19 Geometrical Isomerism Cis trans E Z syn anti Class 11th BSc i NEET JEE And All Examination 1

Geometrical isomerism || configuration OF cis, trans, E&Z nomenclature

Which of the following is true about the complex [PtCl_(2)(NH_(3))(OH_(2))] ? [ Atomic number of Pt=78] (i) It will have two geometrical isomeric forms, cis and trans. (ii) The hybridisation state of Pt(II) is sp^(3) . (iii) It is a square planar complex. (iv) It is a diamagnetic complex. (v) It can show hydrate isomerism. (vi) It is a tetrahedral complex.

While of the following compounds will exhibit geometrical (or cis-trans) isomerism? (i) CH_(3)CH=CHCH_(2)CH_(3) (ii) C_(6)H_(5)CH=CHCH_(3) (iii) CH_(2)=C(CH_(3))_(2) (CH_(3))_(2)C=CH-C_(2)H_(5) Strategy: Essential requirement for any alkene to exhibit geometrical isomerism is that each of the double bonded carbon atoms should be attached to two different atoms or groups of atoms: m!=n and p!=r . Notice that m and p may be same or different Similarly, n and r may be same or different.

According to werner, the arrangement of 6 groups around the metal centre within the co-ordination sphere can lead to three possible geometries (For Q. 1 and Q. 2) : planar hexagon, trigonal prism and octahedral. For a particular geometry, if the groups (i.e. ligands) are arranged in different ways then the possibility of geometrical isomerism will arise. If in RENREW'S universe, [PtBrCl(NH_(3))Py] complex was found to have two stereo-isomers, then according to Werner, which inference can be correct ? (P) Complex must be square planar (Q) Complex may be tetrahedral (R ) Complex may show geometrical isomerism (S) Complex must exhibit optical isomerism

Classify the following alkenes and their derivatives as Z or E (i) (ii) Strategy: This method is preferable to the use of cis-trans beacuse it is not practical to identify cis and trans isomers when the four groups on C=C are different. The letter Z is used when the two high-priority substituets are on the same side of the double bond and the letter E is used when they are on the opposite sides (from the German words zusammen meaning together and entgegen meaning opposite), as shown:

IUPAC Nomenclature OF geometrical Isomeric Compound||Syn-Anti Conformation|| E-Z Nomenclature