Synthesis and Characterization of Thiol-Derivatized Porphyrins and Metalloporphyrin complexes

Abstract

<jats:p> A series of thiol-derivatized porphyrins and the corresponding cobalt and zinc complexes were synthesized from 5-(p-aminophenyl)-10,15,20-triphenylporphyrin ( H <jats:sub>2</jats:sub> TPP - NH <jats:sub>2</jats:sub>), and 5α,15α-bis(o-aminophenyl)porphyrin ( H <jats:sub>2</jats:sub> DPE - ( NH <jats:sub>2</jats:sub>)<jats:sub>2</jats:sub>). These derivatized porphyrins have a different number of thiol appendages attached via amide linkages at different locations. The thiol-derivatized porphyrins made from H <jats:sub>2</jats:sub> TPP - NH <jats:sub>2</jats:sub>, H <jats:sub>2</jats:sub> TPP - NHC ( O )( CH <jats:sub>2</jats:sub>)<jats:sub> n </jats:sub> SH ( n = 2, 4, 5, 10), have one alkyl-thiol appendage attached to the porphyrin through an amide linkage on the p-aminophenyl position. The derivatives made from H <jats:sub>2</jats:sub> DPE -( NH <jats:sub>2</jats:sub>)<jats:sub>2</jats:sub> have two alkyl-thiol appendages attached to the porphyrin through amide linkages on the o-aminophenyl positions on the same face of the porphyrin ring. These thiol-derivatized porphyrins are important adsorbates for the preparation of thiol–porphyrin monolayers on gold. </jats:p>

Chain Length Effect on Photocurrent from Polymethylene-Linked Porphyrins in Self-Assembled Monolayers

“…Integration of the area under the anodic surface waves provides an estimate of the surface coverage, Γ . The values of Γ obtained here using the cyclic voltammetry are quite consistent with those obtained using the UV−visible absorption spectroscopy and those of the similar system reported previously. 2b-d,f,p The somewhat smaller Γ values obtained using the absorption spectroscopy may be attributed to the reduced molar absorptivity of the porphyrins on the gold surface compared with that in the solution. Assuming that the porphyrins are densely packed with a perpendicular orientation to the gold surface, then the area of one molecule is calculated to be 200 Å 2 (20 Å × 10 Å).…”

“…The Soret bands are broadened and red-shifted by about 15 nm relative to the corresponding spectra in a dichloromethane solution. A similar red-shift was reported for SAMs containing porphyrins as terminal chromophores. 2b,f,p The red-shift of the Soret band is probably due to the excitonic interactions among the porphyrins and aggregation in the monolayer microenvironment. , A small red-shift (up to 3 nm) of the Soret band peak position was observed as the chains became longer. This shift may be ascribed to an increase in the π−π interaction among the porphyrin moieties, despite the existence of the bulky tert -butyl groups at the meso -phenyl groups.…”

“…This technique is useful for constructing organized molecular assemblies containing photo- and/or electroactive molecules on gold electrodes. There are a number of reports of SAMs of photoactive molecules, such as porphyrins, azobenzenes, and so on, on gold electrodes. However, a systematic study of the effect of the interfacial structure on the electro- and photochemical properties of these chemically modified electrodes is still lacking. 4a,b, Here we report on the structure and photoelectrochemistry of SAMs of porphyrins on gold electrodes (Figure ).…”

“…Disulfides 1 with different spacer lengths were synthesized as previously described 2d. Their structures were verified using analytical methods including 1 H NMR and matrix-assisted laser desorption ionization time of flight mass spectroscopy…”

Immobilization of sunflower trypsin inhibitor (SFTI-1) peptide onto a gold surface and analysis of its interaction with trypsin

“…18 The disulfide bridge was formed on the resin by simultaneous deprotection of the S-acetamidomethyl group and cyclization of the cysteine residues using iodine in N,Ndimethylformamide (DMF). 19 For the peptide 2, peptide elongation was followed by acylation with 3-(tritylthio)propionic acid 20 on the resin to introduce the blocked thiol moiety at the N-terminus of the peptide. The peptide was cleaved from the resin with concomitant removal of the protecting groups by treatment with a mixture of trifluoroacetic acid-triisopropylsilane-water (95:2.5:2.5, by volume) for 2 h at room temperature.…”