Vibrational spectroscopic studies on the hofmann-Td-type clathrates: M(NH3)2M′(CN)4·2C6H6 (M=Mn or Cd and M′=Cd or Hg0

IR spectra of Mn(NH₃)₂M(CN)₄·2C₆H₆ (M=Cd or Hg), and IR and Raman spectra of Cd(NH₃)₂M(CN)₄·2C₆H₆ (M=Cd or Hg) are reported. The spectral data suggest that the former two compounds are similar in structure to the latter two Td-type clathrates.     

A New Synthetic Framework for 11‐Demethylellipticine

A new synthetic route for the synthesis of 5‐methyl‐6H‐pyrido[4,3‐b]carbazole ( 8 ), so‐called 11‐demethylellipticine, was described. Construction of the tetracyclic structure hexahydro‐1H‐pyrido[4,3‐b]carbazol‐5(6H)‐one skeleton ( 6 ) was also achieved by nucleophilic substitution reaction in the synthetic route. Also new tetrahydrocarbazole derivatives ( 2 , 3 , 4 , and 5 ) were synthesized. Several ellipticine analogs and octahydropyridocarbazole‐based G‐protein coupled receptors inhibitors can also be synthesized from tetracyclic structure ( 6 ) because of carbonyl functionality at position 5.     

Turn-on fluorescent probe for Zn2+ ions based on thiazolidine derivative

In this study, simple on–off fluorescent/UV–visible (UV–Vis) probes were easily prepared using 2-(2-hydroxyphenyl)thiazolidine-4-carboxylic acid ( Sen-1 ) and/or 2-(2-hydroxy-5-nitrophenyl)thiazolidine-4-carboxylic acid ( Sen-2 ) for fast detection of Zn²⁺ ions. Their sensing properties towards common metal ions were investigated using UV–Vis and fluorescence spectroscopies. Sen-1 and Sen-2 displayed a significant change with the addition of Zn²⁺ ions in the UV–Vis spectra. The addition of Zn²⁺ ions induced a 104 nm bathochromic shift for Sen-1 . The binding ratio towards Zn²⁺ metal ions was determined to be 1:1 by using Job plot analysis and fluorescence spectroscopy. The association constant and free energy (ΔG) of Sen-1 and Sen-2 towards Zn²⁺ ions were calculated by the Benesi–Hildebrand equation. The limit of detection of Sen-1 towards Zn²⁺ ions is 3.73 × 10⁻⁸ M, which is about 1/100 of the value recommended by the World Health Organization for drinking water. Sen-1 was successfully applied to detect Zn²⁺ ions in water samples and the fluorescence test strip was prepared for visual detection of Zn²⁺ ions. Finally, the quantum chemical parameters of Sen-1 and Sen-2 , such as highest occupied molecular orbital, lowest unoccupied molecular orbital, and chemical hardness, were investigated by the Becke, three-parameter, Lee–Yang–Parr, Hartree–Fock, and M062x methods.     

An Infrared and Raman Spectroscopic Study of pn-Td-Type dl% -Propylenediaminemetal(II) Tetracyanometallate(II) Benzene Clathrates: M(dl-pn)M'(CN)4.nC6H6 (M = Mn, M' = Zn, Cd or Hg; M = Cd, M' = Cd or Hg; 1≤n≤1.5)

IR spectra of Mn(dl-propylenediamine)M(CN)4.nC6H6 (M = Zn, n = 1.25; M = Cd, n = 1.00 or M = Hg, n = 1.18), and IR and Raman spectra of Cd(dl-propylenediamine)M(CN) 4. 1.5C6H6 (M = Cd or Hg) are reported. The spectral data suggest that the former three compounds are similar in structure to the latter two pn-Td-type clathrates.     

Infrared Spectroscopic Study of the Hofmann-daon-Type Clathrates : M(1,8-diaminooctane)Ni(CN)4⋅G (M=Co, Ni or Cd; G=Aromatic Guest Molecules)

Infrared spectra of M(1,8-diaminooctane)Ni(CN)4G (M= Co, Ni or Cd; G=benzene, chlorobenzene, toluene, p-xylene, naphthalene or biphenyl) compounds are reported. The 1,8-diaminooctane molecules in the host permit the inclusion of bulky guest molecules. The spectral features suggest that the compounds are similar in structure to the Hofmann-type clathrates.     

The rank of sparse random matrices

We determine the asymptotic normalized rank of a random matrix $\mathit{A}$ over an arbitrary field with prescribed numbers of nonzero entries in each row and column. As an application we obtain a formula for the rate of low-density parity check codes. This formula vindicates a conjecture of Lelarge (2013). The proofs are based on coupling arguments and a novel random perturbation, applicable to any matrix, that diminishes the number of short linear relations.