The ESI mass spectrum (positive mode) of the complex shown below contained a peak envelope...

The ESI mass spectrum (positive mode) of the complex shown below contained a peak envelope with m/z (100%), 528.9 (15%), 529.9 (46%), 530.9 (7%), 531.9 (0.5%). A group of peaks of 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?

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(b) Assign the major peak and account for the isotope pattern

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(c) Suggest how the minor peak arises. (Isotopes: see Appendix 5.)