Short answers, pulled from the story.
Russia and the Ottoman Empire fought in numerous Russo-Turkish wars from the late 16th to the early 20th century, constituting one of the longest series of wars in modern history. The two empires also clashed during World War I, with the Russian Caucasus campaign beginning on the 1st of November 1914.
The Bolshevik government under Vladimir Lenin viewed Mustafa Kemal Atatürk's nationalist movement as ideologically aligned with its anti-imperialist goals. Soviet Russia supplied gold and weapons to the Kemalists between 1920 and 1922, which were a key factor in the Kemalists' successful consolidation of power over the former Ottoman Empire.
The Treaty of Moscow, signed on the 16th of March 1921, established friendly relations between the two governments. Under Article II, Turkey ceded Batum and adjacent territory to the Georgian Soviet Socialist Republic, while Kars Oblast went to Turkey. Article III created an autonomous Nakhchivan oblast under Soviet Azerbaijan's protectorate.
On the 24th of November 2015, Turkish F-16 aircraft shot down a Russian Sukhoi Su-24 during an airspace dispute close to the Turkish-Syrian border, shortly after Russia began its military intervention in Syria in support of President Bashar al-Assad. Vladimir Putin described the incident as a stab in the back by the accomplices of terrorists.
Turkey has served as the primary neutral venue for Russia-Ukraine diplomacy. On the 10th of March 2022, the foreign ministers of Russia and Ukraine met in Antalya, Turkey, in the first high-level contact since the invasion began. Turkey also brokered the Black Sea Grain Initiative, with Russia and Ukraine signing the deal in Istanbul on the 22nd of July 2022.
Russia and Turkey are linked by the TurkStream gas pipeline, for which an intergovernmental agreement was signed in October 2016; gas deliveries to Bulgaria through the pipeline began on the 1st of January 2020. Russia is also building the Akkuyu Nuclear Power Plant in Mersin province, Turkey's first fully operational nuclear facility, comprising four power units with a total capacity of 4,800 MW.