More hydra than Janus – Non-classical coordination modes in complexes of oligopyridine ligands

Constable, Edwin C.; Housecroft, Catherine E.

doi:10.1016/j.ccr.2017.06.006

Cited by 50 publications

(33 citation statements)

References 197 publications

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“…Constable and Housecroft described nonclassical coordination modes in complexes of oligopyridine ligands [77]. They wrote that these are "more Hydra than Janus".…”

Section: Oxidation Of Hydrocarbons and Alcohols With Peroxides Catalymentioning

confidence: 99%

Metal Complexes Containing Redox-Active Ligands in Oxidation of Hydrocarbons and Alcohols: A Review

2019

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Ligands are innocent when they allow oxidation states of the central atoms to be defined. A noninnocent (or redox) ligand is a ligand in a metal complex where the oxidation state is not clear. Dioxygen can be a noninnocent species, since it exists in two oxidation states, i.e., superoxide (O2−) and peroxide (O22−). This review is devoted to oxidations of C–H compounds (saturated and aromatic hydrocarbons) and alcohols with peroxides (hydrogen peroxide, tert-butyl hydroperoxide) catalyzed by complexes of transition and nontransition metals containing innocent and noninnocent ligands. In many cases, the oxidation is induced by hydroxyl radicals. The mechanisms of the formation of hydroxyl radicals from H2O2 under the action of transition (iron, copper, vanadium, rhenium, etc.) and nontransition (aluminum, gallium, bismuth, etc.) metal ions are discussed. It has been demonstrated that the participation of the second hydrogen peroxide molecule leads to the rapture of O–O bond, and, as a result, to the facilitation of hydroxyl radical generation. The oxidation of alkanes induced by hydroxyl radicals leads to the formation of relatively unstable alkyl hydroperoxides. The data on regioselectivity in alkane oxidation allowed us to identify an oxidizing species generated in the decomposition of hydrogen peroxide: (hydroxyl radical or another species). The values of the ratio-of-rate constants of the interaction between an oxidizing species and solvent acetonitrile or alkane gives either the kinetic support for the nature of the oxidizing species or establishes the mechanism of the induction of oxidation catalyzed by a concrete compound. In the case of a bulky catalyst molecule, the ratio of hydroxyl radical attack rates upon the acetonitrile molecule and alkane becomes higher. This can be expanded if we assume that the reactions of hydroxyl radicals occur in a cavity inside a voluminous catalyst molecule, where the ratio of the local concentrations of acetonitrile and alkane is higher than in the whole reaction volume. The works of the authors of this review in this field are described in more detail herein.

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“…Constable and Housecroft described nonclassical coordination modes in complexes of oligopyridine ligands [77]. They wrote that these are "more Hydra than Janus".…”

Section: Oxidation Of Hydrocarbons and Alcohols With Peroxides Catalymentioning

confidence: 99%

Metal Complexes Containing Redox-Active Ligands in Oxidation of Hydrocarbons and Alcohols: A Review

2019

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“…Anal. Calcd for [1d](PF 6 ) 2 : C 25 13 Using a protocol similar to that described for the synthesis of [1d](PF 6 ) 2 , the reaction between [Ru(pynp)(CO) 2 (OH 2 ) 2 ](CF 3 13 13 25, 158.70, 157.76, 157.19, 155.92, 155.86, 151.01, 145.17, 144.22, 142.97, 142.70, 140.27, 139.57, 139.51, 131.42, 130.27, 129.16, 127.64, 127.58, 126.57, 126.11, 125.68, 125.63, 122.23, 122.03.…”

Section: General Remarksmentioning

confidence: 99%

“…The following are available online at http://www.mdpi.com/1420-3049/25/1/27/s1, Figure S1: Molecular structure of [Ru(pynp)(CO) 2 (OH 2 )(CH 3 CN)] 2+ , Figure S2: Optimized structures of the monosubstituted precursor of [3] 2+ with the electronic energy difference, Figure S3: Electronic spectra of [1d] 2+ , [1p] 2+ , [2d] 2+ , [2d] 2+ , and [3dp] 2+ , Figure S4: Cyclic voltammograms of [2p] 2+ at various scan rates, Figure S5: Molecular structure of [Ru(pynp) 2 (CH 3 CN) 2 ] 2+ , Figure S6: Molecular structure of [Ru(pynp)(phen)(CO) (C(O)OC 2 H 5 )] + , Table S1: Crystallographic data for [Ru(pynp)(CO) 2 (OH 2 )(CH 3…”

Section: Supplementary Materialsmentioning

confidence: 99%

“…Polypyridines with multiple covalently bonded pyridine groups exhibit unique photophysical and redox properties [1,2]. Among the polypyridines, bipyridine analogues play an important role in the formation of various transition metal complexes as bidentate ligands with two nitrogen donor atoms [3]. Bipyridine analogues function not only as supporting ligands for stabilizing metal complexes, but also as electron pool sites.…”

Section: Introductionmentioning

confidence: 99%

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Coordination Chemistry of Ru(II) Complexes of an Asymmetric Bipyridine Analogue: Synergistic Effects of Supporting Ligand and Coordination Geometry on Reactivities

et al. 2019

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The reactivities of transition metal coordination compounds are often controlled by the environment around the coordination sphere. For ruthenium(II) complexes, differences in polypyridyl supporting ligands affect some types of reactivity despite identical coordination geometries. To evaluate the synergistic effects of (i) the supporting ligands, and (ii) the coordination geometry, a series of dicarbonyl–ruthenium(II) complexes that contain both asymmetric and symmetric bidentate polypyridyl ligands were synthesized. Molecular structures of the complexes were determined by X-ray crystallography to distinguish their steric configuration. Structural, computational, and electrochemical analysis revealed some differences between the isomers. Photo- and thermal reactions indicated that the reactivities of the complexes were significantly affected by both their structures and the ligands involved.

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“…The notation tpy-20 is described in Section 2.3.1. We described this bonding mode as hypodentate and the nomenclature is extended to include coordinated ligands in which the maximum number of potential donor atoms are not involved in binding to a metal centre (38,39).…”

Section: Metallosupramolecular Chemistrymentioning

confidence: 99%

A Journey From Solution Self-Assembly to Designed Interfacial Assembly

Constable

2018

Advances in Inorganic Chemistry

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This article describes the development of concepts in metallosupramolecular chemistry. In particular, the transfer of the concepts from solution phase to metallosupramolecular chemistry at solid-fluid interfaces is discussed. The concept of metal-binding domains is quantified and used for the design of ligands for specific supramolecular applications. The use of weak interactions for the investigation of surface supramolecular chemistry is presented followed by the "surfaces as ligands, surfaces as complexes" approach for the design of functional devices. This conceptual development is placed in the concept the author's own laboratory.This account is about a journey from "traditional" coordination chemistry, through solution phase supramolecular chemistry to the use of the paradigms and methodologies of self-organization and self-assembly in the construction of ordered and hierarchical structures at solid-fluid interfaces. At the end phase of this journey, interactions with atomically well-defined and low-dimensional surfaces as well-as complex nanostructured surfaces will be considered. FROM COORDINATION CHEMISTRY TO METALLOSUPRAMOLECULAR CHEMISTRY Coordination chemistry as molecular recognition"What goes around comes around" -this journey begins with the design of 2,2'bipyridine ligands for application in what came to be known as dye-sensitized solar cells and ends in the development of new methodologies for the design of these and related systems. Rutile (TiO 2 ) is a semiconductor with a band gap of » 3.0 eV and exhibits no photocurrent upon irradiation with light l > 450 nm. In contrast, the complex [Ru(bpy) 2 (1)] exhibits a typical {Ru II (bpy) 3 } absorption close to 450 nm.The complex [Ru(bpy) 2 (1)] binds to the surface of single crystal rutile and acts as a photosensitizer, allowing the photoinjection of electrons directly into the conduction band upon irradiation with visible light l > 450 nm (Figure 1) (3). The photocurrents were modest and it was only when Grätzel used this strategy for the modification of nanostructured TiO 2 surfaces, allowing very high dye-loading, that the method became viable (4,5,6).

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More hydra than Janus – Non-classical coordination modes in complexes of oligopyridine ligands

Cited by 50 publications

References 197 publications

Metal Complexes Containing Redox-Active Ligands in Oxidation of Hydrocarbons and Alcohols: A Review

Metal Complexes Containing Redox-Active Ligands in Oxidation of Hydrocarbons and Alcohols: A Review

Coordination Chemistry of Ru(II) Complexes of an Asymmetric Bipyridine Analogue: Synergistic Effects of Supporting Ligand and Coordination Geometry on Reactivities

A Journey From Solution Self-Assembly to Designed Interfacial Assembly

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