ChemInform Abstract: Photodimerization of Tetrathiafulvalenecarboxylic Acid Esters in the Crystalline State.

Kreitsberga, Ya. N.; Лиепиньш, Э. Э.; Mazheika, I. B.; Neiland, O. Ya.

doi:10.1002/chin.198623213

Cited by 3 publications

(4 citation statements)

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“…They have oxidation potentials in an attractive range, and are therefore stable in air. Furthermore, the pyrrolo-TTFs have their 2-and 5-positions unsubstituted, allowing easy introduction of new functionalities as demonstrated in Schemes 8,9,and 12. A fundamental understanding of redox-responsive receptors, such as the bis(pyrrolo)-TTF crown 48 and the mono(TTF)-calix [4]pyrrole 51, can aid the design of more complicated systems that may find applications as new sensors or as novel drug delivery systems.…”

Section: Discussionmentioning

confidence: 98%

“…Incorporation of the TTF unit into macrocyclic, molecular, and supramolecular systems therefore often results in mixtures of cis and trans isomers, as in the case (Figure 3) of the macrocyclic TTF derivative [6] 4. The separation of the cis and trans isomers is often impossible, because TTF derivatives are prone to isomerization [7] in the presence of traces of acid [8] or on exposure to light [9] ( Figure 4). The inherent cis/trans complication gives rise to a number of problems: (i) spectral data are difficult to interpret, (ii) physical studies on a mixture of the two isomers often become too complex, since the distribution of the isomers might change during the measurements, and (iii) preparation of single crystals for X-ray studies is more complicated, since an isomeric mixture is generally difficult to crystallize.…”

Section: Applications Of Ttfsmentioning

confidence: 98%

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Pyrrolo‐Tetrathiafulvalenes and Their Applications in Molecular and Supramolecular Chemistry

2003

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Although tetrathiafulvalene and its derivatives have been extensively studied as π-electron donors in the fields of molecular organic metals and electrically conducting materials for more than 30 years, the intriguing potential of tetrathiafulvalene as a building block in molecular and supramolecular chemistry has only recently been developed. Progress in synthetic tetrathiafulvalene chemistry has enabled the preparation of elaborate molecular architectures and, in recent

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Section: Discussionmentioning

confidence: 98%

Section: Applications Of Ttfsmentioning

confidence: 98%

Pyrrolo‐Tetrathiafulvalenes and Their Applications in Molecular and Supramolecular Chemistry

2003

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“…In an ideal system, the CBPQT 4+ ring would only encircle the strongest π-electron donor, that is the TTF unit, thereby creating the possibility for perfect controlover the location of the tetracationic cyclophane (ring) using electrical impulses. The use of the core TTF unit in the dumbbell component, however, suffers from the major drawback that the facile cis/trans isomerization of TTF creates a dumbbell that exists as two inseparable isomers, thereby significantly complicating the NMR spectroscopic assignments of both the dumbbells and the [2]rotaxanes. To overcome this shortcoming, the isomer-free MPTTF unit has already found widespread use in the construction of bistable [2]rotaxanes, although it is known experimentally 2b,c,i that, in MPTTF-based bistable [2]rotaxanes, the CBPQT 4+ ring does not encircle the MPTTF unit exclusively but also resides on the NP station to some significant extent.…”

Section: Introductionmentioning

confidence: 99%

Functionally Rigid Bistable [2]Rotaxanes

et al. 2007

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Two-station [2]rotaxanes in the shape of a degenerate naphthalene (NP) shuttle and a nondegenerate monopyrrolotetrathiafulvalene (MPTTF)/NP redox-controllable switch have been synthesized and characterized in solution. Their dumbbell-shaped components are composed of polyether chains interrupted along their lengths by (i) two pi-electron-rich stations-two NP moieties or a MPTTF unit and a NP moiety-with (ii) a rigid arylethynyl or butadiynyl spacer situated between the two stations and terminated by (iii) flexibly tethered hydrophobic stoppers at each end of the dumbbells. This modification was investigated as a means to simplify both molecular structure and switching function previously observed in related bistable [2]rotaxanes with flexible spacers between their stations and incorporating a cyclobis(paraquat-p-phenylene) (CBPQT4+) ring. The nondegenerate MPTTF-NP switch was isolated as near isomer-free bistable [2]rotaxane. Utilization of MPTTF removes the cis/trans isomerization that characterizes the tetrathiafulvalene (TTF) parent core structure. Furthermore, only one translational isomer is observed (> 95 < 5), surprisingly across a wide temperature range (198-323 K), meaning that the CBPQT4+ ring component resides, to all intents and purposes, predominantly on the MPTTF unit in the ground state. As a consequence of these two effects, the assignment of NMR and UV-vis data is more simplified as compared to previous donor-acceptor bistable [2]rotaxanes. This development has not only allowed for much better control over the position of the ring component in the ground state but also for control over the location of the CBPQT4+ ring during solution-state switching experiments, triggered either chemically (1H NMR) or electrochemically (cyclic voltammetry). In this instance, the use of the rigid spacer defines an unambiguous distance of 1.5 nm over which the ring moves between the MPTTF and NP units. The degenerate NP/NP [2]rotaxane was used to investigate the shuttling barrier by dynamic 1H NMR spectroscopy for the movement of the CBPQT4+ ring across the new rigid spacer. It is evident from these measurements that the rigid spacer poses a much lower barrier to the 1.0 nm movement of the CBPQT4+ ring from one station to another as compared with previous systems-a finding that is thought to be a result of the combination of fewer favorable interactions between the spacer and the CBPQT4+ ring and a relatively unimpeded path between the two NP stations. This example augers well for exploiting rigidity during the development of well-defined bistable [2]rotaxanes, which are unencumbered by the excesses of structural conformations that have characterized the first generations of molecular switches based on the donor-acceptor recognition motif.

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“…In appropriate bis-, tris-, and tetrasubstituted TTF derivatives, the [CC] double bond linking the two five-membered rings can adopt cis or trans configurations. The cis / trans isomerization of some of these TTF derivatives can be controlled chemically, electrochemically, or photochemically, thus offering the possibility of generating molecular-sized switches . To gain further insight into the factors governing the cis / trans isomerization, we synthesized a small and rigid cyclophane incorporating a TTF unit bridged by [SCH 2 CH 2 O] linkages to a 1,5-dioxynaphthalene ring system.…”

Section: Introductionmentioning

confidence: 99%

Tetrathiafulvalenenaphthalenophanes: Planar Chirality and cis/trans Photoisomerization

et al. 2000

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A cyclophane incorporating one 1,5-dioxynaphthalene ring system and one tetrathiafulvalene (TTF) unit bridged by [SCH(2)CH(2)O] linkages has been synthesized. In this cyclophane, the TTF unit can adopt either cis or trans configurations. In addition, the 1, 5-dioxynaphthalene ring system imposes one element of planar chirality on this cyclophane. A second element of planar chirality is introduced by the trans form of the TTF unit. Thus, the cyclophane exists in diastereoisomeric forms as three pairs of enantiomers. The enantiomeric pairs associated with the cis form of the TTF unit, as well as one of those associated with the trans form, have been isolated by crystallization, and their structures assigned in the solid state by single-crystal X-ray analyses. In solution, cis/trans isomerization occurs when either the cis or the trans form of the cyclophane is exposed to light. The photoisomerization reaction can be followed by (1)H NMR and UV-vis spectroscopies, as well as by HPLC. The photoisomerization quantum yield has been measured at two different excitation wavelengths (406 and 313 nm). In both cases, the trans --> cis process (Phi = 0.20 at 406 nm) is much more efficient than the reverse cis --> trans process (Phi = 0.030 at 406 nm). Since the absorption spectra of the trans and cis isomers are different and the quantum yield of the trans --> cis photoisomerization reaction depends on the excitation wavelength, the mole fraction of the two diastereoisomers present at the photostationary state depends on the wavelength of the exciting light. No isomerization occurs when the solutions, regardless of the mole fraction of the two diastereoisomers, are stored in the dark.

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ChemInform Abstract: Photodimerization of Tetrathiafulvalenecarboxylic Acid Esters in the Crystalline State.

Abstract: The title compounds (I) and (IV) are photolyzed in the solid state to yield the dimers (II) and (V).

Cited by 3 publications

References 0 publications

Pyrrolo‐Tetrathiafulvalenes and Their Applications in Molecular and Supramolecular Chemistry

Pyrrolo‐Tetrathiafulvalenes and Their Applications in Molecular and Supramolecular Chemistry

Functionally Rigid Bistable [2]Rotaxanes

Tetrathiafulvalenenaphthalenophanes: Planar Chirality and cis/trans Photoisomerization

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