Question

132 CHAPTER 4. Experimental technic 4.25 The UV-V (2.0 x 10-5 max(E) = 324 (45 10 quartz cu the meas coloured Reaction of HL (drawn below) with Cu(O,CMe), H.O in MeOH with addition of pyridine (py) yields Cu L (0 CMe)(py)4(MeOH Show that a MALDI-TOF mass spectrum with envelopes at m/: 977 and 611 is consistent with formulation. Me Me to be? Rationa recorde What The U gold 0 4.26 Amax 303 OH OH OH H3L [Data: J.D. Crane et al. (2004) Inorg. Chem. Comm., vol. 7, p. 499.) 4.20 What is the rule of mutual exclusion? Give two examples of molecular species to which this rule applies. 4.21 The vz vibrational wavenumber for [BF4]" comes at 1070 cm!, whereas the corresponding band for BC14), [BBra] and [BL] comes at 722, 620 and 533 cm , respectively. Rationalize this trend. 1 Vibrational wavenumber for IT

Answer 1

Page: 4. The proposed formula is [ Cup 2 (0C Mese (F), (Mett)?]. Let this be represented by M. The starting material is cu CO2 emel Heo and contains cu 20. The M has four of two 130, two [Me coafe neutral MeOH and py ligands. It is clear that there is a net balance of charges and hence M is a neutral species. MALDI-TOF is used and so H, NG ar ko add to neutral fragments. The most intense peaks in the peak envelopes come at m/2 977 and 611 and are assigned as follows m/z 977 [M-2 by-MedH+ HJC m/2 611 EM-L-204-2by - 2 Me OH + 2H] (4-20 For centro symmetric molecules, the rule of mutual exclusion states that vibrations that are IR active are Raman inactive, and vibrations that are IR inactive are Raman active For example, No 2 0 are two molecular species for which this rule applies.

4.21 No corresponds to the asymmetric The wave number is given by the stretch. equation: 1 27CM where! ma+m2 mam 1.e, u = mim2 mitm2 It means with the increase of reduced mass (M), wave number (s) decreases. Boron is commun to Lory J. [QUE, LeBryje 2 CATAL Let mass of B be my. me follows the order i X CUF. As the terms – and (1) become smalles alone the series F to a to Brto I, so the wavenumber also becomes smaller [Bryl [B cly] [ BBry] [enggo 1670 cm 3 722 cm 620cmt 5836 Wave number decreases