Macrocycles tetrathia

Moyer et al. [8] performed a systematic study of the impregnation of a macrocycle, tetrathia-l4-crown-4 (TT14CA), onto polystyrene-divinylbe-nzene sulfonic acid (PS-DVB) strong-acid resin beads to obtain an SIR for extraction of Cu(II) from sulfuric acid. Four different impregnation procedures were tested, as can be seen in Fig. 4. In their study the effects of different parameters, such as the organic solvent used and hydration steps, were tested in order to improve the copper extraction ability. 

In particular, the macrocyclic tetrathia-crown ethers L1364-L1366 have been built according to Equation (6.28) [94]. Yields of these substances obtained in the presence of CS2CO3 in DMF amount to 88, 72 and 76%, respectively, and exceed those achieved by the alternative synthetic route in the presence of Na" " by 5-10... 

Although the first all-sulfur macrocycles were prepared many years ago " the first systematic study of such compounds was initiated by Busch and his coworkers , who were interested in the cation binding properties of such ligands. A sequential synthesis was utilized to produce 1,4,8,11-tetrathiacyclotetradecane [tetrathia-14-crown-4 (70)] . In the first step, 1,3-propanedithiol is metallated using sodium and alkylated with 2-chloroethanol. The diol was then treated with thiourea to form the dimercapto-dithioether compound 9. The latter was once again metallated with sodium and allowed to react with 1,3-dibromopropane. The yield of 70 in the ring closure step, conducted at high dilution in absolute ethanol, was 7.5% after recrystallization. The entire sequence is illustrated in Eq. (6.8) . ... 

The related manganese(I) complexes of type /uc-[MnL(CO)3] (where L is one of the tetrathia macrocycles 1,4,7,10-tetrathiacyclododecane, 1,4,8-11-tetrathiacyclotetradecane, or 1,4,7,10,13-pentathiacyclopentadecane) were obtained by reaction of /hc-[Mn(CO)3(CH3COO)3] with L in acetonitrile. These species are readily decarbonylated with Me3NO to yield the corresponding ci5-[Mn(CO)2(L)]+ species. The facial arrangements in the products containing the 12- and 15-membered ring macrocycles were confirmed by X-ray structure determinations. 

The tetrathia macrocycles containing up to 13-membered chelate rings are too small to encircle the nickel(II) atom in a square-planar chelation like tetraaza macrocycles do, and give rise to dinuclear complexes. In contrast, a planar chelation was found with the 14-membered macrocycle l,4,8,ll-[S4]-14-ane.1967... 

Becher and co-workers have reported [2]catenanes, [3]pseudocatenanes, and [4]pseudocatenanes using tetrathiaful-valene-based thiacrown ethers <1996CEJ624>. Macrocycles 171 and 172 formed the corresponding [2]catenanes in 12% and 14% yields, respectively (Scheme 24). 

The C ium Effect Syntheses of Medio- and Macrocyclic Compounds Table 8. Yields of the tetrathia crowns 69a-c... 

Buter and Kellogg 62, 63), large-scale synthesis of thioether macrocycles can now be achieved in good yields (2 77,223,224,226). Octathia Ss-donor macrocycles have been synthesized as 2 -t- 2 products from the cyclization reactions employed to form tetrathia S4-donor ligands 59, 61,83,147,209). 

Formation and dissociation rate constants for [Cu([15]aneS5)] have been measured and compared to related tetrathia macrocyclic complexes (92,180,207,232). The effect of [IbJaneSs on the configurational stability and reactivity of a cyclopropylcopper complex has been monitored (215). 

In 1994 Cava and coworkers reported the synthesis of the tetrathiophene-containing systems 4.183 and 4.184. The first of these was the non-conjugated tetrathiaporphyrinogen-(2.1.2.1) 4.183. This species was isolated in remarkably high yield (78%) from the reductive McMurry coupling of dialdehyde 4.182 (Scheme 4.5.5). Dehydrogenation of this macrocycle was effected by treatment with DDQ, followed by hydrazine. This afforded the neutral aromatic tetrathia[22]porphyrin-(2.1.2.1) systems 4.184 in 82% yield. 

Figure 7-65 shows the X-ray structure of the complex [7,16-bis(ferrocenylmethyl)-l,4,10,13-tetrathia-7,16-diaza-cyclooctadecane]copper(i), [CuL ] and that of the free ligand L [186]. The copper(i) centre assumes a distorted tetrahedral geometry. With respect to the macrocyclic conformation of the free ligand, which possesses two gauche and two anti C-S-C-C bonds and two anti N-C-C-S bonds, complexation with copper (i) maintains the two gauche and two anti C-S-C-C bonds, but the two N-C-C-S bonds become gauche. 

Fig. 7-65. Crystal structure of (a) the macrocyclic ligand 7,16-bis(ferrocenylmethyl)-l,4,10,13-tetrathia-7,16-diaza-cyclooctadecane (b) one of the three independent molecules of its copper(i) complex (as PFg salt). Cu-S4, 2.27 A Cu-S7, 2.35 A (reproduced by permission of the Royal Society of Chemistry).

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