Electrochemistry and blocking properties of thin films of platinum phenylethynyl complexes

Kershman, Jacob R.; Paris, Kelly E.; Stamey, James A.; Pyati, Radha

doi:10.1016/j.jelechem.2006.09.011

Cited by 5 publications

(5 citation statements)

References 19 publications

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“…To verify that the observed electrochemical process was not due to protonation of the ethynyl group, the model compound 5 , trans -Pt(PBu 3 ) 2 (CCPh) 2 , was investigated as well. The electrochemical properties of this compound are known but not in the presence of acid. , In the absence of acid, this compound exhibits an irreversible oxidation peak at ∼1.2 V versus Ag/AgCl, and a transfer of 1.43 ± 0.21 electron in a benzene/acetonitrile mixture containing 5 was observed . In this work we obtained the same results (see Supporting Information).…”

Section: Resultssupporting

confidence: 75%

Conjugated Organometallic Polymer Containing a Redox-Active Center

et al. 2008

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The new conjugated organometallic polymer (-spacer-C[triple bond]C-Pt(PBu3)2-C[triple bond]C-)n (3; spacer = para-bis(diphenyl(tetramethyl)quinone diimine) and the cyclic mononuclear model complex, spacer'-C[triple bond]C-Pt(PEt3)2-C[triple bond]C x CuCl (4; spacer' = ortho-diphenyl-2,3,5,6-tetramethyl-1,4-benzoquinone diimine) were synthesized from the 1:1 condensation of the corresponding diethynyl ligands (2-para and 2-ortho (para- and ortho-diethynyl-diphenyl-2,3,5,6-tetramethylquinone diimine), respectively), with the trans-Pt(PBu3)2Cl2 for polymer 3 and cis-Pt(PEt3)2Cl2 for 4. The materials were characterized by GPC, DSC, ATG, and electrochemistry for polymer 3, and by X-ray diffraction for 4. Polymer 3 exhibits a M(n) of 18500, M(w) of 25000 with a PD of 1.37. The trans-geometry about Pt in polymer 3 was confirmed by 31P NMR and IR/Raman spectroscopy. The cyclic voltammogram study on the model complex trans-Pt(PBu3)2(C[triple bond]CPh)2, spacer 1-para (Me3Si-C[triple bond]C-R-C[triple bond]C-SiMe3; R = para-diphenyl-2,3,5,6-tetramethyl-1,4-benzoquinone diimine) and polymer 3 demonstrated that polymer 3 in the presence of trifluoroacetic acid (TFA) exhibits a quasi reversible 2-electron reduction process centered at 0.48 V versus SCE corresponding to the reduction of the protonated quinone diimine unit into the corresponding diamine. The UV-vis spectra of the spacer 2-para (440 nm) and polymer 3 (502 nm) are characterized by red-shifted charge transfer (CT) absorptions (C6H4C[triple bond]C --> quinone diimine for 2-para; and (C6H4C[triple bond]C)2Pt --> quinone diimine for polymer 3). These assignments are corroborated by density-functional theory (DFT) and time-dependent density-functional theory (TDDFT) computations. Polymer 3 is not luminescent in the solid state or in solution at 77 K and 298 K.

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Section: Resultssupporting

confidence: 75%

Conjugated Organometallic Polymer Containing a Redox-Active Center

et al. 2008

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“…The CV of trans-PhCtCPt(PEt 3 ) 2 CtCPh was also studied and compared well with the literature. 20,21 This compound exhibits an irreversible oxidation peak at ∼1.2 V vs Ag/AgCl, and 1.43 ( 0.21 electron was transferred in a benzene/acetonitrile mixture. 21 This irreversible oxidation peak was also observed by us at 1.17 V vs SCE in acetonitrile (+0.1 M TBAPF 6 ) with 1.1 ( 0.2 transferred electron.…”

Section: Resultsmentioning

confidence: 99%

Conjugated Oligomers and Polymers of cis- and trans-Platinum(II)-para- and ortho-bis(ethynylbenzene)quinone Diimine

et al. 2008

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Three conjugated polymers of the type (−spacer−CC−PtL2−CC−) n , with spacer = para- and ortho-bis(diphenyl(tetramethoxy)quinone diimine) and L = PEt3, were synthesized as the cis- and trans-isomers about the Pt. The three combinations (spacer/PtL2Cl2), ortho/trans, para/trans, and para/cis led to polydispersed polymers, which upon fractionation provided more monodispersed materials with M n ranging from 3600 to 32400 (GPC). The spacer ortho-bis(diphenylethynyl)tetramethoxyquinone diimine reacts with cis-PtL2Cl2 to form small oligomers and a chelate cyclic complex (7), which was used as a model compound. All materials along with the aryl−CC−PtL2− CC−aryl models (L = PEt3; aryl = C6H5, 2,4,6-C6H2Me3; 2,4,5-C6H2Me3) were studied by 1H and 31P NMR, IR, UV–vis, TGA, DSC, luminescence spectroscopy, photophysics, and cyclic voltammetry. The UV–vis spectra exhibit an intramolecular low-energy and low-intensity charge transfer band (CT) assigned to π(Ph−CC) (for organics) and π/d xy ((Ph−CC)2Pt) (for organometallics) to the π*(quinone diimine), as demonstrated by comparison with a corresponding amine derivative (i.e., no CT band) and corroborated by DFT and TDDFT. The polymers and 7 are not luminescent at room temperature (solid and solution). However in 2MeTHF at 77 K, the polymers bearing the combination ortho/trans and para/cis as well as the model compound 7 exhibit higher energy phosphorescence (T n → S0) originating from the ππ*/d xy ((Ph−CC)2Pt) excited states. A correlation between the structural parameters (angle made by the PtP2(CC)2 vs the aryl planes, angle made by the aryl and the quinone diimine planes, molecular weight) with the calculated oscillator strength, absorptivities, and the observed position of the lowest energy absorption bands is demonstrated. Finally, upper energy delayed fluorescence (S n → S0) was detected for the polymers and 7 at 77 K and was assigned to T1−T1 interactions via aggregation as its intensity varies with the concentration.

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“…12 The CV of trans-PhC CPt(PBu 3 ) 2 CCPh was also studied in this work and compared well (SCE, this work, and Ag/AgCl reference electrodes have only 20 mV difference) with those of the literature. 13,14 This compound exhibits an irreversible oxidation peak at ∼1.2 V (weak) and 1.43 vs Ag/AgCl. 14 Some of the compounds could not be investigated because they decomposed in an acidic medium.…”

Section: Chartmentioning

confidence: 99%

Reduced and Oxidized Forms of the Pt-Organometallic Version of Polyaniline

et al. 2012

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This work represents an effort to synthesize all four forms of polyaniline (PANI) in its organometallic versions. Polymers containing substituted 1,4-benzoquinone diimine or 1,4-diaminobenzene units in the backbone exhibiting the general structure (C≡CC(6)H(4)-N═C(6)X(4)═N-C(6)H(4)C≡C-PtL(2))(n) and (C≡CC(6)H(4)NH-C(6)X(4)-NHC(6)H(4)C≡C-PtL(2))(n) along with the corresponding model compounds (C≡CC(6)H(4)-N═C(6)X(4)═N-C(6)H(4)C≡C)(PtL(2)Cl)(2) and (C≡CC(6)H(4)NH-C(6)X(4)-NHC(6)H(4)C≡C)(PtL(2)Cl)(2) (L = PBu(3); X = H, F, Cl) were synthesized. The polymers and corresponding model compounds were characterized (including (1)H and (31)P NMR, IR, mass spectra, elemental analysis, and X-ray structure determinations) and investigated for their redox properties in the absence and in the presence of acid. Their optical properties, including ns transient spectroscopy were also investigated. These properties were interpreted through density functional theory (DFT) and time-dependent DFT (TDDFT) computations. These materials are found to be oligomers (GPC) with thermal stability (TGA) reaching 350 °C. The greatest stabilities were found in the cases with X = F. Using a data bank of 8 X-ray structures of diimine derivatives, a relationship between the C═N bond distance and the dihedral angle between the benzoquinone ring and the flanking phenyl planes is noted. As the size of the substituent X on the benzoquinone center increases, the degree of conjugation decreases as demonstrated by the C═N bond length. The largest dihedral angles are noted for X = Cl. These polymers exhibit drastic chemical differences when X is varied (X = H, F, Cl). The completely reduced polymer (C≡CC(6)H(4)NH-C(6)H(4)-NHC(6)H(4)C≡C-PtL(2))(n) (i.e., X = H) was not chemically accessible whereas in the cases of X = F, Cl, these materials were obtained and represent the first examples of fully reduced organometallic versions of PANI (i.e., leucoemaraldine). For the (C≡CC(6)H(4)-N═C(6)X(4)═N-C(6)H(4)C≡C-PtL(2))(n) polymers, the completely oxidized form for X = H was isolated (pernigraniline), but for X = F and Cl, only the largely reduced mixed-valence form (i.e., emaraldine) was obtained via chemical routes. In acidic solutions, the chemically accessible polymer for X = H, (C≡CC(6)H(4)-N═C(6)H(4)═N-C(6)H(4)C≡C-PtL(2))(n), exhibits two chemically reversible waves indicating that the reduced form (C≡CC(6)H(4)NH-C(6)H(4)-NHC(6)H(4)C≡C-PtL(2))(n) can be generated. The absorption spectra of the highly colored diimine-containing species exhibit a broad charge transfer band (assigned based on DFT calculations (B3LYP); C(6)H(4)C≡C-PtL(2)-C≡CC(6)H(4) → N═C(6)X(4)═N) in the 450-800 nm window red shifting according X = H → Cl → F, consistent with their relative inductive effect. The largest absorptivity is measured for X = H because this polymer is fully oxidized whereas for the cases where X = F and Cl, these polymers exists in the mixed valence form. The ns transient absorption spectra of two polymers (X = F; reduced and mixed-valence polymers) were measured. The t...

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Electrochemistry and blocking properties of thin films of platinum phenylethynyl complexes

Cited by 5 publications

References 19 publications

Conjugated Organometallic Polymer Containing a Redox-Active Center

Conjugated Organometallic Polymer Containing a Redox-Active Center

Conjugated Oligomers and Polymers of cis- and trans-Platinum(II)-para- and ortho-bis(ethynylbenzene)quinone Diimine

Reduced and Oxidized Forms of the Pt-Organometallic Version of Polyaniline

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