This is a Sonnar formula lens, first introduced in 1952. It was produced in Nikon S-Mount, Contax RF Mount, Leica Thread Mount, and Nikon F-Mount. In 1973 or so, the Nikkor 105/2.5 changed to a Planar formula, supposedly a little bit sharper. This 1952 lens is known for it's out-of-focus...
To add- prices on clean Nikkor-PC 10.5cm F2.5 in Leica Mount are way down, I picked up a second one in super-clean condition for under $200. In F-Mount, between $100~$150 in the same condition. In F-Mount, Nikon switched to a Planar design ~1970, so you want an earlier one.
The 105/1.8 is a Xenotar 5 elements in 5 groups, essentially a simplified double-Gauss.
The Sonnar is an Asymmetric design. The rear element has a focal length about the same as the completed lens, the front section is a Telephoto design with focal length "roughly" 2.5x that of the completed lens. The rendering is "just different".