Science Forums 2

[UncleAl]

Who can propose a tetradentate ligand with a -4 charge such that three of them chelate two Co(3+) to give a helicate complex as described below?

Uncle Al likes salts of chiral complex ions with geometrically (nearly) identical cations and anions. Example: Resolved [Co(en)3](3+) is almost exactly superposable upon [Co(ox)3](3-),

http://www.mazepath.com/uncleal/xions.png
stereoimages

to make the two mirror-image salts,

http://www.mazepath.com/uncleal/xsalt.png
stereoimages

One can get very clever and create helicates by linking bidentate ligands. Here we look at homochiral [Co(phen)3](3+) and [Co2(bisphen)3](6+)

http://www.mazepath.com/uncleal/xheli.png
stereoimages

It obviously works for [Co(bipy)3](3+) and [Co2(bisbipy)3](6+), too. Now for the fun part! Who can propose a helicate ligand that will give isomorphous [Co2(ligand)3](6-)?

Don't be shy!