10.1021/om0202219.s001
Masako Abe
Masako
Abe
David G. Hilmey
David G.
Hilmey
Corey E. Stilts
Corey E.
Stilts
Dinesh K. Sukumaran
Dinesh K.
Sukumaran
Michael R. Detty
Michael R.
Detty
21-Telluraporphyrins. 1. Impact of 21,23-Heteroatom
Interactions on Electrochemical Redox Potentials, <sup>125</sup>Te
NMR Spectra, and Absorption Spectra
American Chemical Society
2002
chemical shift
Electrochemical oxidation
cyclic voltammetry
absorption maxima
reduction potentials
Soret bands
extinction coefficients
125 Te NMR Spectra
1. Impact
δ 834. Oxidation
oxotelluraporphyrin 12
Electrochemical Redox Potentials
analogues 4
Te nucleus
Se
S nucleus
TCBQ
125 Te NMR spectrum
Absorption Spectra meso
van der Waals contact
chalcogen
boron trifluoride etherate
125 Te NMR chemical shift
2002-06-07 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/21-Telluraporphyrins_1_Impact_of_21_23-Heteroatom_Interactions_on_Electrochemical_Redox_Potentials_sup_125_sup_Te_NMR_Spectra_and_Absorption_Spectra/3772449
<i>meso</i>-Tetraphenyl-21-chalcogenaporphyrins <b>4</b>−<b>6</b> (S, Se, and Te as 21-chalcogen atoms,
respectively) and <i>meso</i>-tetraphenyl-21,23-dichalcogenaporphyrins <b>7</b>−<b>10</b> [(S,S), (Se,S),
(Se,Se), and (Te,S) combinations as 21,23-chalcogen atoms, respectively] were prepared by
condensation of the appropriate 2,5-bis(phenylhydroxymethyl)chalcogenophene <b>11</b> with (1)
benzaldehyde, pyrrole, tetrachlorobenzoquinone (TCBQ), and boron trifluoride etherate for
the preparation of <b>4</b>−<b>6</b> or (2) the appropriate 2,5-bis(1-phenyl-1-pyrrolomethyl)chalcogenophene <b>13</b>, TCBQ, and boron trifluoride etherate for the preparation of <b>7</b>−<b>10</b>. Electrochemical oxidation and reduction potentials were measured by cyclic voltammetry for <b>4</b>−<b>10</b>
and indicated that oxidation of 21-telluraporphyrins <b>6</b> and <b>10</b> was more facile (more cathodic)
than for the other analogues in the series and <b>10</b> was more readily oxidized than <b>6</b>. The
band I absorption maxima of 21-telluraporphyrins <b>6</b> and <b>10</b> were at shorter wavelengths
than those of the corresponding analogues containing only sulfur and/or selenium chalcogen
atoms. The extinction coefficients, ∈, of the Soret bands of <b>6</b> and <b>10</b> were 7.6 × 10<sup>4</sup> and 7.2
× 10<sup>4</sup> M<sup>-1</sup> cm<sup>-1</sup>, respectively, which is significantly smaller than analogues <b>4</b>, <b>5</b>, and <b>7</b>−<b>9</b>,
which have corresponding values of >2 × 10<sup>5</sup> M<sup>-1</sup> cm<sup>-1</sup>. The <sup>125</sup>Te NMR spectrum of <b>6</b> gave
a chemical shift of δ 834. Oxidation of <b>6</b> to oxotelluraporphyrin <b>12</b> gave a <sup>125</sup>Te NMR chemical
shift of δ 1045. 21-Tellura-23-thiaporphyrin <b>10</b> gave a <sup>125</sup>Te NMR chemical shift of δ 1039,
perhaps reflecting deshielding of the Te nucleus by the less than van der Waals contact
with the S nucleus.