Chem. Mater. 1991,3, 1013-1015
1013
Charge Transport and Optical Properties of the First Highly Conductive One-Dimensional Molecular Metal Containing F1uoride Counterion s: (TSeT)F0.25C10.50
B
John A. Schlueter, Yuji Orihashi, Mercouri G. Kanatzidis,? Wenbin Liang, and Tobin J. Marks* Department of Chemistry and Materials Research Center Northwestern University Evanston, Illinois 60208-31 13
Donald C. DeGroot, Henry 0. Marcy, William J. McCarthy, and Carl R. Kannewurf Department of Electrical Engineering and Computer Science and Materials Research Center Northwestern University Evanston, Illinois 60208-31 13
I Figure 1. Projection of the crystal structure of (TSeT)Fo,25Cb.w (1) on the ab plane illustrating two distinct types of channels: Se bounded and C-H bounded. Thermal ellipsoids are drawn at the 50% level and hydrogen atoms are suppressed.
Tamotsu Inabe Institute for Molecular Science Myodaiji, Okazaki 444, Japan Received July 22, 1991 Revised Manuscript Received October 1, 1991
Tetrachalcogenafulvalenes(A) form the basis for a large and extensively investigated class of metallic and superconducting charge-transfer salts.' Tetrachalcogenatetracenes (B)2offer an attractive, far less developed class
E-E I
.
6-6 B
A
E = S , Se, Te of precursors which are equally amenable to framework modification3 as well as electrochemical crystal growth technique^.^ A number of halide salts prepared in this manner (Cl-, Br-, I-) are highly conductive and exhibit strong interchain structural interaction^.^ In an effort to further modify crystal packing, we have prepared the first charge-transfer salts of any donor containing the smallest possible halide counterion (F-). We report here on the properties of one of them, the mixed anion molecular metal (TSeT)F0.25Cb.50. t Current address: Department of Chemistry, Michigan State University, East Lansing, MI 48824. (1)(a) Williams, J. M.; Schultz, A. J.; Geiser, U.; Carlson, K. D.; Kini, A.M.; Wang, H. H.; Kwok, W.-K.; Whango, M.-H.; Schirber, J. E. Science 1991,252,1501-1508and references therein. (b) JGrome, D. Science 1991, 252,1509-1514 and references therein. (c) Marks, T. J. Angew. Chem., Int. Ed. Engl. 1990,29,857-879.(d) Ishiguro, T.;Yamagi, K. Organic Superconductors; Springer-Verlag: Berlin, 1990. (e) Saito, B., Kagoshima, S., Eds. The Physics and Chemistry of Organic Superconductors; Springer-Verlag: Berlin, 1990. (f) Kresin, V. Z., Little, W. A., Eds. Organic Superconductioity; Plenum Press: New York, 1990. (9) Conwell, E., Ed. Highly Conducting Quasi-One-Dimensional Organic Crystals; Academic Press: San Diego, CA, 1988.
0897-4756/91/2803-1013$02.50/0
Exceedingly thin, black, lustrous needles of (TSeT)(1) were grown on Pt electrodes using high-temF0.25Cb.50 perature, anaerobic, galvanostatic electrocrystallization techniques5 (1.0 pA a t 70 'C). The electrolyte was 0.1 M (n-Bd4N+F- in rigorously dried 1,1,2-trichloroethane (TCE) with the anode compartment saturated with neutral TSeT.6 Elemental analysis of bulk samples harvested after 2 weeks indicates the composition (TSeT)F,,26Cb.60.7 This Se:C1 ratio was confirmed on a number of individual crystals by SEM/EDS (using known (TSeT)Cb.w as a calibrant), while the presence of F was confirmed by wavelength dispersive spectroscopy on the same crystals. Neither FT-IR (the absence of transitions at 2100-2050, 1600,and 1235-1205 cm-' 8, nor the diffraction data (vide infra) provide any evidence for HF2- ions. Since the recrystallized electrolyte was chloride-free (
