Reactivity of hydride bridges in a high-spin [Fe3(μ-H)3]3+ cluster: reversible H2/CO exchange and Fe–H/B–F bond metathesis† †Electronic supplementary information (ESI) available: Experimental and theoretical procedures and figures, crystallographic details, and theoretical structures. CCDC 1523783 and 1523784. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc05583d Click here for additional data file. Click here for additional data file

• Published in: Chemical science (Cambridge) Vol. 8; no. 5; pp. 4123 - 4129
• Main Authors: Anderton, Kevin J., Knight, Brian J., Rheingold, Arnold L., Abboud, Khalil A., García-Serres, Ricardo, Murray, Leslie J.
• Format: Journal Article
• Language: English
• Published: Royal Society of Chemistry 11.04.2017
• Subjects: Chemistry
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c6sc05583d

The triiron trihydride complex Fe 3 H 3 L ( 1 ) [where L 3– is a tris(β-diketiminate)cyclophanate] reacts with CO and with BF 3 ·OEt 2 to afford (Fe I CO) 2 Fe II (μ 3 -H) L ( 2 ) and Fe 3 F 3 L ( 3 ), respectively. The triiron trihydride complex Fe 3 H 3 L ( 1 ) [where L 3– is a tris(β-diketiminate)cyclophanate] reacts with CO and with BF 3 ·OEt 2 to afford (Fe I CO) 2 Fe II (μ 3 -H) L ( 2 ) and Fe 3 F 3 L ( 3 ), respectively. Variable-temperature and applied-field Mössbauer spectroscopy support the assignment of two high-spin (HS) iron( i ) centers and one HS iron( ii ) ion in 2 . Preliminary studies support a CO-induced reductive elimination of H 2 from 1 , rather than CO trapping a species from an equilibrium mixture. This complex reacts with H 2 to regenerate 1 under a dihydrogen atmosphere, which represents a rare example of reversible CO/H 2 exchange and the first to occur at high-spin metal centers, as well as the first example of a reversible multielectron redox reaction at a designed high-spin metal cluster. The formation of 3 proceeds through a previously unreported net fluoride-for-hydride substitution, and 3 is surprisingly chemically inert to Si–H bonds and points to an unexpectedly large difference between the Fe–F and Fe–H bonds in this high-spin system.