4750 Chem. Mater., Vol. 22, No. 16, 2010
Stoll et al.
assembly of electronic materials. 2-Aminopyrimidines are a
class of compounds which are suitable for solid state self-
assembly by non-covalent interactions,12,13 and closely
related nitrogen-based heterocyclic molecules and silver(I)
based complexes have recently been employed in the design
of organic semiconductors.14-16 Various silver(I) complexes
of 2-aminopyrimidines are known, and silver coordination
is a versatile tool for the self-assembly of 2-aminopyri-
midines in the solid state. Several silver-based coordination
polymers have been described in the literature,17 especially a
summary of the various binding modes of silver(I) and
2-aminopyrimdines has been reported in reference 17c.
For all these silver complexes the solid state assembly is
strongly affected by the silver counterion used. Therefore,
the counterion controlled self-assembly is a promising
method for the solution based synthesis of organic electro-
nics. Herein, we report the synthesis and characterization of
new metal organic coordination polymers suitable for
electronic materials based on perfluorinated arene functio-
nalized 2-aminopyrimidine 2 and silver(I) salts. The semi-
conducting properties of the compounds are investigated by
optical methods showing that these polymers display a new
class of conductive materials with an emissive excited state.
The optical properties can be easily tuned by changing the
silver counterion or by the reversible solvent extrusion and
interchange. Also, the electrical conductivity was proven in
a preliminary experiment on a thin crystalline film of 4.
(HRMS) was obtained using 7.0 T Fourier Transform Ion Cyclo-
tron Resonance Mass Spectrometer APEX III, Bruker Daltonik.
IR spectra were recorded on a Thermo Electron Nicolet 380 FT IR
spectrometer. Elemental analyses were performed on a LECO
CHNS-932. Thermodynamic data were determined in DSC mea-
surements using a DSC-Q100 (TA Instruments). Typically measure-
ments were performed in the temperature range from 0 to 300 °C
under nitrogen with cooling and heating rates of 10 °C min-1
.
Absorption is measured with a UV/vis double beam spectrometer
(Shimadzu UV-2550). Excitation-emission spectra were obtained
by using a custom-built setup with a 75 W Xe lamp, two astigmatism-
corrected spectrometers for signal processing, and a back-thinned
CCD camera (Roper Scientific) for detection. Details of this
method can be found elsewhere.18 A short-pulse laser system based
on a regeneratively amplified Ti:sapphire laser (pulse duration:
3 ps) with subsequent frequency-tripling and detection with a streak
camera has been used for simultaneous time- and wavelength-
resolved measurements.19 Electrical conductivity was measured in
a two point probe array on a Keithley 2000 Multimeter. Single-
crystal X-ray analyses were carried out with a Nonius Kappa-
CCD diffractometer by using Mo KR radiation of the wavelength
˚
0.71073 A. The structures were solved and refined with SHELX-
9720 with refinements on F2. All hydrogen atoms were refined
isotropically. All hydrogen atoms were refined at calculated posi-
tions using a riding model. Basic crystal parameters and structure
refinements are summarized in Table S1 (Supporting Informa-
tion). X-ray powder diffraction measurements were performed
on a Philips X’pert pro MPD PW 3040/60 diffractometer using
Cu KR radiation on a glass substrate. X-ray powder diffraction
measurements of 2 were performed on a Philips PW 1050/37
diffractometer using Cu KR radiation on an aluminum substrate.
Synthesis. l-(Dimethylamino)-3-(dimethyliminio)-2-penta-
fluorophenyl-prop-l-ene perchlorate 1. 2,3,4,5,6-Pentafluoropheny-
lacetic acid (1 g, 4.4 mmol) was suspended in a mixture of dimethyl-
formamide (3 mL, 2.83 g, 39 mmol) and phosphoryl chloride
(2 mL, 3.29 g, 21 mmol) and heated to 80 °C for 3 h. The mixture
was given on ice (5 g) and conc. Mg(ClO4)2 soln (10 mL) was
added. The resulting precipitate was filtered off and washed with
diluted Mg(ClO4)2 soln. After recrystallization from ethanol the
product was obtained as yellowish solid (1.36 g, 3.4 mmol, 77%).
M.p.: 173-177 °C. 1H NMR (500 MHz, CDCl3): δ = 8.18 (s, 2H),
3.43 (s, 6H), 2.69 (s, 6H) ppm. 19F NMR (470 MHz, CDCl3): δ =
-135.8 (d, 3J(F,F) = 17.2 Hz, 2F), -148.9 (s), -159.0 (t, J(F,F) =
17.8 Hz, 2F) ppm. 13C NMR (125 MHz, CDCl3): δ = 165.2, 145.2
(m), 142.3 (m), 137.8 (m), 107.4 (m), 86.6, 49.6, 38.6 ppm. IR
(ATR): ν~ = 1600, 1525, 1497, 1399, 1081(ClO4-), 982, 961, 872,
819, 622 cm-1. HRMS (ESI): m/z calcd for C13H14F5N2 [M]þ:
293.10717; found 293.10685.
Experimental Section
Materials and Methods. Pentafluorophenyl acetic acid was
commercially purchased from Acros Organics. NMR spectra
were recorded on a Bruker AM Avance DRX500 spectrometer
without external standard. High-resolution mass spectrometry
(12) Stoll, I.; Brodbeck, R.; Neumann, B.; Stammler, H.-G.; Mattay, J.
CrystEngComm 2009, 11, 306–317.
(13) (a) Etter, M. C.; Adsmond, D. A. J. Chem. Soc., Chem. Commun.
1990, 589–591. (b) Krische, M. J.; Lehn, J.-M.; Kyritsakas, N.; Fischer,
J.; Wegelius, E. K.; Nissinen, M. J.; Rissanen, K. Helv. Chim. Acta
1998, 81, 1921–1930. (c) Krische, M. J.; Lehn, J.-M.; Kyritsakas, N.;
Fischer, J.; Wegelius, E. K.; Rissanen, K. Tetrahedron 2000, 56, 6701–
6706.
ꢀ
ꢀ
(14) Ortiz, R. P.; Casado, J.; Hernandez, V.; Lopez Navarrete, J. T.;
Letizia, J. A.; Ratner, M. A.; Facchetti, A.; Marks, T. J. Chem.;
Eur. J. 2009, 15, 5023–5039.
(15) Southward, R. E.; Thompson, D. W. Chem. Mater. 2004, 16, 1277–
1284.
(16) (a) Li, X.-G.; Hua, Y.-M.; Huang, M.-R. Chem.;Eur. J. 2005, 11,
4247–4256. (b) Li, X.-G.; Huang, M.-R.; Hua, Y.-M. Macromolecules
2005, 38, 4211–4219. (c) Li, X.-G.; Huang, M.-R.; Jin, Y.; Yang, Y.-L.
Polymer 2001, 42, 3427–3435.
5-Pentafluorophenyl-pyrimidin-2-ylamine 2. To a suspension
of the iminium perchlorate 1 (700 mg, 1.8 mmol) and guanidine
hydrochloride (0.4 g, 4 mmol) in tert-butanol (40 mL) sodium tert-
butoxide (0.4 g, 4 mmol) was added and refluxed for 2 h. The
solvent was removed in vacuo, and water was added. After
filtration the remaining precipitate was recrystallized from
ethanol to afford 2 (384 mg, 1.5 mmol, 83%) as colorless
solid. 1H NMR (500 MHz, (CD3)2SO): δ = 8.38 (s, 2H, ArH),
7.17 (2H, s, NH2) ppm. 19F NMR (470 MHz, (CD3)2SO): δ =
-143.5 (dd, J(F,F) = 24.0 Hz, J(F,F) = 6.9 Hz 2F), -156.5
(17) (a) Smith, G.; Cloutt, B. A.; Lynch, D. E.; Byriel, K. A.; Kennard,
C. H. L. Inorg. Chem. 1998, 37, 3236–3242. (b) Xu, A.-W.; Su, C.-Y.;
Zhang, Z.-F.; Cai, Y.-P.; Chen, C.-L. New J. Chem. 2001, 25, 479–482.
(c) Wang, Y.-H.; Chu, K.-L.; Chen, H.-C.; Yeh, C.-W.; Chan, Z.-K.;
Suen, M.-C.; Chen, J.-D.; Wang, J.-C. CrystEngComm 2006, 8, 84–93.
(d) Lin, C.-Y.; Chan, Z.-K.; Yeh, C.-W.; Wu, C.-J.; Chen, J.-D.; Wang,
J.-C. CrystEngComm 2006, 8, 841–846. (e) Luo, G.-G.; Huang, R.-B.;
Chen, J.-H.; Lin, L.-R.; Zheng, L.-S. Polyhedron 2008, 27, 2791–2798.
(f) Luo, G.-G.; Huang, R.-B.; Zhang, N.; Lin, L.-R.; Zheng, L.-S.
Polyhedron 2008, 27, 3231–3238. (g) Yang, H.-L.; Yang, S.; Qiu,
X.-Y.; Shao, S.-C.; Ma, J.-L.; Sun, L.; Zhu, H.-L. Z. Kristallogr. 2004,
219, 157–158. (h) Chi, Y.-N.; Huang, K.-L.; Cui, F.-Y.; Xu, Y.-Q.; Hu,
C.-W. Inorg. Chem. 2006, 45, 10605–10612. (i) Zhu, H.-L.; Yang, S.;
Ma, J.-L.; Qiu, X.-Y.; Sun, L.; Shao, S.-C. Acta Crystallogr., Sect. E
2003, 59, 1046–1047. (j) You, Z.-L.; Zhu, H.-L. Acta Crystallogr.,
Sect. C 2004, 60, 623–624. (k) Luo, G.-G.; Sun, D.; Xu, Q.-J.; Zhang,
N.; Huang, R.-B.; Lin, L.-R.; Zheng, L.-S. Inorg. Chem. Commun.
2009, 12, 436–439.
(18) Lotte, K.; Plessow, R.; Brockhinke, A. Photochem. Photobiol. Sci.
2004, 3, 348–359.
€
(19) Plessow, R.; Brockhinke, A.; Eimer, W.; Kohse-Hoinghaus, K.
J.Phys. Chem. B 2000, 104, 3695–3704.
(20) Sheldrick, G. M. SHELX-97, program for crystal structure refine-
€
€
ment; University of Gottingen: Gottingen, Germany, 1997.