Synthesis and Structural Characterization of Butadienylcalcium‐based Heavy Grignard Reagents and a Ca₄[O] Inverse Crown Ether Complex

Abstract

The structure elucidation of heavy Grignard reagents (RAeX, Ae = Ca, Sr,a nd Ba, X = halides) has been greatly strived after,mainly because of their inaccessibility and remarkable instability.The synthesis of aseries of butadienylcalcium compounds is presented, including 1-calcio-4-lithio-1,3-butadiene,1,4-dicalcio-1,3-butadiene,and aCa 4 [O] inverse crownether complex, via the reaction between 1,4-dilithio-1,3butadienes and calcium iodide in THF.S ingle-crystal X-ray analysis of these unprecedented heavy Grignardr eagents revealed unique structural characteristics and bonding modes. Preliminary reaction chemistry was investigated. This study provides anovel class of alkenyl heavy Grignardreagents and au seful synthetic strategy for otherwise unavailable reactive organometallic compounds. Angewandte ChemieCommunications Angewandte Chemie Communications 9189

Alkali-Metal-Mediated Synergistic Effects in Polar Main Group Organometallic Chemistry

“…70 A 2,3-phenyl substituted 1,4-dilithio 1,3-butadiene has also been used as a precursor to organocalcium species, though significantly not calcium-based cyclopentadienes. 71 1-Calcio-4lithio-1,3-butadiene (51) was formed by a 1:1 metathesis reaction with calcium iodide in THF solution, which upon standing in THF for a day produced an indenyllithium product (52). Increasing the stoichiometry of the salt to two equivalents with a 2,3-dimethyl substituted dilithio species put two calcium centers on the open butadienyl framework in a mixture of two distinct products (Scheme 37), namely, a homometallic dicalcio diiodide derivative (53) and a heterometallic dimeric dicalcio-monolithio triiodide derivative (54).…”

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.…”