The 100th #chempaperaday was "A millennial overview of transition metal chemistry" by F.A. Cotton. Interestingly enough, my 203rd paper is another great article by him.
In this article, he highlights a few selected areas of inorganic chemistry and obviously his contributions to these areas. In fact, he paved the way for several of these. When chemists just put their hands on an NMR instrument, he started to do VT experiments to study the fluctional behavior of several organometallic compounds. Incredible work. There is also a few pages on the iron dimer that I just posted, the discovery of agostic interactions, his proposal to use hapticity and so on.
"Prior to the report on ferrocene, no one worked in the field of transition metal organometallic chemistry because no one believed that there was any such field to work in."