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Upstream product

• 89-95-2 2-methyl-benzyl alcohol 
• 109-76-2 Trimethylenediamine 
• 99124-33-1 dihydroxy-2,2' bis(propene-1 yl)-3,3' biphenyle 
• 73429-23-9 2,2′-di(allyloxy)-biphenyl 
• 72216-56-9 3,3'-diallyl-2,2'-dihydroxy-1,1'biphenyl 
• 1806-29-7 2,2'-dihydroxybiphenyl 
• 90-02-8 salicylaldehyde 
• 99124-34-2 3,3'-bis-formylbiphenyl-2,2'-diol 

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• 2287-28-7 N,N'-bis(2-hydroxybenzyl)-1,3-diaminopropane 

Relevant academic research and scientific papers

Partially cyclopentadienyl-substituted tetranuclear lanthanide Schiff base complexes

Treatment of Cp3Ln (Ln=Pr, Nd) with an equimolar amount of the Schiff base bis(acetylacetone)ethylenediamine (H2acacen) half hydrate (H2L1·1/2H2O) or bis(salicylidene)trimethylenediamine (H2saltn) half hydrate (H2L2·1/2H2O) in THF affords three novel μ-hydroxo-bridged tetranuclear organolanthanide complexes [η5-CpLn2L2(μ-OH)] 2·nTHF, L=L1, n=4, Ln=Pr (1), Nd (2); L=L2, n=2, Ln=Nd (3). A reaction scheme was proposed in which the cyclopentadienyl lanthanide coordination motif [CpLnL] (A) and the hydroxyl lanthanide motif [LnL(OH)] (B) cross-reacted and then dimerized through the μ-hydroxo bridges to give the tetranuclear Ln complexes containing an Ln4O8 skeleton with two reciprocally oriented face-sharing defect cubanes. In each monomeric species [CpLn2L2(OH)] (C) the Ln atoms are 8- or 9-coordinated. All complexes have been characterized by EA, IR and Mass spectroscopy.

Functionalized Salen ligands linking with non-conjugated bridges: unique and colorful aggregation-induced emission, mechanism, and applications

A series of novel, simple, and colorful Salen ligands (56 samples), salicylaldehyde-based bis-Schiff bases, linking with different non-conjugated alkyl bridges ((CH2)n, n = 2-9, 12; cyclohexyl) and containing different electron-accepting (-NO2, -F, and -Cl), electron-donating (-OMe, -OH, and -NEt2), or sterically hindering (-t-butyl) substituents or a π-extended system (naphthalene ring) have been designed and synthesized. The photophysical properties of these Salen ligands can be well-tuned by the introduction of side functional substituents, π-extended systems, and central N-alkyl chain bridges. It is unusual that they contain a small π-conjugated system but display strong blue, green, and red aggregation-induced emission (AIE) with large Stokes shifts (up to 162 nm) and high fluorescence quantum yields (up to 0.44 and 0.75 in water and in solid, respectively). Combining with their advantages of AIE and good stability and biocompatibility, the Salen ligands can be potentially used in mechanofluorochromism (crystal-defect-induced emission) and living cell imaging. Moreover, the inherent relationships between their chemical structures and AIE properties are studied, which provide unequivocal insights for the design of AIE-active dyes.

Synthesis, spectral and electrochemical studies of some Schiff base N 2O2 complexes

Schiff base metal complexes of different stoichiometries and modes of interactions were synthesized and characterized using different metals Mn, Co, Ni, Cu by elemental analysis, spectral (IR and UV-Vis) methods and magnetic susceptibility studies. Electrochemical studies were performed for some of Schiff base complexes (Cu-salpr, Cu-salen, and Cu-salph·H2O) and of H2-salen and its corresponding Ni, Co, and Cu complexes on the corrosion behaviour of steel in 1 M sulphuric acid solution and were studied by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The stoichiometry of Fe and Mn (salen, salpr and salph) complex was studied by using different spectrophotometric methods.

Methylene spacer-regulated structural variation in cobalt(II/III) complexes with bridging acetate and salen- or salpn-type Schiff-base ligands

Two linear, trinuclear mixed-valence complexes, [CoII{(μ- L1)-(μ-OAc)CoIII(OAc)}2] (1) and [Co II{(μ-L2)(μ-OAc)CoIII(OAc)}2] (2) and two mononuclear CoIII complexes [CoIII{L 3}(OAc)] (3), and [CoIII{L4}(OAc)] (4) were prepared and the molecular structures of 1, 2 and 4 elucidated on the basis of X-ray crystallography [OAc = Acetate ion, H2L1 = H 2Salen = 1,6-bis(2-hydroxyphenyl)-2,5-diazahexa-1,5-diene, H 2L2 = H2Me2-Salen = 2,7-bis(2-hydroxyphenyl)-2,6-diazaocta-2,6-diene, H2L3 = H2Salpn = 1,7-bis(2-hydroxyphenyl)-2,6-diazahepta-1,6-diene, H 2L4 = H2Me2Salpn = 2,8-bis(2-hydroxyphenyl)-3,7-diazanona-2,7-diene]. In complexes 1 and 2, the acetate groups show both monodentate and bridging bidentate coordination modes, whereas chelating bidentate acetate is present in 4. The terminal Co IIIN2O4 centres in 1 and 2 exhibit uniform facial arrangements of both non-bridged N2O and bridging O 3 donor sets and the CoII centre is coordinated to six (four phenoxo and two acetato) oxygen atoms of the bridging ligands. The effective magnetic moment at room temperature corresponds to the presence of high-spin CoII in both 1 and 2. The complexes 1 and 2 are thus CoIII(S = 0)-CoII(S = 3/2)-CoIII(S = 0) trimers. Complexes 3 and 4 are monomeric and diamagnetic containing low-spin CoIII(S = 0) with chelating tetradentate Schiff base and bidentate acetate. Calculations based on DFT rationalise the formation of trinuclear or mononuclear complexes. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.

Stereoselective ring-opening polymerization of a racemic lactide by using achiral salen- and homosalen-aluminum complexes

Highly isotactic polylactide or poly(lactic acid) is synthesized in a ring-opening polymerization (ROP) of racemic lactide with achiral salen- and homosalen-aluminum complexes (salenH2 = N,N′-bis(salicylidene) ethylene-1,2-diamine; homosalenH2 = N,N′-bis(salicylidene) trimethylene-1,3-diamine). A systematic exploration of ligands demonstrates the importance of the steric influence of the Schiff base moiety on the degree of isotacticity and the backbone for high activity. The complexes prepared in situ are pure enough to apply to the polymerizations without purification. The crystal structures of the key complexes are elucidated by X-ray diffraction, which confirms that they are chiral. However. analysis of the 1H and 13C NMR spec tra unambiguously demonstrates that their conformations are so flexible that the chiral environment of the complexes cannot be maintained in solution at 25°C and that the complexes are achiral under the polymerization conditions. The flexibility of the back-bone in the propagation steps is also documented. Hence, the isotacticity of the polymer occurs due to a chain-end control mechanism. The highest reactivity in the present system is obtained with the homosalen ligand with 2.2-dimethyl substituents in the backbone (ArCH=NCH2CMe2CH2N=CHAr), whereas tBuMe2Si substituents at the 3-positions of the salicylidene moieties lead to the highest selectivity (Pmeso,= 0.98; T m = 210°C). The ratio of the rate constants in the ROPs of racemic lactide and L-lactide is found to correlate with the stereoselectivity in the present system. The complex can be utilized in bulk polymerization, which is the most attractive in industry, although with some loss of stereoselectivity at high temperature, and the afforded polymer shows a higher melting temperature (Pmeso = 0.92, Tm up to 189°C) than that of homochiral poly(L-lactide) (Tm = 162-180°C). The "livingness" of the bulk polymerization at 130°C is maintained even at a high conversion (97-98%) and for an extended polymerization time (1-2 h).

Synthesis, antiinflammatory and analgesic activity of new hexahydropyrimidine derivatives

A number of potentially active hexahydropyrimidine derivatives of pharmaceutical interest have been synthesized. Various diSchiff's bases prepared by reacting different aromatic aldehydes with 1,3-diaminopropane were suitably reduced to give their tetrahy

Effects of diamine bridge length and substituents on the spectral properties of N,N′-bis(α-substituted salicylidene)diamines in solution

Absorption and fluorescence spectra of thirteen N,N′-bis(α-substituted salicylidene)diamines in solution were investigated with the intention of investigating the role of the substituent and diamine bridge length on their optical properties. The fluorescence efficiency was improved by an increase in the electron-donating property of the substituents on the azomethine carbon accompanied by an increase of the n→π* transition absorption. However, the effect did not occur for the substituents on the azomethine nitrogen, in which no drastic changes in fluorescence efficiency could be observed. Through the investigation of the diamine bridge length effects, it was found that a diamine Schiff base seems to form neither an inter- nor an intramolecular dimer with any peculiar fluorescence in the solution even if it has a long methylene bridge. It was also suggested that the diamine Schiff base has a third fluorescence species in the excited state, which might be a pre-keto form, the existence of which is strongly affected by the hydrogen bond strength between the hydroxy and azomethine groups.

Stability Constants of Cobalt-, Nickel- and Zinc(II) Complexes of some Tetradentate Imine-phenol Ligands

The stability constants of bivalent Co, Ni and Zn with Schiff base derived ligands have been determined potentiometrically by Calvin-Bjerrum technique as adopted by Irving and Rossotti and spectrophotometrically by Job's method of continuous variation in 80 percent (v/v) DMSO-water medium at 35+/-0.1 deg and ionic strength of 0.2 mol dm-3.

Syntheses de recepteurs macrocycliques contenant des groupements hydroxyles ou methoxyles convergents, dans une geometrie definie, effet de matrice du bore

The synthesis of new tetraazacyclophanes is reported.The macrocycles are composed of biaryl units incorporated in the macroring by imination reactions at their 3- and 3'-positions with α,ω-diamines.The biaryl units are substituted at their 2- and 2'-posit