Synthesis and Characterization of Alkoxide-Bridged Heterometallic Clusters of Cerium and Copper

Hayato Tsurugi; Yuri Ikeda; Koichi Shinohara; Satoru Shirase; Nozomi Toya; Shinji Tanaka; Kazushi Mashima

doi:10.1021/acs.inorgchem.9b01213

Synthesis and Characterization of Alkoxide-Bridged Heterometallic Clusters of Cerium and Copper

Inorg Chem. 2019 Oct 7;58(19):12565-12572. doi: 10.1021/acs.inorgchem.9b01213. Epub 2019 Sep 10.

Authors

Hayato Tsurugi¹, Yuri Ikeda¹, Koichi Shinohara¹, Satoru Shirase¹, Nozomi Toya¹, Shinji Tanaka¹, Kazushi Mashima¹

Affiliation

¹ Department of Chemistry, Graduate School of Engineering Science , Osaka University , Toyonaka, Osaka 560-8531 , Japan.

PMID: 31502454
DOI: 10.1021/acs.inorgchem.9b01213

Abstract

We prepared alkoxide-bridged heterometallic clusters of cerium and copper by the complexation of two metal alkoxides: treatment of Ce(O^tBu)₄ with [Cu(O^tBu)]₄ in a 1:1 metal ratio produced an alkoxide-bridged tetranuclear cluster, Ce₂Cu₂(O^tBu)₁₀ (1). Upon adding 4-substituted pyridine derivatives to complex 1, trinuclear clusters, Ce₂Cu(O^tBu)₉(L) (2a: L = DMAP (4-dimethylaminopyridine); 2b: L = BPY (4,4'-bipyridine)), were obtained along with the release of 0.25 equiv of [Cu(O^tBu)]₄, in which a three-coordinated copper center was involved. In contrast, reaction of 1 with 4 equiv of 2,6-dimethylphenylisocyanide (XylNC) and 0.5 equiv of [Cu(O^tBu)]₄ resulted in the selective formation of CeCu₂(O^tBu)₆(CNXyl)₂ (3). In addition, Ce₂K(O^tBu)₉ was used for complexation with CuCl₂ by salt-elimination, giving Ce₂CuCl(O^tBu)₉ (4) including a five-coordinated copper center. These complexes 1-4 were characterized by crystal structure determination as well as cyclic voltammetry of 1, 2a, and 4. The cyclic voltammogram of 4 in CH₂Cl₂ and THF suggested that reorganization of the coordination sphere around the copper center was observed for 4 during the Cu(I/II) redox processes assisted by the coordination of THF.