The influence of substituents (R) at N1 atom of furan-2-carbaldehyde thiosemicarbazones {(C4H3O)HC2N3–N(H)–C1(S)N1HR} on bonding, nuclearity, H-bonded networks of copper(I) complexes

Insight into the Anticancer Activity of Copper(II) 5-Methylenetrimethylammonium-Thiosemicarbazonates and Their Interaction with Organic Cation Transporters

A series of four water-soluble salicylaldehyde thiosemicarbazones with a positively charged trimethylammonium moiety ([H2LR]Cl, R = H, Me, Et, Ph) and four copper(II) complexes [Cu(HLR)Cl]Cl (1-4) were synthesised with the aim to study (i) their antiproliferative activity in cancer cells and, (ii) for the first time for thiosemicarbazones, the interaction with membrane transport proteins, specifically organic cation transporters OCT1-3. The compounds were comprehensively characterised by analytical, spectroscopic and X-ray diffraction methods. The highest cytotoxic effect was observed in the neuroblastoma cell line SH-5YSY after 24 h exposure and follows the rank order: 3 > 2 > 4 > cisplatin > 1 >>[H2LR]Cl. The copper(II) complexes showed marked interaction with OCT1-3, comparable to that of well-known OCT inhibitors (decynium 22, prazosin and corticosterone) in the cell-based radiotracer uptake assays. The work paves the way for the development of more potent and selective anticancer drugs and/or OCT inhibitors.

Coordination of 1-methyl-1,3-dihydro-2H-benzimidazole-2-selone to zinc and cadmium: Monotonic and non-monotonic bond length variations for [H(sebenzimMe)]2MCl2 complexes (M = Zn, Cd, Hg)

The reactions of 1-methyl-1,3-dihydro-2H-benzimidazole-2-selone, H(sebenzimMe), towards the zinc and cadmium halides, MX2 (M = Zn, Cd; X = Cl, Br, I), afford the adducts, [H(sebenzimMe)]2MX2, which have been structurally characterized by X-ray diffraction. The halide ligands of each of these complexes participate in hydrogen bonding interactions with the imidazole N-H moieties, although the nature of the interactions depends on the halide. Specifically, the chloride and bromide derivatives, [H(sebenzimMe)]2ZnX2 and [H(sebenzimMe)]2CdX2 (X = Cl, Br), exhibit two intramolecular N-H•••X interactions, whereas the iodide derivatives, [H(sebenzimMe)]2ZnI2 and [H(sebenzimMe)]2CdI2, exhibit only one intramolecular N-H•••I interaction. Comparison of the M-Se and M-Cl bond lengths of the chloride series, [H(sebenzimMe)]2MCl2 (M = Zn, Cd, Hg), indicates that while the average M-Cl bond lengths progressively increase as the metal becomes heavier, the variation in M-Se bond length exhibits a non-monotonic trend, with the Cd-Se bond being the longest. These different trends provide an interesting subtlety concerned with use of covalent radii in predicting bond length differences. In addition to tetrahedral [H(sebenzimMe)]2CdCl2, [H(sebenzimMe)]3,CdCl2•[H(sebenzim)Me]4CdCl2, which features both five-coordinate and six-coordinate coordinate centers, has also been structurally characterized. Finally, the reaction between CdI2 and H(sebenzimMe) at elevated temperatures affords the 1-methylbenzimidazole complex, [H(sebenzimMe)]-[H(benzimMe)]CdI2, a transformation that is associated with cleavage of the C-Se bond.

Crystal structures of the Schiff base derivatives (E)-N'-[(1H-indol-3-yl)methyl-idene]isonicotino-hydrazide ethanol monosolvate and (E)-N-methyl-2-[1-(2-oxo-2H-chromen-3-yl)ethyl-idene]hydrazinecarbo-thio-amide

The crystal structures of two title Schiff base derivatives, C15H12N4O·C2H6O (1·EtOH) and C13H13N3O2S (2), were determined at 110 and 100 K, respectively. In the crystal of compound 1·EtOH, the (E)-N'-[(1H-indol-3-yl)methyl-idene]isonicotinohydrazide and ethanol mol-ecules are linked by O-H⋯O, N-H⋯O and N-H⋯N hydrogen bonds, forming a tape structure running along the b-axis direction. The tapes are weakly linked via a C-H⋯N inter-action. In the crystal of compound 2, (E)-N-methyl-2-[1-(2-oxo-2H-chromen-3-yl)ethyl-idene]hydrazinecarbo-thio-amide mol-ecules are linked via N-H⋯O and C-H⋯O hydrogen bonds, forming a helical chain along the b-axis direction. The chains are further linked into a layer expanding parallel to (102) through C-H⋯S inter-actions.

Unusual borane addition to conjugated dienylphosphanes under frustrated Lewis pair conditions

Dimesitylphosphinoisoprene 9a reacts with a series of R-B(C6F5)2 boron Lewis acids by isomerization and subsequent 1,4-P/B addition to give the heterocyclic phosphonium/borate zwitterionic products 13. Subsequent hydride abstraction from the isoprenyl derived methyl group by trityl cation proceeds with elimination of the R-B(C6F5)2 reagent to give the heterocyclic phosphonium system 20.

Crystal structure of di-μ-iodido-bis-[(dimethyl sulfoxide-κO)(tri-phenyl-phosphane-κP)copper(I)]

The centrosymmetric dinuclear title compound, [Cu2I2(C2H6OS)2(C18H15P)2], represents the first example of a CuI complex ligated by an O-bound dimethyl sulfoxide ligand. In the crystal, the two tetrahedrally coordinated Cu(I) atoms are bridged by two μ2-iodido ligands in an almost symmetrical rhomboid geometry. The loose Cu⋯Cu contact of 2.9874 (8) Å is longer than the sum of the van der Waals radii of two Cu atoms (2.8 Å), excluding a significant cupriophilic inter-action in the actual dimer. C-H⋯O and C-H⋯I hydrogen bonding interactions as well as C-H⋯π(aryl) interactions stabilize the three-dimensional supramolecular network.