Cis-Trans & Enantiomeric Profiling Matrix

Isomeric Formulas:

$$\begin{aligned} [Ma_2b_2] &\implies \text{Square Planar: } 2 \text{ GI } (cis, trans) \mid 0 \text{ Optical Isomers} \\ [Ma_4bc] &\implies \text{Octahedral: } 2 \text{ GI } (cis, trans) \mid 0 \text{ Optical Isomers} \\ [M(AA)b_2c_2] &\implies \text{Octahedral: } 3 \text{ Stereoisomers } (1 \text{ trans } + 2 \text{ cis enantiomers}) \end{aligned}$$

Concept: Determines geometrical (cis/trans) and optical activity by analyzing structural plane/center of symmetry. Square planar complexes with coordination number 4 ($$sp^2d$$ or $$dsp^2$$) never exhibit optical isomerism because the molecular plane itself acts as a permanent Plane of Symmetry (POS).

• Notation:
  • $$a, b, c$$ = Monodentate ligands;
  • $$AA$$ = Symmetrical bidentate ligand (e.g., ethylenediamine, $$\text{en}$$).
  • $$cis$$-isomer has identical groups at $$90^\circ$$ positions; $$trans$$-isomer has identical groups at $$180^\circ$$ positions.