Pyrazinoethylenedithiotetrathiafulvalene: a new unsymmetrical π-donor

The interaction of ICP4 with cell/infected-cell factors and its state of phosphorylation modulate differential recognition of leader sequences in herpes simplex virus DNA.

“…Genetic analyses demonstrated that it is not possible to dissociate the sequences present in the promoter/leader region of the thymidine kinase gene (the model f sequence used in this study) which are required for basal level expression from those needed to activate transcription of the gene during virus infection (Coen et al, 1986;Eisenberg et al, 1985;Zipser et al, 1981). Failure to detect direct binding of ICP4 to the fl-promoter (nts -197 to -11, data not shown) and leader ( Figure 4B) probes, and the demonstration that the same host proteins are utilized for complex formation in extracts from mock-infected and infected cells (Papavassiliou and Silverstein, 1990a), suggests that activation of transcription from this gene occurs as a consequence of the interaction of ICP4 with cell and infected-cell factors. Thus, the requirement for an infected cell-specific factor(s) to form ICP-4-containing complexes with the fl-promoter (Papavassiliou and Silverstein, 1990b) and leader ( Figure 4B) probes supports this mode of action.…”

“…Therefore, these complexes have a very low Kd(0bs) which is unaffected by the state of phosphorylation of ICP4. The fl-leader complexes formed in extracts from infected cells are much more labile than those formed in extracts from mock-infected cells ( Figure 8A; Papavassiliou and Silverstein, 1990b). However, after AP treatment of the infected-cell extract the stability of the $-leader complex that formed, and which lacked ICP4 (Figure 2B, lane 7), was like that of complexes formed in untreated extracts from mock-infected cells ( Figure 8B).…”

Tetrathiafulvalene-based group XV ligands: Synthesis, coordination chemistry and radical cation salts

“…Following this work, several symmetrical (76)(77)(78)(79), or unsymmetrical (80-85) TTFs bearing one or two fused pyrazine rings have been prepared by trialkyl phosphite cross-coupling reactions of the appropriate pyrazino-1,3-dithiole-2-one or 2-thione (Scheme 24) [56][57][58][59][60][61]. Selenium analogues have also been prepared according to this strategy [62].…”

Synthesis, Structure and Properties of an Unsymmetrical Tetraselenafulvalene Donor Fused with a Pyrazino-Ring (PEDTTSeF) and its Cation Radical Salt

“…On the other hand, recently the pyrazino-condensed TTF-type donors have received attention as materials for realizing the 2D conducting property through the N±S and S±S intermolecular contacts. [4] Such a 2D network has been observed, for example, in the salts of pyrazinoethylenedithio-TTF (PEDTTTF), synthesized by G. C. Papavassiliou et al [5,6] So far, however, no metallic salts based on PEDTTTF have been found to be stable at low temperatures. With this in mind, we focused on introducing the TSeF framework to PEDTTTF in order to realize the intermolecular network through the N±S and N±Se contacts and to stabilize the metallic state.…”

“…[3,4c] One efficient way to increase the width of the stop band (to make it overlap along all crystal directions) is to increase the refractive-index contrast between the spheres and the matrix material. Different approaches have been demonstrated for this purpose, for example, the use of spherical particles (such as TiO 2 ) with refractive indices ³ 2.5, [5] or the incorporation of semiconductor nanoparticles (such as CdS) into the void spaces among the spherical beads. [ …”