Group 11 silver and gold

Zeise ssalt, K[PtCl3(ri -C2H4)], is a well-known organo-metaUic Pt(II) complex and is discussed in Section 24.10. 

The relativistic contraction of the 6s orbital (see Box 13.3) is greatest for Pt and Au. Among the properties that this influences are enthalpies of electron attachment. In contrast to other rf-block metals, Pt and Au possess negative values for the enthalpy of attachment of the first electron at 298 K. For reaction 22.142, = -205kJmor a 

The free electrons in this system result in behaviour. 

Both metals react with halogens (see below), and gold dissolves in liquid BrF3, forming [BrF2] [AuF4] . The dissolution of Ag and Au in cyanide solutions in the presence of air is used in their extraction from cmde ores (eq. 22.4). 

with the A-donors of the nucleotide base coordinating to the Pt(II) centre GG intra-strand crosslinks are formed by cisplatin. A recent Pt(II) complex to enter into clinical trials is the triplatinum species shown below. Preliminary results show that the complex is significantly more active than cisplatin, and is capable of forming inter-strand crosslinks involving three base pairs in DNA. 

Hambley (2001) Journal of the Chemical Society, Dalton Transactions, p. 2711 - Platinum binding to DNA Structural controls and consequences . 

Jansen, J. van der Zwan, J. Reedijk, H. den Dulk and J. Brouwer (1999) European Journal of Inorganic 

Chemistry, p. 1429 - A tetranuclear platinum compound designed to overcome cisplatin resistance . 

Reedijk (1996), Chemical Communications, p. 801 - Improved understanding in platinum antitumour chemistry . 

Stable oxidation states for the group 11 metals differ in contrast to the importance of Cu(II) and Cu(I), silver has only one stable oxidation state, Ag(I), and for gold, Au(in) and Au(I) are dominant, with Au(III) being the more stable. Relativistic effects (discussed in Box 13.2) are considered to be important in stabilizing Au(III). As we have already noted, discussing oxidation states of the heavy /-block metals in terms of independently obtained physicochemical data is usually impossible owing to the absence of IE values and the scarcity of simple ionic 

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See also in sourсe #XX -- [ , , , , , , , , , , , , , , , , ]

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