Zinc(II) Silanethiolates With Piperazine‐Based Ligands: Structural Diversity and Catalytic Activity in Allyl Alcohol Oligomerization

ABSTRACT This study focused on the development of non‐toxic, stable catalysts for oligomerization processes. We present the synthesis and detailed characterization of four novel zinc(II) silanethiolate complexes incorporating piperazine‐derived ligands: [Zn{( t BuO) 3 SiS} 2 (ppz)] n ( 1 ), [Zn 3 {SSi(O t Bu) 3 } 6 (amppz) 2 ] ( 2 ), [Zn 2 {( t BuO) 3 SiS} 4 (bappz)] ( 3 ), and [Zn{( t BuO) 3 SiS} 2 (bappz)] n ( 4 ). The complexes display diverse structural motifs, ranging from discrete dinuclear and trinuclear clusters to 1D coordination polymers. Their structures were elucidated with the use of single‐crystal X‐ray diffraction and supported by DFT calculations (M11‐L/def2‐SVP). The catalytic application was evaluated in the oligomerization of allyl alcohol activated by Et 2 AlCl. All complexes exhibited catalytic activity, however the dinuclear complex 3 demonstrated the highest efficiency (109 g·mmol −1 ·h −1 ). A detailed structure–activity relationship (SAR) analysis, supported by Non‐Covalent Interaction (NCI) indices, reveals that the higher productivity of 3 is attributed to the balance between stability accessibility of the metallic center. Mechanistic DFT studies (NEB method) propose a ligand‐assisted activation pathway for 3 , which involves the dissociation of a hemilabile aminopropyl arm and a subsequent N 2 S 2 → NOS 2 coordination sphere rearrangement, which opens the metal center for substrate binding. MALDI‐TOF‐MS analysis of the products confirmed the formation of oligomers ranging from dimers to heptadecamers. These findings highlight the potential of zinc silanethiolates as tuneable, environmentally benign precatalysts.