Synthesis and Characterization of Cyclic Oligomeric [cis-Mo(CO)₄(Ph₂P(C₄H₂S)₂PPh₂)]_n and Model Complexes for the Edge and Corners in the Cyclic Oligomer

Abstract

Conducting organometallic polymers are an interesting class of materials because they combine the electronic properties of metals with the simpler processing requirements of organic polymers. In an approach to incorporating poly(thiophene) segments into controlled three-dimensional environments, we have synthesized 5,5′-bis(diphenylphosphino)-2,2′bithiophene, Ph 2 P(C 4 H 2 S) 2 PPh 2 , and have reacted this ligand with Mo(CO) 4 (nbd) in a 1:1 ratio. The product of this reaction is a cyclic oligomer, as indicated by the presence of only cis-Mo(CO) 4 absorptions in the IR spectrum and the absence of resonances of free phosphines in the 31 P{ 1 H} NMR spectrum. Size exclusion chromatography of the polymer in THF gives an M h n value of 6.0 × 10 3 and M h w value of 9.7 × 10 3 for the polymer. To better understand the structural features of the polymer, model complexes for the edge, Mo(CO) 5 (Ph 2 P(C 4 H 2 S) 2 -PPh 2 )Mo(CO) 5 , and the corner, cis-Mo(CO) 4 (Ph 2 P(C 4 H 2 S) 2 H) 2 and cis-Mo(CO) 4 (Ph 2 PC 4 H 2 S)H) 2 , of the cyclic polymer have been prepared and characterized. X-ray crystal structures of Ph 2 P-(C 4 H 2 S) 2 PPh 2 and the edge model have also been determined.

Organophosphorus π-Conjugated Materials

“…One of the most popular heterole building blocks used to construct π-conjugated organophosphorus materials is the thiophene moiety (Chart ). − Genuine thiophene-based systems have long been successfully established in molecular electronics, and these units were also expected to benefit the properties of the corresponding P-containing materials. The major focus of the related research is the ability of phosphorus to coordinate transition metals. ,− This allows for the linkage of the desirable features of the organic π-conjugated unit (e.g. (semi)conductivity, luminescence, flexibility) with some electronically interesting functional properties of metal complexes (e.g.…”

Synthesis, linear and nonlinear optical properties of phosphonato-substituted bithiophenes derived from 2,2′-biphenol

“…The syntheses of diphenylphosphine-substituted oligothiophenes in moderate to high yields by the reactions of lithiated oligothiophene with chlorodiphenylphosphine are well known. [24][25][26][27] Unfortunately, the reaction of a lithiated bithiophene with 2,2′-biphenylylenephosphochloridite ester does not yield the phosphonate-substituted bithiophenes because the lithiated bithiophene substitutes both P-O and P-Cl bonds of the 2,2′-biphenylylenephosphochloridite ester.…”

Syntheses, Crystal Structures and Photophysical Measurements of Phosphite‐Substituted Schiff Base and Azobenzene Li­gands

“…However, the expected longer C-O bonds of the ligands trans to ligand 2 were not observed, and this is likely due to the crystal-packing forces in the solid-state crystal structure. [29,30] …”