Ruthenium

Ruthenium is a chemical element with symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is inert to most other chemicals. The Baltic German scientist Karl Ernst Claus discovered the element in 1844, and named it after his homeland, the Russian Empire (one of Russia's Latin names is Ruthenia). Ruthenium usually occurs as a minor component of platinum ores; annual production is about 20 tonnes. Most ruthenium produced is used for wear-resistant electrical contacts and the production of thick-film resistors. A minor application of ruthenium is its use in some platinum alloys, and as a catalyst.

Characteristics

Physical properties

A polyvalent hard white metal, ruthenium is a member of the platinum group and is in group 8 of the periodic table:

However, it has an atypical configuration in its outermost electron shells: whereas all other group 8 elements have 2 electrons in the outermost shell, in ruthenium, one of those is transferred to a lower shell. This effect can be observed in the neighboring metals niobium (41), rhodium (45), and palladium (46).

Tetrasodium tris(bathophenanthroline disulfonate)ruthenium(II)

Tetrasodium tris(bathophenanthroline disulfonate)ruthenium(II) (Na₄Ru(bps)₃) is a coordination compound containing a ruthenium center. In this form, it is the salt of a sulfonic acid. This compound is an extension of the well known phenanthroline series of coordination compounds. Ruthenium(II) tris(bathophenanthroline disulfonate), referring to the anionic fragment, is used as a protein dye in biochemistry for differentiating and detecting different proteins in laboratory settings.

In recent years, 2-D electrophoresis has been widely accepted as a standard procedure to separate complex protein mixtures in proteome studies (Proteomics). Protein visualisation by Ruthenium(II) tris(bathophenthroline disulfonate) has become a firmly established and widely used method in proteomic analysis and a crucial step in protein expression profiling.

For protein detection, it is advantageous to use fluorescent labels containing chromophores which have longer excitation wavelength and emission wavelength than the aromatic amino acids. The dyes used for this important step should combine attributes like good signal to background ratio (contrast), broad linear dynamic range, broad application range, photochemical stability and compatibility to protein identification techniques, e.g. mass spectrometry (MS) or Western blotting.

Isotopes of ruthenium

Naturally occurring ruthenium (Ru) is composed of seven stable isotopes. Additionally, 27 radioactive isotopes have been discovered. Of these radioisotopes, the most stable are ¹⁰⁶Ru, with a half-life of 373.59 days; ¹⁰³Ru, with a half-life of 39.26 days and ⁹⁷Ru, with a half-life of 2.9 days.

Twenty-four other radioisotopes have been characterized with atomic weights ranging from 86.95 u (⁸⁷Ru) to 119.95 u (¹²⁰Ru). Most of these have half-lives that are less than five minutes, excepting ⁹⁵Ru (half-life: 1.643 hours) and ¹⁰⁵Ru (half-life: 4.44 hours).

The primary decay mode before the most abundant isotope, ¹⁰²Ru, is electron capture and the primary mode after is beta emission. The primary decay product before ¹⁰²Ru is technetium and the primary product after is rhodium.

Relative atomic mass: 101.07(2).

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