Contrasting crystal packing arrangements in triiodide salts of radical cations of chiral bis(pyrrolo[3,4-d])tetrathiafulvalenes

Abstract

Crystal structures of six 1:1 triiodide salts of a series of enantiopure bis(pyrrolo[3,4-d])TTF derivatives, the first structures of radical cation salts reported for this bis(pyrrolo) donor system, show three different arrangements of triiodide ions, organised either in head-to-tail pairs, in infinite lines, or in a castellated arrangement. The complex crystal structures, obtained by electrocrystallisation, are influenced by the presence of solvent, for example changing an ABCABC packing arrangement to ABAB with inclusion of THF, as well as by the size of the chiral side chain.

Hexakis(2,3,6-tri-O-methyl)-α-cyclodextrin–I5− complex in aqueous I−/I3− thermocells and enhancement in the Seebeck coefficient

“…The absorbance of Me 18 -α-CD–I 5 – increased similarly to that of Me 18 -α-CD–I 3 – below the Me 18 -α-CD concentration of 2.1 mM, but it showed an abrupt decrease beyond this host concentration. This indicates that Me 18 -α-CD–I 5 – underwent comproportionation to two Me 18 -α-CD–I 3 – molecules according to eqn (4) 54–57Me 18 -α-CD–I 5 – + Me 18 -α-CD + I – ⇌ 2Me 18 -α-CD–I 3 – …”

Main-Group-Based Electro- and Photoactive Chiral Materials

“…Note also that bis­(pyrrolo)-TTFs containing chiral N-appended groups, together with charge-transfer complexes with I 3 – ,and TTF-sulfoxides with stereogenic sulfur atoms have been also described, , yet no conducting salts based on these families of donors have been reported so far.…”

“…Note also that bis(pyrrolo)-TTFs containing chiral Nappended groups, 66 together with charge-transfer complexes with I 3 − , 67 and TTF-sulfoxides with stereogenic sulfur atoms have been also described, 68,69 yet no conducting salts based on these families of donors have been reported so far. TTF-containing chiral chains and units able to promote selfassembly through hydrogen bonding and π−π stacking represent valuable building blocks toward electroactive helical aggregates provided with supramolecular chirality.…”

Synthesis and structures of polyiodide radical cation salts of donors combining tetrathiafulvalene with multiple thiophene or oligo-thiophene substituents

“…In the case of the chiral bis(pyrrolo)TTFs 28-29 (Scheme 4), the neutral donors form chiral stacks related by 4 3 or near 4 3 axes, but their triiodide salts forego this packing arrangement entirely, preferring to align triiodide ions side by side with donors. 25 The shortest S⋯I contacts lie in the range 3.58-3.70 Å. Shao has reported details of polyiodide complexes of donors 22-23 (Scheme 3), analogous to 15A and 15B, in which the four thiophenes are replaced by 4-fluorophenyl and 3-fluorophenyl groups respectively. The former forms a 22.I 3 .I 2 complex and the latter forms a salt of the donor dication of 23 with a polymeric polyiodide chain crosslinked with iodine molecules.…”