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George S Tint - One of the best experts on this subject based on the ideXlab platform.
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bile alcohol glucuronides regioselective o glucuronidation of 5β cholestane 3α 7α 12α 25 Tetrol and 24 nor 5β cholestane 3α 7α 12α 25 Tetrol
Carbohydrate Research, 1993Co-Authors: B. Dayal, Gerald Salen, Janak Padia, Sarah Shefer, George S TintAbstract:Abstract A facile and regiocontrolled procedure for the preparation of 5β-cholestane-3α,7α,12α,25-Tetrol-3-O-β- d -glucuronide and its corresponding C-26 analogue is described. The method involves direct coupling of bile alcohols, namely, 5β-cholestane-3α,7α,12α-25-Tetrol and 24-nor-5β-cholestane-3α,7α,12α,25-Tetrol to methyl (tetra-O-acetyl-β- d -glucopyranuronate) in the presence of a Lewis acid, tin(IV) chloride, in dichloromethane. The resulting anomeric pairs of 1,2-trans- and 1,2-cis-glucuronides of Tetrols were resolved by analytical and preparative thin-layer chromatography, and their identities were established by high-resolution 1H NMR spectroscopy and by chemical-ionization and fast-atom-bombardment mass spectrometry. The method described has a practical advantage over the traditional two-step synthesis involving bromides as it is more efficient and uses inexpensive and less toxic materials. It is suggested that these compounds will be useful for studying permeability of the blood-brain barrier in cerebrotendinous xanthomatosis (CTX).
Benita Barton - One of the best experts on this subject based on the ideXlab platform.
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inclusion ability of host Tetrol 2 r 3 r 1 1 4 4 tetraphenylbutane 1 2 3 4 tetraol for selected saturated cyclic and aromatic alcohol ketone and amine guest compounds
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2019Co-Authors: Benita Barton, Sasha-lee Dorfling, Eric C HostenAbstract:In this work, we investigated the host ability of Tetrol [(+)-(2R,3R)-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol] in the presence of two guest series, namely saturated cyclohexanone, cyclohexanol and cyclohexylamine on the one hand, and aromatic/saturated combinations of aniline, cyclohexylamine, phenol and cyclohexanol on the other. Tetrol formed complexes with all of these guests in single solvent experiments, while mixed complexes were obtained when the host was recrystallized from guest mixtures. However, most notably, Tetrol showed enhanced selectivities for the amino-containing cyclic organic compounds compared with the ketone and alcohol, results of which allude to the potential of purifying various combinations of such compounds through host‒guest chemistry. We conducted single crystal X-ray diffraction experiments in order to reveal the underlying reasons for the selectivity displayed by Tetrol for these amines.
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Inclusion ability of host Tetrol [(+)-(2 R ,3 R )-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol] for selected saturated cyclic and aromatic alcohol, ketone and amine guest compounds
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2019Co-Authors: Benita Barton, Sasha-lee Dorfling, Eric C HostenAbstract:In this work, we investigated the host ability of Tetrol [(+)-(2R,3R)-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol] in the presence of two guest series, namely saturated cyclohexanone, cyclohexanol and cyclohexylamine on the one hand, and aromatic/saturated combinations of aniline, cyclohexylamine, phenol and cyclohexanol on the other. Tetrol formed complexes with all of these guests in single solvent experiments, while mixed complexes were obtained when the host was recrystallized from guest mixtures. However, most notably, Tetrol showed enhanced selectivities for the amino-containing cyclic organic compounds compared with the ketone and alcohol, results of which allude to the potential of purifying various combinations of such compounds through host‒guest chemistry. We conducted single crystal X-ray diffraction experiments in order to reveal the underlying reasons for the selectivity displayed by Tetrol for these amines.
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Host selectivity considerations of compound (+)-(2R,3R)-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol (Tetrol) in the presence of o-, m- and p-cresol guest isomers
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2019Co-Authors: Sasha-lee Dorfling, Benita BartonAbstract:In this work, (+)-(2 R ,3 R )-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (Tetrol) was investigated for its feasibility as a host compound for its possible future employment in the separation of the cresol isomers ( ortho -, meta - and para -cresol, o -, m - and p -Cr). Of the three, only m - and p -Cr were enclathrated by this host compound, and host:guest ratios were consistently 2:1. When Tetrol was presented with equimolar mixed cresols, the host displayed significant selectivity for the para isomer, and a host selectivity order of p -Cr (64.9%) > m -Cr (23.8%) > o -Cr (11.3%) was observed. More notably, however, Tetrol’s selectivity for this isomer was enhanced (70.4%) when it was recrystallized from an equimolar binary mixture of m - and p -Cr, the two isomers that are the most onerous to separate by conventional means. Furthermore, Tetrol remained selective for p -Cr even when this isomer was present in the mixture in low quantities relative to the meta isomer. Thermal analyses confirmed that p -Cr formed the more thermally stable complex with the host compared with the inclusion compound containing the m -Cr guest, and this correlated with the observed selectivity order.Graphical abstractHost selectivity considerations of compound (+)-(2 R ,3 R )-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol (Tetrol) in the presence of o -, m - and p -cresol guest isomers.
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Complexes of Tetrol with selected heterocyclics: unconventional host–guest hydrogen bonding and the correlation with host selectivity
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2018Co-Authors: Benita Barton, Sasha-lee Dorfling, Eric C HostenAbstract:Here we investigate and compare the more salient characteristics of host–guest complexes of (+)-(2 R ,3 R )-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol (Tetrol) with four heterocyclic guests, morpholine, piperidine, pyridine and dioxane. These guests each formed inclusion compounds with Tetrol, and host:guest ratios were either 1:2 or 1:1. Single crystal diffraction experiments revealed unprecedented host behaviour in the presence of both piperidine and dioxane with respect to the mode of host–guest hydrogen bonding employed. Furthermore, by utilizing ^1H-NMR spectroscopy or gas chromatography (as applicable) as methods for analysing complexes obtained from competition experiments, we were able to identify the host selectivity order, and were gratified to discover that this order correlated precisely with host–guest hydrogen bond distance.
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host behaviour of related compounds Tetrol and dmt in the presence of two different classes of aromatic guest compounds
Tetrahedron, 2018Co-Authors: Benita Barton, Sasha-lee Dorfling, Lize De Jager, Eric C Hosten, Cedric W Mccleland, Pieter L PohlAbstract:Abstract The host potential of two closely-related compounds, Tetrol [(+)-(2R,3R)-1,1–4,4-tetraphenylbutane-1,2,3,4-tetraol] and DMT [(−)-(2R,3R)-2,3-dimethoxy-1,1,4,4-tetraphenylbutane-1,4-diol], were compared when recrystallized from two different classes of guests, namely toluene, ethylbenzene, cumene and aniline, N-methylaniline, N,N-dimethylaniline. Tetrol formed complexes with only aniline and N-methylaniline (host:guest ratios, 2:3 and 2:4), while DMT included all six guests with a consistent ratio (2:1). Aniline competition experiments showed that Tetrol preferred aniline (67%), followed by N-methyl- (29%) and N,N-dimethyl- (4%) aniline; surprisingly, this order was exactly reversed for DMT [N,N-dimethylaniline (62%) > N-methylaniline (32%) > aniline (6%)]. Crystal diffraction analyses revealed that Tetrol formed stabilizing hydrogen bonds with guests, behaving as both donor and, for the first time, acceptor (in 2Tetrol∙4N-methylaniline). DMT did not form bonds of this type with any guests. Furthermore, the host packing was isostructural for all DMT complexes but was guest-dependent for Tetrol. Thermal analyses showed that complex stabilities correlated precisely with the host preferences.
Eric C Hosten - One of the best experts on this subject based on the ideXlab platform.
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inclusion ability of host Tetrol 2 r 3 r 1 1 4 4 tetraphenylbutane 1 2 3 4 tetraol for selected saturated cyclic and aromatic alcohol ketone and amine guest compounds
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2019Co-Authors: Benita Barton, Sasha-lee Dorfling, Eric C HostenAbstract:In this work, we investigated the host ability of Tetrol [(+)-(2R,3R)-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol] in the presence of two guest series, namely saturated cyclohexanone, cyclohexanol and cyclohexylamine on the one hand, and aromatic/saturated combinations of aniline, cyclohexylamine, phenol and cyclohexanol on the other. Tetrol formed complexes with all of these guests in single solvent experiments, while mixed complexes were obtained when the host was recrystallized from guest mixtures. However, most notably, Tetrol showed enhanced selectivities for the amino-containing cyclic organic compounds compared with the ketone and alcohol, results of which allude to the potential of purifying various combinations of such compounds through host‒guest chemistry. We conducted single crystal X-ray diffraction experiments in order to reveal the underlying reasons for the selectivity displayed by Tetrol for these amines.
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Inclusion ability of host Tetrol [(+)-(2 R ,3 R )-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol] for selected saturated cyclic and aromatic alcohol, ketone and amine guest compounds
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2019Co-Authors: Benita Barton, Sasha-lee Dorfling, Eric C HostenAbstract:In this work, we investigated the host ability of Tetrol [(+)-(2R,3R)-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol] in the presence of two guest series, namely saturated cyclohexanone, cyclohexanol and cyclohexylamine on the one hand, and aromatic/saturated combinations of aniline, cyclohexylamine, phenol and cyclohexanol on the other. Tetrol formed complexes with all of these guests in single solvent experiments, while mixed complexes were obtained when the host was recrystallized from guest mixtures. However, most notably, Tetrol showed enhanced selectivities for the amino-containing cyclic organic compounds compared with the ketone and alcohol, results of which allude to the potential of purifying various combinations of such compounds through host‒guest chemistry. We conducted single crystal X-ray diffraction experiments in order to reveal the underlying reasons for the selectivity displayed by Tetrol for these amines.
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Complexes of Tetrol with selected heterocyclics: unconventional host–guest hydrogen bonding and the correlation with host selectivity
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2018Co-Authors: Benita Barton, Sasha-lee Dorfling, Eric C HostenAbstract:Here we investigate and compare the more salient characteristics of host–guest complexes of (+)-(2 R ,3 R )-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol (Tetrol) with four heterocyclic guests, morpholine, piperidine, pyridine and dioxane. These guests each formed inclusion compounds with Tetrol, and host:guest ratios were either 1:2 or 1:1. Single crystal diffraction experiments revealed unprecedented host behaviour in the presence of both piperidine and dioxane with respect to the mode of host–guest hydrogen bonding employed. Furthermore, by utilizing ^1H-NMR spectroscopy or gas chromatography (as applicable) as methods for analysing complexes obtained from competition experiments, we were able to identify the host selectivity order, and were gratified to discover that this order correlated precisely with host–guest hydrogen bond distance.
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host behaviour of related compounds Tetrol and dmt in the presence of two different classes of aromatic guest compounds
Tetrahedron, 2018Co-Authors: Benita Barton, Sasha-lee Dorfling, Lize De Jager, Eric C Hosten, Cedric W Mccleland, Pieter L PohlAbstract:Abstract The host potential of two closely-related compounds, Tetrol [(+)-(2R,3R)-1,1–4,4-tetraphenylbutane-1,2,3,4-tetraol] and DMT [(−)-(2R,3R)-2,3-dimethoxy-1,1,4,4-tetraphenylbutane-1,4-diol], were compared when recrystallized from two different classes of guests, namely toluene, ethylbenzene, cumene and aniline, N-methylaniline, N,N-dimethylaniline. Tetrol formed complexes with only aniline and N-methylaniline (host:guest ratios, 2:3 and 2:4), while DMT included all six guests with a consistent ratio (2:1). Aniline competition experiments showed that Tetrol preferred aniline (67%), followed by N-methyl- (29%) and N,N-dimethyl- (4%) aniline; surprisingly, this order was exactly reversed for DMT [N,N-dimethylaniline (62%) > N-methylaniline (32%) > aniline (6%)]. Crystal diffraction analyses revealed that Tetrol formed stabilizing hydrogen bonds with guests, behaving as both donor and, for the first time, acceptor (in 2Tetrol∙4N-methylaniline). DMT did not form bonds of this type with any guests. Furthermore, the host packing was isostructural for all DMT complexes but was guest-dependent for Tetrol. Thermal analyses showed that complex stabilities correlated precisely with the host preferences.
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complexes of Tetrol with selected heterocyclics unconventional host guest hydrogen bonding and the correlation with host selectivity
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2018Co-Authors: Benita Barton, Sasha-lee Dorfling, Eric C HostenAbstract:Here we investigate and compare the more salient characteristics of host–guest complexes of (+)-(2R,3R)-1,1-4,4-tetraphenylbutane-1,2,3,4-tetraol (Tetrol) with four heterocyclic guests, morpholine, piperidine, pyridine and dioxane. These guests each formed inclusion compounds with Tetrol, and host:guest ratios were either 1:2 or 1:1. Single crystal diffraction experiments revealed unprecedented host behaviour in the presence of both piperidine and dioxane with respect to the mode of host–guest hydrogen bonding employed. Furthermore, by utilizing 1H-NMR spectroscopy or gas chromatography (as applicable) as methods for analysing complexes obtained from competition experiments, we were able to identify the host selectivity order, and were gratified to discover that this order correlated precisely with host–guest hydrogen bond distance.
B. Dayal - One of the best experts on this subject based on the ideXlab platform.
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bile alcohol glucuronides regioselective o glucuronidation of 5β cholestane 3α 7α 12α 25 Tetrol and 24 nor 5β cholestane 3α 7α 12α 25 Tetrol
Carbohydrate Research, 1993Co-Authors: B. Dayal, Gerald Salen, Janak Padia, Sarah Shefer, George S TintAbstract:Abstract A facile and regiocontrolled procedure for the preparation of 5β-cholestane-3α,7α,12α,25-Tetrol-3-O-β- d -glucuronide and its corresponding C-26 analogue is described. The method involves direct coupling of bile alcohols, namely, 5β-cholestane-3α,7α,12α-25-Tetrol and 24-nor-5β-cholestane-3α,7α,12α,25-Tetrol to methyl (tetra-O-acetyl-β- d -glucopyranuronate) in the presence of a Lewis acid, tin(IV) chloride, in dichloromethane. The resulting anomeric pairs of 1,2-trans- and 1,2-cis-glucuronides of Tetrols were resolved by analytical and preparative thin-layer chromatography, and their identities were established by high-resolution 1H NMR spectroscopy and by chemical-ionization and fast-atom-bombardment mass spectrometry. The method described has a practical advantage over the traditional two-step synthesis involving bromides as it is more efficient and uses inexpensive and less toxic materials. It is suggested that these compounds will be useful for studying permeability of the blood-brain barrier in cerebrotendinous xanthomatosis (CTX).
Robert J Hurtubise - One of the best experts on this subject based on the ideXlab platform.
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new methodology for the characterization of anti bpde dna adducts and Tetrol i 1 with solid matrix phosphorescence
Analytica Chimica Acta, 2004Co-Authors: Barry W Smith, Robert J HurtubiseAbstract:Abstract Novel solid-matrix phosphorescence (SMP) methods were developed for the detection and characterization of (±)- anti -benzo[a]pyrene- trans -7,8-dihydrodiol-9,10-epoxide ((±)- anti -BPDE)-DNA adducts and a hydrolysis product of the (±)- anti -BPDE-DNA adducts, Tetrol I-1, by using the heavy-atom salts, thallium nitrate and sodium iodide, to enhance the solid-matrix phosphorescence. Thallium nitrate was much more effective for enhancing the SMP of the (±)- anti -BPDE-DNA adducts and Tetrol I-1. Thus, the results from TlNO 3 were emphasized. The amount of TlNO 3 adsorbed on the solid matrix was varied over a wide range, and SMP intensities, lifetimes, and spectra were acquired. Fundamental equations and calculated photophysical parameters were used to interpret the data and characterize the samples. The data indicated that there were two major populations of the (±)- anti -BPDE-DNA adducts and Tetrol I-1 adsorbed on the solid matrix. Because DNA was adsorbed so strongly to the solid matrix, the (±)- anti -BPDE-DNA adducts interacted in a uniform manner with increasing amounts of TlNO 3 . However, Tetrol I-1 responded in a more random fashion with the increase in the amount of TlNO 3 . The methods developed can be used to compare the SMP of small molecular-weight metabolites and DNA samples modified at different levels of (±)- anti -BPDE. Also, the methodology can be employed for DNA samples that are adducted with any material that would give measurable SMP.
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New methodology for the characterization of (±)-anti-BPDE-DNA adducts and Tetrol I-1 with solid-matrix phosphorescence
Analytica Chimica Acta, 2004Co-Authors: Barry W Smith, Robert J HurtubiseAbstract:Abstract Novel solid-matrix phosphorescence (SMP) methods were developed for the detection and characterization of (±)- anti -benzo[a]pyrene- trans -7,8-dihydrodiol-9,10-epoxide ((±)- anti -BPDE)-DNA adducts and a hydrolysis product of the (±)- anti -BPDE-DNA adducts, Tetrol I-1, by using the heavy-atom salts, thallium nitrate and sodium iodide, to enhance the solid-matrix phosphorescence. Thallium nitrate was much more effective for enhancing the SMP of the (±)- anti -BPDE-DNA adducts and Tetrol I-1. Thus, the results from TlNO 3 were emphasized. The amount of TlNO 3 adsorbed on the solid matrix was varied over a wide range, and SMP intensities, lifetimes, and spectra were acquired. Fundamental equations and calculated photophysical parameters were used to interpret the data and characterize the samples. The data indicated that there were two major populations of the (±)- anti -BPDE-DNA adducts and Tetrol I-1 adsorbed on the solid matrix. Because DNA was adsorbed so strongly to the solid matrix, the (±)- anti -BPDE-DNA adducts interacted in a uniform manner with increasing amounts of TlNO 3 . However, Tetrol I-1 responded in a more random fashion with the increase in the amount of TlNO 3 . The methods developed can be used to compare the SMP of small molecular-weight metabolites and DNA samples modified at different levels of (±)- anti -BPDE. Also, the methodology can be employed for DNA samples that are adducted with any material that would give measurable SMP.
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Characterization of Tetrol I-1 and (+/-)-anti-BPDE-DNA adducts with solid-matrix fluorescence quenching.
Applied Spectroscopy, 2003Co-Authors: Barry W Smith, Robert J HurtubiseAbstract:The solid-matrix fluorescence (SMF) quenching of (±)-anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE)-DNA adducts and a hydrolysis product of the DNA adducts, Tetrol I-1, were investigated by using thallium nitrate and sodium iodide to quench the SMF. Several fluorescence quenching models were evaluated for both (±)-anti-BPDE-DNA adducts and Tetrol I-1. The SMF quenching phenomena were quite different with the two salts for the (±)-anti-BPDE-DNA adducts and Tetrol I-1. Generally, with thallium nitrate as a quencher, a two-site model with two independent quenching sites was applicable to both the (±)-anti-BPDE-DNA adducts and Tetrol I-1 data. However, with sodium iodide, the SMF quenching data for Tetrol I-1 were fit to the sphere of action model, but the (±)-anti-BPDE-DNA adducts SMF quenching data were qualitatively related to a BET isotherm. From the SMF quenching data, unique information was acquired for the quasi-intercalated BPDE-DNA adducts and the external form of the BPDE-DNA adducts. In addition, insights were obtained on how the adsorbed salts interacted with the solid matrix and with the (±)-anti-BPDE-DNA adducts and Tetrol I-1.
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characterization of Tetrol i 1 and anti bpde dna adducts with solid matrix fluorescence quenching
Applied Spectroscopy, 2003Co-Authors: Barry W Smith, Robert J HurtubiseAbstract:The solid-matrix fluorescence (SMF) quenching of (±)-anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE)-DNA adducts and a hydrolysis product of the DNA adducts, Tetrol I-1, were investigated by using thallium nitrate and sodium iodide to quench the SMF. Several fluorescence quenching models were evaluated for both (±)-anti-BPDE-DNA adducts and Tetrol I-1. The SMF quenching phenomena were quite different with the two salts for the (±)-anti-BPDE-DNA adducts and Tetrol I-1. Generally, with thallium nitrate as a quencher, a two-site model with two independent quenching sites was applicable to both the (±)-anti-BPDE-DNA adducts and Tetrol I-1 data. However, with sodium iodide, the SMF quenching data for Tetrol I-1 were fit to the sphere of action model, but the (±)-anti-BPDE-DNA adducts SMF quenching data were qualitatively related to a BET isotherm. From the SMF quenching data, unique information was acquired for the quasi-intercalated BPDE-DNA adducts and the external form of the BPDE-DNA adducts. In addition, insights were obtained on how the adsorbed salts interacted with the solid matrix and with the (±)-anti-BPDE-DNA adducts and Tetrol I-1.
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Fluorescence of Tetrols, Tetrols Complexed with DNA, and Benzo[a]pyrene-DNA Adducts in Methanol/Water Solutions
Applied Spectroscopy, 2000Co-Authors: Paul B. Steinbach, Robert J HurtubiseAbstract:Several solution fluorescence parameters were acquired for the four Tetrol hydrolysis products of benzo[a]pyrene-trans-7,8-dihydrodiol9,10-epoxide (BPDE)-DNA adducts, Tetrols complexed with DNA, and BPDE-DNA adducts in several methanol/water solvents. The relative polarity of the environment for the Tetrols and BPDE-DNA adducts was determined by using a modified definition of the R value that is commonly employed for pyrene. The R values for the Tetrols and BPDE-DNA adducts were calculated by obtaining the ratios of the intensities of the two major fluorescence emission bands at 380 and 400 nm (I380/I400). The positions of the hydroxyl groups on the hydroaromatic ring of the Tetrols were compared in reference to the R values and the changes in the R values as a function of methanol/water composition. This approach resulted in a method for determining whether the hydroxyl groups in the 9 and 10 positions were on the same side or opposite sides of a hydroaromatic ring. The Tetrols intercalated between the DNA bases showed quite different fluorescence spectra compared to Tetrols not complexed with DNA. Also, the quasi-intercalated BPDE-DNA adducts gave significant changes in the R values with an increase in methanol in the solvent, and excitation spectra showed large shifts and changes in shape with an increase in methanol. The approaches developed provide unique structural and polarity information on Tetrols and BPDE-DNA adducts.
