HPLC–ELSD法测定三乙醇胺单、双、三酯季铵盐的含量

建立正相高效液相色谱–蒸发光散射检测法测定工业样品中的三乙醇胺单、双、三酯季铵盐的含量。以正己烷–甲醇–四氢呋喃(体积比85∶10∶5,加0.5 mL三氟乙酸调节至pH 3.50)为流动相,等度洗脱三乙醇胺单、双、三酯季铵盐,色谱柱为HP–氨基正相柱,柱温27℃,流量1.0 mL/min,蒸发光散射检测器漂移管温度80℃,载气流量2.6 L/min。三乙醇胺单、双、三季铵盐质量浓度的自然对数与各自对应的色谱峰面积和的自然对数呈良好的线性,相关系数(r~2)分别为0.991 4,0.996 7,0.991 5。测定结果的相对标准偏差为0.6%~2.6%(n=6),加标回收率分别为98.6%,101.2%,97.9%。该方法准确快速,可以为三乙醇胺单、双、三酯季铵盐的生产工艺优化提供理论数据。     

Comparisons of phosphorothioate with phosphate transfer reactions for a monoester,diester, and triester: isotope effect studies

Phosphorothioate esters are sometimes used as surrogates for phosphate ester substrates in studies of enzymatic phosphoryl transfer reactions. To gain better understanding of the comparative inherent chemistry of the two types of esters, we have measured equilibrium and kinetic isotope effects for several phosphorothioate esters of p-nitrophenol (pNPPT) and compared the results with data from phosphate esters. The primary (18)O isotope effect at the phenolic group ((18)k(bridge)), the secondary nitrogen-15 isotope effect ((15)k) in the nitro group, and (for the monoester and diester) the secondary oxygen-18 isotope effect ((18)k(nonbridge)) in the phosphoryl oxygens were measured. The equilibrium isotope effect (EIE) (18)k(nonbridge) for the deprotonation of the monoanion of pNPPT is 1.015 +/- 0.002, very similar to values previously reported for phosphate monoesters. The EIEs for complexation of Zn(2+) and Cd(2+) with the dianion pNPPT(2-) were both unity. The mechanism of the aqueous hydrolysis of the monoanion and dianion of pNPPT, the diester ethyl pNPPT, and the triester dimethyl pNPPT was probed using heavy atom kinetic isotope effects. The results were compared with the data reported for analogous phosphate monoester, diester, and triester reactions. The results suggest that leaving group bond fission in the transition state of reactions of the monoester pNPPT is more advanced than for its phosphate counterpart pNPP, while alkaline hydrolysis of the phosphorothioate diester and triester exhibits somewhat less advanced bond fission than that of their phosphate ester counterparts.     

液相色谱-质谱法分析季戊四醇油酸酯

提出了高效液相色谱-质谱法测定单、双季戊四醇油酸酯中单酯、双酯、三酯和四酯的含量。样品经正己烷-异丙醇(9+1)溶剂溶解后,以Lichrospher Si100-5色谱柱(4.6mm×250mm,5μm)为分离柱,以不同体积比的正己烷和异丙醇混合溶液为流动相梯度淋洗。采用总离子流图的峰面积归一化法对单、双季戊四醇油酸酯中单酯、双酯、三酯和四酯的含量进行定量,用质谱法做鉴别。     

Simplified speciation and improved phosphodiesterolytic activity of hydroxo complexes of trivalent lanthanides in aqueous DMSO

Potentiometric titrations of La(III), Nd(III), and Eu(III) perchlorates by Me 4N(OH) in 80% vol aq DMSO revealed formation of predominantly mononuclear complexes M(OH)n(3- n) (n = 1, 2, or 3) and a single binuclear complex M2(OH)(5+). Kinetics of the cleavage of two phosphate diesters, bis (4-nitrophenyl) phosphate (BNPP) and 2-hydroxypropyl 4-nitrophenyl phosphate (HPNPP), and a triester, 4-nitrophenyl diethyl phosphate (paraoxon), were studied as a function of metal and Me4N(OH) concentrations in the same medium. Rate of BNPP cleavage is second-order in metal and is proportional to the product of concentrations of M(OH)2(+) and M(OH)3 species. Rate of HPNPP cleavage is proportional to [M(OH)3](3) for La(III) and Nd(III) and to [M(OH)3](2) for Eu(III). Proposed mechanism for BNPP hydrolysis involves formation of M2(OH)5(diester) intermediate followed by intramolecular nucleophilic attack of hydroxide anion on the phosphoryl group of the substrate. Proposed mechanism for HPNPP cleavage involves formation of M3(OH)9(diester)(-) or M2(OH)6(diester)(-) intermediates followed by the general base-assisted intramolecular cyclization of HPNPP. The latter mechanism is supported by observation of the solvent kinetic isotope effect k H/kD = 2.9 for Eu(III) catalyzed HPNPP cleavage. The efficiency of catalysis in 80% DMSO is much higher than in water. The reaction rate observed in the presence of 1 mM metal in neutral solution surpasses the rate of background hydrolysis by a factor of 10(12)-10(13) for BNPP and 10(10) for HPNPP. The increased catalytic activity is attributed principally to the preferable solvation of lanthanide ions by DMSO, which creates an anhydrous microenvironment favorable for reaction in the coordination sphere of the catalyst. The catalytic activity of lanthanides in paraoxon hydrolysis is much lower with the estimated efficiency of catalysis about 10(5) for 1 mM La(III).     

S(N)2 Mechanism for Alcoholysis, Aminolysis, and Hydrolysis of Acetyl Chloride

First-order solvolysis rate constants are reported for solvolyses of acetyl chloride in methanol and MeOD, and in binary aqueous mixtures with acetone, acetonitrile, ethanol, methanol, and trifluoroethanol at 0 degrees C. Product selectivities (S = [MeCOOR]/[MeCOOH] x [water]/[alcohol]) are reported for solvolyses in ethanol/ and methanol/water at 0 degrees C. Solvolyses of acetyl chloride show a high sensitivity to changes in solvent ionizing power, consistent with C-Cl bond cleavage. As the solvent is varied from pure ethanol (or methanol) to water, S values and rate-rate profiles show no evidence for the change in reaction channel observed for solvolyses of benzoyl and trimethylacetyl chlorides. However, using rate ratios in 40% ethanol/water and 97% trifluoroethanol/water (solvents of similar ionizing power but different nucleophilicities) to compare sensitivities to nucleophilic attack, solvolyses of acetyl chloride are over 20-fold more sensitive to nucleophilic attack than benzoyl chloride. The solvent isotope effect of 1.29 (MeOH/MeOD) for acetyl chloride is similar to that for p-methoxybenzoyl chloride (1.22) and is lower than for benzoyl chloride (1.55). Second-order rate constants for aminolyses of acetyl chloride with m-nitroaniline in methanol at 0 degrees C show that acetyl chloride behaves similarly to p-methoxybenzoyl chloride, whereas benzoyl chloride is 40-fold more sensitive to the added amine. The results indicate mechanistic differences between solvolyses of acetyl and benzoyl chlorides, and an S(N)2 mechanism is proposed for solvolyses and aminolyses by m-nitroaniline of acetyl chloride (i.e. these reactions are probably not carbonyl additions, but a strong sensitivity to nucleophilic attack accounts for their high rates).     

Palladium(II)-catalyzed oxidation of aldehydes and ketones. 1. Carbonylation of ketones with carbon monoxide catalyzed by palladium(II) chloride in methanol.

Unsubstituted or alkyl-substituted cyclic ketones react with PdCl2 in methanol under a CO atmosphere to give mainly acyclic diesters along with some acyclic chloro-substituted monoesters. The monosubstituted cyclic ketones, 2-hydroxy- and 2-methoxycyclohexanone, do not give ring cleavage but rather produce 2-(carbomethoxy)cyclohex-2-en-1-one. 13CO labeling experiments indicate one CO is inserted in forming the diester product so the second ester group must arise from the original ketone group. Two mechanisms are possible for the diester reaction. One involves initial Pd(II)-CO2CH3 insertion across the double bond of the enol form of the ketone while the second involves initial addition of Pd(II)-OCH3 followed by CO insertion into the new Pd(II)-carbon bond formed. Pd(II) elimination and acid-catalyzed ring cleavage produce the second methyl ester group in both routes. The chloro-substituted monoester is formed by initial Pd(II)-Cl insertion across the double bond followed by the acid-catalyzed ring cleavage. The 2-(carbomethoxy)cyclohex-2-en-1-one must result from elimination of water or methanol from the alpha-ketoester product formed by the initial methoxycarbonylation of the enol form of the ketone. As expected, the acyclic ketone, 2-decanone, formed methyl acetate and a mixture of methyl nonanoate and 1-chlorooctane as products.     

Reactivity study of a hydroperoxodicopper(II) complex: hydroxylation, dehydrogenation, and ligand cross-link reactions

Employing a binucleating phenol-containing ligand PD'OH, a mu-phenoxo-mu-hydroperoxo dicopper(II) complex [Cu(II)2(PD'O-)(-OOH)(RCN)2](ClO4)2 (1, R = CH3, CH3CH2 or C6H5CH2; lambda(max) = 407 nm; nu(O-O) = 870 cm(-1); J. Am. Chem. Soc. 2005, 127, 15360) is generated by reacting a precursor dicopper(I) complex [Cu(I)2(PD'OH)(CH3CN)2](ClO4)2 (2) with O2 in nitrile solvents at -80 degrees C. Species 1 is unable to oxidize externally added substrates, for instance, PPh3, 2,4-tert-butylphenol, or 9,10-dihydroanthracene. However, upon thermal decay, it hydroxylates copper-bound organocyanides (e.g., benzylcyanide), leading to the corresponding aldehyde while releasing cyanide. This chemistry mimics that known for the copper enzyme dopamine-beta-monooxygenase. The thermal decay of 1 also leads to a product [Cu(II)3(L")2(Cl-)2](PF6)2 (6); its X-ray structure reveals that L" is a Schiff base-containing ligand which apparently derives from both oxidative N-dealkylation and then oxidative dehydrogenation of PD'OH; the chloride presumably derives from the CH2Cl2 solvent. With an excess of PPh3 added to 1, a binuclear Cu(I) complex [Cu(I)2(L')(PPh3)2](ClO4)2 (5) with a cross-linked PD'OH ligand L' has also been identified and crystallographically and chemically characterized. The newly formed C-O bond and an apparent k(H)/k(D) = 2.9 +/- 0.2 isotope effect in the benzylcyanide oxidation reaction suggest a common ligand-based radical forms during compound 1 thermal decay reactions. A di-mu-hydroxide-bridged tetranuclear copper(II) cluster compound [{Cu(II)2(PD'O-)(OH-)}2](ClO4)4 (8) has also been isolated following warming of 1. Its formation is consistent with the generation of [Cu(II)2(PD'O-)(OH-)]2+, with dimerization a reflection of the large Cu...Cu distance and thus the preference for not having a second bridging ligand atom (in addition to the phenolate O) for dicopper(II) ligation within the PD'O- ligand framework.     

Copper(II) complexes of novel N-alkylated derivatives of cis,cis-1,3,5-triaminocyclohexane. 2. Metal-promoted phosphate diester hydrolysis

Aqueous copper(II) N,N',N' '-trimethyl-cis,cis-1,3,5-triaminocyclohexane (Cu(tach-Me(3))(2+)(aq)) promotes the hydrolysis of activated phosphate diesters in aqueous medium at pH 7.2. This complex is selective for cleavage of the phosphate diester sodium bis(p-nitrophenyl) phosphate (BNPP), the rate of hydrolysis of the monoester disodium p-nitrophenyl phosphate being 1000 times slower. The observed rate acceleration of BNPP hydrolysis is slightly greater than that observed for other Cu(II) complexes, such as [Cu([9]aneN(3))Cl(2)] ([9]aneN(3) identical with 1,4,7-triazacyclononane). The rate of hydrolysis is first-order in phosphate ester at low ester concentration and second-order in [Cu(tach-Me(3))](2+)(aq), suggesting the involvement of two metal complexes in the mechanism of substrate hydrolysis. The reaction exhibits saturation kinetics with respect to BNPP concentration according to a modified Michaelis-Menten mechanism: 2CuL + S <==> LCu-S-CuL --> 2CuL + products (K(M) = 12.3 +/- 1.8 mM(2), k(cat) = (4.0 +/- 0.4) x 10(-)(4) s(-1), 50 degrees C) where CuL (triple bond) [Cu(tach-Me(3))](2+), S (triple bond) BNPP, and LCu-S-CuL is a substrate-bridged dinuclear complex. EPR data indicate that the dicopper complex is formed only in the presence of BNPP; the active LCu-S-CuL intermediate species then slowly decays to products, regenerating monomeric CuL.     

Comparison of the photochemical behaviors of α-tocopherol and its acetate in organic and aqueous micellar solutions

Photoionization is known to take place when α-tocopherol (TOH) is excited to the S(1) state in a polar medium. It has been previously suggested that TO(?) is formed only as a result of proton release by TOH(?+), a process that is expected to occur, in a protic solvent, on the subnanosecond time scale. Recent redeterminations of the molar absorption coefficients of e(aq)(–) (Hare J. Phys. Chem. A 2010, 114, 1766) and of TOH(?+) and TO(?) (Naqvi J. Phys. Chem. A 2010, 114, 10795) have paved the way for testing the above suggestion, even if subnanosecond time resolution is not available, since it implies the equality of [e(aq)(–)](0) and [TO(?)](0), where [···](0) denotes the concentration of the enclosed species immediately after a nanosecond laser pulse. Nanosecond pump-probe spectroscopy of TOH in aqueous micellar solution (AMS) and two organic solvents with similar polarities (acetonitrile and methanol) has revealed that prompt formation of TO(?) through dissociation (TOH + hν → TO(?) + H(?)) is not negligible even in AMS. In acetonitrile, TOH(?+) and TO(?) are formed with comparable yields, and the former converts quantitatively into TO(?) within 15 μs. In methanol, TO(?) was observed, but no evidence was found for electron ejection from TOH. Only one photoproduct, namely TO(?), could be detected when α-tocopherol acetate (TOAc) was excited to the S(1) state in several polar and nonpolar solvents; TOAc has been found to be a more efficient energy degrader than TOH.     

薄层扫描法测定蔗糖脂肪酸酯中的各组成酯

 建立了蔗糖脂肪酸酯中一酯～三酯的薄层分离定性及薄层扫描定量方法。以氯仿 甲醇 醋酸 水 (体积比为 80∶1 0∶8∶1 )为展开剂 ,双波长反射法锯齿扫描 ,测定波长为 530nm ,参比波长为 70 0nm ,线性范围为 4μg～60 μg ,相关系数为0 9940～ 0 9980 ,平均回收率为 96 45%～ 98 73% (RSD为 2 8%～ 3 3% ,n =3)。方法可靠 ,数据准确 ,操作简便易行 ,线性范围宽。     

Solvent extraction of copper(II) with chlorendic acid

The solvent extraction of Cu(II) with chlorendic acid has been studied The composition of the extracted species appears to be a function of pH. In the pH range 3.2-4.6, a monomeric species exists [Cu(II)(L(2-)], while at pH values greater than 4.5, a dimer in the form of [Cu(II)(L(2-)). H(2)L](2) and/or [Cu(II)(HL(-))(2)](2) is extracted.     

Tuning charge recombination rate constants through inner-sphere coordination in a copper(I) donor-acceptor compound

The coordination compounds [Cu(bpy-MV2+)(PPh3)2](PF6)3, where bpy-MV2+ is the 1-(4-(4'-methyl-2,2'-bipyridin-4-yl)butyl)-1'-methyl-4, 4'-bipyridinediium(2+) cation, and [Cu(dmb)(PPh3)2](PF6), where dmb is 4,4'-dimethyl-2,2'-bipyridine, have been prepared and characterized. Visible light (417 nm) excitation of [Cu(bpy-MV2+)(PPh3)2]3+ at room temperature leads to rapid intramolecular electron transfer, kcs > 1 x 10(8) s-1, to form a charge-separated state with an electron localized on the pendant viologen group and a copper(II) metal center, abbreviated [CuII-bpy-MV.+]. This state recombines to ground-state products with first-order rate constants that can be tuned with solvent over a approximately 10(7)-10(5) s-1 range. The activation parameters were determined from temperature-dependent electron-transfer data with Arrhenius analysis. A model is proposed wherein a solvent molecule is coordinated to Cu(II) in the charge-separated state, [(S)CuII-bpy-MV.+]. Visible light excitation of [Cu(dmb)(PPh3)2](PF6) in argon-saturated dichloromethane produces long-lived photoluminescent excited states, tau = 80 ns, that are dynamically quenched by the addition of Lewis basic solvents. The measured quenching constants each correlate well with the lifetime of the charge-separated state measured after excitation of [Cu(bpy-MV2+)(PPh3)2]3+ in the corresponding solvent.     

Synthesis, spectroscopic and electrochemical studies of N,N-bis[(E)-2-thienylmethylidene]-1,8-naphthalenediamine and its Cu(II) complex: DNA cleavage and generation of superoxide anion

A novel tetradentate Cu(II) complex of the type, [CuL](NO(3))(2) was synthesized by the interaction of Schiff base ligand, N,N-bis[(E)-2-thienylmethylidene]-1,8-naphthalenediamine, L obtained by the condensation of thiophene-2-carboxaldehyde and 1,8-diaminonaphthalene. The formation of Schiff base ligand, L and its Cu(II) complex was confirmed on the basis of results of elemental analyses, mass, FT-IR, (1)H and (13)C{(1)H} NMR spectral studies. UV-Vis, EPR and magnetic susceptibility data support a square planar environment around Cu(II) ion. However, molar conductance values confirmed 1:2 electrolytic nature for the Cu(II) complex. The electrochemical studies of Cu(II) complex was carried out by using cyclic voltammetry which revealed the complex to exhibit quasi reversible process. The biological activity of Cu(II) complex such as ability to bind DNA and DNA cleavage were studied where the Cu(II) complex was shown to cause considerable DNA cleavage and also generated reactive oxygen species such as superoxide anion. Since it is known that various anticancer drugs act through induction of oxidative stress that is mediated by reactive oxygen species, our results suggest a putative role of Cu(II) complex similar to various anticancer drugs.     

Radical polymerizations and copolymerizations of dimethylstannyl dimethacrylate and trimethylstannyl methacrylate

The radical polymerizations and copolymerizations of dimethylstannyl dimethacrylate (DSM) and trimethylstannyl methacrylate (TSM) in dimethylformamide (DMF) were studied. These monomers did not polymerize thermally, but easily underwent polymerization in the presence of α,α′-azobisisobutyronitrile and on irradiation with ultraviolet light. The polymer obtained from TSM was soluble in DMF and methanol, but that from DSM was insoluble in any organic solvents; this polymer probably consists of a network structure. These polymers were converted to poly(methyl methacrylate) (PMMA) by means of acid hydrolysis and then methylation with diazomethane. The content of syndiotactic triad was determined from infrared spectra of PMMA derived from the polymers of DSM and TSM. It was noted that the content of syndiotactic triad was greater in the radical polymerization of TSM than those of DSM at every temperature investigated. The differences in the activation enthalpy (ΔΔH?) and in the activation entropy (ΔΔS?) between isotactic and syndiotactic additions were determined as follows: for DSM, ΔΔH? = ～0 cal/mole, ΔΔS? = ?0.856 eu; for TSM, ΔΔH? = 229 cal/mole, ΔΔ = ?1.09 eu. From the radical copolymerizations of DSM and TSM with styrene at 60°C, the copolymerization parameters, Q and e, were evaluated as follows: for DSM, Q = 1.36, e = 0.41; for TSM, Q = 0.45, e = ?0.37. These results were compared with the reported effects of stannic chloride and zinc chloride on the radical polymerization of methyl methacrylate.     

Synthesis, X-ray crystal structures, and phosphate ester cleavage properties of bis(2-pyridylmethyl)amine copper(II) complexes with guanidinium pendant groups

Three new derivatives of bis(2-pyridylmethyl)amine (DPA) featuring ethylguanidinium (L (1)), propylguanidinium (L (2)), or butylguanidinium (L (3)) pendant groups have been prepared by the reaction of N, N- bis(2-pyridylmethyl)alkane-alpha,omega-diamines with 1 H-pyrazole-1-carboxamidine hydrochloride. The corresponding mononuclear copper(II) complexes were prepared by reacting the ligands with copper(II) nitrate and were isolated as [Cu(LH (+))(OH 2)](ClO 4) 3. xNaClO 4. yH 2O ( C1: L = L (1), x = 2, y = 3; C2: L = L (2), x = 2, y = 4; C3: L = L (3), x = 1, y = 0) following cation exchange purification. Recrystallization yielded crystals of composition [Cu(LH (+))(X)](ClO 4) 3.X ( C1': L = L (1), X = MeOH; C2': L = L (2), X = H 2O; C3': L = L (3), X = H 2O), which were suitable for X-ray crystallography. The crystal structures of C1', C2', and C3' indicate that the DPA moieties of the ligands coordinate to the copper(II) centers in a meridional fashion, with a water or methanol molecule occupying the fourth basal position. Weakly bound perchlorate anions located in the axial positions complete the distorted octahedral coordination spheres. The noncoordinating, monoprotonated guanidinium groups project away from the Cu(II)-DPA units and are involved in extensive charge-assisted hydrogen-bonding interactions with cocrystallized water/methanol molecules and perchlorate anions within the crystal lattices. The copper(II) complexes were tested for their ability to promote the cleavage of two model phosphodiesters, bis( p-nitrophenyl)phosphate (BNPP) and uridine-3'- p-nitrophenylphosphate (UpNP), as well as supercoiled plasmid DNA (pBR 322). While the presence of the guanidine pendants was found to be detrimental to BNPP cleavage efficiency, the functionalized complexes were found to cleave plasmid DNA and, in some cases, the model ribose phosphate diester, UpNP, at a faster rate than the parent copper(II) complex of DPA.     

Non-aqueous,reversed-phase,high-performance,thin-layer chromatography and column liquid chromatography of metal complexes of porphine

Summary The chromatographic mobility of 21H, 23H-porphine and its Ni(II), Cu(II), Zn(II) and Pd(II) complexes were investigated by high-performance thin-layer chromatography on an octadecyl-bonded, silica gel plate with various polar organic solvents including alcohols, acetonitrile, dimethylsulfoxide and propylenecarbonate. The mobility generally decreases according to the central metal ion of the complex as follows: Zn(II)>(free porphine)>Ni(II)>Pd(II)>Cu(II). Methanol is a good choice of solvent for the separation of these metal porphine complexes. Successful separation of porphine and the four metal complexes is accomplished within 13 min on a LiChrosorb RP-18 column with methanol eluent.     

Synthesis, Reactivity, and Spectroscopic Properties of meso-Triaryl-5-oxaporphyrins

[meso-Triaryl-21,23-didehydro-23H-5-oxaporphyrinato](trifluoroacetato)zinc(II) was prepared by the reaction of meso-triarylbilindione with acetic anhydride and zinc acetate, and it was isolated as a trifluoroacetate salt. The X-ray crystallographic study demonstrated that the trifluoroacetate anion was coordinated to the zinc ion. [21,23-Didehydro-10,15,20-tris(4-methoxycarbonylphenyl)-23H-5-oxaporphyrinato](trifluoroacetato)zinc(II) 3a was dissolved in various organic solvents such as toluene, chloroform, diethyl ether, ethyl acetate, acetone, acetonitrile, methanol, DMSO, and DMF, although it readily reacted with alcohols and DMF to yield linear tetrapyrroles. The solubility of 3a in toluene was 4.2 ± 0.1 g dm(-3) at room temperature. 3a showed characteristic UV-vis absorption at 649 nm and fluorescence emission at 657 nm in chloroform. The fluorescence quantum yields of 3a, [21,23-didehydro-10,15,20-triphenyl-23H-5-oxaporphyrinato](trifluoroacetato)zinc(II) (3c), and [21,23-didehydro-10,15,20-tris(4-methoxyphenyl)-23H-5-oxaporphyrinato](trifluoroacetato)zinc(II) (3b) were 0.071, 0.071, and 0.050, respectively. Reaction of 3a with EtOH afforded the zinc complex of 19-ethoxybilinone, and it proceeded 2 orders of magnitude faster than that of [β-octaalkyl-21,23-didehydro-23H-5-oxaporphyrinato]zinc(II). The reaction with alcohols was sensitive to steric bulk of the alcohols; the rate of reaction with i-PrOH was 2700 times faster than that of t-BuOH at 303 K. The reaction of [meso-triaryl-21,23-didehydro-23H-5-oxaporphyrinato]zinc(II) with water proceeded 3 orders of magnitude slower than that with EtOH.     

Preferential solvation and solvation shell composition of free base and protonated 5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphyrin in aqueous organic mixed solvents

The solvatochromic properties of the free base and the protonated 5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) were studied in pure water, methanol, ethanol (protic solvents), dimethylsulfoxide, DMSO, (non-protic solvent), and their corresponding aqueous-organic binary mixed solvents. The correlation of the empirical solvent polarity scale (E(T)) values of TPPS with composition of the solvents was analyzed by the solvent exchange model of Bosch and Roses to clarify the preferential solvation of the probe dyes in the binary mixed solvents. The solvation shell composition and the synergistic effects in preferential solvation of the solute dyes were investigated in terms of both solvent-solvent and solute-solvent interactions and also, the local mole fraction of each solvent composition was calculated in cybotactic region of the probe. The effective mole fraction variation may provide significant physico-chemical insights in the microscopic and molecular level of interactions between TPPS species and the solvent components and therefore, can be used to interpret the solvent effect on kinetics and thermodynamics of TPPS. The obtained results from the preferential solvation and solvent-solvent interactions have been successfully applied to explain the variation of equilibrium behavior of protonation of TPPS occurring in aqueous organic mixed solvents of methanol, ethanol and DMSO.     

A heterobimetallic ruthenium(II)-copper(II) donor-acceptor complex as a chemodosimetric ensemble for selective cyanide detection

A trinuclear heterobimetallic Ru(II)-Cu(II) donor-acceptor complex, [Ru(II)((t)Bubpy)(CN)(4)-[Cu(II)(dien)](2)](ClO(4))(2) ((t)Bubpy = 4,4'-di-tert-butyl-2,2'-bipyridine; dien = diethylenetriamine) (1), has been synthesized and successfully used as an chemodosimetric ensemble for the specific detection of cyanide in aqueous DMF. X-ray crystallography, solid and solution IR spectroscopy, and conductivity measurements reveal that complex 1 is a one-dimensional polymer in the crystalline state and dissociates into its [Ru(II)((t)Bubpy)(CN)(2)[(CN)Cu(II)(dien)L](2)](2+) (L = solvent) monomeric units in polar solvents. The MLCT transition and luminescence properties of the solvatochromic [Ru(II)((t)Bubpy)(CN)(4)](2)(-) donor are perturbed by the coordination of two Cu(II) acceptors but restored in the presence of CN(-). Spectroscopic and mass spectrometric studies confirm the cleavage of the cyano bridge between Ru(II) and Cu(II) of the chemodosimetric ensemble after the binding of cyanide to the Cu(II) centers. The overall binding constant, K(B), between 1 and CN(-) is measured to be (7.39 +/- 0.23) x 10(6) M(-2). A detection limit of 1.2 microM (0.03 ppm) of CN(-) in aqueous DMF (pH 7.4) is achievable. Thermodynamic evaluation shows that the analyte specificity of chemodosimeter 1 is attributable to the relative stability of the donor-acceptor complex to that of adducts formed between the acceptor metal center and the analytes.     

Cu2{[18]ane-N6} complexes: structures, magnetism, and phosphate monoester binding

A novel Cu(II)2 complex of the [18]ane-N6 macrocycle ([18]ane-N6 = 1,4,7,10,13,16-hexaazacyclooctadecane) was prepared from the reaction between [18]ane-N6 and Cu(II) salts such as Cu(NO3)2 and Cu(OAc)2. A structural study of the complex derived from Cu(OAc)2 (1) revealed a Cu(II)2 core encircled by a [18]ane-N6 ligand and two mu-O-OAc ligands. The facile replacement of mu-O-OAc by a phosphate monoester [PO3(OR)2-] yielded a number of bis(phosphate monoester)dicopper complexes with ROPO3(2-) as hydrogen phosphate (HPO4(2-), 3a), phenyl phosphate [PO3(OPh)2-, 3b], glycerol 2-phosphate [PO3(OCH(CH2OH)2)2-, 3c], alpha-d-gluocose phosphate [PO3(C6H11O6)2-, 3d], and dl-alpha-glycerol phosphate [PO3(OCH2CHOHCH2OH)2-, 3e]. Structural studies of compounds 3a-d confirmed both the retention of the Cu2{[18]ane-N6} core and a mu-O-PO3(OR) coordination mode. Displacement of acetate by a phosphate monoester in an aqueous solution was accompanied by a significant change in the visible absorption, which enables the establishment of relative association constants of PO3(OR)2- on the order of 10(4) in the unbuffered solution and 10(3) in the buffered solution (HEPES). Measurement of the magnetic susceptibility of compound 3a over the temperature range of 5-300 K and subsequent modeling revealed a weak antiferromagnetic coupling (J = -1.1 cm(-1)) between two Cu(II) centers.