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Organotin mefenamic complexesÐpreparations, Organotin mefenamic complexesÐpreparations, spectroscopic studies and crystal structure of a spectroscopic studies and crystal structure of a triphenyltin ester of mefenamic acid: novel antitriphenyltin ester of mefenamic acid: novel antituberculosis agents tuberculosis agents C NMR spectroscopies. The crystal structure of 1 has been determined by X-ray crystallography. X-ray analysis revealed a pseudo-pentacoordinated structure containing Ph 3 Sn coordinated to the carboxylato group. The structural distortion is a displacement from the tetrahedron toward the trigonal bipyramid. Significant CÐH±p interactions and intramolecular hydrogen bonds stabilize the structure 1. The polar imino hydrogen atom participates in intramolecular hydrogen bonds. Complex 1 is self-assembled via CÐH±p and stacking interactions. Vibrational and NMR data are discussed in terms of the crystal structure and the proposed structures for 1±3. Compounds 1 and 3 were tested for antimycobacterial activity against Mycobacterium tuberculosis H37Rv.

The novel triphenyl adduct of 2‐[(2,6‐dimethylphenyl)amino]benzoic acid (HDMPA; 1), i.e., [SnPh3(DMPA)] (2), the dimeric tetraorganostannoxane [Ph2(DMPA)SnOSn(DMPA)Ph2]2 (3), and the monomeric adduct [SnPh2(DMPA)2] (4), where DMPA is monodeprotonated HDMPA, have been prepared and structurally characterized by means of IR, 1H‐NMR, and 13C‐NMR spectroscopy. The structures of 1 and 2 have been determined by X‐ray crystallography. Single‐crystal X‐ray‐diffraction analysis of 1 revealed that there are two molecules in the asymmetric unit, HD1 and HD2, differing in conformation, both forming centrosymmetric dimers linked by H‐bonds between the carboxylic O‐atoms. X‐Ray analysis of 2 revealed a pentacoordinate structure containing Ph3Sn coordinated to the carboxylato group. Significant CH/π interactions and intramolecular H‐bonds stabilize the structures of 1 and 2, which self‐assembled via CH/π and π/π‐stacking interactions. The Ph3Sn adduct 2 was found to be a promising antimycobacterial lead compound, displaying activity against Mycobacterium tuberculosis H37Rv. The cytotoxiciy in the Vero cell line is also reported.

The N- and C-terminal blocked hexapeptide Ac-Leu-Ala-His-Tyr-Asn-Lys-amide (LAHYNK) representing the 80–85 fragment of histone H2B was synthesized and its interactions with Cu(II) and Ni(II) ions were studied by potentiometric, UV-Vis, CD, EPR, and NMR spectroscopic techniques in solution. Our data reveal that the imidazole N(3) nitrogen atom is the primary ligating group for both metal ions. Sequential amide groups deprotonation and subsequent coordination to metal ions indicated an {Nimidazole, 3Namide} coordination mode above pH∼9, in all cases. In the case of Cu(II)-peptide system, the almost exclusive formation of the predominant species CuL in neutral media accounting for almost 98% of the total metal ion concentration at pH 7.3 strongly indicates that at physiological pH values the sequence -LAHYNK- of histone H2B provides very efficient binding sites for metal ions. The imidazole pyrrole N(1) ionization (but not coordination) was also detected in species CuH−4L present in solution above pH ∼ 11.

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