Imidazolium-based ionic liquid derivative/Cu<Superscript>II</Superscript> complexes as efficient catalysts of the lucigenin chemiluminescence system and its application to H<Subscript>2</Subscript>O<Subscript>2</Subscript> and glucose detection

The effects of six synthetic imidazolium-based ionic liquids (ILs) on the Cu^II-catalyzed chemiluminescence of lucigenin (Luc-CL) in the pH range 6.0–11 were investigated. Preliminary experiments found that the CL emission was strongly enhanced or inhibited in the presence of the ILs. The degree of enhancement or inhibition of the CL intensity in the presence of each IL was related to the molecular structure of the IL, the medium used, and the pH. The maximum enhancement of the CL intensity was observed at pH 9.0 (amplification factor?=?443). This decrease in the pH at which maximum CL enhancement occurred and the substantial signal amplification of the Luc-CL may be related to a strong interaction between Cu^II and the imidazolium ring of superior ILs at this pH. Additionally, the formation of IL microdomains in semi-aqueous media permitted more solubility of the product yielded by the Luc-CL reaction (N-methylacridone), which could increase the CL intensity. To obtain consistent data on the catalytic efficiency of Cu^II in the presence of various ILs as well as the corresponding CL emission intensities, fluorescence quantum yields (Φ _F) of lucigenin were measured under the same conditions. Comparison of the data pointed to the mechanism that controls the properties of Luc-CL in the presence of the Cu^II/IL complexes. Based on the catalytic effect of the Cu^II/IL complex and the measurement of the enzymatically generated H₂O₂, a novel, simple, and sensitive CL method for determining glucose with a detection limit (LoD) of 6.5 μM was developed. Moreover, this method was satisfactorily applied to the determination of glucose in human serum and urine samples.

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Graphical Abstract The lucigenin chemiluminescence assay for H₂O₂ and glucose using imidazolium–based ionic liquid derivatives/Cu^II complexes as efficient catalysts at pH 9.0

     

Synthesis of New Phosphonium Ylides Containing Thiophene and Furan Rings and Study of Their Reaction with Mercury(II) Halides: Spectral and Structural Characterization

Reactions of phosphonium ylides (4‐MeC₆H₄)₃PCHC(?O)(2‐C₄H₃S) (tptpy), Ph₃PCHC(?O)(2‐C₄H₃O) (fppy), and (4‐MeC₆H₄)₃PCHC(?O)(4‐BrC₆H₄) (bbtppy) with HgX₂ (X=Cl, Br, and I) in equimolar ratios in MeOH as solvent leads to the binuclear products 1 – 3 (Scheme 1). The bridge‐splitting reaction of the binuclear complex [{HgI₂(bbtppy)}₂] ( 3c ) by DMSO yields the mononuclear complex [HgI₂?(bbtppy) (DMSO)] ( 3d ) (Scheme 2). This bridge‐splitting reaction can also be a method for the synthesis of mononuclear products. C‐Coordination of the ylide and O‐coordination of DMSO are demonstrated by a single‐crystal X‐ray‐analysis of the mononuclear complex 3d . Characterization of the obtained compounds was also performed by means of elemental analysis and IR and ¹H‐, ³¹P‐, and ¹³C‐NMR spectroscopy. A theoretical study of some Hg^II complexes with phosphonium ylides is also reported.     

Hydrazone- and hydrazide-containing N-substituted glycines as peptoid surrogates for expedited library synthesis: application to the preparation of Tsg101-directed HIV-1 budding antagonists

Replacing the Pro6 in the p6(Gag)-derived 9-mer "P-E-P-T-A-P-P-E-E" with N-substituted glycine (NSG) residues is problematic. However, incorporation of hydrazone amides ("peptoid hydrazones") can be readily achieved in library fashion. Furthermore, reduction of these hydrazones to N-substituted "peptoid hydrazides" affords a facile route to library diversification. This approach is demonstrated by application to Tsg101-binding compounds designed as potential HIV budding antagonists. [reaction: see text]     

Synthesis and Characterization of Mesoporous Titanosilicate as an Adsorbent for Toxic Metal Ions

Hexagonal mesoporous titanosilicates (Ti‐MCM‐41) have been prepared using cetyltrimethylammonium bromide (CTAB) as the structure directing agent under the mild alkaline conditions. Powder X‐ray diffraction, nitrogen gas sorption, FTIR spectroscopy and thermogravimetry analysis of samples have confirmed that well ordered MCM‐41 type mesoporous materials were prepared. The potential of removing toxic metal ions from waste waters using mesoporous titanosilicates was evaluated. Separation of Co^II‐U^VI, Cs^I‐U^VI and Sm^III‐U^VI has been developed on columns of this adsorbent.