Σχέση Ιράν-Τουρκίας κοινά συμφέροντα και αντιπαλότητες.

At present, it is important to stress that Iran and Turkey are the two most important players in the Greater Middle East, a region which has become — in many senses — the “center of political gravity” of the world.
Iran and Turkey both have common interests in the region, even though they are rivals and compete with each other and have differences.
Common interests:

1. Both countries follow Islamic ideology, whereas Turkey is moderate and Iran is radical, but the situation in Turkey will not continue on the same path which it trod for the last three-quarters of the 20th Century. Turkey will have to go back to either secular Kemalism or move further toward Islam since Islam and democracy cannot concur with each other, despite the claims in this transitional period that Turkey exemplifies “democratic Islam”. If there is such a path, then it is more attuned to the careful steps which the Kingdom of Morocco is taking. 2. Both countries had very close strategic relations with the U.S. Iran, of course, has postured itself as the enemy of the U.S. since 1979, and Turkey is gradually changing its direction, as it did with its policy towards Israel in mid-2010, and the establishment in 2008 of its partnership with Russia. 3. Both countries are working together and are becoming strategic partners. 4. Trade and economic relations between Iran and Turkey have been improving tremendously, in spite of U.S. sanctions 5. Both have common interests with Syria to check the Kurdish movement and prevent the creation of an independent Kurdish state. There are more than 20 million Kurds in Turkey and around eight million in Iran. 6. Iran and Turkey both have interests in Iraq and in the stability (or otherwise) of Iraq.

Rivalries:

1. While Iran and Turkey have predominantly Muslim populations, Iran is Shia and Turkey is Sunni. We need to remember that the two empires of Safavid Iran and the Ottoman Turks fought ideological wars for 250 years. 2. Turkey is slowly and skillfully following a path of pan-Turkism/Ottomanism — even though pan-Turkism is, as most in modern Turkey forget, diametrically opposed to Ottomanism as it was originally expressed by Atatürk — and this new messianic pan-Turkist/Ottomanist set of goals will soon bring Turkey into conflict with Iran, which has Turkic speaking (Azari) populations in the North. 3. Both claim leadership in the region. 4. Turkey is concerned at the prospect of a military nuclear Iran which, with its resources and history and strong cultural identity, would at least attempt to be “lord paramount” of the region. For this reason alone, Turkey has begun steps to build its own nuclear energy and military nuclear options. 5. Iran and Turkey compete in Central Asia and the Caucasus. This competition started after the downfall of the Soviet empire. 6. Turkey is a member of NATO, whereas the theocracy of Iran and NATO are bêtes noires.

In a nutshell, in spite of differences, there are compatibilities in ideology, religion, economy, and geopolitics which bring Turkey and Iran closer.
This cooperation will continue with the present leaderships of the two countries, unless there is change in policy of Iran or Turkey.
http://www.worldtribune.com/worldtribune/WTARC/2010/me_iran1085_11_02.asp