Combinations of Chelate Rings

FIGURE 9-12 Right- and Left-handed Propellers, (a) Left-handed propeller and helix traced by the tips of the blades, (b) Right-handed propeller and helix traced by the tips of the blades. 

FIGURE 9-15 Labeling of Chiral Rings. The rings are numbered arbitrarily Ri through R5. The combination R1-R4 is A, R1-R5 is A, and R2-R5 is A. The notation for this stracture is then AAA-(ethylenedia-minetetraacetato)cobaltate(III). 

Rotate the figure to place one ring horizontally across the back, at the top of one of the triangular faces. 

If the rotation from Step 2 is counterclockwise, the structure is designated lambda (A). If the rotation is clockwise, the designation is delta (A). 

Considering only the four O — N rings, there are three useful pairs, Ri-R4 and 

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