Heterobimetallic dioxygen activation: Synthesis and reactivity of mixed Cu-Pd and Cu-Pt bis(μ-oxo) complexes

John T. York, Antoni Llobet, Christopher J. Cramer, William B. Tolman

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49 Citations (Scopus)

Abstract

Heterobimetallic CuPd and CuPt bis(μ-oxo) complexes have been prepared by the reaction of (PPh 3 ) 2 MO 2 (M = Pd, Pt) with LCu(I) precursors (L = β-diketiminate and di- and triamine ligands) and characterized by low-temperature UV-vis, resonance Raman, and 1 H and 31 P{ 1 H} NMR spectroscopy in conjunction with DFT calculations. The complexes decompose upon warming to yield OPPh 3 , and in one case this was shown to occur by an intramolecular process through crossover experiments using double-labeling (oxo and phosphine). The reactivity of one of the complexes, L Me2 Cu(μ-O) 2 Pt(PPh 3 ) 2 (L Me2 = β-diketiminate), with a variety of reagents including CO 2 , 2,4-di-tert-butylphenol, 2,4-di-tert-butylphenolate, [NH 4 ][PF 6 ], and dihydroanthracene, was compared to that of homometallic Pt 2 and Cu 2 counterparts. Unlike typical [CU 2 (μ-O) 2 ] 2+ cores which have electrophilic oxo groups, the oxo groups in the [Cu(μ-O) 2 Pt] + core behave as bases and nucleophiles, similar to previously described Pt 2 compounds. In addition, however, the [Cu(μ-O) 2 Pt] + core is capable of oxidatively coupling 2,4-di-terf-butylphenol and 2,4-di-tert-butylphenolate. Theoretical evaluation of the electron affinities, basicities, and H-atom transfer kinetics and thermodynamics of the Cu 2 and CuM (M = Pd, Pt) cores showed that the latter are more basic and form stronger O-H bonds. © 2007 American Chemical Society.
Original languageEnglish
Pages (from-to)7990-7999
JournalJournal of the American Chemical Society
Volume129
Issue number25
DOIs
Publication statusPublished - 27 Jun 2007

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