skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Altering the Polymorphic Accessibility of Polycyclic Aromatic Hydrocarbons with Fluorination

Abstract

Here, substituting hydrogen with fluorine is an extensively employed strategy to improve the macroscopic properties of compounds for use in fields as diverse as pharmaceutics and optoelectronics. The role fluorine substitution plays on polymorphism—the ability of a compound to adopt more than one crystal structure—has not been previously studied. Yet, this understanding is important as different polymorphs of the same compound can result in drastically different bulk properties (e.g., solubility, absorptivity, and conductivity). Strategies to either promote or suppress the crystallization of particular polymorphs are thus desired. Here, we show that substituting hydrogen with fluorine affects the polymorphic behavior of contorted hexabenzocoronene (cHBC). A polycyclic aromatic hydrocarbon and molecular semiconductor, cHBC exhibits two polymorphs (i.e., P2 1/c crystal structure which we refer to as polymorph I and a triclinic crystal structure which we refer to as polymorph II) that are accessible through postdeposition processing of amorphous films. While the same two polymorphs remain accessible in fluorinated derivatives of cHBC, fluorination appears to favor the formation of polymorph I, with progressively smaller energy barrier for transformation from polymorph II to polymorph I with fluorination.

Authors:
 [1];  [2];  [3]; ORCiD logo [4]; ORCiD logo [5]
  1. Princeton Univ., Princeton, NJ (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Cornell Univ., Ithaca, NY (United States)
  3. Columbia Univ., New York, NY (United States); New Jersey City Univ., Jersey City, NJ (United States)
  4. Columbia Univ., New York, NY (United States)
  5. Princeton Univ., Princeton, NJ (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1399740
Report Number(s):
LLNL-JRNL-713258
Journal ID: ISSN 0897-4756; TRN: US1702851
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 29; Journal Issue: 10; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY

Citation Formats

Hiszpanski, Anna M., Woll, Arthur R., Kim, Bumjung, Nuckolls, Colin, and Loo, Yueh -Lin. Altering the Polymorphic Accessibility of Polycyclic Aromatic Hydrocarbons with Fluorination. United States: N. p., 2017. Web. doi:10.1021/acs.chemmater.7b00627.
Hiszpanski, Anna M., Woll, Arthur R., Kim, Bumjung, Nuckolls, Colin, & Loo, Yueh -Lin. Altering the Polymorphic Accessibility of Polycyclic Aromatic Hydrocarbons with Fluorination. United States. doi:10.1021/acs.chemmater.7b00627.
Hiszpanski, Anna M., Woll, Arthur R., Kim, Bumjung, Nuckolls, Colin, and Loo, Yueh -Lin. 2017. "Altering the Polymorphic Accessibility of Polycyclic Aromatic Hydrocarbons with Fluorination". United States. doi:10.1021/acs.chemmater.7b00627.
@article{osti_1399740,
title = {Altering the Polymorphic Accessibility of Polycyclic Aromatic Hydrocarbons with Fluorination},
author = {Hiszpanski, Anna M. and Woll, Arthur R. and Kim, Bumjung and Nuckolls, Colin and Loo, Yueh -Lin},
abstractNote = {Here, substituting hydrogen with fluorine is an extensively employed strategy to improve the macroscopic properties of compounds for use in fields as diverse as pharmaceutics and optoelectronics. The role fluorine substitution plays on polymorphism—the ability of a compound to adopt more than one crystal structure—has not been previously studied. Yet, this understanding is important as different polymorphs of the same compound can result in drastically different bulk properties (e.g., solubility, absorptivity, and conductivity). Strategies to either promote or suppress the crystallization of particular polymorphs are thus desired. Here, we show that substituting hydrogen with fluorine affects the polymorphic behavior of contorted hexabenzocoronene (cHBC). A polycyclic aromatic hydrocarbon and molecular semiconductor, cHBC exhibits two polymorphs (i.e., P21/c crystal structure which we refer to as polymorph I and a triclinic crystal structure which we refer to as polymorph II) that are accessible through postdeposition processing of amorphous films. While the same two polymorphs remain accessible in fluorinated derivatives of cHBC, fluorination appears to favor the formation of polymorph I, with progressively smaller energy barrier for transformation from polymorph II to polymorph I with fluorination.},
doi = {10.1021/acs.chemmater.7b00627},
journal = {Chemistry of Materials},
number = 10,
volume = 29,
place = {United States},
year = 2017,
month = 4
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on April 25, 2018
Publisher's Version of Record

Save / Share:
  • Workers in coke oven plants have a higher incidence of lung cancer than the general population. They are exposed to a variety of chemicals, in particular the polycyclic aromatic hydrocarbons (PAH), including benzo(a)pyrene. To evaluate the genotoxic effects of PAH exposure, air samples and urine samples were analyzed for PAH by capillary gas chromatography and high-performance liquid chromatography, respectively. Since benzo(a)pyrene is activated to 7 beta,8 alpha-dihydroxy-(9 alpha,10 alpha)-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE) and binds to DNA, we have used ultrasensitive enzymatic radioimmunoassay and synchronous fluorescence spectrophotometry to measure BPDE-DNA adducts in lymphocyte DNA. The results show that workers were exposed to highmore » concentrations of atmospheric PAH. However, the mean PAH exposure levels are reduced 60% when the workers wore masks during work. When compared to exposure levels, the urinary excretion of PAH was relatively low. Approximately one-third of the workers had detectable putative BPDE-DNA adducts in lymphocytes by ultrasensitive enzymatic radioimmunoassay, and 10% of the samples had emission peaks at 379 nm by synchronous fluorescence spectrophotometry. The four most positive samples were the same in both of the assays. Antibodies to an epitope(s) on BPDE-DNA were found in the sera of approximately one-third of the workers. Detection of DNA adducts and antibodies to these adducts are internal indicators of exposure to benzo(a)pyrene.« less
  • The {sup 32}P-postlabeling assay, thin-layer chromatography, and reverse-phase high-pressure liquid chromatography (HPLC) were used to separate DNA adducts formed from 10 polycyclic aromatic hydrocarbons (PAHs) and 6 nitrated polycyclic aromatic hydrocarbons (NO{sub 2}-PAHs). The PAHs included benzo[j]fluoranthene, benzo[k]fluoranthene, indeno[1,2,3-cd]pyrene, benzo[a]pyrene, chrysene, 6-methylchrysene, 5-methylchrysene, and benz[a]anthracene. The NO{sub 2}-PAHs included 1-nitropyrene, 2-nitrofluoranthene, 3-nitrofluoranthene, 1,6-dinitropyrene, 1,3-dinitropyrene, and 1,8-dinitropyrene. Separation of seven of the major PAH-DNA adducts was achieved by an initial PAH HPLC gradient system. The major NO{sub 2}-PAH-DNA adducts were not all separated from each other using the initial PAH HPLC gradient but were clearly separated from the PAH-DNA adducts. Amore » second NO{sub 2}-PAH HPLC gradient system was developed to separate NO{sub 2}-PAH-DNA adducts following one-dimensional TLC and HPLC analysis. HPLC profiles of NO{sub 2}-PAH-DNA adducts were compared using both adduct enhancement versions of the {sup 32}P-postlabeling assay to evaluate the use of this technique on HPLC to screen for the presence of NO{sub 2}-PAH-DNA adducts. To demonstrate the application of these separation methods to a complex mixture of DNA adducts, the chromatographic mobilities of the {sup 32}P-postlabeled DNA adduct standards (PAHs and NO{sub 2}-PAHs) were compared with those produced by a complex mixture of polycyclic organic matter (POM) extracted from diesel emission particles. The diesel-derived adducts did not elute with the identical retention time of any of the PAH or NO{sub 2}-PAH standards used in this study. HPLC analyses of the NO{sub 2}-PAH-derived adducts (butanol extracted) revealed the presence of multiple DNA adducts.« less
  • Photoinduced toxicity of polycyclic aromatic hydrocarbons (PAHs) occurs via photosensitization reactions (e.g., generation of singlet-state oxygen) and by photomodification (photooxidation and/or photolysis) of the chemicals to more toxic species. The quantitative structure-activity relationship (QSAR) described in the companion paper predicted, in theory, that photosensitization and photomodification additively contribute to toxicity. To substantiate this QSAR modeling exercise it was necessary to show that toxicity can be described by empirically derived parameters. The toxicity of 16 PAHs to the duckweed Lemna gibba was measured as inhibition of leaf production in simulated solar radiation (a light source with a spectrum similar to thatmore » of sunlight). A predictive model for toxicity was generated based on the theoretical model developed in the companion paper. The photophysical descriptors required of each PAH for modeling were efficiency of photon absorbance, relative uptake, quantum yield for triplet-state formation, and the rate of photomodification. The photomodification rates of the PAHs showed a moderate correlation to toxicity, whereas a derived photosensitization factor (PSF; based on absorbance, triplet-state quantum yield, and uptake) for each PAH showed only a weak, complex correlation to toxicity. However, summing the rate of photomodification and the PSF resulted in a strong correlation to toxicity that had predictive value. When the PSF and a derived photomodification factor (PMF; based on the photomodification rate and toxicity of the photomodified PAHs) were summed, an excellent explanatory model of toxicity was produced, substantiating the additive contributions of the two factors.« less
  • Supercritical fluid extraction (SFE) with CO/sub 2/ is a rapid alternative to liquid solvent extraction for the recovery of organic air pollutants collected on polyurethane foam (PUF) sorbent plugs. Quantitative recovery (> 95%) of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) ranging from naphthalene to perylene, several heteroatom-containing PAHs, and n-alkanes ranging from C/sub 12/ to C/sub 24/ was achieved with 10-20 min extractions. Class-selective extraction of n-alkanes versus PAHs resulted from the sequential extraction of the same PUF plug at 80 and 380 atm. Directly coupled SFE with gas chromatography (SFE-GC) allowed a PUF sample to be analyzed inmore » < 1 hr including sample collection, extraction, analyte concentration, and GC separation. The application of SFE and coupled SFE-GC for the extraction and analysis of organic air pollutants that have been collected on PUF is demonstrated for cigarette smoke, diesel exhaust, and roofing tar volatiles.« less
  • For identification of the substances chiefly responsible for the carcinogenic action of the emission condensate from coal-fired residential furnaces, the implantation method was used as a carcinogen-specific bioassay for comparison of the carcinogenic effect of various fractions with that of a total sample of flue gas condensate tested in 2 or 3 different doses. After implantation into the lungs of Osborne-Mendel rats, the condensate from coal-fired residential furnaces, a fraction containing polycyclic aromatic hydrocarbons (PAHs) and thiaarenes (sulfur-containing polycyclic aromatic compounds (S-PACs)) with 4-7 rings, as well as fraction containing more polar polycyclic aromatic compounds (PACs) and PAHs with highermore » molecular weight, induced lung carcinomas and sarcomas. According to probit analysis, the fraction containing PAHs plus S-PACs with 4-7 rings accounted for about 68.2% of the total carcinogenicity of flue gas condensate, whereas the fraction containing more polar PACs and higher PAHs accounted for about 54.6%. All other fractions, such as nonaromatic compounds and PACs with 2 and 3 rings, constituting about 70% of the weight of the total condensate, seemed not to be carcinogenic. Only 1.4% of the total carcinogenicity of the flue gas condensate was found to be attributable to the amount of benzo(a)pyrene (CAS: 50-32-8) present in the condensate (1.14 mg/g condensate). The contribution of more than 100% of both active fractions to the total carcinogenicity (68.2 and 54.6%) may suggest an interrelation of the fractions.« less