Photochemical, electrochemical, and chemical formation of the .pi.-cation-radical species of magnesium phthalocyanine. Analysis of the absorption and MCD spectra of [MgPc(-1)].bul.+

Ough, Edward A.; Gasyna, Zbigniew; Stillman, Martin J.

doi:10.1021/ic00010a016

Cited by 103 publications

(138 citation statements)

References 2 publications

Supporting

Mentioning

118

Contrasting

Unclassified

Order By: Relevance

“…Although several band shapes are possible for these calculations, we feel that the Gaussian shape is satisfactory in accurately reproducing the absorption and MCD spectral envelopes of the experimental data. This is a compromise, but the previously reported spectral fits (10,11,21) and the data presented here do show placement of bands where one would expect them and the resultant fit forms reasonable envelopes in both the absorption and MCD spectra. The most significant constraint on the fitting is the requirement to place bands in both the absorption and MCD envelopes at the same energy and with similar band width values.…”

Section: Spectral Envelope Deconvolution Calculationsmentioning

confidence: 62%

“…Assuming that all four isomers are present in solution, we can use the electronic spectra to determine whether the isomers have similar or different transition energies. When the isomers have different transition energies, the bands in the Q region should be broadened and the spectral envelope should be less resolved than the same region in MgPc(-2) (1 1) and ZnPc(-2) (1,11,20,21). Aside from the split bands in the region of the Qoo transition, the Q region of MgPcN,(-2) and ZnPcN,(-2) displays the spectral sharpness and clarity seen in the unsubstituted phthalocyanines.…”

Section: Discussionmentioning

confidence: 99%

“…assigned as a combination of several vibrational progressions, Q,,,; (iii) a "windown region between 580 and 450 nm; and finally, (iv) between 400 and 250 nm, a region of more intense, broader bands that essentially overlap to the solvent cutoff at 250 nm (1). MCD A terms are measured under each of the major absorption bands (1,10,11,(19)(20)(21)(22).…”

Section: Spectroscopic Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Absorption and magnetic circular dichroism spectra of nitrogen homologues of magnesium and zinc phthalocyanine

Ough¹,

Stillman²,

Creber³

1993

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

Absorption and magnetic circular dichroism (MCD) spectra are reported for the metallophthalocyanine-N-isologs: magnesium-3,4-pyridinoporphrazine (MgPcN,(-2)), zinc-3,4-pyridinoporphyrazine (ZnPcN4(-2)), and zinc-3,4-pyridazinoporphyrazine (ZnPcN8(-2)). Band deconvolution calculations, which couple both the absorption and the MCD spectra, are reported for each complex. The presence of the peripherally fused pyridine rings in MgPN4(-2) and ZnPcN4(-2) reduces the molecular symmetry and splits the degenerate Q band into its x and y components with zero field splitting parameters (AQ.,) of 224 and 279 cm-', respectively. Band fitting results for ZnPcN8 (-2) show that with the fused pyridazine rings the degeneracy in the 'E, excited state is retained and the MCD envelope in the region of the Q, transition can be described by an MCD A term. Comparison of the fitted band energies with the results reported for ZnPc(-2) (T. Nyokong, Z. Gasyna, and M.J. Stillman. Inorg. Chem. 26, 1087Chem. 26, (1987) and MgPc(-2) (E.A. Ough, T. Nyokong, K.A.M. Creber, and M.J. Stillman. Inorg. Chem. 27,2725Chem. 27, (1988) shows that as the number of nitrogens substituted increases from 0 to 8, the Q band blue shifts from 671 nm in ZnPc(-2) to 664 nm in ZnPcN4(-2) (midpoint between the x and y components) to 654 nm in ZnPcN8(-2) and from 672 nm in MgPc(-2) to 666 nm in MgPcN4(-2) (midpoint). These results demonstrate that chemical modification (symmetric and asymmetric) of the peripherally fused benzene rings influences both the energy and the symmetry of the states that form the inner 18-T-electron system. EDWARD A. OUGH, MARTIN J. STILLMAN et KATHERINE A.M. CREBER. Can. J. Chem. 71, 1898Chem. 71, (1993. On a determine les spectres d'absorption et de dichroiisme circulaire magnetique (DCM) des N-isologues suivants de m~tallonaphthalocyanines : magnCsium-3,4-pyridinoporphrazine (MgPcN4(-2)), zinc-3,4-pyridinoporphrazine (ZnPcN4(-2)) et zinc-3,4-pyridazinoporphrazine (ZnPcN8(-2)). Pour chacun des complexes, on a effectue des calculs de deconvolution de bande qui permettent de coupler les spectres d'absorption et de DCM. La presence de noyaux pyridines condenses d'une f a~o n peripherique dans de MgPcN4(-2) et dans le ZnPcN4(-2) reduit la syrnetrie moleculaire et dedouble la bande Q degenkree en ses composants x et y avec des paramktres de couplage de champ zero (AQ,) de 224 et 279 cm-' respectivement. Un ajustement des bandes du ZnPcN8(-2) montre qu'avec les cycles pyridazines condenses la degCnCrescence de l'etat excite 'E, est conservke et que l'enveloppe du DCM dans la region de la transition Qoo peut &tre decrite par un terme A du DCM. Une comparaison des energies des bandes ajustees avec les rksultats rapport& pour le ZnPc(-2) (T. Nyokong, Z. Casyna et M.J. Stillman. Inorg. Chem. 26, 1087) et pour le MgPc(-2) (E.A. Ough, T. Nyokong, K.A.M. Creber et M.J. Stillman. Inorg. Chem. 27, 2725) montre que lorsque le nombre d'atomes d'azote substitues augmente de 0 a 8, la bande Q se deplace de 671 nm dans le ZnPc(-2) 2 664 nm dans le ZnP...

show abstract

Section: Spectral Envelope Deconvolution Calculationsmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Section: Spectroscopic Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Absorption and magnetic circular dichroism spectra of nitrogen homologues of magnesium and zinc phthalocyanine

Ough¹,

Stillman²,

Creber³

1993

Can. J. Chem.

Self Cite

View full text Add to dashboard Cite

show abstract

“…(ii) Spectroelectrochemistry (a) Cation radicals, (a,)', QA,: The spectroscopic changes accompanying the oxidation of TBTAP(C,)Mg (4) and t-BuTBTAP(C,,)H, (13) to their corresponding cation radicals are shown in Figs. 6 and 7.…”

Section: ( I ) Tbtap(c)h2mentioning

confidence: 99%

Electrochemistry and spectroelectrochemistry of substituted tetrabenzotriazaporphine

Tse¹,

Goel²,

Hu³

et al. 1993

Can. J. Chem.

View full text Add to dashboard Cite

. Can. J. Chem. 71, 742 (1993).The spectral and electrochemical properties of tetrabenzo [5, lO,lS]triazaporphine (TBTAP) and its magnesium derivatives having a long alkyl chain attached to the meso carbon have been studied. Both metal-free and metallated species show typical metal-free phthalocyanine-like spectra. Two reduction and two oxidation redox couples have been observed. The cation, anion, and dianion species of these porphyrin derivatives have been electrochemically generated and their electronic spectra are recorded.

show abstract

“…Magnesium porphyrins (Fajer et al 1970, Smalley et al 1983, Slota and Dyrda 2003 and phthalocyanines (van Willigen and Ebersole 1987, Bobrovskii and Kholmogorov 1973, Ough et al 1991, Kim 1986) may form cation radicals and ions via the triplet state upon illumination. For (phthalocyaninato)magnesium both photochemical oxidations and reductions have been shown to occur.…”

Section: Photophysics Of Metallated Tetrapyrrolesmentioning

confidence: 99%

Photochemical Transformations Involving Porphyrins and Phthalocyanines

Sergeeva¹,

Senge²

2012

CRC Handbook of Organic Photochemistry and Photobiology, Third Edition - Two Volume Set

View full text Add to dashboard Cite

Photochemical, electrochemical, and chemical formation of the .pi.-cation-radical species of magnesium phthalocyanine. Analysis of the absorption and MCD spectra of [MgPc(-1)].bul.+

Cited by 103 publications

References 2 publications

Absorption and magnetic circular dichroism spectra of nitrogen homologues of magnesium and zinc phthalocyanine

Absorption and magnetic circular dichroism spectra of nitrogen homologues of magnesium and zinc phthalocyanine

Electrochemistry and spectroelectrochemistry of substituted tetrabenzotriazaporphine

Photochemical Transformations Involving Porphyrins and Phthalocyanines

Contact Info

Product

Resources

About