Preparation and Crystal Structure of Bis(tert-butyltetramethylcyclopentadienyl)dichlorotitanium

2005 ◽  
Vol 70 (10) ◽  
pp. 1589-1603 ◽  
Author(s):  
Lenka Lukešová ◽  
Róbert Gyepes ◽  
Jiří Pinkas ◽  
Michal Horáček ◽  
Jiří Kubišta ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Isomer Mixture ◽  
Sandwich Complex ◽  
Considerable Decrease ◽  
Methyl Group ◽  
Hydrolytic Product ◽  
Butyl Group ◽  
Half Sandwich

[TiCl2(η5-C5Me4t-Bu)2] (1) was prepared by the reaction of [TiCl3(thf)3] with 2 equivalents of Li(η5-C5Me4t-Bu) (made by adding BuLi to a 1.33 molar excess of a mixture of tert-butyltetramethylcyclopentadiene isomers in THF) and subsequent oxidation of the Ti(III) intermediate to 1 by adding aqueous HCl. Neglecting the presence of cyclopentadiene isomers not forming the cyclopentadienide anion in the isomer mixture used for the synthesis of 1 resulted in the formation of hydrolytic product [{TiCl2(η5-C5Me4t-Bu)}2(μ-O)] (2) and a considerable decrease of yield of 1. The half sandwich complex [TiCl3(η5-C5Me4t-Bu)] (3) was obtained by synproportionation of 1 and TiCl4. Crystal structures of 1, 2, and 3 were determined. The electronic absorption spectra of 1 and 3 indicate a stronger electron-donor effect of tert-butyl group compared with methyl group.

Synthesis and characteristics of ethylenediamine-N,N'-di-S-α-isovalerate and isomers of its cobalt(III) complexes

1982 ◽  
Vol 47 (1) ◽  
pp. 210-216 ◽  
Author(s):  
Milan Strašák ◽  
František Bachratý ◽  
Jaroslav Majer
Keyword(s):  
Amino Acids ◽  
Absolute Configuration ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Chemical Parameters ◽  
Methyl Group ◽  
Nmr Data ◽  
Physico Chemical ◽  
Natural Amino Acids ◽  
C Nmr

The synthesis and physico-chemical parameters are described of a new complexone based on natural amino acids, viz. ethylenediamine-N,N'-di-S-α-isovalerate (SS-EDDIV). 1H- and 13C-NMR data revealed that the methyl group in the substance are not equivalent. The isomers of the cobalt(III) complex with the asymmetric tetradentate SS-EDDIV ligand were prepared and separated; their characteristics are given. The absolute configuration of two of the five theoretically feasible isomers was determined based on their electronic absorption spectra and circular dichroism data.

scholarly journals Crystal structure oftrans-N,N′-bis(3,5-di-tert-butyl-2-hydroxyphenyl)oxamide methanol monosolvate

2016 ◽  
Vol 72 (7) ◽  
pp. 918-921
Author(s):  
Miguel-Ángel Velázquez-Carmona ◽  
Sylvain Bernès ◽  
Francisco Javier Ríos-Merino ◽  
Yasmi Reyes Ortega
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Hydroxy Group ◽  
Molecular Conformation ◽  
Methanol Molecule ◽  
Molecular Symmetry ◽  
Methyl Group ◽  
Supramolecular Motifs ◽  
Butyl Group ◽  
Hydroxy Groups

The here crystallized oxamide was previously characterized as an unsolvated species [Jímenez-Pérezet al.(2000).J. Organomet. Chem.614–615, 283–293], and is now reported with methanol as a solvent of crystallization, C30H44N2O4·CH3OH, in a different space group. The introduction of the solvent influences neither the molecular symmetry of the oxamide, which remains centrosymmetric, nor the molecular conformation. However, the unsolvated molecule crystallized as an ordered system, while many parts of the solvated crystal are disordered. The hydroxy group in the oxamide is disordered over two chemically equivalent positions, with occupancies 0.696 (4):0.304 (4); onetert-butyl group is disordered by rotation about the C—C bond, and was modelled with three sites for each methyl group, each one with occupancy 1/3. Finally, the methanol solvent, which lies on a twofold axis, is disordered by symmetry. The disorder affecting hydroxy groups and the solvent of crystallization allows the formation of numerous supramolecular motifs using four hydrogen bonds, with N—H and O—H groups as donors and the oxamide and methanol molecule as acceptors.

Synthesis and Characterization of Binuclear and Trinuclear Cobalt(III) Complexes With Imidazolate Bridges

1986 ◽  
Vol 39 (8) ◽  
pp. 1213 ◽  
Author(s):  
CJ Hawkins ◽  
E Horn ◽  
J Martin ◽  
JAL Palmer ◽  
MR Snow
Keyword(s):  
Crystal Structure ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
The Other ◽  
Synthesis And Characterization ◽  
Ammine Complexes

Two cobalt(III) ammine complexes are described which have an imidazolate ( Im ) ligand bridging cobalt(III) centres . Their electronic absorption spectra, 1H, 13C and 59Co n.m.r . spectra, and electrochemical data are presented. One complex is a bis [ pentaamminecobalt (III)] complex, [(H3N)5Co( Im )Co(NH3)5]5+, and the other has two pentaammineimidazolatocobalt (III) units coordinated in the cis arrangement to tetraamminecobalt (III). The crystal structure of cis - [(NH3)4Co{( Im )Co(NH3)5}2]Cl2(S2O6)2(OH).3.5H2O is reported. The crystals in the form of orange needles are monoclinic: Cc, a 20.18(1), b 17.089(9), c 15.395(7) Ǻ, β 123.76(4)°, Z 4. The structure was refined to R 0.079.

scholarly journals Crystal structure of the η4-ketimine titanium complex (diphenylamido-κN){3-methyl-6-[(4-methylphenyl)(phenylazanidyl)methylidene]cyclohexa-2,4-dien-1-yl-κ2N,C1}(η5-pentamethylcyclopentadienyl)titanium(IV)

2018 ◽  
Vol 74 (1) ◽  
pp. 34-37
Author(s):  
Malte Fischer ◽  
Marc Schmidtmann ◽  
Rüdiger Beckhaus
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Intermolecular Interactions ◽  
Coordination Mode ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Sandwich Complex ◽  
Titanium Complex ◽  
Half Sandwich

The molecular structure of the title titanium(IV) half-sandwich complex, [Ti(η5-C10H15)(η4-C21H19N)(C12H10N)], shows a three-legged piano-stool geometry at the central TiIVatom, comprising of one pentamethylcyclopentadienyl ligand, one bidentate ketimine ligand in an η4-coordination mode and one monodentate diphenylamide ligand. Except for van der Waals forces, there are no significant intermolecular interactions in the crystal.

Synthesis, Properties and Crystal Structure of Di(phthalocyaninato)lanthanum(III), a Partially Oxidized Semiconductor

1995 ◽  
Vol 50 (8) ◽  
pp. 1200-1206 ◽  
Author(s):  
Guido Ostendorp ◽  
Heiner Homborg
Keyword(s):  
Crystal Structure ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Bond Distance ◽  
Mean Value ◽  
The Other ◽  
Orthorhombic Space Group ◽  
Synthesis Properties ◽  
The Mean ◽  
Resonance Raman Spectra

[La(Pc)2] · CH2Cl2 is prepared by anodic oxidation of (nBu4N)[La(Pc2-)2] as slightly soluble black needles crystallizing in the orthorhombic space group Pnma with a = 28.365(5). b = 22.935(3). c = 8.026(3) Å, Z = 4. The La atom is in the center of an antiprismatic coordination polyhedron formed by the eight isoindole N atoms of the two staggered Pc ligands. The mean value of the La -Niso bond distance is 2.51 Å. One Pc ligand is quasi planar, the other is convex. The electronic absorption spectra and IR and resonance Raman spectra of the partially oxidized LaIII diphthalocyanine are reported and compared with those of the protonated complex H[La(Pc2-)2].

Stereochemistry of [carbonato-bis((S)-prolinato)]cobaltate(III) anion

1984 ◽  
Vol 49 (3) ◽  
pp. 680-683 ◽  
Author(s):  
Bohumil Hájek ◽  
Dagmar Sýkorová ◽  
Jiří Chyba
Keyword(s):  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Cd Spectra

The λ-C1-cis(N), δ-C1-cis(N), λ-C2-cis(N) and δ-C2-cis(N) isomers of the complex K[Co((S)-Pro)2CO3] were chromatographically separated and characterized by their electronic absorption spectra and CD spectra.

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