Synthesis and Unexpected Reactivity of Si−H Functionalized Dithieno[3,2-b:2‘,3‘-d]phospholes

Abstract

[reaction: see text]. Si-H functionalized, blue light-emitting dithieno[3,2-b:2',3'-d]phospholes are accessible by reaction of an appropriate bithiophene precursor with a dichlorophosphane. Subsequent functionalization of the central phosphorus center allows for a fine-tuning of the optoelectronic properties of the material. Pt-catalyzed reaction of the Si-H functionalities with alkynes affords the hydrosilation products including a polymer by reaction with 1,7-octadiyne. By contrast, the absence of any substrate leads to the exclusive formation of a polymer via dehydrogenative homocoupling.

Selective Tuning of the Band Gap of π‐Conjugated Dithieno[3,2‐b:2′,3′‐d]phospholes toward Different Emission Colors

“…Bromination of 2 with N ‐bromosuccinimide (NBS) and subsequent in situ oxidation, on the other hand, proceeded more efficiently at room temperature in an acetic acid/chloroform solution following a literature procedure for related thiophenes18 to afford the 2,6‐dibrominated derivative 4 in good yields 19. The oxidation of the phosphorus center in 4 is supported by its 31 P NMR resonance at δ =16.3 ppm that relates to other known dithienophosphole oxides13, 16a,c as well as the diiodo derivative 3 ( δ 31 P=16.3 ppm). The same is true for the 1 H and 13 C NMR resonances for 3 and 4 .…”

Iron‐Catalyzed Dehydrogenative Coupling of Tertiary Silanes

“…They are effective for primary and secondary silanes but are much less active with tertiary silanes 5. Despite the development of Zr,6 Hf,6 Ti/Zr,7 Mn,8 Rh,9 Ir,10 Pd,11 Pt,12 and Sm13 catalysts, the need remains for new methods with cheap and environmentally friendly catalysts.…”

Dehydrogenative Coupling of a Tertiary Silane Using Wilkinson's Catalyst

“…The most conventional used method for the production of high molecular weight polysilanes is the Wurtz‐type condensation of halosilanes in the presence of alkali metals , . The transition metal‐catalyzed Si–Si bond formation has also been thoroughly studied aiming to obtain selective catalysts active under softer reaction conditions . Early transition metal (Group 4) catalysts have been most intensively studied because of their higher catalytic activity, whereas late transition metal complexes, such as Wilkinson's catalyst, can exhibit competing catalytic activities between homodehydrocoupling and substituent redistribution reactions.…”

“…To the best of our knowledge only two examples of dehydrocoupling of tertiary silanes have been previously reported, and in both cases a Pt complex is used as catalyst , …”