Local Solvent Acidities in beta-Cyclodextrin Complexes with PRODAN Derivatives

The local solvent acidities (SA scale) of six 6-carbonyl-2-aminonaphthalene derivatives as beta-cyclodextrin complexes in water are determined through fluorescence quenching. The local polarities (E-T(N) scale) are determined through the shift of the emission center-of-mass. The apparent SA values reflect the solvent structure surrounding the guest\u27s carbonyl group, whereas the apparent E-T(N) values reveal the net polarity of the entire guest molecule. Comparison of these values affords greater insight into the structures of the host-guest complexes. Derivatives 1 and 5 show unusually large acidities, indicative of highly exposed carbonyl groups. The remaining compounds give emission intensities pointing to shielded carbonyl groups. In this study, PRODAN and its derivatives are functioning as dual channel sensors of their local environment

Does PRODAN Possess an O-TICT Excited State? Synthesis and Properties of Two Constrained Derivatives

The synthesis and photophysical properties of 7-(dimethylamino)-3,4-dihydrophenanthren-1(2H)-one (7) and 3-(dimethylamino)-8,9,10,11-tetrahydro-7H-cyclohepta[a]naphthalen-7-one (8) are reported. These compounds possess a cycloalkanone substructure that controls the extent of twisting of the carbonyl group. The six-membered ring in 7 forces the carbonyl group to be coplanar with the naphthalene ring, whereas the seven-membered ring in 8 induces a significant twist. Both have the substructure of PRODAN (6-propionyl-2-(dimethylamino)naphthalene, 1). Comparing the photophysical behavior of these compounds with that of PRODAN and 2,2-dimethyl-1-(4-methyl-1,2,3,4-tetrahydrobenzo[f]quinolin-8-yl)propan-1-one (3) indicates that PRODAN likely emits from a PICT excited state rather than from an O-TICT excited state

Preparation of 5-Bromo-2-naphthol: The Use of a Sulfonic Acid as a Protecting and Activating Group

The preparation of 5-bromo-2-naphthol (4) in three steps from 5-amino-2-naphthol (1) is described. A sulfonic acid group is introduced at the 1-position as an activating and protecting group for the Sandmeyer reaction. The sulfonate group allows for the use of only water and sulfuric acid as solvents. The sulfonic acid is introduced with three equivalents of sulfuric acid, and it is removed in 20% aq. sulfuric acid

Dual-Sensor Fluorescent Probes of Surfactant-Induced Unfolding of Human Serum Albumin

Two extrinsic fluorescent probes, 3-(dimethylamino)-8,9,10,11-tetrahydro-7H-cyclohepta[a]naphthalen-7-one (1) and 7-(dimethylamino)-2,3-dihydrophenanthren-4(1H)-one (2), are used to probe the unfolding of human serum albumin by sodium dodecyl sulfate (SDS). These probes respond separately to the polarity and H-bond-donating ability of their surroundings. Competitive binding experiments show that fluorophore 1 binds to site I (domain IIA) and 2 binds to site II (domain IIIA). The local acidity of 1 in site I is out of the sensing range of 1, whereas the local acidity of 2 in site II is calculated to be nearly zero on Catalans solvent acidity index. Both probes show that the first two equivalents of bound SDS result in a decrease in the local polarity of the binding sites. Each subsequent equivalent of SDS gives rise to a dramatic increase in polarity until HSA is saturated with seven molecules of SDS at the end of the specific binding domain. Compound 2 experiences an increase of acidity of 0.10 on Catalans solvent acidity index through seven equivalents of SDS, but the local acidity for 1 is still out of range. The increase in acidity experienced by 2 is greater than the increase in polarity. This result is consistent with greater exposure of the carbonyl group in 2, but not the bulk of 2, to the aqueous solvent in site II of the SDS-saturated HSA complex

Synthesis and properties of two PRODAN-based fluorescent models of cholesterol

The syntheses and photophysical properties of 1-(5-methylhexyl)-2,3,7,8-tetrahydro-1H-naphtho[2,1-e]indo1-9(6H)-one (7a) and 1-(5-methylhexyl)-23,8,9-terrahydro-1H-naphrho[2,1-e]indol-6(7H)-one (7b) are reported. They are prepared in eight steps from the corresponding bromonaphthylamines. These fluorescent compounds have PRODAN-like cores, and they are structurally similar to cholesterol. Compound 7a is the first reported PRODAN derivative where both the amino and carbonyl groups are constrained to be coplanar with the naphthalene core. Comparing the photophysical behavior of these compounds with related compounds indicates that locking the amino group in a five-membered ring enhances their desirable properties as solvent polarity sensors. (C) 2012 Elsevier B.V. All rights reserved

Green space, blue space, & neonatal health: exploring the relationship between environmental factors & birth outcomes in New York City

Current scholarship points to a protective association between green space and birth outcomes as well a positive relationship between blue space and general wellbeing. There is evidence that these effects are particularly strong for individuals of lower socioeconomic status. I add to this body of literature by exploring the relationship between expectant mothers’ exposure to green and blue spaces and adverse birth outcomes in New York City. Three separate birth outcomes are examined: term low birthweight, preterm birth, and small for gestational age. Data on these outcomes originate from vital statistics birth records for the year 2000. The Normalized Difference Vegetation Index (NDVI), the 2005-2006 NYC Street Tree Census, and access to major green spaces act as measures of residential greenness, while proximity to publicly accessible waterfront areas represents access to blue space. The relationships between these factors and risk of adverse birth outcomes are analyzed through mixed-effects logistic regression models. Individual and neighborhood-level confounding variables are taken into account, and analyses are conducted separately for women in deprived neighborhoods to test for differential effects on mothers of lower socioeconomic status. Results indicate that women in deprived neighborhoods suffer from higher rates adverse birth outcomes as well as lower levels of residential greenness. A significant inverse association between nearby street trees and risk of preterm birth is identified for all women in the study population. However, higher NDVI values are found to be associated with elevated risk of small for gestational age among mothers in deprived neighborhoods. The policy implications of these findings are discussed along with potential directions for future research

1,5-Prodan Emits from a Planar Intramolecular Charge-Transfer Excited State

1-Propionyl-5-dimethylaminonaphthalene (8, 1,5-Prodan) and two derivatives where the amino group is constrained in a seven-membered (9) and five-membered (10) ring are prepared. All three exhibit strong fluorescence and similar degrees of solvatochromism. Their fluorescence is strongly quenched in alcohol solvents. Because the amino group in 9 and especially 10 is forced to be coplanar with the naphthalene ring, the similar photophysical behavior of all three suggests that emission arises from a planar excited state (planar intramolecular charge transfer)

2,5-PRODAN Derivatives as Highly Sensitive Sensors of Low Solvent Acidity

Two 5-acyl-2-dimethylaminonaphthalene derivatives, one with a propionyl group and the other with a fused cyclohexanone ring, are investigated as sensors of H-bond-donating ability in protic solvents of low solvent acidity. Their fluorescence is highly quenched in protic solvents, and the quenching order of magnitude is linearly related to the H-bond-donating ability of the solvent as quantified by the solvent acidity (SA) scale. As the solvent acidity increases from 0.15 to 0.40, the fluorescence for both is quenched by more than a factor of ten; thus, they are extremely sensitive sensors of the hydrogen-bond-donating ability in this weakly acidic range. Preferential solvation studies suggest that quenching occurs from a doubly H-bonded excited state

B-virus from pet macaque monkeys: an emerging threat in the United States?

Of primary concern when evaluating macaque bites are bacterial and B-virus infections. B-virus infection is highly prevalent (80% to 90%) in adult macaques and may cause a potentially fatal meningoencephalitis in humans. We examined seven nonoccupational exposure incidents involving 24 persons and eight macaques. Six macaques were tested for herpes B; four (67%) were seropositive. A common observation was that children were more than three times as likely to be bitten than adults. The virus must be assumed to be a potential health hazard in macaque bite wounds; this risk makes macaques unsuitable as pets

Carbonyl-Twisted 6-Acyl-2-dialkylaminonaphthalenes as Solvent Acidity Sensors

Derivatives of 2-propionyl-6-dimethylaminonaphthalene (PRODAN) with twisted carbonyl groups were investigated as highly responsive sensors of H-bond donating ability. The PRODAN derivative bearing a pivaloyl group (4) was prepared. The torsion angle between the carbonyl and naphthalene is 26° in the crystal. It shows solvatochromism that is similar to five other PRODAN derivatives (1–3, 5, 6). Twisted-carbonyl derivatives 3, 4, and 6 show strong fluorescence quenching in protic solvents. The order of magnitude of the quenching is linearly related to the H-bond donating ability of the solvent (SA) but not to other solvent properties. Binary mixtures of protic solvents show specific interaction effects with respect to quenching and solvatochromism. Aggregation in water is an issue with the pivaloyl derivatives