Versatile coordinating abilities of acyclic N4 and N2P2 ligand frameworks in conjunction with Sn[N(SiMe3)2]2

Abstract

The adaptability of three acyclic tetradentate ligands with the –CHR–CHR– (R = H or alkyl substituent) linker in the backbone: bis(α-iminopyridine) L1 and the reduced form L2 and diaminodiphosphine L3 to stabilize various stannylenes has been explored. The reaction of L1 with two equivalents of Sn[N(SiMe₃)₂]₂ led to the stabilization of a bisstannylene 1 through the ene-amide transformation of L1. The reaction of bisstannylene 1 with B(C₆F₅)₃ and silver trifluoromethane sulfonate led to the formation of ligand stabilized Sn(II) dications 2 and 3 respectively. A mixture of Sn(II) dication 3 and a Sn(II) monocation 4 has been obtained from the reaction between 1 and trimethylsilyl trifluoromethane sulfonate. A 1 : 1 stoichiometric reaction between L3 and Sn[N(SiMe₃)₂]₂ led to the isolation of a dimeric monostannylene 5 having a step-like structure with a Sn₂N₂ central ring. The reaction of L2 with Sn[N(SiMe₃)₂]₂ underwent an electron transfer reaction ultimately leading to bis(α-iminopyridine) isolation.