Journal ArticleDOI
Synthesis, structure, and spectroscopic properties of copper(II) compounds containing nitrogen–sulphur donor ligands; the crystal and molecular structure of aqua[1,7-bis(N-methylbenzimidazol-2′-yl)-2,6-dithiaheptane]copper(II) perchlorate
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In this article, the linear quadridentate N2S2 donor ligand 1,7-bis(N-methylbenzimidazol-2′-yl)-2,6-dithiaheptane (bmdhp) forms mono-and di-hydrate 1 : 1 copper(II) complexes which are significantly more stable toward autoreduction than those of the non-methylated analogue.Abstract:
The linear quadridentate N2S2 donor ligand 1,7-bis(N-methylbenzimidazol-2′-yl)-2,6-dithiaheptane (bmdhp) forms mono- and di-hydrate 1 : 1 copper(II) complexes which are significantly more stable toward autoreduction than those of the non-methylated analogue. The deep green monohydrate of the perchlorate salt crystallises as the mononuclear aqua-complex, [Cu(bmdhp)(OH2)][ClO4]2, in the monoclinic space group P21/n, with Z= 4, a= 18.459(3), b= 10.362(2), c= 16.365(3)A, and β= 117.14(1)°. The structure was solved and refined by standard Patterson, Fourier, and least-squares techniques to R= 0.047 and R′= 0.075 for 3 343 independent reflections with l > 2σ(l). The compound consists of [Cu(bmdhp)(OH2)]2+ ions and ClO4– counter ions. The co-ordination around copper is intermediate between trigonal bipyramidal and square pyramidal, with Cu–N distances of 1.950(4) and 1.997(4)A, Cu–O(water) 2.225(4)A, and Cu–S 2.328(1) and 2.337(1)A. In the solid state, the perchlorate dihydrate's co-ordination sphere may be a topoisomer of the monohydrate's. A new angular structural parameter, τ, is defined and proposed as an index of trigonality, as a general descriptor of five-co-ordinate centric molecules. By this criterion, the irregular co-ordination geometry of [Cu(bmdhp)(OH2)]2+ in the solid state is described as being 48% along the pathway of distortion from square pyramidal toward trigonal bipyramidal. In the electronic spectrum of the complex, assignment is made of the S(thioether)→ Cu charge-transfer bands by comparison with those of the colourless complex Zn(bmdhp)(OH)(ClO4). E.s.r. and ligand-field spectra show that the copper(II) compounds adopt a tetragonal structure in donor solvents.read more
Citations
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Structural variation in copper(I) complexes with pyridylmethylamide ligands: structural analysis with a new four-coordinate geometry index, tau4.
TL;DR: A new geometric parameter for four-coordinate compounds, tau(4), is proposed as an improved, simple metric for quantitatively evaluating the geometry of four- coordinate complexes and compounds.
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Structure and Spectroscopy of Copper−Dioxygen Complexes
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Metal complexes with ‘pincer’-type ligands incorporating N-heterocyclic carbene functionalities
David Pugh,Andreas A. Danopoulos +1 more
TL;DR: The coordination and organometallic chemistry of linear, rigid, tridentate ligands, which incorporate at least one N-heterocyclic carbene and other "classical" donors, is reviewed in this paper.
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Mixed-Ligand Copper(II)-phenolate Complexes: Effect of Coligand on Enhanced DNA and Protein Binding, DNA Cleavage, and Anticancer Activity
Venugopal Rajendiran,Ramasamy Karthik,Mallayan Palaniandavar,Helen Stoeckli-Evans,Vaiyapuri Subbarayan Periasamy,Mohammad Abdulkader Akbarsha,Bangalore Suresh Srinag,Hanumanthappa Krishnamurthy +7 more
TL;DR: The observed IC50 values reveal that complex 4, which effects conformational change on DNA and binds to BSA more strongly, exhibits a cytotoxicity higher than the other complexes, suggesting that 4 can be explored further as a potential anticancer drug.
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Hydrogenase Enzymes and Their Synthetic Models: The Role of Metal Hydrides.
TL;DR: Advances in physical and theoretical characterization of H2ase enzymes and synthetic models have proven key to the study of hydrides in particular, and will guide modeling efforts toward more robust and active species optimized for practical applications.
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