Diehl, 2 in his review of chelate compounds, has pointed out that the bidentate chelate compounds constitute the largest group and are the most thoroughly studied. A recent report3 of a convenient method for the preparation of a-thiopicolinanilide suggested that this substance and some of its analogs should be able to function as bidentate chelate compounds. Because, further, there do not appear to be any reports of studies of similarly ...