Course

Unit III

Theories and Concepts on d-block Coordination CompoundsIntroduction – ligands, nomenclature of coordination compounds, coordination compounds of d-block ions with coordination numbers of 2, 3, 4, 5, 6, 7 and 8. Werners coordination theory, Valence bond theory (VBT), Crystal field theory (CFT), CFSE, effects of CFSE on hydration energies and spinel groups (normal and inverse), types of ligands spectrochemical series, spectral and magnetic properties (spin-only magnetic moments), nephelauxetic effect. Crystal field splitting patterns in complexes having Oh, Td, square planar, square pyramidal and trigonal pyramid geometries, factors affecting the magnitude of CFSE, various types of isomerism in coordination complexes, Jahn-Teller (JT) distortion, manifestation of JT on spectral properties. Molecular orbital theory (MOT), ligand field theory (LFT), molecular orbital energy level diagram for octahedral complexes without pi-bonding, metal-ligand pi-bonding, metal-metal multiple bonds, d-orbital based metal-metal ?, ? and ? bonds in compounds like [Re2Cl8]2- , [Os2Cl8]2- , Cr2(CH3COO)4 and R-Cr(I)-Cr(I)-R. Application of group theory to coordination compounds.

Unit IV

Reaction MechanismComplex equilibrium – formation constants, chelate and macrocyclic effects, factors affecting stability of complexes, methods of determination of stability constants, stability of complex ions in solutions, inert and labile complexes, mechanisms of ligand displacement and addition reactions in octahedral complexes and square planar complexes of platinum cis- and trans-effect, substitution reactions, mechanisms of substitution, kinetic consequences of reaction pathways, dissociation, interchange, association, dissociation, linear free energy relationships, conjugate base mechanism, stereochemistry of reactions (substitution in trans-complexes and substitution in cis-complexes), isomerisation of chelate rings, sigma-bonding and pi-bonding effects, oxidation-reduction reactions, inner and outer sphere electron transfer reactions, conditions for high and low oxidations numbers, reactions of coordinated ligands, hydrolysis of esters, amides and peptides, template reactions, electrophilic substitution, photochemical reactions of coordination compounds. Asymmetric synthesis catalyzed by coordination compounds.

Unit V

Coordination Chemistry of Inner-transition (f-block) Elementsf-block metal ions oxidation states preferences, ligand preferences, coordination numbers and the geometry of the complexes, influence of lanthanide contraction and actinide contraction in their coordination behaviour,shapes of f-orbitals (4f and 5f), nature of bonding of f-orbitals with ligands, various types of coordination compounds of lanthanides and actinides, stereochemistry and reaction mechanism of f-block metal complexes.

Spectral PropertiesStabilization of unusual oxidation states, electronic spectra of transition metal complexes color wheel, Russell- Saunders coupling schemes, term symbols for various dn ions, Orgel diagrams for dn systems, ligand field parameters, Dq, Racah parameter B and nephelauxetic constant b, Tanabe-Sugano (TS) diagrams, evaluation of Dq and other parameters from electronic spectra of transition metal complexes using TS diagrams, charge- transfer transitions, MLCT and LMCT, selection rules and band intensities, Laporte- and spin- selection rules, symmetry, spin-orbit and vibronic coupling effects. Photochemistry of transition metal complexes like [Ru(bipy)3]2+, spectral behaviour of f-block coordination complexes, special features of their absorption and emission properties.

Magnetic PropertiesMagnetic properties of coordination complexes – magnetic susceptibility, contribution of spin-orbit coupling on eff, types of magnetic behaviour – para-, ferro, anti-ferro and ferri-magnetic systems, Curie law, Curie-Wise law, Guoy, Faraday and superconducting quantum interference device (SQUID) methods, Kotani plots, giant magnetoresistance (GMR), anisotropic magnetoresistance (AMR) effect, effects of temperature on magnetic behaviour, tunnelling magnetoresistance (TMR). Magnetism of coordination complexes by multinuclear homo- and heterometallic 3d systems (also with exclusive 4d and 5d metal ions), mixed 3d-4f systems, importance of 4f-metal ions for functional applications. Nanoscale magnetic systems based on coordination complexes – Single Molecule Magnets (SMMs), Single Ion Magnets (SIMs), Single Chain Magnets (SCMs), Spin-crossover complexes, magnetic refringents (magnetic coolers), magnetic storage systems – magnetic random-access memory (MRAM).

TEXTBOOKS1.F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry, John Wiley & Sons, 2009.2.James E. Huheey, Ellen A. Keiter and Richard L. Keiter, Inorganic Chemistry, Principles of Structure and Reactivity, Pearson education, 5th edition, 2009.3.J. D. Lee, Concise Inorganic Chemistry, 5th edition, John Wiley & Sons, 2009.4.P Atkins, T. Overton, J. Rourke, M. Weller, F. Armstrong, Shriver & Atkins Inorganic chemistry, 4th Edition, Oxford University Press, 2008.REFERENCES1.B. Douglas, D. McDaniel and J. Alexander Concepts and Models in Inorganic Chemistry, 3rd Edition, Wiley, 2006.2.Sushanta Dattagupta, A Paradigm Called Magnetism, World Scientific Publishing Co. Pte. Ltd., 2008.3.Helen C. Aspinall, Chemistry of the f-Block Elements, Volume 5 of Advanced chemistry texts, CRC Press, 2001.4.N. N. Greenwood and A. Earnshaw, Chemistry of Elements, Butterworth and Heinemann, 2nd Edition, 20025.J. E. House, Inorganic Chemistry, Academic Press, 2008.6.T. Shinjo (Editor), Nanomagnetism and Spintronics, Elsevier, USA, 2nd Ed., 2014.7.R. A. Layfield and M. Murugesu (Editors), Lanthanides and Actinides in Molecular Magnetism, Wiley- VCH Verlag& Co., 2015.