Structure of aquaoxo(N-salicylidene-L-alaninato)vanadium(IV)

Hämäläinen, Reijo; Turpeinen, Urho; Ahlgrén, Markku

doi:10.1107/s0108270185009222

Cited by 30 publications

(16 citation statements)

References 5 publications

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“…The coordination properties of Cu(I) ions, which form pseudotetrahedral complexes with bipyridine and phenanthroline ligands (15,(22)(23)(24), induce the organization of the oligobipyridine ligands BP2 and BP3. In the present complex, the three copper(I) centers have an almost identical, distorted tetrahedral coordination geometry.…”

Section: Resultsmentioning

confidence: 99%

Spontaneous assembly of double-stranded helicates from oligobipyridine ligands and copper(I) cations: structure of an inorganic double helix.

Lehn¹,

Rigault²,

Siegel³

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

832

539

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Two oligobipyridine ligands containing two and three 2,2'-bipyridine subunits separated by 2-oxapropylene bridges have been synthesized and some of their complexation properties with metal ions have been investigated. In particular, with copper(I) they form, respectively, a dinuclear and a trinuclear complex containing two ligand molecules and two or three Cu(I) ions. In view of the pseudotetrahedral coordination geometry of Cu(I)-bis(bipyridine) sites and of NMR data indicating that the present complexes are chiral, one may assign to these dinuclear and trinuclear species a double-helical structure in which two molecular strands are wrapped around two or three Cu(I) ions, which hold them together. These complexes may thus be termed "double-stranded helicates." Determination of the crystal structure of the trinuclear species has confirmed that it is indeed an inorganic double helix, possessing characteristic features (helical parameters, stacking of bipyridine bases) reminiscent of the DNA double helix. This spontaneous formation of an organized structure by oligobipyridine ligands and suitable metal ions opens ways to the design and study of self-assembling systems presenting cooperativity and regulation features. Various further developments may be envisaged along organic, inorganic, and biochemical lines.Molecular helicity is a fascinating property displayed by chemical and biological macromolecular structures such as the a-helix of polypeptides and the helical conformation of polymers (1,2). Particularly well known is the double helix present in nucleic acids (3), whose structure, formation, and dissociation have been the subject of very extensive studies. Helicity has been analyzed for twisted chains of atoms (4) and its basic geometrical features are found in several types of small molecules (5, 6).We report here results on a class of organic ligands of poly(2,2'-bipyridine)t nature, which, by binding metal ions of specific coordination geometry, undergo spontaneous organization into a helical double-stranded, polymetallic complex, in effect an inorganic double helix, reminiscent of the double-helical structure of nucleic acids (3, 7). Design Principle. Previous work on the dinuclear Cu(I) complex [Cu2(pQP)2](CI04)2 of a special quaterpyridine ligand, pQP, has shown that in this dimeric species, two pQP molecules bind two Cu(I) ions in a distorted tetrahedral coordination geometry, using a bipyridine subunit from each quaterpyridine chain (8); the two pQP molecules possess a twisted, chiral conformation and are wrapped around the two Cu(I) ions (Fig. 1). Related structural features may be found in some other dinuclear metal complexes (9, 10). Suitable modification of the pQP ligand and extension of its basic features might lead to a general class of ligands capable of forming double-helical complexes. Rather than simply using polypyridine chains, it appeared desirable to preserve the basic bipyridine units in the ligand structure and to link several such groups by a bridge that would isolate the co...

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Section: Resultsmentioning

confidence: 99%

Spontaneous assembly of double-stranded helicates from oligobipyridine ligands and copper(I) cations: structure of an inorganic double helix.

Lehn¹,

Rigault²,

Siegel³

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

832

539

View full text Add to dashboard Cite

show abstract

“…Crystal structures of Cu͑I͒ bis-phenanthroline complexes show deviations from an ideal tetrahedral geometry, with the two diimine ligands not exactly perpendicular. 7,26,27 It is however possible that intermolecular forces in a crystal are responsible for these deviations since proton nuclear magnetic resonance ͑NMR͒ spectra of these complexes in solution indicate equivalence of the two ligands on the NMR time scale at room temperature. 28 Lability of ligands in solution was experimentally observed 29 which indicates that the Cu͑I͒-L bond is not very strong resulting in presumably low harmonic frequency for the Cu͑I͒-L stretching motions.…”

Section: Introductionmentioning

confidence: 99%

Cu(I)-2,9-dimethyl-1,10-phenanthroline: Density functional study of the structure, vibrational force-field, and excited electronic states

Zgierski

2003

The Journal of Chemical Physics

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Articles you may be interested inDecay dynamics of α,β-carboxylic methyl esters (CH3OCOCH:CHR) in the lower-lying excited states-Resonance Raman and complete active space self-consistent field calculation study Analytical energy gradient of the symmetry-adapted-cluster configuration-interaction general-R method for singlet to septet ground and excited states Excited state nuclear forces from the Tamm-Dancoff approximation to time-dependent density functional theory within the plane wave basis set framework Nonlocal hybrid density functional theory method is used to study the structure and force field of the copper͑I͒-diphenanthroline cation. It is demonstrated that it possesses D 2d symmetry in the S 0 state, however, deformations to D 2 symmetry with rotated phenanthroline rings are not costly energetically and, in fact, such D 2 structure is the minimum of the T 1 state. Time-dependent DFT method is utilized to calculate the excited electronic states and the visible and UV absorption spectrum. It is shown that the S 3 state of B 2 symmetry and of metal-to-ligand charge transfer ͑MLCT͒ character, is responsible for the ca. 470 nm visible absorption band, while dipole transitions to the S 1 and S 2 states are symmetry forbidden. We find four triplet electronic states closely spaced and lying just below the S 1 state. The ordering and spacing of the lowest triplet and singlet excited states nicely explains the properties of the observed photoluminescence. The calculated maximum of photoluminescence of 759 nm is in a good agreement with the experiment ͑ca. 730 nm͒.

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“…In 1969 Theriot et al [35,36] reported the preparation of the first monomeric and dinuclear V IV O-N-salicylideneamino acidato complexes (later the dinuclear complexes were characterized as V V -containing compounds [105]) and in 1970 Fraústo da Silva and Gillard [5] the first V IV , V V and mixed valence N-salicylideneamino acidato complexes, as well as [V IV O(Sal-Gly)(py)] and [V IV O(Sal-Phe)(py)] (py = pyridine), the first complexes of this type containing coordinated N-heterocyclic ligands. This was followed by many studies involving vanadium-N-salicylideneamino acidato compounds, the 1st single crystal X-ray diffraction (XRD) study being published in 1985 with the structure of [V IV O(Sal-Ala)(H 2 O)] 1 [106] (Fig. 3).…”

Section: IV O-schiff Base Systems Derived From Amino Acidsmentioning

confidence: 99%

Thirty years through vanadium chemistry

Pessoa

2015

Journal of Inorganic Biochemistry

127

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Structure of aquaoxo(N-salicylidene-L-alaninato)vanadium(IV)

Abstract: Abstract.[V(C t0H9NO3)O(HzO)], M r = 276.14, monoclinic, P2~, a= 8.514 (3), b= 7.394 (2), c= 9.210 (

Cited by 30 publications

References 5 publications

Spontaneous assembly of double-stranded helicates from oligobipyridine ligands and copper(I) cations: structure of an inorganic double helix.

Spontaneous assembly of double-stranded helicates from oligobipyridine ligands and copper(I) cations: structure of an inorganic double helix.

Cu(I)-2,9-dimethyl-1,10-phenanthroline: Density functional study of the structure, vibrational force-field, and excited electronic states

Thirty years through vanadium chemistry

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