Jahn-Teller distortions in octahedral copper(II) complexes

Veidis, Mikelis V.; Schreiber, Geoffrey; Gough, T. E.; Palenik, Gus J.

doi:10.1021/ja01035a051

Cited by 118 publications

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“…Hence, Cu I complexes often adopt 4-coordinate tetrahedral geometries, organizing Lewis bases at the farthest possible positions, as expected from the VSEPR (valence shell electron pair repulsion) theory. Cu II d 9 ion undergoes Jahn−Teller distortion 9 with a strong preference for axially distorted over perfectly octahedral structures. Then, a ligand forcing an axial distortion would favor Cu II over Cu I .…”

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confidence: 99%

Entasis through Hook-and-Loop Fastening in a Glycoligand with Cumulative Weak Forces Stabilizing Cu^I

et al. 2015

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The idea of a possible control of metal ion properties by constraining the coordination sphere geometry was introduced by Vallee and Williams with the concept of entasis, which is frequently postulated to be at stake in metallobiomolecules. However, the interactions controlling the geometry at metal centers remain often elusive. In this study, the coordination properties toward copper ions—Cu(II) or Cu(I)—of a geometrically constrained glycoligand centered on a sugar scaffold were compared with those of an analogous ligand built on an unconstrained alkyl chain. The sugar-centered ligand was shown to be more preorganized for Cu(II) coordination than its open-chain analogue, with an unusual additional stabilization of the Cu(I) redox state. This preference for Cu(I) was suggested to arise from geometric constraints favoring an optimized folding of the glycoligand minimizing steric repulsions. In other words, the Cu(I) d(10) species is stabilized by valence shell electron pair repulsion (VSEPR). This idea was rationalized by a theoretical noncovalent interactions (NCI) analysis. The cumulative effects of weak forces were shown to create an efficient buckle as in a hook-and-loop fastener, and fine structural features within the glycoligand reduce repulsive interactions for the Cu(I) state. This study emphasizes that monosaccharide platforms are appropriate ligand backbones for a delicate geometric control at the metal center, with a network of weak interactions within the ligand. This structuration availing in glycoligands makes them attractive for metallic entasis.

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Entasis through Hook-and-Loop Fastening in a Glycoligand with Cumulative Weak Forces Stabilizing Cu^I

et al. 2015

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“…In the case of SmYrbA–Cu, the four equatorial bonds (2.0 Å) have the same length and are shorter than those observed in SmYrbA–Ni/Co whereas the two axial bonds (2.4 Å) are both elongated ( Figure 1 D). This difference is due to the Jahn–Teller effect in crystals of hexacoordinated copper(II) complexes [ 57 ]. It is noticeable that a lithium atom present in the crystallization condition was modeled into the electron density of the high-resolution structures of SmYrbA–Ni and SmYrbA–Cu ( Figure 1 A).…”

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confidence: 99%

Sinorhizobium melilotiYrbA binds divalent metal cations using two conserved histidines

et al. 2020

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Sinorhizobium meliloti is a nitrogen-fixing bacterium forming symbiotic nodules with the legume Medicago truncatula. S. meliloti possesses two BolA-like proteins (BolA and YrbA), the function of which is unknown. In organisms where BolA proteins and monothiol glutaredoxins (Grxs) are present, they contribute to the regulation of iron homeostasis by bridging a [2Fe-2S] cluster into heterodimers. A role in the maturation of iron-sulfur (Fe-S) proteins is also attributed to both proteins. In this study, we have performed a structure-function analysis of SmYrbA showing that it coordinates diverse divalent metal ions (Fe2+, Co2+, Ni2+, Cu2+ and Zn2+) using His32 and His67 residues, that are also used for Fe-S cluster binding in BolA-Grx heterodimers. It also possesses the capacity to form heterodimers with the sole monothiol glutaredoxin (SmGrx2) present in this species. Using cellular approaches analyzing the metal tolerance of S. meliloti mutant strains inactivated in the yrbA and/or bolA genes, we provide evidence for a connection of YrbA with the regulation of iron homeostasis. The mild defects in M. truncatula nodulation reported for the yrbAbolA mutant as compared to the stronger defects in nodule development previously observed for a grx2 mutant suggest functions independent of SmGrx2. These results help clarifying the physiological role of BolA-type proteins in bacteria.

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“…This is indicative of delocalization of the π interaction over the metallocycle in compounds 1 and 2. 22 leads to the nonequivalence of the C-C γ and C-O bonds in the metallocycle, i.e., to partial local ization of the π interaction in the β diketonate ligand. In the crystal structure, the cluster cations form zigzag chains through shortened S eq ...S eq (3.58-3.63 Å) and Se eq ...Se eq (3.54-3.56 Å) contacts (Fig.…”

Section: Resultsmentioning

confidence: 99%

Mechanochemical synthesis and crystal structure of acetylacetonate complexes with the triangular Mo3Q7 4+ core (Q = S or Se)

et al. 2006

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Mechanochemical reactions of inorganic polymers 1 ∞ [Mo 3 Q 7 Br 4 ] (Q = S or Se) with sodium acetylacetonate hydrate lead to excision of the Mo 3 Q 7 4+ cluster core giving rise to the cationic complexes [Mo 3 Q 7 (acac) 3 ] + . Extraction of the reaction mixture with acetone followed by recrystallization from a benzene-hexane mixture afforded the {[Mo 3 S 7 (CH 3 COCHCOCH 3 ) 3 ]Br}•2C 6 H 6 (1) and {[Mo 3 Se 7 (CH 3 COCHCOCH 3 ) 3 ]Br}• •2C 6 H 6 (2) complexes. The structures of complexes 1 and 2 were studied by IR and 1 H NMR spectroscopy and X ray diffraction. Compound 1 was characterized by electrospray mass spectrometry.Many halide and chalcogenide clusters of transition metals are readily available and can be prepared by the high temperature synthesis from simple compounds in high yields. These reactions primarily produce coordina tion polymers, in which cluster fragments are linked to each other through bridging ligands to form one , two , or three dimensional structures characterized by low re activity. 1-4 The reactions of such polymers with melts of PPh 4 X (X = Cl or Br), KNCS, or o phenathroline are used for the synthesis of the discrete complexes [M 3 Q 7 X 6 ] 2-, [Mo 3 Q 7 (phen) 3 ] 4+ , and [Nb 2 (S 2 ) 2 (NCS) 8 ] 4-from one dimensional compounds [M 3 Q 7 X 4/2 X 4 ] and two dimen sional compounds [Nb 2 (S 2 ) 2 X 8/2 ] (M = Mo or W; Q = S or Se). 5-7 Another method for excision of the cluster core from solid coordination polymers is based on mecha nochemical reactions with solid reagents. 8,9 The use of mechanochemistry in the synthesis of coordination com pounds involves the preparation of boranes 10 and 3d metal complexes (β diketonates, cyclopentadienyls, and di thiocarbamates). 11-13 Earlier, we have used the mecha nochemical synthesis for the preparation of derivatives with the cluster cores M 3 Se 7 4+ (M = Mo or W) and Nb 2 Se 4 4+ . 8,14 In some cases, this is the only route to these complexes. In the present study, we performed mechanochemical reactions of the one dimensional inorganic polymers 1 ∞ [Mo 3 Q 7 Br 4/2 Br 2 ] with sodium acetylacetonate hydrate. These reactions followed by ex traction with acetone and crystallization afforded new {[Mo 3 Q 7 (CH 3 COCHCOCH 3 ) 3 ]Br}•2C 6 H 6 complexes (Q = S or Se). The structures of the resulting compounds were established by X ray diffraction. Results and DiscussionThe reactions of the coordination polymers 1 ∞ [Mo 3 Q 7 Br 4 ] with sodium acetylacetonate in a vibration mill lead to excision of the cluster fragments Mo 3 Q 7 giv ing rise to the corresponding [Mo 3 Q 7 (acac) 3 ] + complexes (Q = S or Se):Mo 3 Q 7 Br 4 + 3 Na(acac) → [Mo 3 Q 7 (acac) 3 ]Br + 3 NaBr.These complexes were extracted with acetone. After crystallization from a benzene-hexane mixture, the com plexes were isolated as crystal solvates with two benzene molecules, {[Mo 3 S 7 (CH 3 COCHCOCH 3 ) 3 ]Br}•2C 6 H 6 (1) and {[Mo 3 Se 7 (CH 3 COCHCOCH 3 ) 3 ]Br}•2C 6 H 6 (2). Low yields of the mechanochemical reactions are com pensated by the fact that the starting polym...

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Jahn-Teller distortions in octahedral copper(II) complexes

Cited by 118 publications

References 0 publications

Entasis through Hook-and-Loop Fastening in a Glycoligand with Cumulative Weak Forces Stabilizing Cu^I

Entasis through Hook-and-Loop Fastening in a Glycoligand with Cumulative Weak Forces Stabilizing Cu^I

Sinorhizobium melilotiYrbA binds divalent metal cations using two conserved histidines

Mechanochemical synthesis and crystal structure of acetylacetonate complexes with the triangular Mo3Q7 4+ core (Q = S or Se)

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Jahn-Teller distortions in octahedral copper(II) complexes

Cited by 118 publications

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Entasis through Hook-and-Loop Fastening in a Glycoligand with Cumulative Weak Forces Stabilizing CuI

Entasis through Hook-and-Loop Fastening in a Glycoligand with Cumulative Weak Forces Stabilizing CuI

Sinorhizobium melilotiYrbA binds divalent metal cations using two conserved histidines

Mechanochemical synthesis and crystal structure of acetylacetonate complexes with the triangular Mo3Q7 4+ core (Q = S or Se)

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Entasis through Hook-and-Loop Fastening in a Glycoligand with Cumulative Weak Forces Stabilizing Cu^I

Entasis through Hook-and-Loop Fastening in a Glycoligand with Cumulative Weak Forces Stabilizing Cu^I