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J L Sessler

Publications and source records attributed to J L Sessler.

27 records · Page 2Linked to original sources
PubMed1995

A non-ionic water-soluble pentaphyrin derivative. Synthesis and cytotoxicity.

The synthesis of the water soluble tetrahydroxypentaphyrin derivative, 1, is described. This species, which forms complexes with both small neutral molecules and uranyl cation, has been studied as a possible cytotoxic agent. Cytotoxic studies performed with the human T lymphoma cell line (JURKAT) revealed that pentaphyrin 1 exhibits toxicity at microM concentrations comparable with other water soluble, porphyrin-type systems such as the pyridinium metalloporphyrins.

Antineoplastic Agents↗
PubMed1994

Spectroscopy and photosensitization of sapphyrins in solutions and biological membranes.

A spectroscopic and photophysical study of three new sapphyrin molecules is presented. The sapphyrin backbone that was derivatized to make them water soluble possesses an absorption band around 700 nm, a desired property for biological photosensitization. We studied the absorption and fluorescence spectra, from which evidence for aggregation in solvents of different polarities was obtained. The extent of aggregation is correlated with the nature of the attached moiety. The absolute quantum yields of singlet oxygen production were measured, with 1,3-diphenyl isobenzofuran as a model target, and were 0.13-0.18 in ethanol. The binding constants to liposomes and to cells were determined spectroscopically and were found to correspond to the hydrophobicities of the compounds, with an additional effect, ascribed to the sugar moiety, which was found in the case of one of the sapphyrins. The efficiency of photodamage to Staphylococcus aureus by sapphyrins and hematoporphyrin was equivalent, on the basis of cells killed per microgram of sensitizer in the incubation mixture.

Escherichia coli↗
PubMed1991

Structure of aqua-hexakis(mu 2-benzoato)-bis(methanol)-mu 3-oxo-triiron(III) benzoate ethanol methanol solvate.

[Fe3(O)(C7H5O2)6(CH3OH)2(H2O)]-[C7H5O2]-C2H5OH-CH3OH (1/1/1), Mr = 1191.56, triclinic, P1-, a = 11.591 (3), b = 13.308 (2), c = 20.154 (3) A, alpha = 96.910 (12), beta = 96.95 (2), gamma = 114.10 (2) degrees, V = 2767.1 (9) A3, Z = 2, Dx = 1.43 g cm-3, mu = 8.471 cm-1, Mo K alpha radiation, lambda = 0.7107 A, F(000) = 1234, T = 198 K, R = 0.0522 for 6252 reflections [Fo greater than or equal to 4 sigma (Fo)]. The complex has nearly D3h symmetry with two coordinated CH3OH molecules and one coordinated H2O molecule. The coordination around the Fe atoms is essentially octahedral. Each Fe atom lies slightly out of the plane of the O atoms of the bridging benzoates and is directed towards the mu 3-O atom. The average Fe--O distances are 1.907 (2) A for the mu 3-O atom and 2.010 (1) A for the benzoate O atoms.

Benzoates↗
PubMed1991

In vitro photodynamic inactivation of herpes simplex virus with sapphyrins: 22 pi-electron porphyrin-like macrocycles.

The photodynamic inactivation of HSV-1, a virus having a membranous envelope, with both a decaalkyl sapphyrin and its dicarboxy-substituted analog was studied. The decaalkyl sapphyrin was as efficient in the inactivation of HSV-1 on a per macrocycle basis as DHE, whereas the efficiency of the dicarboxy-substituted sapphyrin was approximately two orders of magnitude less. Fluorescence studies of sapphyrin's binding to liposomes and VSV suggested that the decaalkylsapphyrin bound monomerically to cholesterol-rich regions of the viral envelope, whereas its charged analog localized in a more polar environment.

Animals↗
PubMed1984

CO bond angle changes in photolysis of carboxymyoglobin.

Previous studies [Chance, B., Fischetti, B., & Powers, L. (1983) Biochemistry 22, 3820-3829] of the local structure changes around the iron in carboxymyoglobin on photolysis at 4 K revealed that the iron-carbon distance increased approximately 0.05 A but was accompanied by a lengthening of the iron-pyrrole nitrogen bonds of the heme (approximately 0.03 A) that was not as large as that found in the deoxy form. Further analysis of these data together with comparison to model compounds indicates that the Fe-C-O bond angle in carboxymyoglobin is bent (127 +/- 4 degrees), having a structure identical, within the error, with the "pocket" porphyrin model compound FePocPiv(1-MeIm)(CO) [Collman, J. P., Brauman, J. I., Collins, T. J., Iverson, B. L., Lang, G., Pettman, R., Sessler, J. L., & Walters, M. A. (1983) J. Am. Chem Soc. 105, 3038-3052]. On photolysis, this angle decreases by 5-10 degrees. In addition, correlation is observed between the increase in the length of the Fe-C bond and the decrease of the Fe-C-O angle. These results suggest that the rate-limiting step in recombination is the thermal motion of CO in the pocket to achieve an appropriate bonding angle with respect to the iron. These changes constitute the first molecular picture of the photolysis process, as well as the structure of the geminate state, and are important in clarifying nuclear tunneling parameters.

Carbon↗
PubMed1982

Stereochemistry of iron in deoxyhaemoglobin.

The EXAFS of human deoxyhaemoglobin closely resembles that of a synthetic model in which the displacement of the iron from the mean porphyrin plane is 0.426 +/- 0.004 A, similar to the displacement of 0.56 +/- 0.03 A found by single crystal X-ray analysis of deoxyhaemoglobin. We find the same Fe-N of 2.06 +/- 0.01 A distance as Eisenberger et al., but show that the displacement of the iron from the nitrogen plane cannot be calculated from that distance.

Electron Probe Microanalysis↗
PubMedDate not supplied

Nuclear magnetic relaxation dispersion studies of water-soluble gadolinium(III)-texaphyrin complexes.

Water proton 1/T1 nuclear magnetic relaxation dispersion (NMRD) profiles were measured for a water-soluble gadolinium(III) texaphyrin (Gd-tex) complex as a function of temperature and in the presence and absence of 5% human serum albumin (HSA). Upon dissolving the complex in water (0.259 mM), the water relaxivity values decreased with time but remained higher than those of free GD3+(aq) at all fields. Concurrent measurements of free Gd3+ using metallochromic dyes indicated that demetallation of the texaphyrin did not occur over a period of several days at 37 degrees C. The high relaxivity values and shape of the NMRD profile of this complex may be ascribed to a combination of large water coordination number (q estimated at 3.5) and long tau R. Upon mixing an aqueous solution of the complex with 5% HSA, the low-field water relaxivity slightly decreased whereas the high-field relaxivity increased relative to the free complex in water, and the relaxivities became nearly independent of temperature. These observations indicate that water exchange between the inner coordination sphere of Gd-tex and bulk water becomes limiting in the presence of HSA.

Contrast Media↗