Thiacalixarene
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A Thiacalixarene is a macrocycle or cyclic oligomer based on a condensation product of a phenol derivative and sulfur. The word thiacalixarene is derived from thia (as sulfur) and calixarene. Thiacalixarenes have hydrophobic cavities that can hold smaller molecules or ions and belong to the class of cavitands known in Host-guest chemistry. Thiacalixarene nomenclature is straightforward and involves counting the number of repeating units in the ring and include it in the name. A calix[4]arene has 4 units in the ring and a calix[6]arene has 6.
Synthesis
Thiacalixarenes are synthetized using phenol derivatives and sulfur. The chemical reaction ranks under electrophilic aromatic substitutions followed by an elimination of water and then a second aromatic substitution. The reaction is base catalysed. Calixarenes are difficult to separate because it is all too easy to end up with complex mixtures of linear and cyclic oligomers with different numbers of repeating units. With finely tuned starting materials and reaction conditions synthesis can also be surprisingly easy.
Structure
Thiacalixarenes, like calixarene are characterised by a three-dimensional basket (vase or chalice shape). In thiacalix[4]arene derivatives, the internal volume is around 10 cubic nanometers. Thiacalixarenes are characterised by a wide upper rim and a narrow lower rim. With phenol as a starting material, the 4 hydroxyl groups are intrannular on the lower rim. The basket form (cone conformation) is stabilized by hydrogen bonding between the four hydroxyl group. In case of substituted hydroxyl group, other conformers can be observed, like 1,2 or 1,3 alternate.
S 1.20040 14.59710 10.16600
C 2.76600 14.98570 9.37340
C 2.77710 15.65700 8.16740
C 3.95380 15.99340 7.53530
C 3.95380 14.57650 9.99720
O 3.95380 13.84840 11.12830
C 3.95380 16.75960 6.17960
C 5.06080 16.19090 5.28140
C 3.09970 18.10220 6.33760
C 0.81290 13.03490 9.37340
C 0.13600 13.01750 8.16740
C -0.20560 11.84700 7.53530
C 1.21930 11.84700 10.00550
O 1.95630 11.84700 11.12830
C -0.94890 11.84700 6.17960
C -0.39540 10.74130 5.28140
C -2.29320 12.70000 6.31270
H 1.95160 15.89240 7.76150
H 5.06240 16.65690 4.45550
H 5.89740 16.29360 5.71050
H 4.88840 15.27000 5.12670
H -0.10120 13.84360 7.76480
H -0.85400 10.74440 4.45460
H 0.53140 10.89770 5.13410
H -0.50770 9.90090 5.70890
C 5.13040 15.65700 8.16740
C 5.14150 14.98570 9.37340
S 6.70710 14.59710 10.16600
C 7.09460 13.03490 9.37340
C 7.77150 13.01750 8.16740
C 8.11310 11.84700 7.53530
C 7.77150 10.67650 8.16740
C 7.09460 10.65910 9.37340
S 6.70710 9.09690 10.16600
C 5.14150 8.70830 9.37340
C 5.13040 8.03700 8.16740
C 3.95380 7.70060 7.53530
C 2.77710 8.03700 8.16740
C 2.76600 8.70830 9.37340
S 1.20040 9.09690 10.16600
C 0.81290 10.65910 9.37340
C 0.13600 10.67650 8.16740
C -0.39540 12.95270 5.28140
H -0.85400 12.94960 4.45460
H 0.53140 12.79630 5.13410
H -0.50770 13.79310 5.70890
C -2.29320 10.99400 6.31270
H -0.10120 9.85040 7.76480
C 3.95380 9.11750 9.99720
O 3.95380 9.84560 11.12830
H 1.95160 7.80160 7.76150
C 3.95380 6.93440 6.17960
C 2.84670 7.50310 5.28140
H 2.84510 7.03710 4.45550
H 2.01010 7.40040 5.71050
H 3.01910 8.42400 5.12670
C 5.06080 7.50310 5.28140
H 5.06240 7.03710 4.45550
H 5.89740 7.40040 5.71050
H 4.88840 8.42400 5.12670
C 4.80780 5.59180 6.33760
C 3.09970 5.59180 6.33760
H 5.95590 7.80160 7.76150
C 6.68820 11.84700 10.00550
O 5.95120 11.84700 11.12830
H 8.00870 9.85040 7.76480
C 8.85640 11.84700 6.17960
C 8.30290 10.74130 5.28140
H 8.76150 10.74440 4.45460
H 7.37610 10.89770 5.13410
H 8.41520 9.90090 5.70890
C 8.30290 12.95270 5.28140
H 8.76150 12.94960 4.45460
H 7.37610 12.79630 5.13410
H 8.41520 13.79310 5.70890
C 10.20070 12.70000 6.31270
C 10.20070 10.99400 6.31270
H 8.00870 13.84360 7.76480
H 5.95590 15.89240 7.76150
C 2.84670 16.19090 5.28140
H 2.84510 16.65690 4.45550
H 2.01010 16.29360 5.71050
H 3.01910 15.27000 5.12670
C 4.80780 18.10220 6.33760
O 3.95380 11.84700 6.02990
C 3.95380 11.84700 7.04460
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