Lewis Base Adducts of Barium/Copper tert-Butoxides:  Synthesis and Thermolysis of [BaCu₂(O^tBu)₄]_n and [L₂Ba₂Cu₄(O^tBu)₈] (L = Me₃NO and Et₃PO). X-ray Crystal Structure of [(Me₃NO)₂Ba₂Cu₄(O^tBu)₈]

Reaction of copper(I) mesityl with [Ba(O^tBu)₂(t-BuOH)₂]₄ yields insoluble [BaCu₂(O^tBu)₄]_n, which dissolves by adduct formation (L = Me₃NO or Et₃PO) to form soluble L₂Ba₂Cu₄(O^tBu)₈. For L = Me₃NO, this molecule is shown by X-ray diffraction to have a structure based on a trans-Ba₂Cu₄ octahedron, with all Ba/Cu edges bridged by μ₂-O^tBu units; one L binds to each Ba. Bulk thermolysis, TGA, and product analysis have revealed that O^tBu units undergo not only O/C cleavage but also C/C cleavage, the latter to form carbonate and nonvolatile hydrocarbon products, in addition to BaO and CuO. The intended oxidant Me₃NO shows no great tendency to oxidize Cu(I).