New non-metallocene, bridged-zirconium center catalysts were prepared by Schiff base condensations reaction of two equivalents of appropriate 2-hydroxybenzaldehyde with one equivalent of 4,4 0 -methylene bis(2-methylcyclohexylamine), and subsequent metathesis reaction with ZrCl 4 (THF) 2 , and tested for ethylene polymerization reaction at different conditions. Catalyst productivities were found to be high, in the range of 29.5 9 10 3 kg/moleÁZrÁh to 2.3 9 10 3 kg/moleÁZrÁh, dependents on the polymerization condition. The molecular weight of the product, i.e. polyethylene, varied from 397,000 to 988,000. 13 C NMR study of the polymers indicate that fraction of branches and end groups percentage range from 0.01 to 0.55. X-ray diffraction analysis showed that polyethylene samples had highly crystalline structure within the orthorhombic space group (Pnam) and carbon-carbon interatomic distance of 0.154061 nm and the C-C-C angle of 112.192°.
A series of 20 Schiff base ligands derived from 2-aminothiazole and its derivatives and aryl aldehydes with either [RhCl(PPh3)3] or [Rh(µ-Cl)(COD)]2 in the presence of 4 equivalents of PPh3 lead to an Rh(III) cyclometallated complex and the imine ligand (C-H) bond has been added to the metal (C-M-H). The complexes were investigated by using I.R., 1H, 13C and 31P NMR Spectroscopic techniques. The signal of the (C-H) ligand was observed as trans to the nitrogen atom in the complex which is a donor ligand.
Graphical Abstract:
Total synthesis of hydridothiazole rhodium complexes possessing rhodium hydride signal at δ (-14.60 to-15.04) ppm, trans to N-donor ligand and iminoyl carbon (7C=N) signal in Rh (III) observed at δ (220.1-237.6)ppm, lower field and suggestive of carbine like properties.
IR،UV1،H- and 13C-NMR chemical shifts are reported for a series of 20 imines Ar(X)CH=R (R’ = thiazole derivatives, thiadiazole and benzothiazole). The stereochemistry of the imines were determined through their NMR spectral data. The imines were found to exist in solution as only a single E-isomer at ambient temperature. Interestingly ،the carbon-13 shifts for azomethine group (imines) (CH=N) carbons which are affected by both (X) and (Y) substituents. UV and IR spectra of some of the title compounds are also reported.
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