Structural zinc(II) thiolate complexes relevant to the modeling of Ada repair protein: Application toward alkylation reactions

The TtZn(II)-bound perchlorate complex [TtZn–OClO3] 1 (Ttxyly = hydrotris[N-xylyl-thioimidazolyl]borate) was used for the synthesis of zinc(II)-bound ethanthiothiol complex [TtZn–SCH2CH3] 2 and its hydrogen-bond containing analog Tt–ZnSCH2CH2–NH(CO)OC(CH3)33. These thiolate complexes were examined as structural models for the active sites of Ada repair protein toward methylation reactions. The Zn[S3O] coordination sphere in complex 1 includes three thione donors from the ligand Ttixyl and one oxygen donor from the perchlorate coligand in ideally tetrahedral arrangement around the zinc center. The average Zn(1)–S(thione) bond length is 2.344 Å, and the Zn(1)–O(1) bond length is 1.917 Å.