Activation and functionalisation of carbon dioxide by bis-tris(pyrazolyl)borate-supported divalent samarium and trivalent lanthanide silylamide complexes

• Published in: Dalton transactions : an international journal of inorganic chemistry 2024-07, Vol.53 (28), p.11884-11894
• Main Authors: Chowdhury, Tajrian, Wilson, Claire, Farnaby, Joy H
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Coordination polymers; Crystallography; Isocyanates; Ligands; Molecular structure; Samarium; Single crystals; Structural analysis
• ISSN: 1477-9226; 1477-9234; 1477-9234
• DOI: 10.1039/d4dt01382d

Synthesis and reactivity with carbon dioxide (CO 2 ) of divalent samarium in the bis-tris(pyrazolyl)borate ligand environment has been reported. In addition, CO 2 activation and functionalisation by lanthanide silylamides in the bis-tris(pyrazolyl)borate ligand environment was demonstrated. Reduction of the Sm( iii ) precursor [Sm(Tp) 2 (OTf)] (Tp = hydrotris(1-pyrazolyl)borate; OTf = triflate) with KC 8 yielded the insoluble Sm( ii ) multi-metallic coordination polymer [{Sm(Tp) 2 } n ] 1-Sm . Addition of 1,2-dimethoxyethane (DME) to 1-Sm enabled isolation of the monomeric complex [Sm(Tp) 2 (DME)] 1-Sm(DME) . Complex 1-Sm(DME) reduced CO 2 to yield the oxalate-bridged dimeric Sm( iii ) complex [{Sm(Tp) 2 } 2 (μ-η 2 :η 2 -O 2 CCO 2 )] 2-Sm . The reactions of heteroleptic Ln( iii ) silylamide complexes [Ln(Tp) 2 (N′′)] (Ln = Y, Sm; N′′ = N(SiMe 3 ) 2 ) with CO 2 yielded monomeric Ln( iii ) silyloxides [Ln(Tp) 2 (OSiMe 3 )] 3-Ln and trimethylsilyl isocyanate (O&z.dbd;C&z.dbd;NSiMe 3 ). Complexes 3-Ln are the first crystallographically characterised examples of Ln( iii )-OSiMe 3 bonds accessed via CO 2 activation and functionalisation. Full characterisation data are presented for all complexes, including solid-state molecular structure determination by single-crystal X-ray diffraction. The activation and functionalisation of carbon dioxide by bis-tris(pyrazolyl)borate-supported divalent samarium and trivalent lanthanide silylamide complexes have been reported.