2.2. Electronic Structures 2.2.1 UV-vis-NIR Spectroscopy. The UV-vis-NIR absorption spectrum of product 3 was markedly different from that of 2, which contained a strong peak with a maximum at 632 nm, a broad shapeless peak below 500 nm, and a less intense peak in the NIR region with a maximum at 1125 nm (Figure and S9Aa). The peak at 632 nm was asymmetrically split into two peaks with broad maxima at 590 and 620 nm (Figure and S9Ab). In addition, 3 provided a pair of new, partially overlapped asymmetrical peaks with broad maxima at 475 and 523 nm. Interestingly, there were no significant changes in the shape or position of the peak in the NIR region, indicating that the structural difference, from 2 to 3, did not greatly affect the absorption properties of icosahedral Au12Pt. The UV-vis-NIR spectrum of 4 was also similar to that of 3 (Figure and). However, peaks in the range of 570-680 nm showed an opposite trend. Specifically, 4 provided a more intense absorption peak at approximately 620 nm, whereas 3 generated a higher absorption peak at approximately 590 nm.