MOSCOW — Russia has shown a burst of diplomatic energy before talks here Saturday with the UN envoy on Syria, perhaps seeing a chance for a breakthrough that would temper the criticism it has drawn in the West and the Arab world during the course of the nearly two-year-old Syrian conflict.

Russia’s foreign minister, Sergey V. Lavrov, on Friday made his first overtures toward the largest exile Syrian opposition coalition, saying that he had requested a meeting with its leader, Sheik Ahmad Moaz al-Khatib. The United States, Britain, and several Persian Gulf nations have recognized the coalition as the sole representative of the Syrian people, but Moscow has so far refused.