Formation of Radical Trications and Diradical Dications by the Polarographie Reduction of 1,1"-Alkanediyl-bis- (1'-alkyl-4,4'-bipyridinium) Tetraquaternary Salts

Abstract

<jats:p>Six 1′,1″-alkanediyl-bis(1′-alkyl-4,4'-bipyridinium) tetraquaternary salts have been prepared and their reduction and redox properties studied by polarography and cyclic voltammetry. They are reduced to radical trications and diradical dications at potentials (E<jats:sub>c</jats:sub>) of about -0.20 V and -0.35 V, respectively. </jats:p>

A New Motif for the Self-Assembly of [2]Pseudorotaxanes; 1,2-Bis(pyridinium)ethane Axles and [24]Crown-8 Ether Wheels

“…[14] The BF À 4 salts were precipitated from water by the addition of NaBF 4 or NH 4 BF 4 and recrystallized before use. DB24C8 was purchased from Aldrich and used as received.…”

Formation of Triradical Trications from Hexaquaternary Salts Derived from 4,4'-Bipyridine

“…A t lower poten tial (E 0 ---0.70 V) there were indications of a sec ond reduction wave probably due to the formation of neutral species of type (15) but this wave was not always distinct. It is interesting to note that the for mation of the triradical trications occurs at a poten tial slightly higher than the potential of E 0 = -0.27 V obtained for the reduction of (1; R = C H 3, n -2) to the diradical dication (2; R = C H 3; az = 2) [1]. Like paraquat (13), the two diquaternary salts (4; n = 2, X = C IO 4) and (4; n = 3, X = C104) and the two hexaquaternary salts (3; n = 2) and (3; n = 3) gave intense violet colorations in aqueous solution on treatment with zinc dust due to the formation of the radical species (11) and (14).…”

“…We recently reported the preparation of tetraquaternary salts derived from 4,4'-bipyridine of the type (1; R = Me or Et, n = 2 ,3 or 4) [1], and showed that they were reversibly reduced to diradical dicat ions (2; R = Me or Et, n = 2, 3 or 4) by the uptake of two electrons. Reversible redox systems of this type are of interest as components of electrochromic memory display devices [2][3][4][5], as bielectronic mediators [6,7] and as components of redox active membranes [8].…”

“…Reaction of 4,4'-bipyridine, however, with 1,2-dibromoethane usually results in the forma tion of polyviologens [10,11] or the diquaternary salt (5) [1] depending on reaction conditions. The m ono quaternary salt, l-(2-bromoethyl)-4,4'-bipyridinium bromide (6) has also been isolated but in an impure state [12].…”

Solid‐state Supramolecular Architectures by p‐Sulfonatocalix[4]arene with Bispyridinium Derivatives

“…16 Guest molecules 1,2-bis(pyridinium)ethane (BPDE) and 1,2-bis(4,4'-dipyridinium)ethane (BDPDE) were synthesized according to common preparation method for bispyridiniums. 17 …”