Advanced Inorganic Chemistry Past Paper 2024 PDF

CY 505 – ADVANCED INORGANIC CHEMISTRY 2024 Course Instructor: Prof. R. Chandrasekar  Books Journals  Organometallic chemistry is the study of chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal. (M-C bond) Org...

CY 505 – ADVANCED INORGANIC CHEMISTRY 2024 Course Instructor: Prof. R. Chandrasekar  Books Journals  Organometallic chemistry is the study of chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal. (M-C bond) Organometallic compounds are distinguished by the prefix "organo-" (e.g., organopalladium compounds), and include all compounds which contain a bond between a metal atom and a carbon atom of an organyl group. In addition to the traditional metals (alkali metals, alkali earth metals, transition metals, and post transition metals), lanthanides, actinides, semimetals, and the elements boron, silicon, arsenic, and selenium are considered to form organometallic compounds. Examples of organometallic compounds include Gilman reagents – Li and Cu. Grignard reagents - Mg Tetracarbonyl nickel and ferrocene are examples of organometallic compounds containing transition metals. Organolithium compounds such as n-butyllithium (n-BuLi) Organozinc compounds such as diethylzinc (Et2Zn) Organotin compounds such as tributyltin hydride (Bu3SnH) Organoborane compounds such as triethylborane (Et3B) Organoaluminium compounds such as trimethylaluminium (Me3Al). A naturally occurring organometallic complex is methylcobalamin (a form of Vitamin B12), which contains a cobalt-methyl bond. This complex, along with other biologically relevant complexes are often discussed within the subfield of bioorganometallic chemistry.  Organometallic chemistry is important - Why ? Organometallic catalysts decrease the Temperature and Pressure (fuel) in chemical process 25 Billion Dollars industry in 1981! Effective atomic number (EAN) = Z – ON + 2(CN) Fe(CO)5 Z = atomic number Sum of the electron in the metal + ON = Oxidation number electrons donated by the ligands CN = coordination number Alternative to EAN is 18 Electron Rule ns2(n-1)d10np6 EAN = 26-0+2(5) = 36 Same as Kr! Stable configuration - Not strictly obeyed ! Total capacity of 9 orbitals (s,p,d) 2+6+10=18 Outer shell electronic configuration – 18 e- in the valence orbitals Advantages: (i) 18 e- rule same for all rows of the periodic chart, eliminating the need to remember a different EAN for each Nobel gas. (ii) easy to recall since it is the total capacity of 9 orbitals. 18 Electron Rule - Electron rich central metal (low ox.st) and ligands that are good -acceptors, in general adhere to the rule. - by counting outer shell electrons surrounding each metal atom in a complex, one can reasonably predict whether the complex will be stable and/or M-M bonds present or not Two methods of electron count: (1) Neutral atom count (2) Oxidation state count More foolproof - More realistic - (does not require correct (reflects the precise number of electrons assignment of metal ox st) available for donation on a ligand) - Not strictly obeyed! (Reasons can be understood from MO description of bonding in complexes)  MO theory and 18 e- Rule What is a stable e- configuration ? Complexes tend to adhere to the rule; if they have large o making occupation of eg* unfavourable, including 4d and 5d series elements ABO Empty Form 18 e- complex , not more than 18 e- E o