Syntheses and X-ray crystal structures of poly(pyridylsulfanylmethyl)arenes: new multi-armed molecules

Synthesis of fluorinated trithioether compounds

“…with two thioether (S2 and S3) below the central ring and the third (S1) above the central ring. This arrangement is identical to that observed in the X-ray structure of the abovecited tripodal ligand including phenylthiomethyl as functional group [23], as well as for 1,3,5-tris(2-pyridylthiomethyl)-2,4,6-trimethylbenzene [24]. In contrast, some closely related tripodal compounds built-up on 2,4,6-trimethylbenzene adopt, at least in the solid state, a cis,cis,cis arrangement, for instance with 4-methylthiazol-2-ylthiomethyl [25] or 2-pyrimidinylthiomethyl [26] as substituents at positions 1, 3, and 5 of the central benzene.…”

“…Unexpectedly, a different orientation for the phenyl rings was observed in the case of 1,3,5-tris(phenylthiomethyl)-2,4,6-trimethylbenzene [23], with one dihedral angle close to 908 and the two others close to 08 ( Table 2, entry 4). It is worth noting that a conformation corresponding to three dihedral angles close to 908 has been observed both for cis,trans,trans [24] and cis,cis,cis [25,26] molecules. Interestingly, these dihedral angles seem to be related to the nature of the substituent at S atoms rather than by the general arrangement of thioether groups, cis,trans,trans, or all-cis: orthogonally arranged rings are favored in the cases of S atoms substituted by an aromatic ring including an unsubstituted ortho-heteroatom, which is unable to give close contacts with H atoms of the methylene groups.…”

“…In this field, tripodal ligands with arene cores have been designed for construction of cagelike architectures [12][13][14][15], and polythiolate and polythioether ligands possess an unusual potential for structure control in crystal construction. So, interesting crystal structures of transition metal complexes with tripodal trithiolate [16,17] and polythioether [18][19][20][21][22] ligands have been reported, and some examples of organic polythioether ligands have been structurally characterized [21,[23][24][25][26].…”

Ligand Design in Multimetallic Architectures: Six Lessons Learned

“…Once again the crystal structure of the free ligand, which could potentially adopt many conformations, shows that it has the eight arms locked into a specific conformation in which the donor groups alternate on opposite faces of the central core. 39 Thus, the use of flexible ligands can provide access to interesting molecular architectures without complete loss of control in the self-assembly process.…”

Octasubstituted biphenylenes: is there a favoured conformation?

“…The X-ray crystal structure of octaethylbiphenylene revealed that this compound adopts an ababbaba conformation in the solid state rather than the fully alternating abababab conformation that was calculated to be the most stable (Taha et al, 2000;Marks et al, 2003). However, we previously prepared the new eight armed ligand octakis(2-pyridylmethylsulfanyl)biphenylene and were encouraged to find that in the solid state it was preorganized into the fully alternating abababab conformation (McMorran & Steel, 2003). We now report the synthesis of octakis(pyrazol-1-ylmethyl)biphenylene and the X-ray crystal structure of its ethanol solvate (1).…”