Shape-persistent conjugated macrocycles are challenging synthetic targets with interesting properties and potential for a number of applications. In contrast to the standard kinetic approaches to macrocycles, reversible Schiff-base condensation offers a one-step, thermodynamic route to large macrocycles. These macrocycles, which feature “salen”-type coordination environments and an interior tha...

Complexes of Cu(II), Ni(II) and Mn(II) containing a novel homotrinuclear Schiff base metal complexes were synthesized by using 2,3-pentanedione, p-phenylenediamine and 2-aminobenzaldehyde. The complexes of the type [LM 3 Cl 6 ]. The characterization and nature of bonding of the trinuclear complexes have been deduced from elemental analysis, molar conductivity, FT-IR, UV-visible, magnetic and EP...

6,7-dimethyl-8-ribityllumazine synthase (lumazine synthase) catalyzes the condensation of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione and 3,4-dihydroxy-2-butanone 4-phosphate. Presteady state kinetic experiments using the enzyme from the hyperthermophilic bacterium Aquifex aeolicus were monitored by multiwavelength photometry. An early optical transient absorbing around 330 nm is interpre...

BACKGROUND The oxidative transformation of benzoin to benzil has been accomplished by the use of a wide variety of reagents or catalysts and different reaction procedures. The conventional oxidizing agents yielded mainly benzaldehyde or/and benzoic acid and only a trace amount of benzil. The limits of practical utilization of these reagents involves the use of stoichiometric amounts of corrosiv...

A novel Schiff base ligand N-(4-phenylthiazol-2yl)-2-((2-thiaxo-1,2-dihydroquinolin-3-yl)methylene)hydrazinecarboxamide (L) obtained by the condensation of N-(4-phenylthiazol-2-yl)hydrazinecarboxamide with 2-thioxo-1,2-dihydroquinoline-3-carbaldehyde and its newly synthesized Cu(II), Co(II), Ni(II), and Zn(II) complexes have been characterized by elemental analysis and various spectral studies ...

The Sn(IV) atom in the title compound, [Sn(C(6)H(5))(C(14)H(19)N(4)S)Cl(2)], exists within a distorted octa-hedral geometry defined by the N,N',S-tridentate monodeprotonated Schiff base ligand, two mutually trans Cl atoms, and the ipso-C atom of the Sn-bound phenyl group; the latter is trans to the azo-N atom. The greatest distortion from the ideal geometry is found in the nominally trans angle...

A simple Schiff-base receptor 2 was prepared. It exhibits an “off-on-type” mode with high sensitivity in the presence of Al3+. The receptor 2 exhibited a high association constant with submicromolar detection for Al3+ in EtOH–H2O (95:5 v/v) solution. The addition of EDTA quenches the fluorescence of the receptor 2·Al3+ complex offering receptor 2 as a reversible chemosensor.

This contribution describes the synthesis of a novel pyrazole-pyrrole building block and its use in the formation of a non-aromatic, Schiff base-type macrocycle incorporating a chromophore and H-bonding donor and acceptor functionalities inside and outside of the macrocycle, which makes it predestined for molecular recognition systems.

The Complexes of the type ML2 and M′L [where M= Cu(II), Co(II), Ni(II) and Mn(II); M′= Zn(II), Cd(II) and Hg(II)] with the Schiff base ligand (HMeOQMAMQ) L=3-[(2-hydroxy-6-methoxyquinolin-3-ylmethylene)amino]-2-methyl-3H-quinazoline-4-one, have been synthesized. Their characterizations have been done by elemental analysis, conductance data, magnetic susceptibility measurements, H NMR, electroni...