Discotic mesomorphism in oxovanadium(IV) complexes possessing four alkyl substituents

Tantrawong, Sukrit; Styring, Peter; Goodby, John W.

doi:10.1039/jm9930301209

Cited by 19 publications

(5 citation statements)

References 8 publications

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“…Synthesis. Synthetic procedures for alkylated dibenzoylmethanes, HL- n , involving a coupling reaction between derivatives of acetophenone and methyl benzoate, and the Ru(III) mixed chelate complexes have been described in the literature, , from which the present preparations were adapted. A representative case of n = 3 is described below, and lists of analytical data for others will follow.…”

Section: Methodsmentioning

confidence: 99%

“…1-(3,4-Dioctyloxyphenyl)-3-(4 ‘ -octyloxyphenyl)propane-1,3-dione (HL-3). 28f A 5.0 g quantity of 3,4-dioctyloxyacetophenone (13 mmol) prepared above was reacted with an excess of NaH (1.27 g, 53 mmol) in 150 mL of DME under nitrogen atmosphere. An equimolar amount of methyl 4-octyloxybenzoate 28b was added, and the mixture was refluxed overnight.…”

Section: Methodsmentioning

confidence: 99%

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ΔΛ-Isomerism of Mixed 1,3-Diketonate Complexes of Ru(III)A Designed New Source of Chirality in Nematic Liquid Crystals

et al. 2005

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A high-power chiral dopant system involving 6-coordinate metal complexes was designed on the basis of a shape model. Accordingly, a series of mixed 1,3-diketonate complexes of Ru(III), [Ru(acac) 2 (L-n)], in which acac ) acetylacetonate and L-n ) dibenzoylmethanate substituted with n octyloxy groups (abbreviated as Ru-n hereafter), was prepared and optically resolved. Their performance as chiral dopants was evaluated in terms of helical twisting power (HTP) in a room-temperature nematic liquid crystal, N-(4-methoxybenzylidene)-4-n-butylaniline (MBBA), by measuring the helical pitch lengths and CD spectra for the induced chiral nematic phases. The ∆-and Λ-enantiomers induced macroscopic lefthanded (M) and right-handed (P) helices, respectively, and the (absolute) values for HTP have proven to be remarkably large, e.g. M ) 1.8 × 10 2 µm -1 in the case of Λ-Ru-2. The induced CD spectra for the dilute MBBA* materials (the asterisk denotes in this paper that MBBA has been doped with a chiral substance) were fit to the interpretation that persistent helical alignment of host molecules was generated. We also performed quantum chemical calculations for the optimum configuration of model Al(III) complexes with and without MBBA molecules and found that two liquid crystal molecules will eventually form a negative dihedral angle (left-handed twist) over the ∆-enantiomer of dialkylated complex.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

ΔΛ-Isomerism of Mixed 1,3-Diketonate Complexes of Ru(III)A Designed New Source of Chirality in Nematic Liquid Crystals

et al. 2005

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“…Among its complexes, the vanadyl acetylacetonate (VO(acac) 2 ) is certainly the most representative species. VO(acac) 2 has been the subject of many experimental investigations devoted to its interesting paramagnetic − and physicochemical ,, properties, mainly associated with the 3d 1 electronic configuration.…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure of Bis(2,4-pentanedionato-O,O‘)oxovanadium(IV). A Photoelectron Spectroscopy, Electronic Spectroscopy, and ab Initio Molecular Orbital Study

et al. 1996

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The electronic structure of the title VO(acac)(2) complex has been investigated using effective core potential configuration interaction ab initio calculations, UV-photoelectron spectroscopy, and electronic spectroscopy. The metal-ligand bonding with the equatorial acac(-) ligands is dominated by sigma interactions involving the filled ligand orbitals and the empty orbitals of the d(1) vanadium(IV) ion. The oxovanadium interactions involve a larger metal-d participation thus resulting in a strong V-O bonding having partial triple-bond character. Additional three-orbital-four-electron stabilizing interactions involving the filled acac(-) MOs and the oxovanadium orbitals further reinforce both the axial and equatorial bonds. The unpaired metal-d electron is completely localized in the nonbonding d(x)()()2(-)(y)()()2 orbital. The low ionization energy of the photoelectron spectrum has been fully assigned on the basis of combined DeltaSCF and configuration interaction calculations. The same theoretical approach has, in addition, provided a good fitting of frequencies associated with "d-d" and charge transfer electronic transitions.

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“…Under these circumstances, vanadium compounds can be exploited to produce organic semiconductors, magnetic materials and display devices [3] [4]. Vanadium complexes have been a growing topic of research because of their versatile physicochemical properties [4] [5].…”

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confidence: 99%

Synthesis and Evaluation of the Semiconductor Behavior in Vanadium Indanone Derivatives Thin Films

Lozano-González¹,

Sánchez-Vergara²,

Alvarado-Beltrán³

et al. 2017

AMPC

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In this work, we propose a method to synthesize vanadium (IV) 2-benzyli-dene-1-indanone derivatives, used to prepare film structures by thermal evaporation. The complexes possess high melting point allowing the using of vacuum deposition methods. All the samples were grown at room temperature (25˚C) and low deposition rates (0.4 Å/s). The surface morphology and structure of the deposited films were studied by scanning electron microscopy (SEM) and spectroscopy dispersive energy (EDS). Optical absorption studies of the complex films were performed in the 200 -1100 nm wavelength range. The Tauc band gap (Eg) of the thin films was determined from the (αhν) 1/2 vs. hν plots for indirect transitions. The vanadium (IV) complex films show optical activation energies in the range of organic semiconductors. Multilayer nylon 11/vanadium indanone devices were fabricated using ITO and silver electrodes. The d.c. electrical properties of the device were also investigated. It was found that the temperature-dependent electric current in the structure showed a semiconductor behavior. At lower voltages below 7 V, the current density in the forward direction was found to obey an ohmic I-V relationship; for higher voltages above 7 V, the conduction was dominated by a space-charge-limited (SCLC) mechanism. The electrical activation energies (Ea) of the complexes were in the 2.17 -2.31 eV range.

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Discotic mesomorphism in oxovanadium(IV) complexes possessing four alkyl substituents

Cited by 19 publications

References 8 publications

ΔΛ-Isomerism of Mixed 1,3-Diketonate Complexes of Ru(III)A Designed New Source of Chirality in Nematic Liquid Crystals

ΔΛ-Isomerism of Mixed 1,3-Diketonate Complexes of Ru(III)A Designed New Source of Chirality in Nematic Liquid Crystals

Electronic Structure of Bis(2,4-pentanedionato-O,O‘)oxovanadium(IV). A Photoelectron Spectroscopy, Electronic Spectroscopy, and ab Initio Molecular Orbital Study

Synthesis and Evaluation of the Semiconductor Behavior in Vanadium Indanone Derivatives Thin Films

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