A Rare Low‐Spin CoIV Bis(β‐silyldiamide) with High Thermal Stability: Steric Enforcement of a Doublet Configuration
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Authors: | David Zanders Goran Ba
i Dominique Leckie Oluwadamilola Odegbesan Jeremy Rawson Jason D Masuda Anjana Devi Sen T Barry |
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Institution: | David Zanders,Goran Bačić,Dominique Leckie,Oluwadamilola Odegbesan,Jeremy Rawson,Jason D. Masuda,Anjana Devi,Seán T. Barry |
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Abstract: | Attempted preparation of a chelated CoII β‐silylamide resulted in the unprecedented disproportionation to Co0 and a spirocyclic cobalt(IV) bis(β‐silyldiamide): Co(NtBu)2SiMe2]2] ( 1 ). Compound 1 exhibited a room‐temperature magnetic moment of 1.8 B.M. and a solid‐state axial EPR spectrum diagnostic of a rare S= configuration for tetrahedral CoIV. Ab initio semicanonical coupled‐cluster calculations (DLPNO‐CCSD(T)) revealed the doublet state was clearly preferred (?27 kcal mol?1) over higher spin configurations only for the bulky tert‐butyl‐substituted analogue. Unlike other CoIV complexes, 1 had remarkable thermal stability, and was demonstrated to form a stable self‐limiting monolayer in preliminary atomic layer deposition (ALD) surface saturation experiments. The ease of synthesis and high stability make 1 an attractive starting point to investigate otherwise inaccessible CoIV intermediates and for synthesizing new materials. |
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Keywords: | atomic layer deposition cobalt coupled-cluster calculations density functional calculations EPR spectroscopy |
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