Polythioether macrocycle

First, the sulfur atom from a thiirane is added to one of the carbon atoms of the thiirane ligand of the complex, with formation of a zwitterionic intermediate. The zwitterionic intermediate undergoes elimination of ethylene to yield a reactive alkene disulfide tungsten complex. The dithietane ligands from two or more molecules, then combine to form the cyclic polysulfides. If the macrocyclization of thiirane catalyzed by W(CO)s(SC2H4) is performed in the presence of DMAD, small quantities of polythioether macrocycles 156 and 157 are formed <1997OM1430>. 

Contrary to the extensive studies on the coordination properties of polythioether macrocycles (35-42), little information is available about cyclic... 

Polythioether macrocycles or thiacrowns, as they have been called, have attracted attention because of their ability to serve as good ligands for the transition... 

Condensation of dicesium 2-thioxo-l,3-dithiole-4,5-diselenolate with fo/s-alkylating polythioethers under high dilution conditions afforded the TTF-containing macrocycles possessing soft donor sites and 12-, 15-, and 18-membered rings <%JCS(P1)1995>. 

Macrocyclic lattice hosts, 14 111 Macrocyclic mercuracarboranes, 4 216-217 Macrocyclic oligoesters, 25 125 Macrocyclic polymers, 14 252 Macrocyclic polythioethers, 23 707 Macrocylic ligands, 7 576 Macroemulsions, 10 113 16 433-434 Macrofouling organisms, in industrial water treatment, 26 149-150 Macrolide antibiotics, 15 271-320. See also Macrolides... 

Poly(monosulfide)s, 23 702-711 aliphatic, 23 702-704 aromatic, 23 706 conjugated polymers, 23 709 macrocyclic polythioethers, 23 707 poly(arylene sulfide)s, 23 704-706 poly(monosulfide ketone)s, 23 709-711 polythiophenes, 23 708 tetrathiafulvalene polymers,... 

A wide range of macrocyclic polythioethers are known and have been obtained by elegant synthetic routes (102), yet relatively few of these macrocycles have been by template methods, unless the sodium ion serves to coordinate the sulfur atom in the reactions of disodium salts of thiols with dihalides. Some examples of macrocycles prepared by this route are LXX-LXXII (5), LXXIII and LXXIV (120), and LXXV (15). 

Among the polymers preparcd by the above method, polyketoamine 410 and polythioether 411 are mentioned here it is worth observing that the latter derivatives are often accompanied by variable amounts of macrocyclic compounds formed by competitive cycli/ation reaction, depending on reaction conditions (concentration of reactants, catalyst, etc.) and type of reacting spccics. ... 

The variation in the complexation properties by this substitution (polyether to polythioether) was used by Cram for ion complexation and by Inouye for the synthesis of macrocycles for sugar recognition (Scheme 35) [71,88]. 

Macrocyclic polythioethers form coordination compounds with many transition metal ions [55] and, owing to their moderate rr-acidity (intermediate between that of amines and phosphines), can exert a stabilizing effect on lower oxidation states of the encircled metal [56]. Copper complexes of thiacrowns have been widely investigated, even in view of the fact that they can be considered convenient models in the study of redox properties of cuproproteins (systems whose active site is a copper center bound to the thioether groups of methionine residues [57]). 

We confine attention to macrocyclic polythioethers that contain at least three Sulfur atonis within the macrocyclic ring and have at least two methylene units between S atoms (i.e., excluding dithioacetals). The review discusses neither sulfur-containing cyclophanes nor their metal complexes. 

A review of recent developments in synthetic organic sulphur chemistry included much valuable material pertinent to cyclic sulphur compounds, and another review covered photocycloaddition reactions of thiocarbonyl compounds with olefins to give 1,4-dithians and cycloadditions with dienes to give thian derivatives. Macrocyclic polythioethers and their complexes have been reviewed, and in other articles the conformational aspects of multisulphur heterocycles, sulphur-containing [2,2]metacyclophanes, and other cyclic sulphur compounds have been discussed. Other reviews mention configurational aspects of cyclic sulphur compounds. ... 

The phthalimides, that serve as starting materials for these photomacrocylization reactions are readily prepared by N-alkylation of potassium phthalimide with polyamide, polyether, and polythioether-linked mesylates or hahdes. As seen by viewing the processes included in Schemes 11 through 16, irradiation of the phthaHmido-silylpolyamides, -ethers and -thioethers in MeOH solution does indeed result in modestly to highly efficient production of the corresponding macrocyclic products. 

---