Synthesis and electropolymerization of N-heterocyclic carbene complexes of Pd(ii) and Pt(ii) from an emissive imidazolium salt with a terthiophene backbone

Abstract

The synthesis of an emissive terthiophene-based imidazolium iodide as the corresponding N-heterocyclic carbene (NHC) preligand (4), and its Pd and Pt–NHC complexes (5a, 5b), along with their electropolymerized electrochromic polymers (P1–3) are reported.

Thiophene-Based Trimers and Their Bioapplications: An Overview

“…Commonly, nitro groups are introduced in positions 3 and 4 of 2,5-dibromothiophene. The resulting 2,5-dibromo-3,4-dinitrothiophene is coupled with organotin or organoboron thiophene derivatives in a metal-catalyzed Stille or Suzuki reaction, thus affording 3′,4′-dinitro trimers [ 27 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 , 171 , 172 , 173 , 174 , 175 , 176 , 177 , 178 , 179 ]. In some cases, the organotin or organoboron thiophene derivatives carried alkyl or ether chains, that were in this way introduced on the resulting dinitroterthiophene [ 101 , 180 , 181 , 182 , 183 , 184 , 185 , 186 , 187 , 188 , 189 , 190 ].…”

“…For this reason, nitro groups are sometimes reduced after the formation of the trimer. In this case, iron metal in acetic acid solvent has been used as an alternative to SnCl 2 /HCl for the nitro reduction [ 165 , 171 ]. Other reduction methods involve H 2 on Ni in ethanol [ 185 ], H 2 on Pd/C in ethyl acetate [ 201 ] or Zn metal in acetic acid [ 184 ].…”

“…Thiophenes carrying amines can be coupled with nitro- or imido- thiophenes: the presence of both electron donating and electron withdrawing pending groups confers to the resulting trimers a strong zwitterionic-like character [ 202 ]. 3,4-diaminothiophene is a widely used trimers building block, not only because of amines electron donating properties, but also as an intermediate for the synthesis of extended conjugated systems such as thienopyrazines [ 167 , 199 , 203 ], thienothiadiazoles [ 173 , 186 , 190 , 204 ], thienoimidazoles [ 171 , 205 ], thienoselenadiazoles [ 206 ], and more complex aromatic structures based on those. The preparation of trimers carrying N-linked amide [ 207 ], carbamate [ 197 ], ethyloxyamyl [ 208 ] and oxamate [ 209 ] groups is obtained by amine acylation with the corresponding acyl chlorides or anhydrides.…”

“…The heterocycle is obtained by reaction with N-thionylaniline [ 165 , 173 , 184 , 186 , 189 , 426 , 427 ]. Similarly, the pendant group thienoimidazole ( Scheme 21 , IV) is obtained from the reaction between a 3′,4′-trimer diamine and trimethylorthoformate [ 171 ] acyl chloride or acetic acid in strong acid conditions [ 428 ]. Finally, thieno[3,4-b]thiophene is a common monomer employed for the formation of trimers [ 429 , 430 , 431 , 432 ].…”

Magnetism and Luminescence of a MOF with Linear Mn3 Nodes Derived from an Emissive Terthiophene-Based Imidazole Linker

“…Similarly, 2-aryl-4,6-di(2-thienyl)thieno[3,4-b]imidazole derivatives ( 3 ) have been studied as the electron donor species in dye-sensitized solar cells [ 18 ]. As part of a wider study of terthiophene-based imidazole molecules, we recently reported the preparation of 4,6-di(2-thienyl)thieno[3,4-b]imidazole ( 4 , DTTI) [ 19 ] ( Scheme 1 ). An easily prepared derivative of 4 is the dicarboxylic acid derivative, 5,5′-1 H -thieno[3,4-d]imidazole-4,6-diyl) bis (thiophene-2-carboxylic acid) ( 5 , TIBTCH 2 ); here, we present an investigation of its efficacy in the construction of new emissive MOFs.…”