The structure of (1Z,3Z)-1,4-bis(trimethylsilyl)-1,4-bis(lithiotetramethylethylenediamine)-2,3-dimethyl-1,3-butadiene. A double bridged dilithium compound

Computational Studies on the Reaction from Silyl 1,4‐Dilithio 1,3‐butadiene to Lithio Silole

“…In previous theoretical reports, it was explained that 1,4‐dilithio 1,3‐butadiene, which is structurally similar to 1 , adopts a doubly‐bridged structure of the s‐cis conformer, because the doubly‐bridged structure is more stable than the non‐bridged structure of the s‐trans conformer . In the case of 1 examined in this study, the s‐cis conformer with the doubly‐bridged Li structure, 1 , was 38.9 kcal/mol more stable than the s‐trans conformer, 1 ′ at the CCSD level of theory, as shown in Scheme .…”

Selective Transformation of Well‐Defined Alkenyllithiums to Alkenylmagnesiums via Transmetalation

“…In comparison, the length of terminal Mg−C(sp 3 ) bond [2.202(4) Å] is longer than the classic Mg−C(sp 3 ) bonds [e.g., Mg−C distances in ( t Bu 2 Mg) 2 2.14 Å] . The lengths of the bridged Li−C(sp 2 ) bond are 2.234(6) and 2.266(6) Å, respectively, which are longer than those of dilithio reagent 1 a and might indicate a weaker coordination between Li atom and butadienyl ligand. The Mg1 and Li1 atoms are located on the opposite sides of the butadienyl skeleton plane.…”

Electronic Push–Pull Modulation by Peripheral Substituents in Pentaaryl Boroles

“…The number of structurally characterized 1,4-dilithio-1,3-butadienes is limited. Some examples are reported, [74][75][76][77][78][79][80][81] including three monomeric species [74][75][76] (all featuring three or four donor sites) and as olvent-free trimer. [77] Dimeric aggregates with a donor-site/Li ratio 1i nclude the parent [(PhC) 4 Li 2 (THF) 2 ] 2 with one THF donor at each Li ion, [80] and two derivatives with two donors, justaso bserved for [2·Et 2 O] 2 .…”