Gold-halogen bonds

The chemistry of compounds with gold-germanium bonds has developed considerably since Schmidbaur and coworkers reported the first derivatives obtained by the insertion reaction of GeCl2 (as its dioxane complex) into a gold-halogen bond [75]. Both neutral and ionic compounds have been reported and a larger structural diversity in comparison with the silicon analogs has been established (Table 4.4). 

In these complexes, the gold-metal bonds are apparently weak and polar and, in man cases, the metal carbonyl anion can be displaced by donor ligands (equation go)716 726>732,733 a well as by halogens and similar reagents.721... 

Other gold(III) complexes containing one gold-carbon bond include the isonitrile complexes [AuX3(CNR)] (131) and the trimeric imino compounds [Au3 C(OR)=NR 3X6] (X = Br or I), which have been prepared (155) by oxidative addition of halogen to the gold(I) species. 

Shirman T, Kaminker R, Freeman D, van der Boom ME (2011) Halogen-bonding mediated stepwise assembly of gold nanoparticles onto planar surfaces. ACS Nano 5 6553-6563... 

As well as the adsorption of halogen atoms or molecules, the adsorption of halide anions to gold surfaces has been extensively studied and a comprehensive review of the area has been published by Magnussen [168]. The degree of specific adsorption to gold surfaces increases in the order F < Cl < Br < 1 with only weakly specifically adsorbed. The presence of halide anions can also affect the electrodeposition of organic molecules such as pyridine on Au surfaces with chloride and bromide solutions suppressing the formation of ordered N-bonded pyridine layers [169]. 

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