis-CHH-), 1.92 (s, br, -NCCH3). 13
C
1
NMR (125 MHz, CD2Cl2): d 150.8 (s, C N), 144.0 (dm, JCF
259.21 Hz, Ar-Cortho), 143.9 (dm, 1JCF 257.25 Hz, Ar-Cpara), 136.7
(dm, 1JCF 258.23 Hz, Ar-Cmeta), 109.5 (m br, Ar-Cipso), 65.6 (s, cy-
Synthesis of [Cu(I)(2.1)(CO)][PF6] (2.3). Carbon monoxide
was bubbled through a CH2Cl2 solution (10 mL) 2.2 (0.05 g,
1
2
0.10 mmol) for h to give a pale yellow solution. The product was
CH), 36.2 s, cy-CH2), 14.3 (s, -NCCH3). 19F{ H} NMR (282 MHz,
precipitated by addition of n-hexane (20 mL) and dried in vacuo.
1
10916 | Dalton Trans., 2010, 39, 10910–10919
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1
The (0.08 g, 76%) cream solid of 2.3 was obtained. H NMR
Synthesis of [Cu(I)(7.1)(CO)][PF6] (7.3). Carbon monoxide
was bubbled through a CH2Cl2 solution (5 mL) of 7.2 (0.1 g,
(499.9 MHz, CD2Cl2): d 8.66 (s, 3H, HC N), 7.09 (d, 3H, 3JHH
7.08 Hz, H6Ar), 6.96 (s, 3H, H3Ar), 6.81 (d, 3H, JHH 7.63 Hz,
1
3
0.09 mmol) for h to give a pale yellow solution. The product
2
3
H5Ar), 4.16 (s, br, 3H, -CH-N ), 2.40 (dt, 3H, JHH 15.00 Hz,
was precipitated by addition of n-hexane (10 mL) and dried in
3JHH 3.80 trans-CHH-), 2.21 (s, 9H, ortho-ArCH3), 2.19 (s, 9H,
vacuo to give 7.3 (0.08 g, 86%). H NMR (299.9 MHz, CD2Cl2):
1
para-ArCH3), 2.02 (d, 3H, JHH 14.65 Hz, cis-CHH-). 13C NMR
d 8.84 (s, 3Hb, HC N), 7.97 (t, 3H, 4JHH 1.47 Hz, Hpara-Ar), 7.86
3
4
(100.6 MHz, CD2Cl2): d 163.8 (s, C N), 140.1 (s, Ar-C2), 135.0 (s,
Ar-C4), 129.0 (s, Ar-C3), 125.8 (s, Ar-C6), 125.4 (s, Ar-C5), 124.4 (s,
Ar-C1), 63.7 (s, cy-CH), 35.8 (s, cy-CH2), 19.32 (s, ortho-ArCH3)
and 16.8 (s, para-ArCH3). IR/cm-1 (CH2Cl2): n(CO) 2091.8 s.
(d, 6H, JHH 1.3 Hz, Hortho-Ar), 4.37 (s, 3Ha, -CH-N =), 2.51 (dt,
3H, 2JHH 15.41 Hz, 3JHH 3.80 Hz, trans-CHH-), 2.34 (d, 3H, 2JHH
15.05 Hz, cis-CHH-). 13C NMR (75.57 MHz, CD2Cl2): d 165.1 (s,
C
N), 136.3 (s, Ar-Cipso), 132.2 (q, 2JCF 34.04 Hz, Ar-Cmeta), 128.3
1
(s, Ar-Cpara), 125.3 (s, Ar-Cortho), 122.4 (q, JCF 272.87 Hz, -CF3),
Synthesis of [Cu(I)(3.1)(CO)][PF6] (3.3). Carbon monoxide
was bubbled through a CD2Cl2 solution of 3.2 (0.02 g), which had
been loaded in the NMR tube, for 12 h to give a pale yellow solution.
1H NMR (300 MHz, CD2Cl2): d 8.74 (s, 3H, HC N), 7.54 (t,
9H, HAr), 7.42 (t, 6H, HAr), 4.28 (s, 3H, -CH-N ), 2.50 (d, 3H,
3JHH 14.90 Hz, trans-CHH-), 2.21 (m, 3H, cis-CHH-). 13C NMR
(100 MHz, CD2Cl2): d CO signal not observed, 166.4 (s, C N),
134.9 (s, Ar-Cipso), 131.9 (s, Ar-Cpara), 128.7 (s, Ar-Cortho), 128.3 (s,
Ar-Cmeta), 66.2 (s, cy-CH), 37.2 (s, cy-CH2). ESI mass spectrum:
m/z; 456.15 [M-(-CO, PF6)]+. CI HR mass spectrum: m/z =
456.1495 [M-(-CO, PF6)]+ (calcd 456.1504). IR/cm-1 (CD2Cl2):
n(CO) 2092 s.
66.1 (s, Ctach-N), 36.3 (s, -CtachH2). 19F{ H} NMR (282.78 MHz,
1
CD2Cl2): d -63.88 (m, 18F, -CF3), -70.72 (s, 3H, PF6), -73.24 (s,
3H, PF6). IR/cm-1 (CH2Cl2): n(CO) 2099 s.
Synthesis of [Cu(I)(8.1)(CO)][PF6] (8.3). Carbon monoxide
was bubbled through a CH2Cl2 solution (5 mL) of 8.2 (0.5 g,
1
2
0.59 mmol) for h to give a pale yellow solution. The product was
precipitated by addition of n-hexane and dried in vacuo. The cream
1
solid of 8.3 (0.45 g, 92%) was obtained. H NMR (400.2 MHz,
CD2Cl2): d 8.91 (br s, 3H, HC N), 7.71 (d, 3H, 3JHH 7.8 Hz, Hortho
-
3
3
Ar), 7.58 (t, 3H, JHH 7.9 Hz, Hpara-Ar), 7.51 (t, 3H, JHH 7.3 Hz
3
H
meta5-Ar), 7.36 (d, 3H, JHH 7.3 Hz, Hmeta3-Ar), 4.36 (br s, 3H,
-CH-N ), 2.55 (dt, 3H, 3JHH 15.1 Hz, 3JHH 3.7 Hz, trans-CHH-),
Synthesis of [Cu(I)(4.1)(CO)][PF6] (4.3). Carbon monoxide
was bubbled through a CD2Cl2 solution of 4.2 (0.04 g, 0.005 mmol)
which had been loaded in the NMR tube, for h to give a pale
2.21 (d, 3H, JHH 15.8 Hz, cis-CHH-). 13C NMR (100.62 MHz,
3
CD2Cl2): d 164.6 (s, C N), 133.9 (s, Ar-C5), 132.1 (s, Ar-C6),
1
2
131.3 (s, Ar-C4), 128.9 (s, Ar-C1), 128.0 (q, 2JCF 32.29 Hz, Ar-C2),
1
yellow solution. H NMR (399.8 MHz, CDCl3): d 8.75 (s, 3H,
1
126.3 (s, Ar-C2), 123.8 (q, JCF 273.66 Hz, Ar-CF3), 65.5 (s, cy-
HC N), 4.32 (s, 3H, -CH-N ), 2.52 (dt, 3H, 3JHH 15.00 Hz, 3JHH
CH), 36.4 (s, cy-CH2). ESI mass spectrum: m/z; 660.11 [M-(-CO,
PF6)]+. CI HR mass spectrum: m/z = 660.1117 [M-(-CO, PF6)]+
(calcd 660.1132). IR/cm-1 (CH2Cl2): n(CO) 2093.6 s.
3
3.70 Hz, trans-CHH), 2.15 (s, 9H, para-CH3), 1.99 (d, 3H, JHH
14.43 Hz, cis-CHH-), 1.99 (s, 18H, meta-CH3) and 1.90 (s, 18H,
ortho-CH3). 13C NMR (100.6 MHz, CD2Cl2): d 166.3 (s, C N),
134.9 (s, Ar-Cortho), 130.9 (s, Ar-Cmeta), 130.6 (s, Ar-Cpara), 128.4 (s,
Ar-Cipso), 63.4 (s, cy-CH), 35.2 (s, cy-CH2), 15.1 (Ar–Cmeta), 14.4 (s,
Ar–Cortho), and 13.3 (Ar-Cortho). IR/cm-1 (CD2Cl2); n(CO) 2091 s.
Synthesis of [Cu(I)(9.1)(CO)][PF6] (9.3). Carbon monoxide
was bubbled through a CH2Cl2 solution (10 mL) of 9.2 (0.13 g,
1
2
17.73 mmol) for h to give a pale yellow solution. The product
was precipitated by addition of n-hexane to give 9.3 (0.116 g, 92%).
1H NMR (400.18 MHz; CD2Cl2): d 8.78 (s, br, 3H, HC N), 7.49
(ddd, 3H, 3JHH 7.33 Hz, 4JHH 1.71 Hz, H5-Ar), 7.41 (br d, 3H, 3JHH
7.3 Hz, H5-Ar), 7.00 (d, 3H, 3JHH 8.3 Hz, H3-Ar), 6.87 (t, 3H, 3JHH
7.3 Hz, H4-Ar), 4.25 (br s, 3H, -CH-N ), 3.87 (s, 9H, –O–CH3),
2.47 (dt, 3H, 2JHH 14.7 Hz, 3JHH 4.0 Hz, trans-CHH-), 2.17 (d, 3H,
3JHH 14.9 Hz, cis-CHH-). 13C NMR (125.7 MHz, CD2Cl2): d 163.6
(s, C N), 158.7 (s,Ar-C2), 133.5 (s, Ar-C5), 128.7 (s, Ar-C6), 124.0
(s, Ar-C1), 120.0 (s, Ar-C3), 111.2 (s, Ar-C4), 65.9 (cy-CH), 55.7 (s,
–O–CH3), 37.5 (cy-CH2). IR/cm-1 (CH2Cl2): n (CO) 2089.4 s.
Synthesis of [Cu(I)(5.1)(CO)][PF6] (5.3). Carbon monoxide
was bubbled through a CD2Cl2 solution of 5.2 (0.02 g), which
had been loaded in the NMR tube, for 1 h to give a pale yellow
solution. 1H NMR (499.9 MHz, CD2Cl2): d 8.33 (s, 3H, HC N),
3
3
7.22 (t, 3H, JHH 8.39 Hz, HparaAr), 6.37 (d, 6H, JHH 8.24 Hz,
H
metaAr), 4.00 (s, br, 3H, -CH-N ), 3.43 (s,18H, -OCH3), 2.27
(d, br, 3H, 3JHH 14.95 Hz trans-CHH-), 2.09(d, br, 3JHH 14.95 Hz,
3H, cis-CHH-). 13C NMR (125 MHz, CD2Cl2): d CO signal not
observed, 158.5 (s, C N), 157.8 (s, Ar-Cortho), 131.8 (s, Ar-Cpara),
111.6 (s, Ar-Cmeta), 102.8 (s, Ar-Cipso), 65.8 (s, cy-CH), 54.2 (s,
-OCH3), 36.8 (s, cy-CH2). IR/cm-1 (CD2Cl2): n(CO) 2073 s.
X-Ray experimental
Synthesis of [Cu(I)(6.1)(CO)][PF6] (6.3). Carbon monoxide
was bubbled through a CD2Cl2 solution of 6.2 (0.04 g), which had
been loaded in the NMR tube, for 1 h to give a very pale yellow
solution. 1H NMR (400.18 MHz, CD2Cl2): d 8.36 (s, 3H, HC N),
4.28 (s, 3H, -CH-N ), 2.50 (dt, 3H, 2JHH 15.23 Hz, 3JHH 4.04 Hz,
trans-CHH-), 2.10 (d, br, 3H, 2JHH 14.86 Hz, cis-CHH-). 13C NMR
An X-ray diffraction experiment on 9.2 was carried out at 100 K
on a Bruker Microstar diffractometer using Cu-Ka radiation (l =
˚
1.54178 A) and the rest were carried out at 100 K on a Bruker
Apex II Kappa CCD diffractometer using Mo-Ka radiation (l =
˚
0.71073 A). Intensities were integrated from several series of
1
(75 MHz, CD2Cl2): d 151.6 (C N), 146.5 (dm, JCF 259.21 Hz,
exposures measuring 0.5◦ in w or j using the Apex II or proteum
program.25 Absorption corrections were based on equivalent
reflections using SADABS,26 and structures were refined against
1
1
Ar-Cortho), 143.2 (dm, JCF 257.25 Hz, Ar-Cpara), 139.2 (dm, JCF
258.23 Hz, Ar-Cmeta), 110.2 (m br, Ar-Cipso), 66.3 (cy-CH), 37.0
1
2
(cy-CH2). 19F{ H} NMR (282 MHz, CD2Cl2): d -72.05 (s, 3F,
all Fo data with hydrogen atoms (on carbon atoms) riding in
PF6), -74.56 (s, 3F, PF6), -139.18 (d, 6F, 3JFF 16.24 Hz, Ar-Fortho),
-150.41 (t, 3F, 3JFF 20.56 Hz, Ar-Fpara), -162.05 (m, 6F, Ar-Fmeta).
IR/cm-1 (CD2Cl2): n(CO) 2091.3 s.
calculated positions using SHELXL.27
Structure 9.1·CH2Cl2 and 3.2·CH2Cl2 were non-merohedral
twins with two and three domains respectively, which were
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Dalton Trans., 2010, 39, 10910–10919 | 10917
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Table 6 X-Ray crystallography data of 3.2·CH2Cl2, 7.2, 8.2 and 9.2·CH2Cl2
Compound
3.2·CH2Cl2
7.2
8.2
9.2·CH2Cl2
Colour, habit
Empirical formula
Yellow plate
C54H54Cu3N6,C29H30
CuN4,(PF6)4,CH2Cl2
2140.61
Monoclinic
P21/n
16.3400(7)
13.4089(6)
40.1113(13)
90.00
90.042(2)
90.00
8788.4(6)
4
1.191
Yellow needle
C35H24CuF18N4.
PF6
1051.10
Monoclinic
P21/c
11.1581(3)
18.9132(6)
38.9605(13)
90.00
96.126(2)
90.00
Yellow plate
C32H27CuF9N4.
PF6
847.09
Cubic
Yellow plate
C32H36CuN4O3.
PF6. CH2Cl2
818.09
M
Crystal system
Triclinic
¯
Space group
P213
P1
˚
a/A
15.2741(8)
15.2741(8)
15.2741(8)
90.00
11.5586(18)
12.640(2)
14.529(2)
67.007(4)
72.472(4)
70.142(4)
1802.7(5)
2
˚
b/A
˚
c/A
a (◦)
b (◦)
g (◦)
90.00
90.00
3563.4(3)
4
0.766
3
˚
V/A
8175.1(4)
8
0.717
Z
m/mm-1
3.263
100(2)
T/K
100(2)
100(2)
100(2)
Reflections: (measured/unique/observed)
Rint
20271/20271/22357
—
0.0945
0.2434
—
134390/18814/12880
0.0651
0.0501
0.1278
—
10671/1517/2511
0.0432
0.0314
0.0819
0.012(14)
21258/6187/5722
0.0418
0.0510
0.1421
—
R1(observed reflection)[I ≥ 2 s(I)]
wR2(all reflection)
Flack parameter
Table 7 X-Ray crystallography data of 3.3·CH2Cl2, 5.3·CH2Cl2 and 6.3
Compound
3.3·CH2Cl2
5.3·CH2Cl2
6.3
Colour, habit
Empirical formula
M
Colourless plate
C28H27CuN3O.PF6·CH2Cl2
714.97
Orthorhombic
Pbca
15.1755(8)
17.9772(8)
18.5659(9)
90.00
90.00
90.00
Pale yellow prisms
Colourless
C28H12CuF15N3O.PF6
899.93
C34H39CuN3O7.PF6·CH2Cl2
895.13
Crystal system
Monoclinic
C2/c
27.2710(13)
16.6962(7)
21.3580(17)
90.00
125.248(2)
90.00
7941.8(8)
8
Trigonal
¯
Space group
P3c1
˚
a/A
10.2405(5)
10.2405(5)
38.022(4)
90.00
˚
b/A
˚
c/A
a (◦)
b (◦)
g (◦)
90.00
120.00
3453.1(4)
4
0.822
3
˚
V/A
3488.36(4)
8
1.015
Z
m/mm-1
0.803
100(2)
T/K
100(2)
100(2)
Reflections: (measured/unique/observed)
Rint
26243/9399/3385
0.1148
0.0657
44613/16548/9047
0.0447
0.0510
34014/2661/2400
0.0248
0.0578
R1(observed reflection)[I ≥ 2 s (I)]
wR2(all reflection)
0.1346
0.1593
0.2056
separated using CELLNOW or the APEX II program. The struc-
tures were solved using ShelXS refined for all domains simulta-
neously which resulted in ratios (0.07 : 0.93) and (0.04 : 0.10 : 0.86)
for the structures.
Structural and refinement data for 5.1·6H2O, 7.1 and
9.1·CH2Cl2 are in Table 5, Crystal and refinement data for
3.2·CH2Cl2, 7.2, 8.2 and 9.2·CH2Cl2 are given in Table 6 and the
structural data for 3.3·CH2Cl2, 5.3·CH2Cl2 and 6.3 are in Table 7.
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