Synthesis of Platinum-Containing Conjugated Polymers Bearing Chiral Phosphine Ligands. Study of Geometries and Intermolecular Interactions Leading to Aggregation

Abstract

Platinum (Pt)-containing conjugated polymers were synthesized by the dehydrochlorination coupling polymerization of cis- and trans-dichlorobis­(N-(p-(diphenylphosphino)­benzoyl)-l-valine methyl ester)­platinum­(II) {cis-PtL 2Cl2 and trans-PtL 2Cl2, L = P­(Ph)2-p-C6H4CONHCH­[CH­(CH3)2]­CO2CH3} with 1,4-diethynylbenzene, aiming at obtaining polymers with controlled geometry at the Pt centers. In the polymerization of cis-PtL 2Cl2, the geometry at the Pt centers was controlled by the amine used in the polymerization and the reaction temperature. The formed polymer with trans-Pt centers exhibited a circular dichroism signal at the main chain chromophore region in CH2Cl2/MeOH mixed solvent. Based on the crystal packing state and non-covalent interaction analysis of a model compound, the chiroptical activity is attributed to aggregation stabilized by intermolecular π–π, CH−π, and hydrogen-bonding interactions between the phosphine ligands.

End Functionalization of Polynorbornene with Platinum–Acetylide Complexes Utilizing a Cross-Metathesis Reaction

“…The UV–vis absorption spectrum of 4b was also simulated using B3LYP and M06 functionals, which predicted the λ max assignable to MLCT/LLCT of the Pt-complex chromophore at 410 and 430 nm, respectively (Figure S48), in good agreement with the observed value [430 nm; Figure b]. ωB97X-D seems to predict the λ max of Pt–acetylide complexes at wavelengths shorter than the observed values. , …”

“…ωB97X-D seems to predict the λ max of Pt−acetylide complexes at wavelengths shorter than the observed values. 54,55 The solution-state photoluminescence of poly(1a) and poly(1b) in CH 2 Cl 2 was examined by comparing with model compounds 4a and 4b in CH 2 Cl 2 , as well as mixtures of poly(1) + 4a and poly(1) + 4b in CH 2 Cl 2 . Consequently, poly(1a), 4a, and a mixture of poly(1a) + 4a only slightly luminesced (Figure S42) at room temperature in a manner similar to Ph−C�C− Pt(PBu 3 ) 2 −C�C−Ph.…”

Synthesis of geometry-controlled platinum-containing polymers bearing optically active bidentate phosphine ligands

“…The phosphine moieties were linked with amide and ester, expecting the formation of intramolecular hydrogen bonding between them, leading to a stable conformation as well as efficient formation of a cyclic cis-Pt complex, referring to a series of studies by Kokan, Kirin and coworkers mentioned above. [17][18][19] 20 In the present study, poly(1-2) was insoluble in common organic solvents including CH 2 Cl 2 , CHCl 3 , DMF, tetrahydrofuran (THF), acetone and dimethyl sulfoxide (DMSO). We were unable to measure the molecular weight by size exclusion chromatography (SEC) or to determine the structure by solution-state nuclear magnetic resonance (NMR), CD or UV-vis absorption spectroscopy.…”

“…[17][18][19] The complexes serve as asymmetry-inducing catalysts and form asymmetric aggregates. We successfully synthesized polyynes with Pt-complex moieties ligated with monophosphines containing an amino acid moiety, 20 in which the Pt center is mainly trans, even when starting from a cis-Pt precursor, due to isomerization during dehydrochlorination. One of the polymers exhibited a chiral secondary structure in CH 2 Cl 2 /MeOH mixed solvent.…”

Synthesis of a platinacycle: determination of the structure and examination of the photophysical properties based on DFT calculations

“…12 We have reported a series of Pt-containing polymers and examined their properties, including absorption-emission control by arylene moieties 14 and phosphine ligands, 15 triplet-triplet annihilation upconversion, 16 catalytic activity for hydrosilylation, 17 formation of chirally regulated structures based on chiral amide susbsituents 18,19 and phosphine ligands. [20][21][22] We have synthesized polymers bearing Pt-bipyridine bis(acetylide) complex moieties in the main chain by dehydrochlorination coupling polymerization of Pt-bipyridine dichlorides and bisethynylarylenes. 22 The polymers chirally aggregate in DMF/MeOH mixed solvent, and exhibit liquid crystallinity mainly based on Pt-Ar interaction between the main chains.…”