Vladimir B. Arion

Oxovanadium(IV) and oxovanadium(IV)-barium(II) complexes with heterotopic macrocyclic ligands based on isothiosemicarbazide

Abstract The macrocyclisation reaction of 3,3′-(3,6-dioxaoctane-1,8-diyldioxy)-bis(2-hydroxy-benzaldehyde) ( 1 ) with S-methylisothiosemicarbazide hydroiodide in the presence of barium triflate, followed by addition of oxovanadium(IV) chloride, yields the dimeric complexes [VOBaL 1 I(I 3 )CH 3 OH] 2 (3) and [VOBaL 1 (CF 3 SO 3 ) 2 (CH 3 OH) 0.5 (H 2 O) 0.5 ] 2 ( 4 ). Starting from 3,3′-(3,6,9-trioxaundecane-1,11-diyldioxy)-bis(2-hydroxybenzaldehyde) ( 2 ), and following the same procedure the polymeric complex {[VOBaL 2 Cl](I 3 )} n ( 5 ) has been obtained. Treatment of 3 , 4 or 5 in chloroform with an aqueous solution of guanidinium sulphate leads to VOL 1 ( 6 ) or VOL 2 ·2H 2 O ( 7 ). Compound 4 has been synthesised in high yield by direct complexation of VOL 1 with barium triflate in methanol. The crystal structures of 3 , 4 and 5 have been determined by X-ray crystallography. Electronic, mass and EPR spectra are reported.

Synthesis, structure and spectroscopic properties of nickel(II) macrocyclic and open-chain complexes resulted from 1-phenyl-butane-1,3-dione mono-S-methylisothiosemicarbazone template self-condensation

Abstract Self-condensation of 1-phenyl-butane-1,3-dione mono- S -methylisothiosemicarbazone ( 6 ) in the presence of nickel(II) acetate in methanol gives rise to a mixture of two complexes: [2,9-bis(methylthio)-5,13-dimethyl-7,14-diphenyl-1,3,4,8,10,11-hexaazacyclotetradeca-2,4,6,9,11,13-hexaenato(2-) N 1 , N 4 , N 8 , N 11 ]nickel(II) ( 7 ) and [1-amino-1,6-bis(methylthio)-4,9-dimethyl-11-phenyl-2,3,4,7,8-pentaazaundeca-1,3,6,8,10-pentaenato(-)-11-olato(-) N 2 , N 4 , N 8 , O ]nickel(II) ( 8 ). Both the macrocyclic complex 7 and the open-chain chelate 8 are characterised by X-ray diffraction methods, which reveal their square-planar structure. Electronic, IR, NMR, electron impact mass spectra and cyclic voltammograms of new compounds are also reported.

Heterodinucleating macrocyclic compounds designed for electrochemical recognition

This paper presents the electrochemical recognition properties of a series of redox-active ionophores containing two distinct complexing cavities: a Schiff base ligand complexed with Ni II ,C u II or Fe III and locked by a flexible polyoxyethylene chain of variable size. Their electrochemical recognition behavior was manifested by the emergence of a new cyclic voltammetry signal or by a progressive redox potential shift upon complexation of their crown ether-like moiety by alkali and alkaline earth metal cations, ammonium cation and protonated dopamine. UV–vis and FAB-MS experiments confirmed the formation of complexes between these receptors and the surveyed cations. Preliminary results have shown that gold electrodes modified by reaction with a receptor containing a thioether group exhibit electrochemical recognition properties similar to those found in homogeneous solution.

The crystal structures of [6-nitro-12,14-dimethyl-3,9-bis(propylsulphonyl)-1,2,4,8,10,11-hexaazacyclotetra-deca-2,4,6,9,12, 14-hexaenato(2-)-N1, N4, N8, N11]nickel(II) and [12,14-dimethyl-3,9-bis(ethylsulphonyl)-1,2,4,8,10,11-hexaazacyclotetra-deca-2,4,6,9,12,14- hexaenato(2-)-N1, N4, N8, N11]nickel(II)

Abstract Hexaazamacrocyclic complexes [6-nitro-12,14-dimethyl-3,9-bis(sulphonyl)- 1,2,4,8,10,11-hexaazacyclotetra-deca-2,4,6,9,12,14-hexaenato(2-)-N1, N4, N8, N11]nickel(II) and [12,14-dimethyl--9-bis(ethylsulphonyl)1,2,4,8,10,11-hexaazacyclotetra-deca-2,4,6,9, 12,14-hexaenato(2-)-N1, N4, N8, N11]nickel(II) have been synthesized by a template procedure starting from an open-chain precursor. The crystal structure of both macrocyclic products showed a square planar coordination geometry with cis-positioned-SR groups relative to the nickel atom.