There is no known direct contact between Christian European powers and the West African empires. A lot of West African gold winds up in Christian Iberia before and during the Reconquista, by way of Muslim merchant intermediaries. And one of the sultan-emperors of Mali, Mansa Musa, famously completed his pilgrimage to Mecca.

For direct contact between Latin Europe and "black" Africa, we look instead to Ethiopia. Ethiopian Christians could plausibly have been in Jerusalem while it was in crusader hands. Certainly later European pilgrims encountered Ethiopians there. By the 15th century, the Iberian powers and Italian city-states (not to mention the Church) were engaged in diplomatic contact with Ethiopia. There was even an Ethiopian Orthodox church in Rome! I've talked a little about one arm of that diplomacy before:

In 1428, ambassadors between King Alfonso V of Aragon and Emperor Ishaq of Ethiopia actually worked to set up a double marriage alliance: Ishaq would marry the king's sister, and the Spanish prince would wed an Ethiopian princess. Nothing came of this, however. In the sixteenth century, the Ethiopians made a half-hearted attempt to revive the hope of a ruling marriage alliance, but they never got around to proposing specifics and the Portuguese weren't the least bit interested, anyway. By that point, the trans-Atlantic slave trade was picking up and Europeans were starting to theorize about patterns that had been developing silently with the growing presence of African slaves in European courts. Literature and legal sources began to delineate hierarchies of skin color, and the (white, Roman) Church pondered questions of skin color, conversion, and the ethics of enslavement.

By that point, too, the Portugeuse were sailing the West African coastline and establishing formal contact with the Kingdom of Kongo in Central Africa; or even rounding the Cape of Good Hope to reach the Swahili city-states!