Synthesis of Novel Ladder Bis-Silicon-Bridged p-Terphenyls

Abstract

The tetralithiation reaction of 2,2',5',2' '-tetrabromo-p-terphenyl followed by a double silacyclization produces bis-silicon-bridged p-terphenyls. On the basis of this convenient method, a series of new ladder-type p-terphenyl derivatives have been synthesized. Their crystal structures and photophysical properties are described.

Structurally Diverse π‐Extended Conjugated Polycarbo‐ and Heterocycles through Pd‐Catalyzed Autotandem Cascades

“…Thus, we selected as eries of symmetrically substituted [5,5'-diamino-(2b); [22] 5,5'-dichloro-(2c); [21] and unsymmetrically substituted [4-chloro-(2d)a nd 4-methyl-2,2'dibromobiphenyl (2e) [23] ]2,2'-dibromobiphenyls. Direct manipulationo fc ommercial 2,2'-dibromobiphenyl led to symmetrically substituted derivatives 2b and 2c.A na utotandem reaction on 2,2'-dibromo-5,5'-dichlorobiphenyl 2c led to the desired substituted spirofluorenes 5b and 5c,a lbeit with moderate to poor yields (Scheme 6).…”

“…[23,38] Unlike the reactions with 26,t he autotandem processes with tetrabromide 27 proceeded successfully,g iving rise to 6,12-dihydroindeno[1,2-b]fluorenes 30.N oteworthy,t hese molecules feature an all-carbon ladderane structure, whichh as been employed as building block for blue emitters, [39] and molecules with other organic electronicsa pplications.…”

New Types of Fluorescent Polymers with Bis‐Silicon‐Bridged p‐Terphenyl as a Building Unit

“…In solution, polymers P2 and P3 have almost identical emission maxima with that of 6,6,12,12‐tetramethyl‐6,12‐disilaindeno[1,2‐ b ]fluorene,10 which has a similar structure to that of the chromophoric building block of the polymers. Compared with that of monomer 2 , the emission maxima of polymers P1 – P3 , which consists of bis‐silicon bridged skeleton and saturated units, are at slightly shorter wavelength, while T2 and P4 , in which the bis‐silicon bridged skeletons are linked with unsaturated spacers, have their emission maxima red‐shifted by 3–4 nm compared with that of 2 .…”

“…1,4‐Bis(phenylethynyl)benzene,11 1‐methyl‐1‐hydro‐silafluorene,12 6,12‐dimethyl‐6,12‐divinyl‐6,12‐disilaindeno[1,2‐ b ]fluorene ( 1 ) and 6,12‐dihydro‐6,12‐dimethyl‐6,12‐disilaindeno[1,2‐ b ]fluorene ( 2 )10 were prepared according to literature procedures. Karstedt's catalyst was obtained from the Wacker Silicones Company.…”

“…Most of the reported systems either contain the silicon‐bridged units in a π ‐conjugated main chain or attach the silicon‐bridged skeletons as pendant groups8 at the side chain of the saturated framework (Scheme , respectively). Recently, Murakami9 and our group10 independently reported new silicon‐bridge containing ring‐fused molecules, the bis‐silicon‐bridged p ‐terphenyls, using two different synthetic approaches. The ease of introduction of functional vinyl and hydro groups at the silicon moiety allows us to further incorporate the new silicon‐bridged skeleton into the polymer chain by a simple catalytic hydrosilylation route to achieve a new type of emissive material that consists of alternate silicon‐bridged chromophores and saturated or unsaturated spacers (Scheme ).…”