Self-assembly of organothallium compounds

mostly thallium-oxygen, compounds are mentioned here, because most organothallium derivatives self-assemble via weaker bonds which can be properly regarded as secondaiy bonds in some borderline cases differentiation is difficult. 

Supramolecular self-organization in the solid state has been observed (by X-ray diffraction) for several thallium-oxygen compounds. The secondary Tl - O bonds in these compounds are rather strong and it is debatable whether these should be regarded as electron-pair donor-acceptor bonds or as secondary bonds. 

Two dimethylthallium(III) phenoxides, Me2T10Ph and Me2T10C6H4Cl-2, 107 and 108, are dimeric, with basically identical Tl-0 distances in the foru-membered ring formed by self-assembly [333]. These are longer than the Tl-O distance expected for a covalent bond, however. Molecular weight determinations in benzene show that the association is maintained in solutions of R2T10Ar derivatives [334] 

Aryloxide compounds of T1(I) without Tl-C bonds, also dimerize. Thus, 2,4,6-tris(trifluoromethyl)phenoxide, TIOC6H2(CF3)3, is a dimer, 109, with identical but longer Tl-0 bonds in a four-membered TI2O2 ring [336]. 

Polymeric self-assembled structures via Tl- O association have been identified in dimethylthallium(III) acetate, Me2T100CMe, 110, dimethylthallium(III) tropolo-nate, 111, dimethylthallium(III) acetylacetonate, 112 [337], and the diethyl-thallium(III) salicylaldehyde derivative 113 [338]. 

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