Dinuclear Organotin Building Blocks and their Conversion into a Tetranuclear Macrocycle Containing Sn-O-Sn Linkages

Six dinuclear organotin building blocks of general composition RR ' R '' SnCH2Si(CH3)(2)-biphenyl-Si(CH3)(2)CH2SnR '' R ' R, in which the tin atoms are separated by a p,p '-biphenylene bridge and carry different substituents [BD1 with R, R '=CH2Si(CH3)(3), R ''=Ph; BD2 with R, R '=CH2Si(CH3)(3), R ''=Cl; BD3, with R, R '=CH2Si(CH3)(3), R ''=I; BD4 with R=CH2Si(CH3)(2)(C5H4FeCp), R ', R ''=Ph; BD5 with R=CH2Si(CH3)(2)(C5H4FeCp), R '=Ph, R=Cl; BD6 with R=CH2Si(CH3)(2)(C5H4FeCp), R '=Ph, R ''=I], were synthesized and characterized by spectroscopic and spectrometric methods. Furthermore, the crystal and molecular structures of BD2 were determined by single-crystal X-ray diffraction (SCXRD) analysis, revealing the formation of molecular strands through intermolecular Cl -> Sn contacts. The 1D coordination polymer [BD2](n) comprises macrocyclic rings of composition [BD2](2) that motivated the generation of a related molecular macrocyclic structure by reaction of BD2 with silver (I) oxide in a 2 : 2 stoichiometry. The [2+2] macrocyclization yielded the 30-membered tetra-nuclear ring structure M1, viz., {[R2SnCH2Si(CH3)(2)-biphenyl-(CH3)(2)SiCH2SnR2](mu-O)}(2), in which two BD2 dinuclear building blocks are linked through two covalent Sn-O-Sn moieties. Examination by DFT calculations at the B3LYP/def2svp and B3LYP/6-31G*(C,H,O,Si)/LanL2DZ(Sn) levels of theory gave energy minima for molecular conformers of M1 carrying the Sn-O-Sn and p,p '-biphenylene bridges in syn- or anti-orientation.

Automated summary

The synthesis and characterization of six dinuclear organotin building blocks were reported, with the crystal and molecular structures of BD2 determined by single-crystal X-ray diffraction analysis, revealing the formation of molecular strands. Additionally, a related molecular macrocyclic structure was generated through reaction and DFT calculations were performed to study the molecular conformers of M1.