One electron oxidation of triferrocenylmethanol: Synthesis, metal atom dynamics, electron delocalization, and the crystal structure of [Fc 3COH]+ PF6 -

The title compound 2 was prepared and its crystal structure was determined at 100 K. The neat solid was examined by temperature dependent 57Fe Mössbauer effect (ME) spectroscopy over the interval 92 < T < 318 K, and evidences two diamagnetic Fe(II) sites and one paramagnetic Fe(III) site. The latter shows spin–lattice relaxation, but there is no evidence of electron delocalization among the three iron sites in the above temperature interval. The mean-square-amplitude-of-vibration of the diamagnetic iron site has been determined from the recoil-free fraction ME resonance, and compared to the neutral Fc3COH homologue (1). The ME dynamical data are in good agreement with the Ui,j value at 100 K extracted from the crystallographic results. The ME parameters at 5 K have also been determined with the sample compound embedded in a paraffin wax matrix as well as pelletized with BN

Mössbauer Spectroscopy and X-ray Diffraction Study of 57Fe-Labeled Tetrachloroferrate(III)-Based Magnetic Ionic Liquids

Four 57Fe-labeled tetrachloroferrates(III) of organic cations (1-butyl-3-methylimidazolium, 1-allyl-3-methylimidazolium, 1-methyl-1-propylpyrrolidinium, tetraphenylphosphonium) were examined by temperature-dependent Mössbauer spectroscopy. The hyperfine and dynamic parameters of the iron(III) site were determined. Single crystal X-ray diffraction data of [Ph4P][FeCl4] were collected at four temperatures (295, 223, 173, and 123 K), and the dynamics of the iron atom inferred from the Mössbauer data and the single crystal Ui,j parameters have been compared

Kloning Manusia

In the last few years, very rapid progress in the cloning technology and its development towards human cloning has become a hotly-debated issue. Cloning, which is the process of formation of a number of individuals with the same genetic structure, can be done by means of embryo-splitting method and nuclear transfer. Human cloning through the nuclear transfer method is directed towards two purposes, i.e. reproduction and therapy. The relatively new transgenic technology can be combined with the cloning technique to produce clones with new genes. However, pros and cons arise concerning the development of research on human cloning, particularly cloning for reproductive purposes. Therefore, there is need for a moratorium period before human cloning can be performed in order that solutions for all kinds of problems related to safety and ethics can be found

Mössbauer spectroscopy of organometallic compounds. Isomerism in [(π-C5H5)Fe(CO)2]2SnCl 2 and related molecules

The Mössbauer spectra of a number of organotin compounds derived from [π-C5H5Fe(CO)2]2 have been examined at liquid nitrogen temperature, using both the 14.4-keV resonance γ radiation of 57Fe and the 23.8-keV resonance γ radiation of 119Sn. These measurements show that for (π-C5H5)Fe(CO)2SnCl3 and (π-C5H5)Fe(CO)2Sn(C6H 5)3 there are no observable conformational changes on dissolution of the crystalline solids in solvents which set to a glassy matrix at low temperatures. The 57Fe Mössbauer parameters in [(π-C5H5)Fe(CO)2]2SnCl 2 and [(π-C5H5)Fe(CO)2]2GeCl 2 are found to be invariant with respect to dissolution, and from these data it is concluded that the anomalous bond distances and bond angles, derived from the X-ray diffraction data for these compounds, arise from the specific bonding interactions within the molecule, and not from stacking forces between molecules in the crystalline state. The 119Sn Mössbauer spectra and infrared data for [(π-C5H5)Fe-(CO)2]2SnCl 2, moreover, show the existence of two structural forms in solution, and these are identified with the two possible rotational isomers obtained by rotation of the metal-metal bond. On the basis of isomer shift systematics, an assignment of the parameters to the two forms can be made.SCOPUS: ar.jinfo:eu-repo/semantics/publishe