Evidence for Charge Delocalization in Diazafluorene Ligands Supporting Low‐Valent [Cp*Rh] Complexes

Ligands based upon the 4,5-diazafluorene core are an important class of emerging ligands in organometallic chemistry, but the structure and electronic properties of these ligands have received less attention than they deserve. Here, we show that 9,9′-dimethyl-4,5-diazafluorene (Me2daf) can stabilize low-valent complexes through charge delocalization into its conjugated π-system. Using a new platform of [Cp*Rh] complexes with three accessible formal oxidation states (+III, +II, and +I), we show that the methylation in Me2daf is protective, blocking Brønsted acid-base chemistry commonly encountered with other daf-based ligands. Electronic absorption spectroscopy and single-crystal X-ray diffraction analysis of a family of eleven new compounds, including the unusual Cp*Rh(Me2daf), reveal features consistent with charge delocalization driven by π-backbonding into the LUMO of Me2daf, reminiscent of behavior displayed by the workhorse 2,2′-bipyridyl ligand. Taken together with spectrochemical data demonstrating clean conversion between oxidation states, our findings show that 9,9′-dialkylated daf-type ligands are promising building blocks for applications in reductive chemistry and catalysis.

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HUMO-LUMO Studies on Methyl Orange Doped ZTS Crystals for Laser Applications

International Journal of Emerging Research in Management and Technology ◽

10.23956/ijermt.v6i6.292 ◽

2018 ◽

Vol 6 (6) ◽

pp. 362

Author(s):

G. Suresh ◽

K. Sambath Kumar ◽

P. Ambalavanan ◽

P. Kumaresan

Keyword(s):

Molecular Electrostatic Potential ◽

Nbo Analysis ◽

Inorganic Materials ◽

Thermo Gravimetric ◽

Laser Applications ◽

Charge Delocalization ◽

Device Applications ◽

Warming Rate ◽

The Stability ◽

Homo Lumo

Zinc Thiourea Sulphate (ZTS), crystal is a magnificent metal natural compound, which consolidates the upsides of both natural and inorganic materials when contrasted and other customary non-linear optical materials and in this way can be utilized as a part of a more extensive scope of uses. Late endeavors at delivering new recurrence transformation materials have concentrated essentially on expanding the extent of the NLO properties that can recurrence twofold low pinnacle control sources, for example, diode lasers. The thermo gravimetric examination (TGA) and differential warm investigation (DTA) were completed utilizing Seiko warm analyzer at warming rate 20°C/min in air to decide the warm dependability of the compound. ZTS crystals were developed by moderate cooling procedure. This empowers the development of mass gems along all the three bearings at an ideal pH. FTIR examines demonstrate that in the spectra of ZTS there is a move in the recurrence band in the low-recurrence district which uncovers that thiourea shapes sulfur-to-zinc securities in the ZTS crystals. The stability and charge delocalization of the molecule were also studied by natural bond orbital (NBO) analysis. The HOMO-LUMO energies describe the charge transfer takes place within the molecule. Molecular electrostatic potential has been analyzed. The developments try in extensive scale with this enhanced pH qualities is required to yield mass crystal appropriate for laser combination tests and SHG device applications.

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Charge delocalization in the ludwigite Fe3O2BO3

Journal of Physics Condensed Matter ◽

10.1088/0953-8984/13/48/105 ◽

2001 ◽

Vol 13 (48) ◽

pp. L949-L954 ◽

Cited By ~ 10

Author(s):

J Larrea ◽

D R Sánchez ◽

F J Litterst ◽

E M Baggio-Saitovitch

Keyword(s):

Charge Delocalization

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The coordination of low-valent Re/Tc with glutarimide dioxime and the fate of Tc in aqueous solution: spectroscopy, ESI–MS and EXAFS

Journal of Radioanalytical and Nuclear Chemistry ◽

10.1007/s10967-021-07738-4 ◽

2021 ◽

Author(s):

Aidan He ◽

Zhihai Fu ◽

Zi Yin ◽

Yuwei Xu ◽

Jinyang Kang ◽

...

Keyword(s):

Aqueous Solution ◽

Esi Ms ◽

Low Valent

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Catalytic Antioxidant Activity of Bis-Aniline-Derived Diselenides as GPx Mimics

Molecules ◽

10.3390/molecules26154446 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4446

Author(s):

Giancarlo V. Botteselle ◽

Welman C. Elias ◽

Luana Bettanin ◽

Rômulo F. S. Canto ◽

Drielly N. O. Salin ◽

...

Keyword(s):

Antioxidant Activity ◽

Hydrogen Bond ◽

Electronic Properties ◽

Partial Charge ◽

Amino Group ◽

Diphenyl Diselenide ◽

Charge Delocalization ◽

Ipso Substitution ◽

Efficient Route ◽

Catalytic Performances

Herein, we describe a simple and efficient route to access aniline-derived diselenides and evaluate their antioxidant/GPx-mimetic properties. The diselenides were obtained in good yields via ipso-substitution/reduction from the readily available 2-nitroaromatic halides (Cl, Br, I). These diselenides present GPx-mimetic properties, showing better antioxidant activity than the standard GPx-mimetic compounds, ebselen and diphenyl diselenide. DFT analysis demonstrated that the electronic properties of the substituents determine the charge delocalization and the partial charge on selenium, which correlate with the catalytic performances. The amino group concurs in the stabilization of the selenolate intermediate through a hydrogen bond with the selenium.

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Facile synthesis of novel, known, and low-valent transition metal phosphates via reductive phosphatization

Journal of Materials Chemistry A ◽

10.1039/d1ta03782j ◽

2021 ◽

Author(s):

Niklas Stegmann ◽

Hilke Petersen ◽

Claudia Weidenthaler ◽

Wolfgang Schmidt

Keyword(s):

Transition Metal ◽

Oxidation States ◽

Facile Synthesis ◽

Metal Phosphates ◽

Low Valent

Novel and known low valent transition metal phosphates (TMPs) are accessible via a novel and facile pathway. The method allows syntheses of TMPs also with reduced oxidation states. The key...

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Low-valent dialkoxytitanium(ii): a useful tool for the synthesis of functionalized seven-membered ring compounds

Chemical Communications ◽

10.1039/d1cc00081k ◽

2021 ◽

Vol 57 (29) ◽

pp. 3603-3606

Author(s):

Florent Bodinier ◽

Youssouf Sanogo ◽

Janick Ardisson ◽

Marie-Isabelle Lannou ◽

Geoffroy Sorin

Keyword(s):

Grignard Reagent ◽

Membered Ring ◽

Ring Compounds ◽

Low Valent

Herein, we describe unprecedented access to all-carbon or heterocyclic seven-membered ring frameworks from 1,8-ene-ynes promoted by inexpensive low-valent titanium(ii) species, readily available from a combination of Ti(OiPr)4 and Grignard reagent.

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Glycan-to-Glycan Binding: Molecular Recognition through Polyvalent Interactions Mediates Specific Cell Adhesion

Molecules ◽

10.3390/molecules26020397 ◽

2021 ◽

Vol 26 (2) ◽

pp. 397

Author(s):

Gradimir Misevic ◽

Emanuela Garbarino

Keyword(s):

Cell Adhesion ◽

Plasma Membranes ◽

Specific Cell ◽

Cellular Interactions ◽

New Paradigm ◽

Tumor Cell Adhesion ◽

Self Recognition ◽

Structural And Functional Properties ◽

Low Valent

Glycan-to-glycan binding was shown by biochemical and biophysical measurements to mediate xenogeneic self-recognition and adhesion in sponges, stage-specific cell compaction in mice embryos, and in vitro tumor cell adhesion in mammals. This intermolecular recognition process is accepted as the new paradigm accompanying high-affinity and low valent protein-to-protein and protein-to-glycan binding in cellular interactions. Glycan structures in sponges have novel species-specific sequences. Their common features are the large size >100 kD, polyvalency >100 repeats of the specific self-binding oligosaccharide, the presence of fucose, and sulfated and/or pyruvylated hexoses. These structural and functional properties, different from glycosaminoglycans, inspired their classification under the glyconectin name. The molecular mechanism underlying homophilic glyconectin-to-glyconectin binding relies on highly polyvalent, strong, and structure-specific interactions of small oligosaccharide motifs, possessing ultra-weak self-binding strength and affinity. Glyconectin localization at the glycocalyx outermost cell surface layer suggests their role in the initial recognition and adhesion event during the complex and multistep process. In mammals, Lex-to-Lex homophilic binding is structure-specific and has ultra-weak affinity. Cell adhesion is achieved through highly polyvalent interactions, enabled by clustering of small low valent structure in plasma membranes.

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