Closed-shell and open-shell square-planar iridium nitrido complexes

ABSTRACT: The influence of a redox-active ligand on spin changing events induced by coordination of exogenous donors is investigated within the cobalt complex [CoII(DPP•2‒)], bearing a redox-active DPP2‒ ligand (DPP = dipyrrin-bis-(o,p-di-tert-butylphenolato) with a pentafluorophenyl moiety on the meso-position. This square planar complex was subjected to coordination of THF, pyridine, tBuNH2 and AdNH2 (Ad = 1‑adamantyl), and the resulting complexes were analyzed with a variety of experimental (XRD, NMR, UV-Vis, HRMS, SQUID, Evans’ method) and computational (DFT, NEVPT2-CASSCF) techniques to elucidate the respective structures, spin states and orbital compositions of the corresponding octahedral bis-donor adducts, relative to [CoII(DPP•2‒)]. This starting species is best described as an open-shell singlet complex containing a DPP•2‒ ligand radical that is antiferromagnetically coupled to a low-spin (S = ½) cobalt(II) center. The redox-active DPPn‒ ligand plays a crucial role in stabilizing this complex, and in its facile conversion to the triplet THF-adduct [CoII(DPP•2‒)(THF)2] and closed-shell singlet pyridine and amine adducts [CoIII(DPP3‒)(L)2] (L = py, tBuNH2 or AdNH2). Coordination of the weak donor THF to [CoII(DPP•2-)] changes the orbital overlap between the DPP•2‒ ligand radical π-orbitals and the cobalt(II) metalloradical d-orbitals, which results in a spin-flip to the triplet ground state without changing the oxidation states of the metal or DPP•2‒ ligand. In contrast, coordination of the stronger donors pyridine, tBuNH2 or AdNH2 induces metal-to-ligand single-electron transfer, resulting in formation of low-spin (S = 0) cobalt(III)-complexes [CoIII(DPP3‒)(L)2] containing a fully reduced DPP3‒ ligand, thus explaining their closed-shell singlet electronic ground states.

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Ligand-Mediated Spin State Changes in a Cobalt-Dipyrrin-Bisphenol Complex

10.26434/chemrxiv.12605333 ◽

2020 ◽

Author(s):

Nicolaas P. van Leest ◽

Wowa Stroek ◽

Maxime A. Siegler ◽

Jarl Ivar van der Vlugt ◽

Bas de Bruin

Keyword(s):

Cobalt Complex ◽

Closed Shell ◽

Open Shell ◽

Triplet Ground State ◽

Redox Active Ligand ◽

Redox Active ◽

Square Planar ◽

Amine Adducts ◽

Meso Position ◽

Electronic Ground

ABSTRACT: The influence of a redox-active ligand on spin changing events induced by coordination of exogenous donors is investigated within the cobalt complex [CoII(DPP•2‒)], bearing a redox-active DPP2‒ ligand (DPP = dipyrrin-bis-(o,p-di-tert-butylphenolato) with a pentafluorophenyl moiety on the meso-position. This square planar complex was subjected to coordination of THF, pyridine, tBuNH2 and AdNH2 (Ad = 1‑adamantyl), and the resulting complexes were analyzed with a variety of experimental (XRD, NMR, UV-Vis, HRMS, SQUID, Evans’ method) and computational (DFT, NEVPT2-CASSCF) techniques to elucidate the respective structures, spin states and orbital compositions of the corresponding octahedral bis-donor adducts, relative to [CoII(DPP•2‒)]. This starting species is best described as an open-shell singlet complex containing a DPP•2‒ ligand radical that is antiferromagnetically coupled to a low-spin (S = ½) cobalt(II) center. The redox-active DPPn‒ ligand plays a crucial role in stabilizing this complex, and in its facile conversion to the triplet THF-adduct [CoII(DPP•2‒)(THF)2] and closed-shell singlet pyridine and amine adducts [CoIII(DPP3‒)(L)2] (L = py, tBuNH2 or AdNH2). Coordination of the weak donor THF to [CoII(DPP•2-)] changes the orbital overlap between the DPP•2‒ ligand radical π-orbitals and the cobalt(II) metalloradical d-orbitals, which results in a spin-flip to the triplet ground state without changing the oxidation states of the metal or DPP•2‒ ligand. In contrast, coordination of the stronger donors pyridine, tBuNH2 or AdNH2 induces metal-to-ligand single-electron transfer, resulting in formation of low-spin (S = 0) cobalt(III)-complexes [CoIII(DPP3‒)(L)2] containing a fully reduced DPP3‒ ligand, thus explaining their closed-shell singlet electronic ground states.

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Transalkylierung und protonenkatalysierte C-C-Spaltung bei n-Butyl-und n-Pentylbenzol in der Gasphase / Transalkylation and Proton Catalyzed C-C-Cleavage of Gaseous n-Butyl and w-Pentyl Benzenes

Zeitschrift für Naturforschung B ◽

10.1515/znb-1979-0325 ◽

1979 ◽

Vol 34 (3) ◽

pp. 495-501 ◽

Cited By ~ 19

Author(s):

C. Wesdemiotis ◽

H. Schwarz ◽

C. C. Van de Sande ◽

F. Van Gaever

Keyword(s):

Hydrogen Exchange ◽

Closed Shell ◽

Open Shell ◽

Molecular Ions ◽

Exchange Reactions ◽

Intramolecular Exchange ◽

Carbon Carbon Bond ◽

Exchange Processes ◽

Reaction Channels ◽

Alkyl Benzenes

Abstract The investigation of several 13carbon and deuterium labelled n-butyl and n-pentyl benzenes demonstrate that chemical ionization (reagent gas: methane) induces specific carbon-carbon bond cleavages of the alkyl group. The extent of competing reaction channels as for instance direct alkene elimination versus dealkylation/reprotonation is analyzed. Partial hydrogen exchange processes between reagent ions and substrate molecules are restricted to the phenyl ring. Intramolecular exchange reactions between the side chain and the aromatic ring which are typical for the open shell molecular ions of alkyl benzenes are not observed for analogous closed shell cations.

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Exploring Cu/Al cluster growth and reactivity: from embryonic building blocks to intermetalloid, open-shell superatoms

Chemical Science ◽

10.1039/d1sc00268f ◽

2021 ◽

Author(s):

Max Schütz ◽

Christian Gemel ◽

Maximilian Muhr ◽

Christian Jandl ◽

Samia Kahlal ◽

...

Keyword(s):

Closed Shell ◽

Building Blocks ◽

Open Shell ◽

Cluster Growth ◽

Powerful Technique

Cu/Al cluster growth reactions leading to open- and closed-shell superatoms are investigated. Therein, LIFDI-MS is presented as a powerful technique for the in situ detection of cluster identities and reactivity patterns.

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Open-Shell and Closed-Shell Quinoid–Aromatic Conjugated Polymers: Unusual Spin Magnetic and High Charge Transport Properties

ACS Applied Materials & Interfaces ◽

10.1021/acsami.0c15893 ◽

2021 ◽

Author(s):

Yunseul Kim ◽

Yeon-Ju Kim ◽

Yeong-A Kim ◽

Eunhwan Jung ◽

Yoonjung Mok ◽

...

Keyword(s):

Conjugated Polymers ◽

Charge Transport ◽

Transport Properties ◽

Closed Shell ◽

Open Shell ◽

High Charge

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Stresses and Deformations of Toroidal Shells of Elliptical Cross Section: With Applications to the Problems of Bending of Curved Tubes and of the Bourdon Gage

Journal of Applied Mechanics ◽

10.1115/1.4010404 ◽

1952 ◽

Vol 19 (1) ◽

pp. 37-48

Author(s):

R. A. Clark ◽

T. I. Gilroy ◽

E. Reissner

Keyword(s):

Cross Section ◽

Cross Sections ◽

Practical Interest ◽

Closed Shell ◽

Open Shell ◽

Elliptical Cross Section ◽

Axially Symmetric ◽

Elliptical Cross ◽

Two Parameters ◽

Toroidal Shells

Abstract This paper is concerned with the application of the theory of thin shells to several problems for toroidal shells with elliptical cross section. These problems are as follows: (a) Closed shell subjected to uniform normal wall pressure. (b) Open shell subjected to end bending moments. (c) Combination of the results for the first and second problems in such a way as to obtain results for the stresses and deformations in Bourdon tubes. In all three problems the distribution of stresses is axially symmetric but only in the first problem are the displacements axially symmetric. The magnitude of stresses and deformations for given loads depends in all three problems on the magnitude of the two parameters bc/ah and b/c where b and c are the semiaxes of the elliptical section, a is the distance of the center of the section from the axis of revolution, and h is the thickness of the wall of the shell. For sufficiently small values of bc/ah trigonometric series solutions are obtained. For sufficiently large values of bc/ah asymptotic solutions are obtained. Numerical results are given for various quantities of practical interest as a function of bc/ah for the values 2, 1, 1/2, 1/4 of the semiaxes ratio b/c. It is suggested that the analysis be extended to still smaller values of b/c and to cross sections other than elliptical.

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Changes in Electronic Properties of Polymeric One-Dimensional {[M(CN)2]−}n(M = Au, Ag) Chains Due to Neighboring Closed-Shell Zn(II) or Open-Shell Cu(II) Ions

Inorganic Chemistry ◽

10.1021/ic101841a ◽

2011 ◽

Vol 50 (1) ◽

pp. 231-237 ◽

Cited By ~ 18

Author(s):

François Baril-Robert ◽

Xiaobo Li ◽

Michael J. Katz ◽

Andrew R. Geisheimer ◽

Daniel B. Leznoff ◽

...

Keyword(s):

Electronic Properties ◽

Closed Shell ◽

Open Shell ◽

One Dimensional

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Open-shell Donors and Closed-shell Acceptors in Organic Solar Cells

10.26434/chemrxiv.14618622 ◽

2021 ◽

Author(s):

Zhongxin Chen ◽

Yuan Li ◽

Wenqiang Li ◽

Weiya Zhu ◽

Miao Zeng ◽

...

Keyword(s):

Solar Cells ◽

Electron Spin Resonance ◽

Electron Spin ◽

Organic Solar Cells ◽

Ground State ◽

Variable Temperature ◽

Closed Shell ◽

Open Shell ◽

Singlet Ground State ◽

Spin Resonance

The active materials of organic solar cells are widely recognized to show closed-shell singlet ground state and their electron spin resonance signals are attributed to the defects and impurities. Herein, we disclose the inherent open-shell singlet ground state of donors and the closed-shell structure of acceptors via the combination of variable temperature NMR, electron spin resonance, superconducting quantum interference device and theoretical calculation, providing a new perspective to understand the intrinsic molecular structure in organic solar cells.

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LOCALLY PROJECTED MOLECULAR ORBITAL THEORY FOR MOLECULAR INTERACTION WITH A HIGH-SPIN OPEN-SHELL MOLECULE

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633606002696 ◽

2006 ◽

Vol 05 (04) ◽

pp. 819-833 ◽

Cited By ~ 2

Author(s):

SUEHIRO IWATA

Keyword(s):

Molecular Orbital ◽

High Spin ◽

Closed Shell ◽

Open Shell ◽

Coefficient Matrix ◽

Molecular Orbitals ◽

Orbital Method ◽

Stationary Condition ◽

Orbital Theory ◽

Stationary Conditions

Locally projected molecular orbital method for molecular interactions is extended to a cluster consisting of a high-spin open-shell molecule and many closed-shell molecules. While deriving the equations, the Hartee–Fock–Roothaan equation without the orthonormal condition is obtained. The stationary conditions for molecular orbitals are expressed in a form of a generalized Brillouin condition. To obtain the molecular orbital coefficient matrix, which satisfies the stationary condition, a single Fock operator form is presented. For the locally projected molecular orbitals for the open-shell cluster, the working matrix representaion is given.

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