especially AG* for the former case are much smaller than those for Cs+-C221. This could be a result of the larger stability of Cs+-C221 cryptate due to the "cryptate effect". On the other hand, the AS* value for the Cs+-C22 complex is more positive than that for the Cs+-C221 cryptate. We can reasonably assume that this variance is due to the difference between the exchange mechanisms of the cesium ion between the solvated and the complexed sites.

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Microbial degradation of halogenated pollutants in wastewaters may be limited by toxic contaminant concentrations or poor membrane permeability of the target compound. Extracellular catalysts can be used in wastewater treatment schemes to overcome these limitations. Water soluble porphyrins with functional groups suitable for immobilization were synthesized as catalysts for reductive dehalogenation of organic contaminants. Synthesized mesosubstituted porphyrins contained (with one exception) three N‐methyl‐4‐pyridinium substituents and a phenyl substituent having the ‐OH, ‐OCH3, ‐NH2, or ‐C(O)OCH2C6H4‐CH=CH2 group located in the p‐position. Catalytic activity was assessed by measuring carbon tetrachloride disappearance in reactions containing a synthetic porphyrin, dithiothreitol, and tris buffer (pH 8.2). Porphyrins metallated with Co or Ni had higher catalytic activities than those metallated with Fe. Changes in meso substituents also altered catalytic activity, with aminophenyl substitution resulting in porphyrins catalyzing the highest rates of carbon tetrachloride disappearance. Although chloroform, dichloromethane, and carbon monoxide were found to be breakdown products, no methane was detected and <40% of the carbon tetrachloride could be recovered in identified volatile products. When 14C carbon tetrachloride was used as substrate, approximately 80% of the label was found in the aqueous phase of the reaction mixture. Synthetic porphyrins have potential utility in wastewater treatment as catalysts for reductive dehalogenation, but further identification of degradative products is necessary.

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractRecently cationic porphyrin-peptide conjugates were synthesized to enhance the cellular uptake of porphyrins or deliver the peptide moiety to the close vicinity of nucleic acids. DNA binding of such compounds was not systematically studied yet.We synthesized two new porphyrin-tetrapeptide conjugates which can be considered as a typical monomer unit corresponding to the branches of porphyrin-polymeric branched chain polypeptide conjugates. Tetra-peptides were linked to the tri-cationic meso-tri A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Graphical AbstractResearch Highlights We synthesized two new porphyrin-tetrapeptide conjugates. DNA binding of porphyrin conjugates was studied with spectroscopic methods. Peptide conjugates of cationic porphyrins bind to DNA by two distinct binding modes. Binding modes can be identified as intercalation and external binding.

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The reaction of excess F atoms with HN3 in a halocarbon-coated flow reactor has been used to generate and study the quenching reactions of NF(a*A,y-0) at 300 K. Fifteen reagents, selected to represent a variety of chemical interactions, were tested in order to provide a survey of quenching rate constants that could be compared to 02(a*Ag) and NH(a'A). A range of rate constants was found which varied from ~1.0 X 10"u cm3 s"1 for N(CH3)3 to ~1.0 X 10"15 cm3 s"1 for N2, H2, and NO. The.NF(a'A) molecule is much less reactive than NH(a'A), and it seems to more closely resemble 02(alAg). However, the quenching rate constants for NF(a'A) generally are larger than for 02(a'Ag) and show a greater variation from one reagent to another. The self-quenching rate constant for NF(a'A) is (2.2 ± 1.2) X 10"12 cm3 s~* with energy pooling to give NF(b'S+) being a small component of the total self-quenching reaction.

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