passages.id: split_4_validation_527_passage
passages.type: progene_text
passages.text: In contrast , oxygenation of 2b ( R = Me ) affords crystallographically defined [(BIT(OMe,SMe ) ) 2Cu2(mu-OH)2](OTf)2 ( 5 ) , in which the copper centers are oxygenated without accompanying sulfur oxidation .