Stable “Inverse” Sandwich Complex with Unprecedented Organocalcium(I): Crystal Structures of [(thf)2Mg(Br)-C6H2-2,4,6-Ph3] and [(thf)3Caμ-C6H3-1,3,5-Ph3Ca(thf)3]

2009/02/04 by Sven Krieck, Helmar Görls, Lian Yu +2 · 4 citations
Chemistry · Materials Science · #Coordination Chemistry and Organometallics #Magnetism in coordination complexes #Organometallic Complex Synthesis and Catalysis

paper · doi:10.1021/ja808524y

openalex publication_date 2009/02/04 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/22

Abstract

The reaction of bromo-2,4,6-triphenylbenzene with activated magnesium in THF yielded the Grignard reagent [(thf)(2)Mg(Br)-C(6)H(2)-2,4,6-Ph(3)] (1) with a Mg-C bond length of 214.8(3) pm. A similar reaction of bromo-2,4,6-triphenylbenzene with activated calcium led to an "inverse" sandwich complex [(thf)(3)Camu-C(6)H(3)-1,3,5-Ph(3)Ca(thf)(3)] (2) with the calcium atoms on opposite sides of the central arene ring showing small Ca-Ca' and Ca-C distances of 427.9(3) and 259.2(3) pm. This extremely air- and moisture-sensitive complex exhibits thermochomic and solvatochromic behavior. It is paramagnetic with spin of S = 1 (triplet) with an ESR resonance at g = 2.0023. Quantum chemical calculations shed light on the bonding situation in this very unusual dinuclear Ca(I) compound.

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Cited by

• Organometallic Compounds of the Heavier s‐Block Elements—What Next?
• Alkali Metal-Stabilized 1,3,5-Triphenylbenzene Monoanions: Synthesis and Characterization of the Lithium, Sodium, and Potassium Complexes
• The occurrence and representation of three-centre two-electron bonds in covalent inorganic compounds
• Group 2 organometallic chemistry [wikipedia]