The UV-VIS spectrum of a CH2C12 solution of the gold(I) compound shown below with R=Ph is:...

The UV-VIS spectrum of a CH2C12 solution of the gold(I) compound shown below with R=Ph is: λmax(ϵ) = 239 (92 500), 269 (67 000), 286 (72 000), 303 (28 000), 315 nm (21 000 dm3 mol-1 cm-1).

[Data: E.C. Constable et al. (2009) Eur. j. Inorg. Chem., p. 4710.]

(a) π*← π transitions contribute to Ihe observed spectrum. How do these arise?

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(b) Is the compound coloured?

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(c) You are asked to compare the UV-VIS spectra of a series of these compounds with different R substituents. Why should you compare plots of ϵ against λ rather than A against λ?