Question

H 3 893 22 0 22 0 4.17 1064 ncton et al. (1999) Inorg. Chim. Acta, vol. 290, p. 213. Pata LS. Bonningtone er or isomers Appendix 5.) IDau J. Organomet. Che 1.0 mmol of the lig with 0.50 mmol MALDI-TOF mas was run in 1-cyar The most intense mass spectrum v 302.1. Assign the the product that S 14 ESI mass spectrum (positive mode) of the ligand un below exhibits two peaks at m/z 299.2 (base and 321.1. (a) What is a 'base peak'? (b) oest how the observed peaks arise. Data: C Sumby et al. (2009) Tetrahedron, vol. 65, p. 4681.1 15) The ESI mass spectrum (positive mode) of the complex shown below contained a peak envelope with miz! 527.9 (100%), 528.9 (15%), 529.9 (46%), 530.9 (7%), 531.9 (0.5%). A group of peaks of low low intensity and with spacings of m/z=1 was also observed around m/z 994. (a) What is the oxidation state of Cu in the complex? (b) Assign the major peak and account for the isotope pattern. (c) Suggest how the minor peak arises. (Isotopes: see Appendix 5.) [Data: L. Szi p. 2710.] 4.18 In the MALL ligand shov matrix, the peak), 637. HN -Cu- CI 1

Answer 1

1) The compound has a molecular formula, C₁₆H₁₈N₄O₂ with a molecular weight of 298.144.

a) The most intense peak in the mass spectrogram is called the base peak.

b) The peaks observed are [M+1]+ peak and [M+23]+ peaks. which are obtained by proton transfer and sodium ion transfer.

2) The complex has a molecular formula Cu(C₁₃H₁₁ON₂I₂)Cl.It has a molecular weight of 563.884.

a) The oxidation of copper in the complex is +2.

b) The base peak is obtained by the loss of a Cl^- ion. Other peaks (near the base peak) occur due to isotopes of Carbon (C13), Nitrogen (N15) and Oxygen (O18).

c) Peaks at m/z of 994 may occur due to the dimerization of the complex after loss of copper.