A tiara-like octanuclear palladium thiolate complex, [Pd(-SCH 2 CO 2 Me) 2 ] 8 that has a toroidal structure, was synthesized via reactions of either PdCl 2 with methyl thioglycolate/N,N-diisopropylethylamine (DIEA) (conventional method) or [PdCl 2 (MeCN) 2 ] with m-C 6 H 4 (CMe 2 SCH 2 CO 2 Me) 2 (alternative method). In the latter method, the tiara-like complex formed via the corresponding SCS-pincer complex and/or 1:1 PdCl 2 and ligand complexes. With respect to the platinum analogs, the alternative method efficiently produced the tiara-like octanuclear complex, [Pt(-SCH 2 CO 2 Me) 2 ] 8 , in high purity. Small molecules, such as CH 2 Cl 2 , ClCH 2 CH 2 Cl, CH 2 Br 2 , and CH 3 I, were accommodated in the inner voids of the tiara rings to form 1:1 inclusion complexes. These complexes are stabilized by weak CH···X hydrogen bonds (X = Cl or Br) between the methylene protons of four or eight axially positioned methoxycarbonylmethyl groups on the tiara rings and the halogen atoms of the guest molecules, as well as weak coordination of the halogen atoms to the transition-metal atoms.2

An iodine molecule was successfully inserted into the inner cavity of a tiara-like octanuclear palladium thiolate complex, [Pd(μ-SCH 2 CO 2 Me) 2 ] 8 . The included iodine molecule coordinated weakly to six palladium atoms in both linear and bent [a] 4073 modes, as confirmed by X-ray crystallography and DFT calculations. The inclusion complex reacted with an excess amount of I 2 to produce a disulfide, which was accompanied by decomposition of the tiara ring.

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