The daughter of South African jazz pianist Abdullah Ibrahim, Tsidi “Jean Grae” Ibrahim has been a bafflingly marginal player in the New York hip-hop underground for some years now. This Week is a belated attempt to push this thoughtful, urbane rapper into the mainstream. For the most part, it succeeds, as Grae cruises eloquently over booming, soul-sampling backdrops that recall Jay-Z’s recent triumphs (9th Wonder, one of the Jigga’s producers, helms the outstanding “Supa Luv”). Grae’s strength, however, may turn out to be her commercial downfall: a wry solipsism that compels her to detail an ordinary life far removed from rap’s gaudier fantasies.