Ni Dithiolenes – A Theoretical Study on Structure–Property Relationships

Avramopoulos, Aggelos; Reis, Heribert; Mousdis, George A.; Παπαδόπουλος, Μάνθος Γ.

doi:10.1002/ejic.201300534

Cited by 14 publications

(16 citation statements)

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“…This is a remarkable observation, because lithiation of 5 – 7 leads to a large increase of γ zzzz and a decrease of DC, as compared to the nonlithiated ones. In another series of derivatives, we have found that both DC and γ zzzz follow the same trend …”

Section: Resultsmentioning

confidence: 66%

“…The molecular structures of (NiBDT) m +1 (RA) m and their lithiated derivatives were optimized by using the broken symmetry (U)B3LYP/6-31G* method. The latter approach has been shown to provide fairly accurate geometries for conjugated systems, including transition metal atoms . Both (NiBDT) m +1 (RA) m and their lithiated analogues are planar and lie on the XoZ plane (Figures and , Figure S2), with their longitudinal axis oriented along the z axis.…”

Section: Methodsmentioning

confidence: 99%

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A Series of Novel Derivatives with Giant Second Hyperpolarizabilities, Based on Radiaannulenes, Tetrathiafulvalene, Nickel Dithiolene, and Their Lithiated Analogues

et al. 2016

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The main goal of this study was the design/ recognition of a series of derivatives with exceptionally large hyperpolarizabilities, the understanding of the mechanism through which these properties are derived, and the generalization of the resulting findings. Thus, we have studied the structure, a series of properties involving the excitation energies and the diradical character, but mainly the (hyper)polarizabilities of some oligomers of radiaannulene-tetrathiafulvalene (RA-TTF), radiaannulene-bis(ethylene-1,2dithiolato)nickel (RA-NiBDT), and their lithiated analogues. The employed methodology involves MP2 and DFT techniques, approaches for the computation of static and frequency-dependent properties, and techniques for the calculation of electronic and vibrational contributions. The polarizability has been partitioned be employing the fractional occupational Hirshfeld iterative method. Indices for the calculation of the diradical character of the NiBDT oligomers have been employed. We have found that (i) oligomerization increases γ zzzz (second hyperpolarizability), (ii) substitution of TTF with NiBDT leads to a very large increase of γ zzzz , and (iii) lithiation leads to extremely large nonlinearities. The importance of NiBDT and lithium as building blocks for the production of NLO materials is highlighted.

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Section: Resultsmentioning

confidence: 66%

Section: Methodsmentioning

confidence: 99%

A Series of Novel Derivatives with Giant Second Hyperpolarizabilities, Based on Radiaannulenes, Tetrathiafulvalene, Nickel Dithiolene, and Their Lithiated Analogues

et al. 2016

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“…Examination of the literature regarding nickel complexes coordinated to sulfur atoms immediately shows the recurrence of dithiolene and dithiolate ligands. More specifically, complexes of 1,2‐dithiolenes have been the subject of both experimental and theoretical work since the early reports of their synthesis and properties . This is because they exhibit nonlinear optical properties, are of bioinorganic interest owing to their similarity with molybdenum enzymes, and have found application in dye‐sensitized solar cells as chromophores, as catalysts in hydrogen evolution reactions, and as metallodrugs …”

Section: Introductionmentioning

confidence: 99%

Proton‐Reduction Reaction Catalyzed by Homoleptic Nickel–bis‐1,2‐dithiolate Complexes: Experimental and Theoretical Mechanistic Investigations

et al. 2017

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A series of homoleptic monoanionic nickel dithiolene complexes [Ni(bdt)2](NBu4), [Ni(tdt)2](NBu4), and [Ni(mnt)2](NBu4) containing the ligands benzene‐1,2‐dithiolate (bdt2−), toluene‐3,4‐dithiolate (tdt2−), and maleonitriledithiolate (mnt2−), respectively, were employed as electrocatalysts in the hydrogen‐evolution reaction with trifluoroacetic acid as the proton source in acetonitrile. All complexes are active catalysts with TONs reaching 113, 158, and 6 for [Ni(bdt)2](NBu4), [Ni(tdt)2](NBu4), and [Ni(mnt)2](NBu4), respectively. The Faradaic yield for the hydrogen evolution reaction reaches 88 % for 2−, which also displays the minimal overpotential requirement value (467 mV) within the series. Two pathways for H2 evolution can be hypothesized that differ in the sequence of protonation and reduction steps. DFT calculations are in agreement with experimental data and indicate that protonation at sulfur follows the reduction to the dianion. Hydrogen evolves from the direduced–diprotonated form via a highly distorted nickel hydride intermediate. The effects of acid strength and concentration in the hydrogen‐evolving mechanism are also discussed.

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“…For all compounds, tight SCF convergence criteria and fine numerical integration grids ( grid = ultrafine ) were used. In order to evaluate the singlet diradical contribution to the GS in the BS approach, the differences between the total electronic energy of the singlet state (ε S ), the BS-singlet state (ε BS ), and the triplet (ε T ) states were considered: 38 , 91 , 92 …”

Section: Methodsmentioning

confidence: 99%

Diradical Character of Neutral Heteroleptic Bis(1,2-dithiolene) Metal Complexes: Case Study of [Pd(Me₂timdt)(mnt)] (Me₂timdt = 1,3-Dimethyl-2,4,5-trithioxoimidazolidine; mnt^2– = 1,2-Dicyano-1,2-ethylenedithiolate)

et al. 2020

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The reaction of the bis(1,2-dithiolene) complex [Pd(Me2timdt)2] (1; Me2timdt•– = monoreduced 1,3-dimethyl-2,4,5-trithioxoimidazolidine) with Br2 yielded the complex [Pd(Me2timdt)Br2] (2), which was reacted with Na2mnt (mnt2– = 1,2-dicyano-1,2-ethylenedithiolate) to give the neutral mixed-ligand complex [Pd(Me2timdt)(mnt)] (3). Complex 3 shows an intense solvatochromic near-infrared (NIR) absorption band falling between 955 nm in DMF and 1060 nm in CHCl3 (ε = 10700 M–1 cm–1 in CHCl3). DFT calculations were used to elucidate the electronic structure of complex 3 and to compare it with those of the corresponding homoleptic complexes 1 and [Pd(mnt)2] (4). An in-depth comparison of calculated and experimental structural and vis–NIR spectroscopic properties, supported by IEF-PCM TD-DFT and NBO calculations, clearly points to a description of 3 as a dithione-dithiolato complex. For the first time, a broken-symmetry (BS) procedure for the evaluation of the singlet diradical character (DC) of heteroleptic bis(1,2-dithiolene) complexes has been developed and applied to complex 3. The DC, predominant for 1 (n D C = 55.4%), provides a remarkable contribution to the electronic structures of the ground states of both 3 and 4, showing a diradicaloid nature (n D C = 24.9% and 27.5%, respectively). The computational approach developed here clearly shows that a rational design of the DC of bis(1,2-ditiolene) metal complexes, and hence their linear and nonlinear optical properties, can be achieved by a proper choice of the 1,2-dithiolene ligands based on their electronic structure.

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Ni Dithiolenes – A Theoretical Study on Structure–Property Relationships

Cited by 14 publications

References 73 publications

A Series of Novel Derivatives with Giant Second Hyperpolarizabilities, Based on Radiaannulenes, Tetrathiafulvalene, Nickel Dithiolene, and Their Lithiated Analogues

A Series of Novel Derivatives with Giant Second Hyperpolarizabilities, Based on Radiaannulenes, Tetrathiafulvalene, Nickel Dithiolene, and Their Lithiated Analogues

Proton‐Reduction Reaction Catalyzed by Homoleptic Nickel–bis‐1,2‐dithiolate Complexes: Experimental and Theoretical Mechanistic Investigations

Diradical Character of Neutral Heteroleptic Bis(1,2-dithiolene) Metal Complexes: Case Study of [Pd(Me₂timdt)(mnt)] (Me₂timdt = 1,3-Dimethyl-2,4,5-trithioxoimidazolidine; mnt^2– = 1,2-Dicyano-1,2-ethylenedithiolate)

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Ni Dithiolenes – A Theoretical Study on Structure–Property Relationships

Cited by 14 publications

References 73 publications

A Series of Novel Derivatives with Giant Second Hyperpolarizabilities, Based on Radiaannulenes, Tetrathiafulvalene, Nickel Dithiolene, and Their Lithiated Analogues

A Series of Novel Derivatives with Giant Second Hyperpolarizabilities, Based on Radiaannulenes, Tetrathiafulvalene, Nickel Dithiolene, and Their Lithiated Analogues

Proton‐Reduction Reaction Catalyzed by Homoleptic Nickel–bis‐1,2‐dithiolate Complexes: Experimental and Theoretical Mechanistic Investigations

Diradical Character of Neutral Heteroleptic Bis(1,2-dithiolene) Metal Complexes: Case Study of [Pd(Me2timdt)(mnt)] (Me2timdt = 1,3-Dimethyl-2,4,5-trithioxoimidazolidine; mnt2– = 1,2-Dicyano-1,2-ethylenedithiolate)

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Diradical Character of Neutral Heteroleptic Bis(1,2-dithiolene) Metal Complexes: Case Study of [Pd(Me₂timdt)(mnt)] (Me₂timdt = 1,3-Dimethyl-2,4,5-trithioxoimidazolidine; mnt^2– = 1,2-Dicyano-1,2-ethylenedithiolate)