3869
J. Am. Chem. SOC.1995,117, 3869-3870
Communications to the Editor Competing Na+ Solvation: Ether-Shared and Ether-Separated Triple Ions of Perylene DianionlB Hans Bock,* Christian Nather,lb and Zdenek HavlaslC Department of Chemistry University of Frankfurt Marie-Curie-Strasse 11 060439 FrankfudMain, Germany Received August 2, 1994
The thermodynamically favorable solvation especially of cations affects the multidimensional networks of interrelated e q ~ i l i b r i a ' ~such , ~ , ~ as electron transfer and contact ion pair formation as well as aggregation in various ways and, therefore, controls many geochemical to biological processes: For a more detailed study of the interdependencies, Na+ was selected because of its small ionic radius, its high solvation enthalpy,1a%4a and the moderately low reduction potential of sodium metal.4a Na+ forms countless salts, complexes, and organometallic compounds of impressive structural diversity.4asc These include (i) dibenzene s a n d ~ i c h e s(ii) , ~ the surprising 1:1 stoichiometric cocrystallization of solvent-shared [Na+(DME2)2M2-] plus solvent-separated [Na+(DME&][M*-] triple ions of tetraphenylbutadiene d i a n i ~ n and , ~ ~(iii) the ether solvates of radical anion salts [Na+(RO(CH2CH*)O),-lR),][M'-Istretching from almost octahedral [Na+(THF)a] (m = 1, n = 6) to 8-fold(1) (a) Preliminary communication in the summary on charge perturbed and sterically overcrowded molecules: Bock, H.; Ruppert, K.;Nather, C.; Havlas, Z.; H e r r " , H.-F.; Arad, C.; Gobel, I.; John, A.; Meuret, J.; Nick, S.; Rauschenbach, A.; Seitz, W.; Vaupel, T.; Solouki, B. Angew. Chem. 1992, 104, 564; Angew. Chem., Int. Ed. Engl. 1992, 31, 550. (b) Part of Ph.D. Thesis: Nather, C. University of Frankfurt, 1994. (c) On leave from Czech Academy of Sciences, Flemingovo Nam, CZ 16610 Prague. (2) Bock, H. Mol. Liq. Cryst. 1994, 240, 155; Acta Nova Leopoldina 1994, 38, 221. (3) (a) Bock, H.; Nather, C.; Havlas, Z.; John A.; Arad, C. Angew. Chem. 1993,105,931; Angew. Chem., Int. Ed. Engl. 1993,32,875 and references therein. (b) Bock, H.; John, A.; Nather, C.; Havlas, Z . ; Mihokova, E. Helv. Chim. Acta 1994, 77, 41. (c) Bock, H.; Nather, C.; Ruppert, K.;Havlas, Z. J . Am. Chem. SOC. 1992, 114, 6907. (4) (a) Cf., e.g.: Wiberg, N. HollemannlWiberg: Lehrbuch der Anorganischen Chemie; de Gruyter: Berlin, 1985. The first vertical ionization energy of Na, Elv= 5.13 eV, and the hydration enthalpy of [Na+(H20)17], AHf = -390 kJ mol-', both contribute to the rather low first reduction potential, E""(Na) = -2.71 V. The ionic radius r = 97 pm, increasing to covalent contribution,Iafits nicely into a benzene hexagon 113 pm for of 240 pm diameter and, therefore, supports the formation of (C&,)zNa sandwich subunits such as the one observed in the DME solvate (Figure 1 A l (b) Kaim. W.: Schwederski. B. Bioanorpanische Chemie: Teubner: S&ttg&, 1991. (c) Wells, A. F. Structural Inirganic Chemistry, 5th ed.; Oxford University Press: Oxford, 1987. ( 5 ) (a) Bock, H.; Ruppert, K.;Fenske, D. Angew. Chem. 1989,101, 1717; Angew. Chem., Int. Ed. Engl. 1989, 28, 1685. (b) Bock, H.; Ruppert, K.; Havlas, Z.: Fenske, D. Anaew. Chem. 1990,101,1095; Anaew. Chem., Int. Ed. Engl. 1990, 29, 10421 (6) Crystal structure of disodium perylene tetrakis(dimeth0xyethane) [C~OH!~~-(N~+(CH~~(CH~)~OCH~)~)Z]: blue-violet prisms from perylene reduction in DME with 1.5-fold stoichiometric sodium metal mirror, generated at mbar, and covering the deep-blue ether solution with an n-hexane layer; crystal size, 0.5 x 0.4 x 0.4 mm, MW = 658.78 g/mol; a = 953.0(2), b = 1266.1(2), and c = 1528.2(3) pm, a = 86.22(2)O, j3 = 85.36(2)', y = 76.31(?J0, V = 1783.5 x lo6 pm3 (T = 150 K), ecac= 1.227 g/cm , triclinic P1 (No. 2), Z = 2; Mo Ka radiation, p = 0.10 cm-'; four-cycle diffractometer STOE-AED-II,6966 reflections measured within 3' 5 20 5 51°, of which 6535 were independent and used for refinement; structure solution by direct methods and difference Fourier technique (SHELX-86);refinement against (SHELXL-93);R1 = 0.0460 for 5284F0 > 4a(F0); wR2 = 0.1379 for 445 parameters and 6535 reflections; W = l/[(u2(Fo2)0.0848P)2f OSOP]; GOF = 1.068, shift/error 5 0.001, extinction correction, residual electron density 0.53/-0.30 e/A3. C, 0, and Na atoms have been refined anisotropically, the H atoms (after being geometrically ideally positioned) isotropically using the riding model; there are two independent molecules in the asymmetric unit.
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