Iron(II) Complex with a Silacycle-Bridged Biaryl-Based Ligand

Treatment of 2,6-dimethyl-1,1'-biphenyl-substituted chlorosilane with potassium followed by FeBr₂/TMEDA led to the formation of an iron(II) monobromide complex supported by a TMEDA ligand and a carbanion-based ligand containing a six-membered silacycle-bridged biphenyl skeleton. The obtained complex crystallized as a racemic mixture of (Sa, S) and (Ra, R) forms, in which the dihedral angle of the two phenyl rings of the biphenyl moiety was ∼43°.

Heavier element-containing aromatics of [4n+2]-electron systems

While the implication of the aromaticity concept has been dramatically expanded to date since its emergence in 1865, the classical [4n+2]/4n-electron counting protocol still plays an essential role in evaluating the aromatic nature of compounds. Over the last few decades, a variety of heavier heterocycles featuring the formal [4n+2] π-electron arrangements have been developed, which allows for assessing their aromatic nature. In this review, we present recent developments of the [4n+2]-electron systems of heavier heterocycles involving group 13-15 elements. The synthesis, spectroscopic data, structural parameters, computational data, and reactivity are introduced.