JOURNAL OF
POLYMER SCIENCE
WWW.POLYMERCHEMISTRY.ORG
ARTICLE
referred to tetramethylsilane (d 5 0 ppm). X-ray Photoelec-
tron Spectra were obtained using a Kratos XSAM800. Sam-
ples were irradiated with the unmonochromatic Al Ka
radiation. Experimental conditions and details about data
treatment were the same as described elsewhere.27 Sensitiv-
ity factors here used were: C 1s:0.25; O 1s:5 0.66; N
1s:0.42; Cu 2p3/2:4.2; Cl 2p:0.61. HPLC chromatograms
were obtained using Jasco PU-2089 Plux Pumps interfaced
with a MD-1515 Diode Array Detector. The separation was
made through a YMC Pro C18 column using as eluents: H2O
(A) and CH3CN/H2O (B, 75/25 V/V) at the flow rate 0.7 mL/
min, programmed as follows: starting (40% A, 60% B), 5
min (15% A, 85% B), 10 min (15% A, 85% B), 11 min (2%
A, 98% B), 15 min (100% B), 20 min (40% A, 60% B). Chi-
ral samples were characterized using a Dionex Ultimate
3000 equipment provided with a Lux 5u Cellulose-1 column
running with a isocratic eluent program (90% hexane, 10%
isopropanol with 0.9 mL/min flow).
stopped by addition of CDCl3 and the yellow solution was
immediately analyzed by NMR (1H, 13C, DEPT, 2D).
In DMSO
All solutions were prepared under nitrogen using sure seal
NMR tubes. Typically, 4-pentyn-1-oic acid (A, 0.030 g, 0.31
mmol) was added to the catalyst (0.020 g) solution in
DMSO-d6 (ca. 0.3 mL) and the reaction was followed by
NMR.
Calculations
Kinetic Constants
Data on the relative quantity of catalytic products was
obtained by integration of the methylene (B), the methyl (C),
1
or the vinyl (D) signals observed in the H NMR spectra. The
integration of the signals corresponding to the methyl groups
of the camphor ligand were used as internal reference. For
calculation of the constants, the unitary activity was consid-
ered as 1/100th of the integration of the NMR signal in the
spectra obtained upon 4 min reaction, normalized to the
number of magnetic nuclei. A FORTRAN subroutine7 was
used to perform the numerical integration of the complete
set of equations in Scheme 2 (using steps of 0.01 min). The
output was then fed to a least squares routine and the gen-
erated values were optimized till convergence to experimen-
Synthesis of Complexes
The complexes were typically obtained as amorphous com-
pounds, on stirring copper chloride (CuCl) and the adequate
camphor ligand (L) in THF (3 mL) at room temperature (RT)
for about 18 h. Filtration of the precipitate, washing with
n-pentane (ca. 6 mL), and drying under vacuum affords the
Cu(I) complex.
ꢁ
ꢁ
tal values was 0.992 (2; T 5 40 C), 0.999 (2; T 5 60 C) and
0.962 (3; global fitting of 2 loadings).
[(CuCl)4{p-C6H4(NC10H14O)2}]n (1) - CuCl (0.030 g, 0.30
mmol) and 3,30-(p-phenylenebis(azan-1-yl-1-ylidene))bis(1,7,
7-trimethylbicyclo[2.2.1]heptan-2-one) (e, 0.030 g, 0.074
mmol) were stirred in THF to afford a brown precipitate.
Yield 48%. ELEM. ANAL (%) for Cu4Cl4C26H32N2O2: Found: C,
38.9; N, 3.1; H, 4.0; Calc.: C, 39.2; N, 3.5; H, 3.6. IR (cm21):
1750 (tCO), 1641 (tCN), 1591 (tCCarom). 1H NMR (CDCl3,
d ppm): 7.14 (s, 4H), 2.93 (sbr, 1H), 2.17–1.70 (m, 4.0 H),
1.11 (s, 3H), 1.02 (s, 3H), 0.89 (s, 3H). 13C NMR (CDCl3,
d ppm): 204.9, 174.2, 145.9, 122.9, 58.2, 50.8, 45.3, 30.1,
24.4, 21.4, 17.5, 9.1.
Structures
Hartree-Fock ab initio calculations were carried out with
GAMESS-US28 version R3 using a SBKJC basis set.29,30 The
basic repeating units (Cl-Cu-Cl, anionic and CuL, cationic)
were fully optimized without any symmetry or geometric
constrains and were used to generate the representative
dimeric oligomer by simple translation. The oligomer was
again fully optimized without symmetry or geometric
restrains to obtain optimized structures for 1, formed by
sequential, linear (Cl-Cu-Cl) and tetrahedral (CuL) units
[Fig. 1(above)] and 2, formed by sequential, linear (Cl-Cu-Cl)
and trigonal (L-Cu-Cl-Cu-L) units [Fig. 1(below)].
[(CuCl)3(C6H4NC10H14N)] (2) - CuCl (0.108 g, 1.09 mmol)
and camphorquinoxaline (C6H4NC10H14N, 0.10 g, 0.42 mmol)
afforded the compound as an orange precipitate. Yield 78%.
RESULTS AND DISCUSSION
1
ELEM. ANAL for Cu3Cl3C16H18N O ꢀ = THF: Found: C, 38.0; N,
2
2
2
5.1; H, 3.5%. Calc.: C, 37.8; N, 4.9; H, 3.9. IR (cm21): 1508
(tCN). 1H NMR (MeOH-d4, d ppm): 8.15–8.05 (m, 2H), 8.05–
7.77 (m, 2H), 3.16 (d, J 5 4.0, 1H), 2.20–0.90 (m, 4H), 1.48
(s, 3H), 1.18 (s, 3H), 0.64 (s, 3H). 13C NMR (CDCl3, d ppm):
130.1, 129.7, 116.6, 110.4, 68.8, 32.7, 25.3, 20.5, 18.6, 10.4.
Synthesis and Characterization
Camphor complexes [{CuCl}4{p-C6H4(NC10H14O)2}]n (1) and
[{CuCl}3(C6H4NC10H14N)] (2) were obtained in THF, from
reaction of CuCl with the camphor derivatives L1 or L2
(Fig. 2). L1 (bi-camphor) and L2 (camphorquinoxaline)31
were chosen because they can accommodate more than one
metal per ligand and thus bridge or chelate metal sites.
Catalytic Experiments
Solvent Free
The complexes (1 and 2) were formulated based on NMR,
FTIR, ELEM. ANAL, and further confirmed by X-ray photoelec-
tron spectroscopy (XPS).
4-pentyn-1-oic acid (A, 0.030 g, 0.31 mmol) was stirred
under vacuum for no less than 15 min. Then nitrogen was
fluxed in the Schlenk followed by addition of the copper
complex. The solids were then grinded under nitrogen for 2,
6, 18, 24, or 56 h, at RT, 40 ꢁC or 60 ꢁC forming oily mix-
tures. Different loadings of catalysts were screened for reac-
XPS data obtained from complexes 1 and 2, show that the
region Cu 2p displays the same shape for both complexes. As
a representative example, Figure 3 depicts that region for
complex 1. A single peak (a Gaussian-Lorentzian product)
ꢁ
tions at 40 C during 18 h. On completion, the reaction was
WWW.MATERIALSVIEWS.COM
JOURNAL OF POLYMER SCIENCE, PART A: POLYMER CHEMISTRY 2014, 52, 3316–3323
3317