Dilithio Spiro Zincacyclopentadienes and Dizinca[10]cycles: Synthesis and Structural Characterization

Abstract

In this work, we report the synthesis and molecular structures of two kinds of organozinc metallacycles: dilithio spiro zincacyclopentadienes 3 and dizinca[10]cycles 4. Both complexes 3 and 4 were obtained from the reaction of 1,4dilithio-1,3-butadienes 1 with ZnX 2 (X = Cl, Br) in THF. The molecular structure of 3 was determined by single-crystal X-ray structural analysis and shows a spiro ring skeleton in which two zincacyclopentadienes are fused by a Zn(II) atom. Complex 3 represents the first well-defined examples of groups 12 metallacyclopentadienes. The molecular structure of 4 contains a distorted ten-membered dizincacycle. Multinuclear NMR measurements of 3 and 4 were conducted, and the structural transformations between them were observed. In addition, the insertion reaction of these organozinc metallacycles with S 8 or Se were investigated to give their corresponding thiophene or selenophene compounds.

Reactions of Metallacyclopentadiene with Terminal Alkynes: Isolation and Characterization of Metallafulvenallene Complexes

“…Metallacyclopentadiene complexes have attracted considerable interest and are regarded as versatile intermediates for the discovery of new reactions . In many cases, metallacyclopentadienes can react with alkynes, followed by reductive elimination to produce the corresponding benzene derivatives .…”

Formal [2+1] Cycloadditions of a Metallacyclopentadiene Unit with Alkynes: Constructing Tetracyclic Conjugated Frameworks with Bridgehead Metals

“…Conjugated metallacycles have gained increasing interests due to their unique structures, [ 12‐13 ] diverse reactivity, [ 14 ] unusual aromaticity, [ 15 ] distinctive properties, and promising applications. [ 16 ] Thanks to transition metals capable of owning several metal‐carbon bonds, the metal‐bridgehead conjugated polycyclic systems such as spiro metalloles, [ 17 ] metallapentalene derivatives, [ 18 ] and metal‐bridged metallabenzene derivatives [ 19 ] have been realized. Though various bicyclic and tricyclic conjugated metallacycles have been isolated, [ 12,20 ] the tetracyclic conjugated frameworks in which the metal is incorporated into four conjugated rings and that generally exhibit excellent photophysical properties are rarely explored.…”

C,C- and C,N-Chelated Organocopper Compounds

“…Although neutral N,N-chelated spiro copper complexes are relatively common, the anionic C,N- or C,C-cheated spiro counterparts are sporadic. As mentioned above, Xi’s group found that the C,C-bidentate ligand is an excellent platform to build up diversified coordination complexes across the periodic table [ 32 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ]. The chelating effect increases the thermal stability of these organometallic species, facilitating isolation and following characterization.…”