Anion and pH induced spontaneous resolution of Δ- and Λ-[M(H2Biim)3]SO4 (M = Ru2+, Co2+, Ni2+, Mn2+, Fe2+, and Zn2+) enantiomers

Tan, Yu‐Hui; Wu, Jingzhi; Zhou, Haiyun; Yang, Li-Fei; Ye, Bao‐Hui

doi:10.1039/c2ce26334c

Cited by 16 publications

(4 citation statements)

References 75 publications

(43 reference statements)

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“…Indeed, their tris-homoleptic complexes, such as [Fe(phen) 3 ]Cl 2 , are found almost exclusively in the LS state. In contrast, the tris-homoleptic Fe(II) complexes of 2,2′-biimidazole (bim), such as [Fe(bim) 3 ](SO 4 ), are always found in the HS state, due to the weaker π-accepting ability of the five-member rings in the bim ligand. Nevertheless, the complex [Fe(bimz) 3 ](ClO 4 ) 2 (bimz = 2,2′-bis-2-imidazoline, which has less extensive π-conjugated system than that of bim) exhibits SCO, which was explained by the more concentrated π-system of the ligand that helps to strengthen the metal–ligand interaction …”

Section: Introductionmentioning

confidence: 99%

A Simple Approach for Predicting the Spin State of Homoleptic Fe(II) Tris-diimine Complexes

et al. 2017

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We propose a simple method for predicting the spin state of homoleptic complexes of the Fe(II) d ion with chelating diimine ligands. The approach is based on the analysis of a single metric parameter within a free (noncoordinated) ligand: the interatomic separation between the N-donor metal-binding sites. An extensive analysis of existing complexes allows the determination of critical N···N distances that dictate the regions of stability for the high-spin and low-spin complexes, as well as the intermediate range in which the magnetic bistability (spin crossover) can be observed. The prediction has been tested on several complexes that demonstrate the validity of our method.

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Section: Introductionmentioning

confidence: 99%

A Simple Approach for Predicting the Spin State of Homoleptic Fe(II) Tris-diimine Complexes

et al. 2017

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“…In this connection, the spontaneous resolution upon crystallization of achiral precursors has the potential to evolve as a useful method. − As discussed by Bernal in a series of reviews, the spontaneous resolution of discrete six-coordinated cobalt(III) complexes comprised of achiral ligands was first recognized by Werner in the late 19th century. − Subsequently, a few more six-coordinated discrete complexes were reported to undergo spontaneous resolution upon crystallization. − Lennartson and Håkansson and others have even reported conglomerate crystallization in the case of five, − eight, , and nine-coordinated discrete complexes, although four-coordinated discrete chiral complexes containing achiral constituents are scarce. The research group of Enamullah and Janiack first reported spontaneous resolution in the case of a discrete four-coordinated complex, [Rh( N -phenylglycinato)(η 4 -cycloocta-1,5-diene)], which contained the prochiral ligand N -phenylglycine. , Chirality in the complex arises from the nitrogen atom becoming the stereogenic center upon metal coordination.…”

Section: Introductionmentioning

confidence: 99%

Spontaneous Resolution upon Crystallization and Preferential Induction of Chirality in a Discrete Tetrahedral Zinc(II) Complex Comprised of Achiral Precursors

Rajput¹,

Bisht²,

Drew

et al. 2019

Inorg. Chem.

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A pair of enantiomeric tetrahedral complexes (Λ-[Zn(L)2] and Δ-[Zn(L)2]) comprised of the achiral ligand methyl-3-hydroxy-3-phenyl-2-propenedithioate (L) have been synthesized by spontaneous resolution. Two chiral inducers, viz., d-(−)- and l-(+)-tartaric and mandelic acids, have been employed to achieve bulk homochirality and extend the generality of the present work. The work highlights the achievement of bulk homochirality using readily available chiral inducers in the synthesis of a spontaneously resolving chiral tetrahedral zinc(II) complex using achiral starting materials. These findings are established by 30 sets of single-crystal X-ray diffraction data with refined Flack parameters and circular dichroism spectroscopy.

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“…The increases in d (Fe–N) average from ∼2.03 to ∼2.15 Å and in Σ 90 from ∼70 to ∼95° give a clear indication of the temperature-driven SCO taking place in these complexes, with a substantial HS fraction still being present at 110 K. The structural parameters of complexes 2a and 2b also change substantially with temperature (Table ). Complexes 3a and 3b , in contrast, exhibit Fe–N bond lengths typical of the HS state at 230 K. The values observed compare well to those reported for the HS complex [Fe(bim) 3 ](SO 4 ) (2.191–2.205 Å) . At 100 K, the metric parameters observed for 3a and 3b are intermediate between those expected for the HS and LS Fe II ions.…”

Section: Resultsmentioning

confidence: 99%

Power of Three: Incremental Increase in the Ligand Field Strength of N-Alkylated 2,2′-Biimidazoles Leads to Spin Crossover in Homoleptic Tris-Chelated Fe(II) Complexes

et al. 2018

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Homoleptic complexes [Fe(L )]X (L = 1,1'-(α,α'- o-xylyl)-2,2'-biimidazole, L = 1,1'-(α,α'-3,4-dibromo- o-xylyl)-2,2'-biimidazole, L = 1,1'-(α,α'-2,5-dimethoxy- o-xylyl)-2,2'-biimidazole; X = BF or ClO) were synthesized by direct reactions of the Fe(II) precursor salts and bidentate ligands L, L, or L. All mononuclear complexes undergo gradual temperature-driven spin-crossover (SCO) between the high-spin (HS, S = 2) and low-spin (LS, S = 0) states. Complexes with ligands L and L synthesized in methanol exhibit complete SCO with the midpoint of the LS↔HS conversion varying from 233 to 313 K, while complexes with ligand L, crystallized from an ethanol/dichloromethane mixture, exhibit incomplete SCO with the residual HS/LS ratio of ∼1:4 for [Fe(L)](BF) and ∼1:1 for [Fe(L)](ClO). Complexes with L can also be recrystallized from ethanol/dichloromethane, in which case they exhibit very gradual and incomplete SCO, similar to those of the complexes with L. The differences in magnetic behavior have been traced back to peculiarities of molecular packing observed in the corresponding crystal structures. Density-functional theoretical calculations provide justification to the SCO behavior of these complexes, as compared to the HS-only behavior observed for the parent [Fe(bim)] complex with nonalkylated 2,2'-biimidazole (bim).

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Anion and pH induced spontaneous resolution of Δ- and Λ-[M(H2Biim)3]SO4 (M = Ru2+, Co2+, Ni2+, Mn2+, Fe2+, and Zn2+) enantiomers

Cited by 16 publications

References 75 publications

A Simple Approach for Predicting the Spin State of Homoleptic Fe(II) Tris-diimine Complexes

A Simple Approach for Predicting the Spin State of Homoleptic Fe(II) Tris-diimine Complexes

Spontaneous Resolution upon Crystallization and Preferential Induction of Chirality in a Discrete Tetrahedral Zinc(II) Complex Comprised of Achiral Precursors

Power of Three: Incremental Increase in the Ligand Field Strength of N-Alkylated 2,2′-Biimidazoles Leads to Spin Crossover in Homoleptic Tris-Chelated Fe(II) Complexes

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