Molecular Structure Of Metal Alkoxide Precursors

1990 ◽  
Vol 180 ◽  
Author(s):  
C. Sanchez ◽  
P. Toledano ◽  
F. Ribot

ABSTRACTOxo-alkoxides and allied derivatives are the organic counter part of polyanions and polycations. Most of them do not lead to further polymerization and are therefore dead endswhich are grnerally not directly involved in the formation of macromolecular oxide networks. However their well defined structure make them good models for the basic understanding of the first steps of hydrolysis- condensation reactions. The structural characterization of a new metal oxo species Ce6(μ3-O)4(μ3-OH)4(acac)12 obtained via the hydrolysis of acetylacetone modified cerium isopropoxide is presented. Possible mechanisms of formation of this compound as well as for some other titanium Ti6(μ2-O)2(μ3-O)2(μ2-OAc)4(μ2-OPri)6(OPri)6 and niobium Nb8O10(OEt)20 based oxo-alkoxides will be discussed.

Author(s):  
Shabana Noor ◽  
Richard Goddard ◽  
Fehmeeda Khatoon ◽  
Sarvendra Kumar ◽  
Rüdiger W. Seidel

AbstractSynthesis and structural characterization of two heterodinuclear ZnII-LnIII complexes with the formula [ZnLn(HL)(µ-OAc)(NO3)2(H2O)x(MeOH)1-x]NO3 · n H2O · n MeOH [Ln = Pr (1), Nd (2)] and the crystal and molecular structure of [ZnNd(HL)(µ-OAc)(NO3)2(H2O)] [ZnNd(HL)(OAc)(NO3)2(H2O)](NO3)2 · n H2O · n MeOH (3) are reported. The asymmetrical compartmental ligand (E)-2-(1-(2-((2-hydroxy-3-methoxybenzylidene)amino)-ethyl)imidazolidin-2-yl)-6-methoxyphenol (H2L) is formed from N1,N3-bis(3-methoxysalicylidene)diethylenetriamine (H2valdien) through intramolecular aminal formation, resulting in a peripheral imidazoline ring. The structures of 1–3 were revealed by X-ray crystallography. The smaller ZnII ion occupies the inner N2O2 compartment of the ligand, whereas the larger and more oxophilic LnIII ions are found in the outer O2O2’ site. Graphic Abstract Synthesis and structural characterization of two heterodinuclear ZnII-LnIII complexes (Ln = Pr, Nd) bearing an asymmetrical compartmental ligand formed in situ from N1,N3-bis(3-methoxysalicylidene)diethylenetriamine (H2valdien) through intramolecular aminal formation are reported.


Author(s):  
Rayya A. Al Balushi ◽  
Muhammad S. Khan ◽  
Md. Serajul Haque Faizi ◽  
Ashanul Haque ◽  
Kieran Molloy ◽  
...  

In the crystal structure of the title compound, [Cu4Cl6O(C13H9N)4]·CH2Cl2, the core molecular structure consists of a Cu4 tetrahedron with a central interstitial O atom. Each edge of the Cu4 tetrahedron is bridged by a chlorido ligand. Each copper(II) cation is coordinated to the central O atom, two chlorido ligands and one N atom of the 4-phenylethynylpyridine ligand. In the crystal, the molecules are linked by intermolecular C—H...Cl interactions. Furthermore, C—H...π and π–π interactions also connect the molecules, forming a three-dimensional network. Hirshfeld surface analysis indicates that the most important contributions for the packing arrangement are from H...H and C...H/H...C interactions.


2012 ◽  
Vol 1374 ◽  
pp. 49-59 ◽  
Author(s):  
Y. Espinosa-Morales ◽  
J. Reyes ◽  
B. Hermosín ◽  
J. A. Azamar-Barrios

ABSTRACTNatural dyes have been extracted from both plants and animal to give color to textiles and handicrafts. This is the case of purple dye extracted from Justicia spicigera Schldt, an acanthaceae used as a color source since pre-Hispanic period in the Mayan area of Mexico and Central America. Spectroscopic (UV-Vis and FT-IR) and chromatographic (PY-GC/MS) techniques were employed in order to characterize some of their chemical properties. UV-VIS absorption spectra indicates a λmaxpeak at 581 nm, value associated to anthocyanins group under bathochromic effect. On the other hand, a structural characterization realized by FT-IR and Py-GC/MS indicated the presence of polar hydroxibenzoic acids and phenolic compounds which are characteristics of the molecular structure of anthocyanins.


2004 ◽  
Vol 43 (4) ◽  
pp. 1217-1219 ◽  
Author(s):  
Ying Peng ◽  
Guangcai Bai ◽  
Hongjun Fan ◽  
Denis Vidovic ◽  
Herbert W. Roesky ◽  
...  

1988 ◽  
Vol 121 ◽  
Author(s):  
C. Sanchez ◽  
M. Nabavi ◽  
F. Taulelle

ABSTRACTVanadium oxide gels are synthesized through vanadium oxo-alkoxide hydrolysis condensation processes. Different precursors and hydrolysis conditions lead to different sorts of gels. V0(0Amt)3 hydrolyzed with a large excess of water results in red jammy gels with a layered structure. They exhibit electronic and ionic behavior comparable to vanadium pentoxide gels from inorganic precursors. Hydrolysis of VO(OPrn)3 in an alcoholic medium, leads to orange transparent monolithic gels. They have a highly branched polymeric structure. Controlled hydrolysis of vanadium oxo-alkoxide precursors has the further advantage of giving good adherent thin films.


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