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Complexation of Mercury(I) and Mercury(II) by 18-Crown-6: Hydrothermal Synthesis of the Mercuric Nitrite Complex

“…In macrocyclic complexes shorter mercury to oxygen distances (2.1-2. atoms of crown ethers depend on how well the macrocyclic cavity accommodates the mercury ion. The average radius of the macrocyclic cavity for 18-crown-6 is reported as 1.45 A ˚, 68-71 and a centrally coordinated mercurous ion, ionic radius 1.19 A ˚, 72 resembling the observed coordination mode of the mercuric ion [12][13][14][15][16]73 might be expected. Structures of crown ether dimercury(I) complexes 19 show the mercury ion is elevated by approximately 0.4 A ˚from the plane defined by the donor atoms of 18-crown-6, and as much as 1.23 A ˚in the case of 15-crown-5, responsible for variation in Hg-Hg-O angles with increasing Hg-O separation.…”

“…The water molecule located at (x, y, z) acts as a hydrogen donor via H 2WB to the perchlorate oxygens O 1 and O 2 at (x, y, z) to form a bifurcated hydrogen bonding R 1 2 (4)ring motif 78 (Figure 5a). An additional discrete interaction for the same water molecule occurs via H 2WA to perchlorate oxygen O 4 at (1/2x, 11/2y, -z) that when combined with either interaction of H 2WB affords a more elaborate R 2 4 (12)ring motif (Figure 5, panels b, c) generated through a center of inversion 78 at ( 1 / 4 , 1 / 4 , 0).…”

“…NMR studies suggest a tetradentate tripodal nitrogen ligand, tris[(2-(6-methylpyridyl))methyl]amine, acts as a reducing agent in the synthesis of a [L 2 Hg 2 ] 2+ complex using mercuric perchlorate in acetonitrile . Mercury complexes − of 18-crown-6 reported in the Cambridge Crystallographic Database are inevitably of the higher oxidation state suggesting a preference for complexation of the mercuric ion. Not surprisingly synthesis of the asymmetric [LL′Hg 2 ] 2+ complex using 18-crown-6 and 15-crown-5 is performed over elemental mercury, curtailing disproportionation .…”

Formation of Organometallic Species, [M – H]+ Ions and Radical Cations upon Mass Spectrometric Fragmentation of Mercury–Crown Ether Complexes

“…[2][3][4][5][6] Blair et al have studied the binding selectivities of some caged crown ligands (containing nitrogen or sulphur donor atoms) towards Hg 2+ by electrospray ionisation mass spectrometry (ESI-MS). 7 complexes of Hg 2+ with crown ethers containing only oxygen donor atoms have also been studied, 5,6,8,9 but not by mass spectrometry techniques. It has been briefly described in previous paper that organometallic species are formed as a result of collision-induced dissociation "in-source" of Hg 2+ complexes with benzo-crown ethers.…”