Molecular and magnetic structure of the paramagnetic ion pair bis(tetraglyme)rubidium biphenyl, Rb+[CH3O(CH2CH2O)4CH3]2C12H10-

Paramagnetic alkali-aromatic ion-pair structures. The crystal structure of bis[1,2-bis(2-methoxyethoxy)ethane]sodium biphenylide

“…In Table 3 bond distances and angles, averaged to 222 (D 2) symmetry, are compared with the corresponding values in RbBp.2Ttg and KBp.2Ttg, and also with those in neutral biphenyl (Charbonneau & Delugeard, 1976). The pattern of a shortened central C-C bond and lengthened 'inner' C-C bonds as compared with neutral biphenyl is found in all three of the anions and corresponds with the calculated bond-order changes on going from the neutral molecule to the anion (Mooij, Klaassen, de Boer, Degens, van den Hark & Noordik, 1976). The increased ortho-hydrogen repulsion, in comparison with neutral biphenyl, which is caused by the shortening of the central C-C bond, expresses itself in the values of the bond angles at the carbon atoms of the central C-C bond.…”

“…Thereby it is a member of the same category as the crystal structures of RbBp. 2Tg (Mooij, Klaassen, de Boer, Degens, van den Hark & Noordik, 1976)and KBp.2Ttg (Noordik, Schreurs, Gould, Mooij & de Boer, 1978). Crystal structures of some diamagnetic aromatic ion-pairs in which tetramethylethylenediamine or bis-quinuclidine are the coordinating molecules (Rhine, Davis & Stucky, 1975;Walczak & Stucky, 1976) and crystal structures of alkali complexes of cyclooctatetraene (Goldberg, Raymond, Harmon & Templeton, 1974;Noordik, Degens & Mooij, 1975) have been reported to belong to the class of contact ion-pair structures.…”

Structure of Alkali Biphenyl Ion Pairs in Solution and in the Solid State

“…For the solutions studied the correlation times Tc were so large that 1, (we is the Larmor frequency of the electron) and that, accordingly, only secular parts of the various relaxation mechanisms contribute dominantly to T1. Under the assumption that the ion pairs can be described by a static model, which means that at each temperature a well defined ion pair structure exists, the following expressions for the relevant relaxation mechanisms can be derived (12): (T')F = (#) Te (4) (T')D 5td (5) (T1)Q = f(I) ()2 Tr (6) in which A is the averaged Fermi contact interaction constant, D characterizes the dipolar interaction (D:D = Z (Da)2 a and are components of r, the distance between the unpaired electron and the nucleus), eQ is the quadrupole moment, eq the electric field gradient (for simplicity reasons it is assumed that the quadrupole tensor has axial symmetry), and f(I) is equal to 21 + 3/12(21 -1). The correlation times Te, Td and Tr are all proportional to /T, provided Eq.…”

“…The crystal structure of one of its representatives viz, the rubidium biphenyl ion pair was recently solved at this laboratory (5). It appeared that the structure could be characterized as a solvent separated ion pair, in which the cation is completely surrounded by two tetraglyme molecules.…”

An experimental and theoretical study of the low temperature E.S.R. of the cyclooctatetraene and tetramethylcyclooctatetraene anion radicals-in single crystal environments

“…But no matter how fruitful the results of such studies, there is always the element of uncertainty because the studies have been performed in solution and on species whose exact structures can not be known precisely. Therefore, recent studies of aromatic hydrocarbon anions in the solid state, especially in single cr)rsta!s [2][3][4][5][6][7][8][9][10][11][12][13], are of considerable significance. An important result of the single crystal studies is that the conclusions derived from them are consistent with the conclusions drawn from previously reported investigations of ion pair phenomena in solution.…”