Pyrene methanol

Poly[acrylic acid]-poly[pyrene methanol], PAA-PM M = 50,000 DMF Optical sensor... 

Mixture of polyacrylic acid-poly[pyrene methanol] and polyurethane DMF 26 wt.% Optical sensor... 

Similar studies with an electroqam membrane of poly acrylic add-pyrene methanol showing the diange in fluorescence spectra as a function of different concentrations of DNT were measured and are shown in Figure 7. h was fimnd that the fluorescence intensities decreased with increasing DNT concentratioa This fluorescence intensity decrease is mqiected and believed to be due to the quendiing at the i rene-based indicatmr by dectron poor spedes, DNT. 

DNA and RNA quantification, SNP typing, hybridization, and structural alteration have been widely carried out by modified oligonucleotides possessing pyrene derivatives [104-113]. As is known, pyrene-1-carboxaldehyde fluorescence is considerably dependent on solvent polarity [114], being strong in methanol but insignificant in nonpolar solvents [115]. Owing to this property, Tanaka and collaborators developed a pyrenecarboxamide-tethered modified DNA base, PyU 46, and applied it to SNP discrimination in DNA [116-120],... 

Figure 7. Absorption spectra in 15% methanol at 23°C of trans-7,8-dihydroxy-7,8-dihydrobenzo[5]pyrene in native DNA at concentrations of 0.0, 8.0 x l0 5, 1.6 x 10 2.4 x 10, 3.2 x 10 and 4.0 x 10 M. The broken line shows a spectrum in the presence of 3.2 x 10 M DNA and 3.2 x 10 M spermine. (Reproduced with permission from Ref. 15. Copyright 1985, Alan R. Liss.)...

Fig. 16. CEC separation of naphthalene (1), fluorene (2), phenanthrene (3), anthracene (4), pyrene (5),triphenylene (6),andbenzo(a)pyrene (7) using capillary filled with CIO alkyl substituted polyallylamine. (Reprinted with permission from [86]. Copyright 1997 Elsevier). Conditions capillary 50 pm i.d., 48 cm total length, 33 cm active length, field strength 400 V/cm, carrier concentration 20 mg/ml, mobile phase 60 40 methanol-20 mmol/1 borate buffer pH=9.3...

Fig. 7.8. Fluorescence spectra of pyrene in hexane, n-butanol, methanol and acetonitrile showing the polarity dependence of vibronic band intensities (excitation wavelength 310 nm) (reproduced with permission from Kalyanasun-daran and Thomas, 1977b).

Detection of pyrophosphate has also been demonstrated by a simple selfassembling system A-10 (Figure 10.32) with a pyrene-functionalized monoguani-dinium receptor. This receptor was found to self-assemble to form a 2 1 (host -guest) complex with high selectivity for biologically important pyrophosphate ions in methanol. A sandwich-like ground-state pyrene dimer is formed. The character-... 

Chemicals. Antipyrine, carbon monoxide (Matheson, Coleman and Bell, Los Angeles, CA), and 1 CH3-N-antipyrine (11.1 mCi/mM, ICN, Irvine, CA) were purchased. Aldrin (1,8,9,10,11,11-hexa-chloro-2,3-7,6-endo-2,1-7,8-exo-tetracyclo (6.2.1.13,6.02 7) dodeca-A,9-diene) and its epoxide, dieldrin were gifts of Shell Development Co. (Modesto, CA). Each was recrystallized from methanol-water solutions and was greater than 99% pure as determined by gas chromatography. l CH30-p-Nitroanisole (1.9 mCi/mmole) was synthesized (1A) and 3H-benzo(a)pyrene (8.3 Ci/ mmole) was purchased (Amersham-Searle Co., Arlington Heights,... 

In a solution containing oxygen, photolysis yields a mixture of 6,12-, 1,6-, and 3,6-diones. Nitration by nitrogen dioxide forms 6-nitro-, 1-nitro-, and 3-nitrobenzo[a]pyrene. When benzo [a] pyrene in methanol (1 g/L) was irradiated at 254 nm in a quartz flask for 1 h, the solution turned pale yellow. After 2 h, the solution turned yellow and back to clear after 4 h of irradiation. After 4 h, 99.67% of benzo[a]pyrene was converted to polar compounds. One of these compounds was identified as a methoxylated benzo[a]pyrene (Lu et al, 1977). A carbon dioxide yield of 26.5% was achieved when benzo [a] pyrene adsorbed on silica gel was irradiated with light (A, >290 nm) for 17 h (Freitag et al, 1985). 

Benzo [a] pyrene (2.5 mg/L) in a methanol-water solution (3 7 v/v) was subjected to a high pressure mercury lamp or sunlight. Based on a rate constant of 3.22 x 10 Vmin, the corresponding half-life is 0.35 h (Wang et al, 1991). 

Fio. 12. Graph illustrating the dependence of the logarithm of retention factor for aromatic hydrocarbons on the carbon load of octadecyl silica bonded phases prepared from Par-tisil with octadecyhrichlorosilane. Mobile phase methanol-water (70 30) eluitest A, benzene A, naphthalene , phenanthrene , anthracene O, pyrene. Reprinted with permission from Herndon t al. (70). 

Culea et al. reported a quantitative GC-MS analysis of procaine and some neurotransmitters in rat brain tissue [94], Procaine was extracted fi om brain homogenates by the ultrasonication method of Sundlof et al. [95], and was determined in its underivatized form on a 24 m glass capillary column coated with Silar IOC (temperature programmed from 120°C to 225°C at 12°C/min with pyrene as the internal standard). It was found necessary to wash the injector liner and the GC-MS interface stainless steel tubing with 1 1 0.1 M KOH-methanol so that the interface tubing could be coated with a film of OV-17 (from acetone solution), and to condition the apparatus by injecting bis-(trimethylsilyl)-acetamide and triethylamine. 

FIGURE 10.12 Absorption spectra in methanol of benzo[a]pyrene and its 1-, 3-, and 6-nitro derivatives (adapted from Pitts et al., 1978). 

Van den Braken-van Leersum and co-workers (1987) reported that on irradiation in methanol solutions (A > 300 nm), 1-nitropyrene undergoes a rapid conversion via the nitro-nitrite rearrangement, forming 1-hydroxy-pyrene (88%) and l-hydroxy-2-nitropyrene (7%). Under the same conditions, the 4-nitro isomer is more stable than the 1-nitro isomer and 2-nitropyrene is very stable it does not react either with or without oxygen present. 

A fourfold decrease in the IDIIM ratio was observed for the 5.3% peracetylated pyrenylmethyl polyethylenimine derivative in glycerol compared to methanol. The higher viscosity of the glycerol limits the mobility of the attached pyrene group necessary to form excimer, decreases the association rate, and hence lowers ID/IM. These samples at 77°C showed essentially no excimer emission. Clearly, diffusion of the pyrene moieties attached to the polymer side chains is necessary for excimer formation. 

In the presence of D4R species as silica source (second set of experiments Table 1), the aggregation numbers, with and without silica (experiments 11 and 10, respectively), are characteristic of spherical micelles. Moreover, the addition of D4R units has no effect on the pyrene fluorescence lifetime (x), which means that there is no Br /silicate exchange in this micelles-containing system. As it is well known [21], the presence of methanol leads to a decrease of the aggregation number (compare experiments 9 and 10). 

Preparative fractionation of PS with pyrene or OH endgroups was conducted on a silica column (350 x50 mm d0 = 6nm dP 100 pm). The eluent was benzene-cyclohexane (70 30) or chloroform with stepwise increased methanol content (0.01 to 2 %). The fractions obtained formed a series decreasing in molar mass. This might have been due to size exclusion although the column possessed adsorption activity. 

Figure 3. Effect of methanol addition on the emission spectra of pyrene adsorbed on silica gel. The silica gel was heated In vacuum to 700 C for 4 hours.

Methanol concentrations are in mole/g SI02. The excitation wavelength 332 nm. The pyrene coverage is 0.05 mg/g Si02. (Reproduced by permission from Canadian Journal of Chemistry. 62, 1279, 1984.)... 

A solution of substrate (0.20 mmol), pyrene-dimethyltinhydride (1.2 equiv.), and 2,2 -azobisisobutyronitrile (AIBN, 0.1 equiv.) in dry degassed benzene (1-2 ml) was stirred under reflux for 1 h [thin-layer chromatography (TLC) monitoring] under inert atmosphere. The mixture was cooled to room temperature and evaporated. Methanol/dichloromethane (3 2, 4 ml) was added followed by the addition of activated carbon (800 mg). The suspension was stirred for 30 min [the adsorption of the pyrene core was monitored by ultraviolet (UV)]. After filtration, the activated carbon was washed with methanol and the combined filtrates were concentrated to yield the product in pure form. 

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