Calcium stilbene complexes: structures and dual reactivity

Causero, Andrea; Elsen, Holger; Ballmann, Gerd; Escalona, Ana; Harder, Sjoerd

doi:10.1039/c7cc05792j

Cited by 31 publications

(35 citation statements)

References 29 publications

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“…Given the low electron affinity of aromatic benzene (reduction potential: −3.42(5) V vs. SCE), the formation of a complex with a formal C 6 H 6 2− anion is remarkable and consequently a very high redox reactivity can be expected. We reported on the ambivalent reactivity of a binuclear Ca amidinate complex with a bridging trans ‐stilbene dianion that can either function as a Brønsted base or as an two‐electron donor . More recently, Jones and co‐workers reported similar dual reactivity for BDI 2 Mg 2 (DPE) in which DPE 2− bridges two Mg 2+ ions (DPE=1,1,‐diphenylethylene) .…”

Section: Methodsmentioning

confidence: 99%

Low Valent Magnesium Chemistry with a Super Bulky β‐Diketiminate Ligand

et al. 2018

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The steric bulk of the well‐known DIPPBDI ligand (CH[C(CH3)N‐DIPP]2, DIPP=2,6‐diisopropylphenyl) was increased by replacing isopropyl for isopentyl groups. This very bulky DIPePBDI ligand could not stabilize the radical species (DIPePBDI)Mg.: reduction of (DIPePBDI)MgI with Na gave (DIPePBDI)2Mg2 with a rather long Mg‐Mg bond of 3.0513(8) Å. Addition of TMEDA prior to reduction gave complex (DIPePBDI)2Mg2(C6H6), which could also be obtained as its THF adduct. It is speculated that combination of a bulky spectator ligand and TMEDA prevents dimerization of the intermediate MgI radical, which then reacts with the benzene solvent. Complex (DIPePBDI)2Mg2(C6H6), which formally contains the anti‐aromatic anion C6H62−, reacted with tBuOH as a Brønsted base to 1,3‐ and 1,4‐cyclohexadiene and with H2 as a two electron donor to (DIPePBDI)2Mg2H2 and C6H6. It also reductively cleaved the C−F bond in fluorobenzene and gave (DIPePBDI)MgPh, (DIPePBDI)MgF, and C6H6.

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Section: Methodsmentioning

confidence: 99%

Low Valent Magnesium Chemistry with a Super Bulky β‐Diketiminate Ligand

et al. 2018

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“…We reported on the ambivalent reactivity of ab inuclear Ca amidinate complex with abridging trans-stilbene dianion that can either function as aB rønsted base or as an two-electron donor. [24] More recently,J ones and co-workers reported similar dual reactivity for BDI 2 Mg 2 (DPE) in which DPE 2À bridges two Mg 2+ ions (DPE = 1,1,-diphenylethylene). [25] Also complex ( DIPeP BDI) 2 Mg 2 (C 6 H 6 )d isplays dual reactivity (Scheme 3).…”

Section: Communicationsmentioning

confidence: 98%

Low Valent Magnesium Chemistry with a Super Bulky β‐Diketiminate Ligand

et al. 2018

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The steric bulk of the well-known DIPP BDI ligand (CH[C(CH 3 )N-DIPP] 2 ,D IPP = 2,6-diisopropylphenyl) was increased by replacing isopropyl for isopentyl groups.T his very bulky DIPeP BDI ligand could not stabilizet he radical species ( DIPeP BDI)MgC:r eduction of ( DIPeP BDI)MgI with Na gave ( DIPeP BDI) 2 Mg 2 with ar ather long Mg-Mg bond of 3.0513(8) .A ddition of TMEDAp rior to reduction gave complex ( DIPeP BDI) 2 Mg 2 (C 6 H 6 ), which could also be obtained as its THF adduct. It is speculated that combination of abulky spectator ligand and TMEDAp revents dimerization of the intermediate Mg I radical, which then reacts with the benzene solvent. Complex ( DIPeP BDI) 2 Mg 2 (C 6 H 6 ), which formally contains the anti-aromatic anion C 6 H 6 2À ,r eacted with tBuOH as aBrønsted base to 1,3-and 1,4-cyclohexadiene and with H 2 as at wo electron donor to ( DIPeP BDI) 2 Mg 2 H 2 and C 6 H 6 .I ta lso reductively cleaved the C À Fb ond in fluorobenzene and gave ( DIPeP BDI)MgPh, ( DIPeP BDI)MgF,and C 6 H 6 .

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“…Although alkaline earth hydride-mediated reactivity of 1,3,5,7-C 8 H 8 is yet to be described, the reactions of diphenylacetylene with either compound 2 or a similarly dimeric amidinato calcium hydride have been shown to result in reduction to the stilbene dianion, [Ph(H)C-C(H)Ph] 2À . 21,40 Notably, the reductive reactivity of this latter species toward I 2 and H 2 led it to being posited as a potential Ca(I) synthon. With these diverse considerations in mind, we describe herein our observations of the ability of compound 2 to effect the generation of the [COT] 2À dianion.…”

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confidence: 99%