Reactivity of bulky tris(phenylpyrazolyl)methanesulfonate copper(I) complexes towards small unsaturated molecules

Article abstract of DOI:10.1016/j.jorganchem.2012.03.022

Reaction of the tris(3-phenylpyrazolyl)methane sulfonate species (Tpms ^Ph)Li with the copper(I) complex [Cu(MeCN)₄][PF ₆] affords [Cu(Tpms^Ph)(MeCN)] 1. The latter, upon reaction with equimolar amounts of cyclohe

Full text of DOI:10.1016/j.jorganchem.2012.03.022

Journal of Organometallic Chemistry 714 (2012) 47e52
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Journal of Organometallic Chemistry
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Reactivity of bulky tris(phenylpyrazolyl)methanesulfonate copper(I) complexes
towards small unsaturated molecules
,
Bruno G.M. Rocha a, Riccardo Wanke a, M. Fátima C. Guedes da Silva a b, Konstantin V. Luzyanin a,
,
,
*
Luísa M.D.R.S. Martins a c, Piotr Smolénski d, Armando J.L. Pombeiro a
a Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
b Universidade Lusófona de Humanidades e Tecnologias, ULHT Lisbon, Campo Grande 376, 1749-024 Lisbon, Portugal
c Área Departamental de Engenharia Química, ISEL, R. Conselheiro Emídio Navarro, 1959-007 Lisboa, Portugal
d Faculty of Chemistry, University of Wroclaw, Ul F. Joliot Curie 14, PL-50383, Wroclaw, Poland
a r t i c l e i n f o
a b s t r a c t
Reaction of the tris(3-phenylpyrazolyl)methane sulfonate species (TpmsPh)Li with the copper(I) complex
[Cu(MeCN)4][PF6] affords [Cu(TpmsPh)(MeCN)] 1. The latter, upon reaction with equimolar amounts of
cyclohexyl- (CyNC) or 2,6-dimethylphenyl (XylNC) isocyanides, or excess CO, furnishes the corresponding
Cu(I) complexes [Cu(TpmsPh)(CNR)] (R ¼ Cy 2, Xyl 3) or [Cu(TpmsPh)(CO)] 4. The ligated isocyanide in 2 or
3 (or the acetonitrile ligand in 1) is displaced by 3-iminoisoindolin-1-one to afford 5, the first copper(I)
complex containing an 3-iminoisoindolin-1-one ligand. The ligated acetonitrile in 1 undergoes nucleo-
philic attack by methylamine to give the amidine complex [Cu(TpmsPh){MeC(NH)NHMe}] 6, whereas
only the starting materials were recovered from the attempted corresponding reactions of 2 and 3 with
Article history:
Received 6 January 2012
Received in revised form
9 March 2012
Accepted 12 March 2012
Keywords:
Tris(pyrazolyl)methanesulfonate ligand
Copper complexes
Isocyanide
Carbon monoxide
3-Iminoisoindolin-1-one
methylamine. Complexes
1 or 6 form the trinuclear hydroxo-copper(II) species [(m-Cu){Cu(m-
OH)2(TpmsPh)}2] 7 upon air oxidation in moist methanol. In all the complexes the scorpionate ligand
facially caps the metal in the N,N,O-coordination mode.
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
a convenient binding coordination site for various small molecules.
This study was also encouraged by our continued interest on the
Copper complexes play a crucial role in different fields of
science, e.g. in catalysis, coordination, bioinorganic and supramo-
lecular chemistry, and, in particular, the use of poly(pyrazolyl)
copper scaffolds to mimic enzymatic metal centres is well docu-
mented [1e7].
activation of small unsaturated molecules upon coordination to late
transition metals, e.g. isocyanides [30e39], nitriles [40e54], imines
[30,31,42,55e58], and alkynes [59e62], among others.
2. Experimental section
Within our studies on the coordination chemistry of N- and O-
donor ligands [7e26], namely embracing the tris(pyrazolyl)
methane scorpionate-type species [9e24], we have recently
reported [12] the preparation of [Cu(TpmsPh)(MeCN)] (1, Fig. 1),
a new type of copper complexes bearing the sterically hindered
2.1. General materials and experimental procedures
Syntheses were carried out under an atmosphere of dinitrogen,
unless stated otherwise. Solvents were distilled prior to use. The
reagents [Cu(MeCN)4][PF6], cyclohexyl (CyNC) and 2,6-
dimethylphenyl (XylNC) isocyanides (Aldrich) were purchased
and used without further purification. (TpmsPh)Li, [Cu(TpmsPh)(-
MeCN)] (1) [12] and 3-iminoisoindolin-1-one [58] were syn-
thesised in accord to the literature methods. C, H and N analyses
were carried out by the Microanalytical Service of the Instituto
Superior Técnico. Infrared spectra (4000e400 cmꢀ1) were recorded
on a BIO-RAD FTS 3000MX instrument in KBr pellets and far
infrared spectra (400-200 cmꢀ1) were recorded on a Vertex 70
spectrophotometer, in polyethylene and cesium iodide pellets.
Vibrational frequencies are expressed in cmꢀ1; abbreviations: s, m
chelating tris(3-phenylpyrazolyl)methane sulfonate (TpmsPh ꢀ
)
[27e29]. Now, we wish to further explore the steric and electronic
features of this tripodal ligand (which is comparable to cyclo-
pentadienyl on electronic and coordination grounds) for modu-
lating the coordination properties of the metal centre, by testing
the potential use of the nitrile complex 1 as a starting material for
the syntheses of new complexes bearing the {Cu(TpmsPh)} core as
* Corresponding author. Tel.: þ351 2184 19237; fax: þ351 2184 64455.
E-mail address: pombeiro@ist.utl.pt (A.J.L. Pombeiro).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2012.03.022

48
B.G.M. Rocha et al. / Journal of Organometallic Chemistry 714 (2012) 47e52
–
SO3
N
O
N
N
N
N
N
N
N
N
N
Cu
N
C
Me
=
N
N
O
Ph
(TpmsPh –
)
1
Ph
Ph
ꢀ
Fig. 1. Sterically hindered tris(3-phenylpyrazolyl)methane sulfonate (TpmsPh
) and the corresponding acetonitrile copper(I) chelate 1.
and w: strong, medium and weak, respectively. 1H, 13C{1H} and 1H,
1H-COSY NMR experiments were acquired on Bruker 300 and 400
3142 (w), 3059 (m,
(m, (C]N)), 1500 (m), 1459 (m), 1375 (m), 1280 (s), 1236 (s), 1043
(s, (SeO)), 858 (w), 757 (s), 630 (s,
(CeS)), 539 (w) cmꢀ1. 1H NMR
n(CeH)), 2922 (m, n(CeH)), 2153 (s, n(CN)), 1535
n
UltraShieldÔ spectrometers. 1H and 13C chemical shifts
d
are
n
n
expressed in ppm relative to Si(Me)4. Coupling constants are in Hz;
abbreviations: s, singlet; d, doublet; m, complex multiplet; vt,
virtual triplet; br, broad. ESIþ mass spectra were obtained on
a VARIAN 500-MS LC ion trap mass spectrometer (solvent: meth-
(300.130 MHz, CDCl3, 298 K): 7.82 (d, 6H, JHH ¼ 7.5 Hz, o-H (Ph)),
7.76 (d, 1H, JHH ¼ 8.0 Hz, p-H(XyNC)), 7.70 (d, 1H, JHH ¼ 2.5 Hz, 5-H
(pz)), 7.46e7.29 (m br, 9H þ 2H, m-H(XyNC) þ m,p-H (Ph)), 7.19 (d,
2H, JHH ¼ 2.5 Hz, 5-H (pz)), 6.67 (m br, 3H, 4-H (pz)), 2.17 (s, 6H, Me
from (XyNC)).
anol; flow: 20
m
L/min; needle spray voltage: ꢁ5 kV, capillarity
voltage: ꢁ100 V; nebulizer gas (N2): 35 psi; drying gas (N2): 10 psi;
drying gas temperature: 350 ꢂC).
2.1.3. [Cu(TpmsPh)(CO)] (4)
3
mL of a ) (0.042 g,
methanolic solution of Li(TpmsPh
2.1.1. [Cu(TpmsPh)(CyNC)] (2)
0.081 mmol, 1 equiv) were added to a solution (10 mL) of
[Cu(MeCN)4][PF6] (0.030 g, 0.081 mmol, 1 equiv) in the same
solvent contained in a stainless steel vessel. The final solution, with
the in situ generated acetonitrile complex 1, was saturated with
pressurized carbon monoxide (20 atm) and stirred at room
temperature overnight. Then the solvent was removed under
vacuum and the solid washed with cold methanol (5 mL) and dried
to afford 4 as a white powder (0.034 g, 68%). Complex 4 is soluble in
To a methanolic solution (50 mL) of [Cu(MeCN)4][PF6] (0.320 g,
0.86 mmol, 1 equiv) were added 3 mL of a Li(TpmsPh) solution
(0.450 g, 0.85 mmol, 1 equiv) in the same solvent. The colourless
solution was stirred for 5 min at room temperature with precipi-
tation of [Cu(TpmsPh)(MeCN)] (1). The suspension was then stirred
for 15 min and cyclohexyl isocyanide (110 mL, 0.89 mmol, 1.1 equiv)
was slowly added portionwise and the stirring of the reaction
mixture was continued overnight at 20e25 ꢂC. The formed white
powder of 2 was collected by filtration, washed with cold methanol
(2 ꢃ 25 mL), then recrystallized from cold acetone at 5 ꢂC (0.740 g,
88%). Complex 2 is well soluble in medium polarity solvents such as
Me2CO, CHCl3 and CH2Cl2, less soluble in H2O (S25 C z 3 mg mLꢀ1),
ꢂ
MeOH or EtOH and insoluble in Et2O. 4, C29H21N6O4SCu (613.13):
calcd. C 56.81, H 3.45, N 13.71, S 5.23; found C 56.88, H 3.54, N 13.41,
S 5.33. ESIþ-MS: 613 [M]. IR (KBr): 3158, 3125 (w), 2960, 2935 (m),
Me2CO, CHCl3 and CH2Cl2, less soluble in H2O (S25 C z 3 mg mLꢀ1),
2860 (w), 2107 (m,
1356 (m), 1271 (s), 1237 (s), 1078 (s,
(s), 639 (s,
(CeS)), 540 (w) cmꢀ1
n
(CO)), 1535 (m,
n
(C]N)), 1500 (m), 1459 (m),
(SeO)), 1044 (m), 867 (w), 758
.
1H NMR (300.130 MHz, CDCl3,
ꢂ
MeOH, EtOH or DMSO and insoluble in C6H6 and Et2O. 2,
C35H32N7SO3Cu (694.29): calcd. C 60.55, N 14.12, H 4.64, S 4.61;
found C 61.03, N 14.09, H 4.80, S 4.34. ESIþ-MS: 694 [M]þ. IR (KBr):
n
n
298 K): 8.02 (s br, 3H, 5-H (pz)), 7.94 (d, 6H, JHH ¼ 7.5 Hz, o-H (Ph)),
7.49e7.44 (m br, 9H, m,p-H (Ph)), 6.96 (d, 3H, JHH ¼ 2.6 Hz, 4-H
(pz)).
3150 (w), 2935 (m,
(m, (C]N)), 1500 (m), 1458 (m), 1358 (m), 1274 (s), 1235 (s), 1042
(s, (SeO)), 1059 (m), 856 (w), 758 (s), 641 (s, .
(CeS)), 534 (w) cmꢀ1
n(CeH)), 2860 (w, n(CeH)), 2191 (s, n(CN)), 1535
n
n
n
1H NMR (300.13 MHz, CDCl3, 298 K): 8.20e7.66 (m br, 3H þ 6H, 5H
(pz) þ o-H (Ph)), 7.46e7.39 (m br, 9H, m,p-H (Ph)), 6.69 (d, 3H,
JHH ¼ 2.7 Hz, 4-H (pz)), 3.38 (m, 1H, CH(Cy)), 1.50e1.27 (m, 10H,
(CH2)5 (Cy)). 1H NMR (300.130 MHz, CDCl3, 213 K): 9.04 (s br, 1H, 5-
H (pz)), 7.85 (m br, 6H, o-H (Ph)), 7.47 (m br, 9H, m,p-H (Ph)), 7.02 (s
br, 2H, 5-H (pz)), 6.96 (s br, 1H, 4-H (pz)), 6.66 (s br, 2H, 4-H (pz)),
3.16 (m, 1H, CH(Cy)),1.81e1.12 (m br, 10H, (CH2)5(Cy)). X-ray quality
single crystals were grown by slow diffusion of dry diethyl ether in
a concentrated solution of the titled compound in dichloro-
methane, under dinitrogen atmosphere.
2.1.4. [Cu(TpmsPh)(3-iminoisoindolin-1-one)] (5)
Solid 3-iminoisoindolin-1-one (0.008 g, 0.05 mmol,1 equiv) was
added to a chloroform solution (10 mL) of [Cu(TpmsPh)(XylNC)] (3)
(0.036 g, 0.05 mmol, 1 equiv). The resulting orange suspension was
refluxed overnight under dinitrogen, leading to a bright-yellow
solution. The latter was left to stand at room temperature for ca.
1 h, filtered to remove some insoluble materials, and the filtrate
was evaporated to dryness forming a yellowish-orange powder
which was washed with cold diethyl ether (3 ꢃ 5 mL) and dried
under vacuum at 20e25 ꢂC to afford 5 (0.031 g, 84% yield). Reaction
of 1 or 2 with 3-iminoisoindolin-1-one proceeds under similar
conditions furnishing 5 in 81 or 82% yields, respectively. Complex 5
is well soluble in medium polar solvents such as Me2CO, CHCl3 and
CH2Cl2, and insoluble in Et2O. 5, C36H26N8O4SCu (730.25): calcd. C
59.21, H 3.59, N 15.34, S 4.39; found C 59.60, H 3.52, N 15.18, S 4.43.
2.1.2. [Cu(TpmsPh)(XylNC)] (3)
To a methanolic suspension (50 mL) of [Cu(TpmsPh)(MeCN)] (1,
0.200 g, 0.32 mmol, 1 equiv), 2,6-dimethylphenyl isocyanide
(0.046 g, 0.35 mmol, 1.1 equiv) was added portionwise. The milky
mixture was stirred at room temperature overnight under a dini-
trogen atmosphere. The formed white powder of 3 was collected by
filtration, washed with cold methanol (2 ꢃ 25 mL) and dried
(0.180 g, 78%). Complex 3 is well soluble in medium polarity
solvents such as Me2CO, CHCl3 and CH2Cl2, less soluble in H2O
ESIþ-MS: 730 [M þ H]. IR (KBr): 3236 w-m
n
(NeH), 3140 (w), 3097
(C]O) and
(w), 3067 (w), 2922 (m), 1728 (m), 1691 (m), 1624 (s)
n
n
(C]N), 1562 (m)
d
(NeH), 1455 (m), 1383 (m), 1230 (s), 1043 (s)
n(SeO), 858 (w), 758 (s), 637 (s)
n
(CeS) cmꢀ1 1H NMR
.
(400.130 MHz, CDCl3, 298 K): 8.20 (s, br, 1H, NH), 7.86e7.83 (m,
6H þ 3H, o-H (Ph) þ 5-H (pz)), 7.74e7.41 (m, 4H þ 6H þ 3H, 3-
iminoisoindolin-1-one þ m-H (Ph) þ p-H (Ph)), 6.69 (m br, 3H, 4-
H (pz)). 13C{1H} NMR (100.613 MHz, CDCl3, 298 K): 155.1 (C]O),
(S25 C z 3 mg mLꢀ1), MeOH or EtOH, and insoluble in Et2O. 3,
ꢂ
C37H30N7O3SCu (716.30): calcd. C 62.04, N 13.69, H 4.22, S 4.47;
found C 62.43, N 13.13, H 4.43, S 4.14. ESIþ-MS: 716 [M]þ. IR (KBr):

B.G.M. Rocha et al. / Journal of Organometallic Chemistry 714 (2012) 47e52
49
154.6 (s, 3-C (pz)), 136.8 (br, C]N), 135.8 (s, 5-C (pz)), ca. 133.5 (br,
3-iminoisoindolin-1-one(Ph)), 131.7 (s, pz-C (Ph)), ca. 130.5 (br, 3-
iminoisoindolin-1-one(Ph)), 129.0 (s, p-C (Ph)), 128.4 (s, m-C
(Ph)), 127.6 (s, o-C (Ph)), 105.4 (s, 4-C (pz)), 98.0 (br, O3SC).
diffractometer with graphite monochromated Mo-K
a
radiation.
Data were collected at 150 K using omega scans of 0.5ꢂ per frame
and a full sphere of data was obtained. Cell parameters were
retrieved using Bruker SMART software and refined using Bruker
SAINT [63] on all the observed reflections. Absorption corrections
were applied using SADABS [64]. The structures were solved by
direct methods by using the SHELXS-97 package [65] and refined
with SHELXL-97 [66]. Calculations were performed using the
WinGX System-Version 1.80.03 [67] and PLATON/SQUEEZE [68]
was used to correct the data. Crystal data and refinement param-
eters are shown in Table 1.
2.1.5. [Cu(TpmsPh){MeC(]NH)NHMe}] (6)
To a dichloromethane solution (3 mL) of [Cu(TpmsPh)(MeCN)] (1)
(0.040 g, 0.064 mmol, 1 equiv) was added a 2.0 M THF solution of
monomethylamine (32 mL, 0.064 mmol, 1 equiv). The resulting col-
ourless solution was stirred at room temperature for 3 h under
dinitrogen. The solvent was removed under vacuum and the residue
waswashedwith cold methanol(5 mL)and driedtoafford6 (0.026g,
61%). Complex 6 is well soluble in medium polarity solvents such as
3. Results and discussion
Me2CO, CHCl3 or CH2Cl2, less soluble in H2O (S25 C z 4 mg mLꢀ1),
ꢂ
MeOH or EtOH, and insoluble in Et2O. 6, C31H29N8O3SCu (657.23):
[Cu(TpmsPh)(MeCN)] (1) was prepared according to a literature
method by reaction of Li(TpmsPh) with [Cu(MeCN)4][PF6] [12]. It
reacts with cyclohexyl isocyanide (CyNC) and 2,6-dimethylphenyl
isocyanide (XylNC) in dry methanol leading to the formation of
the corresponding isocyanide complexes [Cu(TpmsPh)(CyNC)] (2)
and [Cu(TpmsPh)(XylNC)] (3), isolated as white solids in high yields
(Scheme 1).
calcd. C 56.65, N 17.04, H 4.45, S 4.87; found C 57.10, N 16.98, H 4.67, S
4.62. ESIþ-MS: 657 [M]. IR (KBr): 3323, 3276 (m,
n
(NH)), 3127 (w),
(C]N)), 1499 (m), 1458 (m), 1372 (m),
1268 (s), 1237 (s), 1104, 1078, 1044 (s, (SeO)), 854 (w), 697 (s,
(CeS)), 539 (w) cmꢀ1.1H NMR (400.130 MHz, CDCl3, 298 K): 7.87 (m
3059 (m), 1604, 1532 (m,
n
n
n
br, 6H þ 3H, 5-H (pz) þ o-H (Ph)), 7.43 (m br, 9H, m,p-H (Ph)), 6.71 (s
br, 3H, 4-H (pz)), 3.75 (s b, 1H, NH-Me) 2.17 (s, 3H, Me-C), 1.85 (s br,
3H, Me-NH); 13C{1H} NMR (100.613 MHz, CDCl3-d6, 298 K): 157.2 (s
br, CueN]C), 154.0 (s, 3-C (pz)), 135.9 (s, 5-C (pz)), 131.9 (s, pz-C
(Ph)), 129.1 (s, p-C (Ph)), 128.6 (s, m-C (Ph)), 127.1 (s, o-C (Ph)),
105.2 (s, 4-C (pz)), 96.0 (s, O3SC), 2.3 (s, NH-Me), 1.8 (s, CMe).
These products can also be obtained in a single-pot process,
starting from the precursors of 1, i.e., [Cu(MeCN)4][PF6] and
Li(TpmsPh). The acetonitrile complex 1 is then generated in situ,
without isolation, and further reaction occurs with the appropriate
isocyanide. Compounds 2 and 3 are moderately soluble in MeOH or
EtOH, soluble in CH2Cl2 and CHCl3, and sparingly soluble in water
2.2. Attempted reaction of 2 or 3 with methylamine
(S25 C z 3 mg mLꢀ1). Their variable temperature 1H NMR spectra
ꢂ
indicate [12] that the scorpionate assumes the N,N,O-coordination
mode which is retained in the solid state: their IR spectra display
the nSO typical [29] of the coordinated sulfonate moiety (i.e. strong
and sharp bands at 1042 and 1043 cmꢀ1). Compound 2 exhibits an
X-ray crystal structure with the copper cation in an ON2C envi-
To a dichloromethane solution (3 mL) of [Cu(TpmsPh)(RNC)] (2
or 3, 0.064 mmol, 1 equiv) was added a 2.0 M THF solution of
monomethylamine (32
mL, 0.064 mmol, 1 equiv). The resulting
colourless solution was refluxed for ca. 24 h under dinitrogen. The
solvent was removed under vacuum and the residue was washed
with cold methanol (5 mL) and dried. The obtained solid was
analysed by IR, 1H and 13C NMR and ESI-MS indicating the presence
of the starting 2 or 3.
ronment (Fig. 2). Houser et al. [69] introduced a parameter (
s4) to
describe the geometry of a four-coordinate metal system which is
determined by eq. (1), where
involving the metal.
a
and
b
are the largest angles
(1)
2.2.1. [(m-Cu){Cu(m
-OH)2(TpmsPh)}2] (7)
s4 ¼ ½360 ꢀ ð
a
þ
b
Þꢄ 141ꢂ
=
2.2.1.1. Preparation from complex 6. A methanol/CH2Cl2 (3:1 v:v)
solution (4 mL) of [Cu(TpmsPh){MeC(]NH)NHMe}] (6) (0.025 g,
0.038 mmol) was cooled down and kept, in air, in a fridge at ca. 4 ꢂC
overnight, thereafter the solution was decanted leaving a deep dark/
green crystalline solid of 7 (22 mg, 44%). 7, C56H46N12O10S2Cu3,
(1301.81); calcd. C 51.66, N 12.91, H 3.56, S 4.93; found C 52.01, N
By means of this simple criterion, perfect square planar, trigonal
pyramid or tetrahedral geometries should have 4 values of 0, 0.85
s
or 1, respectively. In complex 2, the s4 parameter has an interme-
diate value (0.65) and its geometry is better described as that of
a seesaw. The Cu1eO1 bond length of 2.377(2) Å, even though long,
12.79, H 3.50, S 4.44. IR (KBr): 3430 (w,
1637 (w, (OeH)), 1535 (m, (C]N)), 1499 (m), 1457 (m), 1378 (m),
1261 (s), 1231 (s), 1079 (s), 1046 (s, (SeO)), 860 (w), 758 (s), 641 (s,
(CeS)) cmꢀ1. X-ray quality single crystals were grown from a cooled
n(OeH)), 3139 (w), 2964 (m),
d
n
Table 1
n
Crystallographic data for compounds 2$Et2O and 7.
n
2$Et2O
7
concentrated solution of 7 in methanol/CH2Cl2 (3:1 v:v).
Crystal shape
Crystal colour
Empirical formula
Formula weight
Crystal system
Space group
a (Å)
Prism
Prism
Green
C56H46Cu3N12O10S2
1301.79
Triclinic
Colourless
(C35H32CuN7O3S)2$C4H10
1462.67
Monoclinic
C2/c
27.422(2)
11.4315(7)
23.0916(17)
106.675(2)
6934.2(8)
4
2.2.1.2. Preparation from complex 1. To a methanolic solution
(4 mL) of [Cu(TpmsPh)(MeCN)] (1) (0.040 g, 0.064 mmol, 1 equiv),
monomethylamine (32 mL, 0.064 mmol, 1 equiv) was added. The
resulting colourless solution was stirred at room temperature for
3 h under dinitrogen. Then the system was open to air and CH2Cl2
(1 mL) was added to the reaction mixture which was further stirred
for 1 h. The resulting green solution was cooled and kept, in air, in
a fridge at ca. 4 ꢂC overnight, to form a dark green powder of 7
(29 mg, 58%).
O
P ꢀ 1
11.8151(11)
11.8270(11)
12.2171(10)
107.437(4)
1578.2(2)
1
b (Å)
c (Å)
b
V (Å3)
Z
rcalc (g cmꢀ3
)
1.401
0.740
3048
28,579/6331
1.370
1.130
2039
14,950/5591
0.0684; 0.1714
0.913
m
(Mo-K
F (000)
Refl. collected/unique
a
) (mmꢀ1
)
2.3. Crystal structure determination
R1 ¼ [I > 2
s
(I)]; wR2 (all data) 0.0464; 0.1093
Single crystals of 2 and 7 were obtained as indicated above.
Intensity data were collected using a Bruker AXS-KAPPA APEX II
GOF
0.984

50
B.G.M. Rocha et al. / Journal of Organometallic Chemistry 714 (2012) 47e52
O
N
N
N
N
N
N
Cu
CO
N
Cu
O
O
4
5
NH
O
–
RNC
NH
NH
CO
–
MeCN
N
N
CNR
N
N
N
N
N
Cu
N
C
Me
Cu
C
N
R
–
MeCN
O
O
1
R = Cy 2, Xyl 3
MeNH2
H
N
N
N
i. MeNH2/MeOH,
ii. O2
Cu
O
C
Me
6
MeHN
O2,
MeOH/H2O
H
O
H
N
N
O
N
N
N
Cu
N
Cu
Cu
O
H
O
H
O
O
7
Scheme 1. Copper complexes bearing TpmsPh ligands.
is within the sum of the corresponding van der Waals radii and is
similar to those of the analogues [Cu(TpmsPh)(MeCN)] (1) and
[Cu(TpmsPh)(HMT)] (HMT ¼ hexamethylenetetramine) [12] and to
the CueOsulfonate bond distances in complex 7 (see below).
Intense nCN stretching bands in the IR spectra of compounds 2
and 3 are seen at 2191 and 2153 cmꢀ1, respectively, values that are
not markedly different from those of the corresponding uncoordi-
nated isocyanides (i.e. 2135 and 2124 cmꢀ1, correspondingly), thus
indicating that their activation upon coordination to the Cu centre
should not be extensive [38,39]. Accordingly, the isocyanide ligand
in 2 or 3 does not undergo attack by a nucleophile such as
methylamine or 3-iminoisoindolin-1-one [31,42,56,58]. In fact, the
unreacted starting compounds were isolated upon attempted
reaction of 2 or 3 with methylamine, whereas isocyanide ligand
displacement occurred with the iminoisoindolinone to give
[Cu(TpmsPh)(3-iminoisoindolin-1-one)] (5, Scheme 1). The same
product can also be obtained upon direct reaction of the acetoni-
trile complex 1 with 3-iminoisoindolin-1-one. It is worthwhile to
point out that examples of complexes containing ligated 3-
iminoisoindolin-1-ones are scarce, and up to date were repre-
sented only by Pt(II) [31], Pd(II) [31] and Zn(II) [57] species,
reported recently by some of us. Hence, within the current study,
we succeed to extend such a type of complexes to copper(I).
Surprisingly, in contrast with the behaviour of the isocyanide
complexes 2 and 3, the reaction of the acetonitrile complex 1 with
methylamine (a stronger protic nucleophile than the above imi-
noisoindolinone) led to the formation of the amidine product
[Cu(TpmsPh){MeC(]NH)NHMe}] (6) derived upon nucleophilic
addition of the amine to the nitrile ligand (Scheme 1). Compound 6
was not successfully crystallized for X-ray analysis, but the 1H NMR
spectrum shows the characteristic resonances for the N2O-coordi-
nation mode [12] that appears to be retained in solution from the
starting material 1. Moreover, the 13C NMR spectrum of 6 displays
the typical C]N carbon resonance at
d 157 ppm drastically shifted
from the carbon resonance of the corresponding nitrile in 1 (i.e.
d
116.18) [12].
The acetonitrile displacement in 1 by carbon monoxide was also
investigated. Many attempts under different conditions, viz. at
various CO pressures (1e6 atm), reaction temperatures
(from ꢀ78 ꢂC to 40 ꢂC) and different solvents (MeOH, CH2Cl2)
within 6e72 h period, were unsuccessful, showing an unexpected
difficulty to achieve the carbonyl analogue of 1. Exclusively by using
a relatively high CO pressure (20 atm) in a closed vessel containing
acetonitrile solution of 1, was possible to isolate from a methanol
solution the expected carbonyl complex [Cu(TpmsPh)(CO)] (4) after
ca. 12 h. The observed difficulty in the preparation of 4, in contrast
Fig. 2. Plot of [Cu(TpmsPh)(CyNC)] (2), with ellipsoids shown at 30% probability (Et2O
molecule was omitted for clarity). Selected bond lengths [Å] and angles [ꢂ]: Cu1eN10
2.022(3); Cu1eN20 2.021(3); Cu1eO1 2.377(2); Cu1eC1 1.835(4); C1eN1 1.151(4);
N1eC2 1.467(4); Cu1eC1eN1 177.1(3); C1eN1eC2 174.7(3); N20eCu1eN10 87.96(10);
C1eCu1eO1 110.67(11); N20eCu1eO1 86.61(9); N10eCu1eO1 82.50(9).

B.G.M. Rocha et al. / Journal of Organometallic Chemistry 714 (2012) 47e52
51
Fig. 3. Plot of [(m-Cu){Cu(m
-OH)2(TpmsPh)}2] (7), with ellipsoids shown at 30% probability. Hydrogen atoms were omitted for clarity. Symmetry codes to generate equivalent atoms:
a) ꢀx, 1 ꢀ y, 1 ꢀ z. Selected bond lengths [Å] and angles [ꢂ]: O1eCu2 1.914(4); O1eCu11.918(5); O2eCu1 1.914(4); O2eCu2 1.913(5); N11eCu1 1.972(5); N21eCu1 1.974(6); O11eCu1
2.361(4); Cu1eCu2 2.7902(8); Cu2eO1eCu1 93.5(2); Cu2eO2eCu1 93.6(2); O2eCu1eO1 79.5(2); O2eCu1eN11 173.5(2); O1eCu1eN11 94.9(2); O2eCu1eN21 99.9(2);
O1eCu1eN21 176.8(2); N11eCu1eN21 85.9(2); O2eCu1eO11 95.00(19); O1eCu1eO11 91.32(19); N11eCu1eO11 88.33(19); N21eCu1eO11 85.60(19).
to the case of related complexes with a comparable scorpionate
respectively). The shortest intramolecular Cu/Cu bond distance in
7 is of 2.7902(8) Å.
ligand but without the sulfonate group [70e72], could suggest an
eventual role of this group. Complex 4 shows nCO at 2107 cmꢀ1
,
consistent with those of the related Cu(I) complex [Cu(TpmPh)(CO)]
[PF6]) [70], bearing the neutral tris(phenylpyrazolyl)methane, and
similar compounds of tris(pyrazolyl)borate and tris(pyrazolyl)
methane [71], and suggesting [72] the retention of the N2O-coor-
dination mode of the scorpionate in 4.
4. Conclusions
The {copper (I)eTpmsPh} moiety provides a reactive scaffold for
small coordinating molecules (such as, nitriles, isocyanides and CO)
leading to a series of k3eTpmsPheCu complexes bearing the coor-
dinated sulfonate arm. These products represent a potential class of
catalysts with a flexible labile ligand that may provide convenient
entries to further reactivity studies [74e77].
Furthermore, although the bulkiness of the {Cu-TpmsPh} moiety
prevents the formation of full sandwich complexes with two
TpmsPh ligands, a polynuclear compound can be formed bearing
such a group at a terminal position. In fact, the trinuclear complex
The metal-activation of the CN triple bond in the CuI compounds
is limited [38,39,50], but could be successfully exploited in the case
of a small and sufficiently strong nucleophile, such as methylamine,
that leads to the formation of the product of nucleophilic addition
to a ligated acetonitrile, i.e. an acetamidine complex, whereas the
bulkier 3-iminoisoindolin-1-one nucleophile displaces the labile
acetonitrile or isocyanide ligands affording the first copper complex
with such a ligand, i.e., [Cu(TpmsPh)(3-iminoisoindolin-1-one)] (5).
Moreover, the formation of the extended tricopper core in
complex 7 provides a promising starting point for the design of
multi-copper(II) biomimetic models, what deserves to be further
explored.
[(m-Cu){Cu(m
-OH)2(TpmsPh)}2] (7) was isolated from a cooled
solution of 6 in methanol/CH2Cl2 left in air. The latter species can
also be obtained directly from 1, via a single pot procedure, in
methanol with MeNH2 followed by exposure to air (Scheme 1). The
formulation of 7 is based on data of elemental analyses, IR spec-
troscopy, and single crystal X-ray diffraction. As it can be inferred
from the inspection of the plot of the molecular structure of 7
(Fig. 3), Cu1 is the case of a five-coordinate metal system, for which
Addison and Reedijk proposed [73] the
metal geometry determined by eq. (2), where
largest angles involving the metal; therefore, 5 may assume values
s
5 parameter to describe the
b
and are the
a
s
of 0 or 1 for perfect square pyramid or trigonal bipyramid geome-
tries, respectively
These examples emphasize the important role of the bulky
scorpionate (TpmsPh ꢀ
which acts as a steric but flexible shield
)
modulating the coordination chemistry of the Cu centre towards
small molecules, namely those indicated above.
s5 ¼ ½ð
b
ꢀ
a
Þꢄ 60ꢂ
(2)
=
According to this criterion, the O3N2 copper environment in 7
features an almost perfect square pyramid (s5 ¼ 0.06). The Cu2
metal cation, being located in an inversion centre, presents
a perfect square planar geometry (s4 ¼ 0). In 7 the CueO bond
distances average 1.915(5) Å while the CueOsulphonate length is,
unsurprisingly (see above), considerably longer (2.361(4) Å).
The geometries of the complexes (seesaw in 2 and square
pyramid for Cu1 in 7) have an influence on several structural
parameters. For example, the Cu1 cation in 2 is 0.815 Å above the
plane defined by the N atoms of the coordinated pyrazolyl rings; in
7 that distance is of 0.917 Å. Moreover, the NeCueN bond angle in 2
Acknowledgements
This work has been partially supported by the Fundação para
a Ciência e a Tecnologia (FCT), Portugal, and its PPCDT program
(FEDER funded) through the research projects PTDC/QUI-QUI/
102150/2008,
PTDC/QUI-QUI/098760/2008,
PTDC/QUI-QUI/
109846/2009, and PEst-OE/QUI/UI0100/2011. RW and BR are
grateful to the FCT and the Group V of Centro de Química Estrutural,
for the fellowships SFRH/BD/23187/2005 and BL-CQE/2010-014,
respectively, while KVL to both the FCT and the Instituto Superior
Técnico (IST) for the research contract (Ciência 2008 Initiative).
Authors also thank the Portuguese NMR Network (IST-UTL NMR
Center) and National MS Network (IST Node) for providing access to
the NMR and ESI-MS facilities, correspondingly.
[87.96(10)ꢂ] is wider than those in
7
[85.9(2)ꢂ] while the
NeCueOsulfonate angles are narrower in the former [av. 84.55(9)ꢂ]
relative to the latter [av. 86.97(19)ꢂ]; consequently, the Cu1/Cqua-
distance in 2 is longer than that in 7 (3.188 and 3.170 Å,
ternary

52
B.G.M. Rocha et al. / Journal of Organometallic Chemistry 714 (2012) 47e52
[33] K.V. Luzyanin, A.G. Tskhovrebov, M.F.C. Guedes da Silva, M. Haukka,
Appendix A. Supplementary material
A.J.L. Pombeiro, V.Y. Kukushkin, Chem.dEur. J. 15 (2009) 5969e5978.
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I.A. Balova, M. Haukka, V.Yu. Kukushkin, Organometallics 30 (2011) 863e874.
[35] A.G. Tskhovrebov, K.V. Luzyanin, F.M. Dolgushin, M.F.C. Guedes da Silva,
A.J.L. Pombeiro, V.Yu. Kukushkin, Organometallics 30 (2011) 3362e3370.
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(2001) 75e112.
CCDC numbers 818625 and 818629 contain the supplementary
crystallographic data for this paper. These data can be obtained free
of charge from the Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
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