scholarly journals The Electronic Structure of Heavy Element Complexes

2000 ◽  
Author(s):  
Bruce E Bursten
Keyword(s):  
Electronic Structure ◽  
Heavy Element ◽  
Heavy Element Complexes

scholarly journals The Coordination Chemistry of Imidomethanedithiolate Di-anions: A Structural Comparison with Their Dithiocarbamate Analogs

Inorganics ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 71
Author(s):  
Peter J. Heard ◽  
Yee Seng Tan ◽  
Chien Ing Yeo ◽  
Edward R. T. Tiekink
Keyword(s):  
Coordination Chemistry ◽  
Heavy Element ◽  
Structural Features ◽  
Structural Comparison ◽  
Structural Motifs ◽  
Bond Lengths ◽  
Heavy Element Complexes

A review of the coordination chemistry along with the structural features of heavy element complexes of dithiocarbimate di-anions in the form of [(R)C=NCS2]2− for R = CN, alkyl, and aryl are described. This class of compound is far less studied compared with the well-explored dithiocarbamate mono-anions formulated as [R(R’)NCS2]− for R/R’ = H, alkyl, and aryl. The coordination chemistry of dithiocarbimate di-anions is dominated by a S,S-chelating mode; rare examples of alternative modes of coordination are evident. When comparisons are available, the structural motifs adopted by metal dithiocarbimate complexes match those found for their dithiocarbamate analogs, with only small, non-systematic variations in the M–S bond lengths.

scholarly journals Creation of an unexpected plane of enhanced covalency in cerium(III) and berkelium(III) terpyridyl complexes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alyssa N. Gaiser ◽  
Cristian Celis-Barros ◽  
Frankie D. White ◽  
Maria J. Beltran-Leiva ◽  
Joseph M. Sperling ◽  
...  
Keyword(s):  
Electron Density ◽  
Heavy Element ◽  
Electronic States ◽  
Relativistic Effects ◽  
Induced Polarization ◽  
Ligand Field ◽  
Spin Orbit ◽  
Experimental Control ◽  
Heavy Element Complexes ◽  
Metal Ligand

AbstractControlling the properties of heavy element complexes, such as those containing berkelium, is challenging because relativistic effects, spin-orbit and ligand-field splitting, and complex metal-ligand bonding, all dictate the final electronic states of the molecules. While the first two of these are currently beyond experimental control, covalent M‒L interactions could theoretically be boosted through the employment of chelators with large polarizabilities that substantially shift the electron density in the molecules. This theory is tested by ligating BkIII with 4’-(4-nitrophenyl)-2,2’:6’,2”-terpyridine (terpy*), a ligand with a large dipole. The resultant complex, Bk(terpy*)(NO3)3(H2O)·THF, is benchmarked with its closest electrochemical analog, Ce(terpy*)(NO3)3(H2O)·THF. Here, we show that enhanced Bk‒N interactions with terpy* are observed as predicted. Unexpectedly, induced polarization by terpy* also creates a plane in the molecules wherein the M‒L bonds trans to terpy* are shorter than anticipated. Moreover, these molecules are highly anisotropic and rhombic EPR spectra for the CeIII complex are reported.

Distribution of R- and S-Process Elements in the Galactic Halo

1988 ◽  
Vol 132 ◽  
pp. 501-506
Author(s):  
C. Sneden ◽  
C. A. Pilachowski ◽  
K. K. Gilroy ◽  
J. J. Cowan
Keyword(s):  
Heavy Element ◽  
Galactic Halo ◽  
Low Noise ◽  
Heavy Elements ◽  
Process Synthesis ◽  
Element Abundances ◽  
Halo Stars ◽  
Abundance Patterns ◽  
R Process ◽  
Process Elements

Current observational results for the abundances of the very heavy elements (Z>30) in Population II halo stars are reviewed. New high resolution, low noise spectra of many of these extremely metal-poor stars reveal general consistency in their overall abundance patterns. Below Galactic metallicities of [Fe/H] Ã −2, all of the very heavy elements were manufactured almost exclusively in r-process synthesis events. However, there is considerable star-to-star scatter in the overall level of very heavy element abundances, indicating the influence of local supernovas on element production in the very early, unmixed Galactic halo. The s-process appears to contribute substantially to stellar abundances only in stars more metal-rich than [Fe/H] Ã −2.

Variation of Heavy Element Lines in the Ap Stars

1976 ◽  
Vol 32 ◽  
pp. 311-320 ◽  
Author(s):  
I.A. Aslanov ◽  
Yu. S. Rustamov ◽  
M. Kowalski
Keyword(s):  
Heavy Element ◽  
Ap Stars

SummaryLines of U II were found in the spectrograms of the Ap stars HR 465, 17 Com A and HD 224801. Pm II lines were found in HR 465. These lines vary in intensity in HR 465 with a period of 6h41m, in 17 Com A of 71m, and in HD 224801 of 6h.

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