passages.id: split_9_validation_529_passage
passages.type: progene_text
passages.text: The sterically hindered BIT(OR,SR' ) ligands 9 and 10 ( R' = t - Bu ; R = H , Me ) and 11 and 12 ( R' = CPh3 ; R = H , Me ) were also prepared and examined for copper coordination / oxygenation .