Structural studies on the glycolato, lactato, and mandelato solid complexes of some bivalent iron series metals

1969 ◽  
Vol 47 (14) ◽  
pp. 2629-2637 ◽  
Author(s):  
Andrew Fischinger ◽  
Allen Sarapu ◽  
Audrey Companion
Keyword(s):  
Color Change ◽  
Electronic Absorption Spectra ◽  
Field Analysis ◽  
Ligand Field ◽  
Blue Color ◽  
Structural Studies ◽  
X Ray ◽  
Tentative Model ◽  
Visible Spectra ◽  
Bivalent Iron

Electronic absorption spectra, infrared vibrational spectra, and X-ray powder patterns have been measured for anhydrous bis(glycolato), bis(lactato), and bis(mandelato) complexes of bivalent Mn, Co, Ni, Cu, and Zn. Despite indications of considerable differences in crystal structure, the visible spectra of all complexes are quite similar to those of analogous hexaaquo complexes. A ligand field analysis yields as new data a spectrochemical series for the ligands[Formula: see text]in agreement with the order of proposed metal–oxygen stretch frequencies and previously measured acid pK's of the ligands.An interesting red to blue color change, observed in all cobalt complexes on heating, is shown to be reversible in the glycolate. A tentative model proposed for the complex appears to be consistent with all the experimental data including the color change phenomena.

scholarly journals Organic Acid Regulated Self-Assembly and Photophysical Properties of Perylene Bisimide Derivatives

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1656
Author(s):  
Ying Wang ◽  
Xinguo Yang ◽  
Siyu Li ◽  
Tao Long ◽  
Wei Li
Keyword(s):  
Organic Acids ◽  
Organic Acid ◽  
Self Assembly ◽  
Color Change ◽  
Photophysical Properties ◽  
Blue Color ◽  
Perylene Bisimide ◽  
Acid Type ◽  
Visible Spectra ◽  
Uv Visible

In this work, perylene bisimide derivatives (PBI-1 and PBI-2) with tertiary amine groups were designed and synthesized. To control the final morphologies and properties of their aggregates, seven kinds of organic acids were used to alter the self-assembly environment. The influence of organic acids on the morphology of the aggregates was investigated. Photophysical properties of the aggregates were markedly affected by the kind and concentration of the organic acid. The thermal and gas sensitivities of the PBI-1 aggregates were studied with the use of UV–visible spectroscopy and digital imaging. The shift of the UV–visible spectra varied with time, temperature, acid type and acid concentration. Furthermore, PBI-1 aggregates showed a red-to-blue color change after addition of seven organic acids, whereas the color of the PBI-2 aggregates remained red. These changes of morphologies, photophysical properties and their thermal and gas sensitivities make these aggregates potentially useful in the fields of optoelectronics or sensors.

Polyamine ligands. III. Five-coordinate complexes with the quinquedentate N,N,N'-Tris[2-(2'-pyridyl)ethylethylenediamine

1971 ◽  
Vol 24 (3) ◽  
pp. 501 ◽  
Author(s):  
AT Phillip ◽  
W Mazurek ◽  
AT Casey
Keyword(s):  
Magnetic Susceptibility ◽  
Diffraction Analysis ◽  
Electronic Absorption ◽  
Metal Ion ◽  
Electronic Absorption Spectra ◽  
Ligand Field ◽  
Field Calculation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Free Amine

The quinquedentate ligand, N,N,N?-tris[2-(2?- pyridyl)ethyl]ethylenediamine (tpen), has been synthesized from ethylenediamine and 2-vinylpyridine. The free amine tpen is thermally unstable, but readily forms chemically stable metal complexes of the composition [M(tpen)](ClO4)2 (M = Cu, Ni, Zn) and [Co(tpen)O2Co(tpen)]- (ClO4)4. In each of these compounds, the amine tpen is bonded to the metal ion through all five of its nitrogen atoms, as indicated by infrared and electronic absorption spectra and magnetic susceptibility measurements. The compound [Ni(tpen)](ClO4)2 shows four d-d transitions whose energies correspond closely to the values predicted from a ligand field calculation for a square pyramidal NiN5 chromophore. This structure has been confirmed by X-ray diffraction analysis. These complexes of tpen are the first reported quinquedentate pentaamine chelate structures of copper(II), nickel(II), and zinc(II).

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

Niobocene Dichloride and Niobocene Diiodide: Electronic Absorption Spectra and Electron Spin Resonance

1998 ◽  
Vol 63 (5) ◽  
pp. 628-635 ◽  
Author(s):  
Jana Holubová ◽  
Zdeněk Černošek ◽  
Ivan Pavlík
Keyword(s):  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Point Group ◽  
Esr Spectra ◽  
Ligand Field ◽  
Orbital Interaction ◽  
Symmetry Point Group ◽  
Spin Orbital ◽  
Halide Ligands

The effect of the halide ligand on the bonding of niobium in niobocene dichloride and niobocene diiodide was investigated. The electronic absorption spectra of the two compounds in the range of d-d transitions were resolved into four bands corresponding to transitions of the d1 electron between five frontier orbitals in a molecule of symmetry point group C2v. The energies of the frontier molecular orbitals were determined relatively to the energy of the orbitals in the spherically symmetric ligand field formed by the appropriate halide ligands. The effect of the halide ligands on the spin-orbital interaction of the HOMO orbital is discussed qualitatively on the basis the ESR spectra.

The Coordination Chemistry of Phosphoryl Compounds Containing the — N(CH3)2 Group, Part VIII

1972 ◽  
Vol 27 (7) ◽  
pp. 759-763 ◽  
Author(s):  
M. W. G. De Bolster ◽  
W. L. Groeneveld
Keyword(s):  
Coordination Chemistry ◽  
General Formula ◽  
Ligand Field ◽  
Chemical Analyses ◽  
X Ray ◽  
Physical Measurements ◽  
Ligand Field Spectra ◽  
Chloride Adduct ◽  
Ligand Field Parameters ◽  
Group Part

A number of new solvates and adducts containing bisphenyldimethylaminophosphine oxide is reported. The solvates have the general formula M[(C6H5)2P(O)N(CH3)2]42+(anion-)2, in which M = Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn and Cd, and the anions are ClO4- and BF4-. The adducts have the general formula M[(C6H5)2P(O)N(CH3)2]2Cl2, where M stands for the same series of metals.The compounds are characterized and identified by chemical analyses and physical measurements.Ligand-field and vibrational spectra have been investigated; values for the ligand-field parameters are reported. It is concluded that coordination takes place via the oxygen atom of the ligand.X-ray powder patterns were used in combination with ligand-field spectra to deduce the coordination around the metal ions.The interesting behaviour of the nickel (II) chloride adduct upon heating is discussed and it is shown that both a square pyramidal and a tetrahedral modification exists.

Synthesis, Characterisation and Structural Studies of [Zn(phen)3][Fe(CN)5(NO)]·2H2O·0.25MeOH and [(bipy)2(H2O)Zn(μ-NC)Fe(CN)4(NO)]·0.5H2O

2003 ◽  
Vol 58 (9) ◽  
pp. 916-921 ◽  
Author(s):  
Amitabha Datta ◽  
Samiran Mitra ◽  
Georgina Rosair
Keyword(s):  
Infrared Spectroscopy ◽  
Thermogravimetric Analysis ◽  
Octahedral Geometry ◽  
Distorted Octahedral Geometry ◽  
Structural Studies ◽  
Crystal Lattices ◽  
X Ray ◽  
X Ray Crystallography ◽  
Distorted Octahedral ◽  
Solvent Molecules

Two new bimetallic complexes [Zn(phen)3][Fe(CN)5(NO)] · 2 H2O · 0.25 MeOH, (1) and [(bipy)2(H2O)Zn(μ-NC)Fe(CN)4(NO)] · 0.5 H2O, (2), have been isolated (where phen = 1,10-phenanthroline and bipy = bipyridyl) and characterised by X-ray crystallography [as the 2 H2O · 0.25 CH3OH solvate for (1) and hemihydrate for (2)] infrared spectroscopy and thermogravimetric analysis. Substitution of phenanthroline for bipyridyl resulted in a cyano-bridged bimetallic species rather than two discrete mononuclear metal complexes. The bond angles of Fe-N-O were shown to be practically linear for both 1 [179.2(7)°] and 2 [178.3(3)°], and the Zn atoms have distorted octahedral geometry. The solvent molecules in both crystal lattices take part in forming hydrogen-bonded networks.

Sign in / Sign up

Export Citation Format

Share Document