Thioether complexes

Various thioether complexes have been synthesized for example, 6-coordination is found in [Ag(18S6)]+ and [Ag(9S3)2]+ but in [Ag(16S6)]+, tetrahedral coordination occurs, with two unused donor atoms in the ligand [59],... 

Azoresorcinol, pyridyl-metal complexes dyes, 6, 74 Azurins, 6, 651, 652 copper(II) complexes, 2, 772 5, 721 electron transfer reactions, 6, 653 NMR, 6, 652 Raman spectra, 6, 652 spectra, 6, 652 thioether complexes, 2, 557 Azurite... 

The and NMR spectra of the thiazole and thioether complexes does not provide any due to identify the coordinated heteroatom although the signal of the... 

NMR experiments where undertaken to determine the site of coordination of the two other complexes. The thioether complex showed an upheld shift for the N-atom in the thioether gold complex and a similar result was obtained in the case of the thiazole compound, confirming imine coordination. 

Thioethers lack the capacity to neutralize positive charge and display weak donor properties. Consequently, they do not readily displace strong donor solvents (water) or strongly bonding anions (such as halides) from the coordination sphere. As a consequence, many thioether complex syntheses employ aprotic or alcoholic solvents and precursor complexes with weakly bound solvents (such as DMSO or acetone) or anions (such as C+3S03 ). Despite the synthetic challenges, a wide range of complexes has been reported, particularly with the cyclic poly-thioethers, where the macrocyclic effect overcomes many of the above difficulties. 

Villamo, O., Barboiu, C., Barboiu, M., Yau-Chun-Wan, W. and Hovnanian, N. (2002) Hybrid organic-inorganic membranes containing a fixed thioether complexing agent for the facilitated transport of silver ions. Journal of Membrane Science, 204, 97-110. 

Fig. 2.9 Chemical formulas of crown thioether complexes and Cu(I I)bis-thiosemicarbazone. 

Crowns, 76 773. See also Crown compounds Crown thioether complexes, 23 707 Crucibles, in fused quartz manufacture, 22 413... 

In the presence of added tin chloride, the reaction is reported to be more synthetically useful (27). Using this technique, Pt(IV) thioether complexes may be synthesized directly from the salts of the [PtCUP-ion, Eq. (29) (29). 

Mercury chloride thioether complexes have been oxidized to the corresponding sulfoxide complexes by treatment with hydrogen peroxide (76) [Eq. (30)]... 

Finally, other chiral donor atoms, P,As (see Problem 9) and in metal complexes have been less systematically studied than nitrogen. Inversion rates in metal ion-thioether complexes have been measured by nmr, but the species are too labile to allow a successful resolution. 

An unusual reaction pattern has been found for the electrochemical and chemical (by ascorbic acid) reduction of the rhenium(II) thioether complex [Re(9S3)2] " (9S3 = 1,4,7-trithiacyclono-nane). Instead of the formation of the corresponding rhenium(I) complex, C bond cleavage and the release of ethene was observed and the brown rhenium(III) species [Re(9S3)(SC2H4SC2H4S)]" (250) was isolated as a BF4 salt. Lfpon electrochemical reduction of [Re(9S3)(SC2H4SC2H4S)]" further loss of ethene was observed while the analogous technetium complex can be reversibly reduced to [Tc(9S3)(SC2H4SC2H4S)]. 

A homoleptic thioether complex can be prepared by the reaction of perrhenate with 9S3 (15b) in glacial add in the presence of SnCl2. Red-brown crystals of [Re(9S3)2][PF6]2 have been isolated and studied structurally showing a mean Re—S distance of 2.37 A. Treatment of [Re(9S3)2] PF6]2 (268) with ascorbic acid does not result in reduction of the rhenium atom but in its oxidation and the release of ethene by decomposition of the cyclic thioether. The resulting rhenium(III) complex [Re(9S3)(SCH2CH2SCH2CH2S)][PF6] has been isolated and studied by X-ray crystallography. ... 

Platinum(II) thiolates can be decomposed in strong acid because of protonation at sulfur (equation 509). This reaction is similar to electrophilic alkylation at the coordinated thiolate, although in this case the thioether complex may be isolable (equation 510). Thiolato ligands are unreactive to nucleophiles, and only under the most forcing conditions does ligand replacement occur. 

Table 44 Formation Constants for some 1 1 Silver(I) Thioether Complexes...

Some reactions of [W(CO)stable thermally, it decomposes at 90 °C in a nitrogen atmosphere. With diazomethane or diazoethane, alkylation of the coordinated H2S occurs, yielding the corresponding thioether complexes. The increased acidity of the H2S ligand allows deprotonation (equation 1). 

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