Bond lengths chelates

In the monomeric structure of 10.21 the solvation of both Li" ions by two THF molecules prevents further aggregation. The four S-N bond lengths are equal at ca. 1.60 A indicating that the negative charge is delocalized over the S(N Bu)4 unit. In the dimer 10.22 one [McS(N Bu)3] anion is coordinated to both Li" ions, one of which is bis-solvated by THF, while the other is chelated only to the unsolvated Li" ion. 

Whereas vicinal hydroxy, mercapto, and hydroselenoaldimines of azoles strongly prefer the aminomethylene tautomeric form (Section II,E,2), their metal chelates 380 are characterized by.pronounced equalization of bond lengths within the chelate ring, which makes their structures similar to those expected for the aldimine tautomeric type. 

The dark red Ir11 binuclear complex [Ir(CO)(P(/i-tolyl)3)(mnt)]2, formed via one-electron oxidation of [Ir(CO)(P(/ -tolyl)3(mnt)] by ferrocenium, contains chelating mnt ligands bridging the Ir—Ir bond.639 The X-ray crystal structure shows square-pyramidal geometry at each Ir, and an Ir—Ir bond length of 2.706(2) A. 

A monomeric selenolato complex of zinc (65) was synthesized with a chelating oxazoline ligand.587 The complex was characterized by X-ray crystal structure, 1H, 13C, and 77Se NMR. These studies demonstrate that the compound is helically chiral and solution studies appear to show retention of chirality in solution. The zinc complex is tetrahedral with a Zn—Se average bond length of 2.378(1) A. 

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