Question

i) Consider the crystal field diagram for a tetrahedral complex and the relative d orbital configuration. Show the purple colour of MnO4 - cannot be from d-d transitions and briefly explain your answer. ii) Draw a simplified molecular orbital diagram (i.e. like those used for ligand field theory in lectures) to show the possible origin of the transition responsible for the purple colour of an aqueous KMnO4 solution. iii) MnO4 - ions actually have two intense transitions, one at 541 nm and one at 311 nm. Use these values to estimate Atet in cm-1 (although Atet cannot be measured directly in this case), and explain your working. iv) Assuming it would dissolve, what you think will happen to the absorption band of MnO4 - if the ion was dissolved in acetonitrile instead of water? Briefly explain your answer.

Answer 1

Mnou han 7 0xidation Skate/ theretohe it hos no e in' ita d-onbital de contigurabion fon MnOu Nacanb no e in e d-on6ital possibility oA d-d bhonsibion 9ince there is there no Mno4. Hence tha punple colown is not from d-dl thansibion Punple colowr of Mno is dne to Lis and to metal charge btrans fer electhon Aom Mo houwing gruater Lisand choaraeten ma ves to MO nowi mone Metal chanacter e These are ahange Thanefer selection unle alloseol A ighy inten ge Mnon ntense punple colour. has 14ence

MO AOh MnDu atz ehtz Mn 40 Nr 44 MO onbital of 2 Aais fued,electn thansition from tnere onbitol te & taleo plode giving MCT Simee Com