S. K. Sahni

Mixed ligand complexes of ruthenium(III), rhodium(III) and iridium(III) with dipicolinic acid and some monobasic bidentate nitrogen, oxygen donor ligands

Abstract The trivalent ruthenium, rhodium and iridium complexes of dipicolinic acid and its mixed ligand complexes with several nitrogen, oxygen donor molecules, of types: Na[M(dipic) 2 ]·2H 2 O and [M(dipic)(N-O)]· n H 2 O (where M = Ru(III), Rh(III) or Ir(III); dipicH 2 = dipicolinic acid; NOH represents different nitrogen, oxygen donor molecules, viz., picolinic acid, nicotinic acid, isonicotinic acid, glycine, aminophenol, o - or p -aminobenzoic acid), have been synthesized and characterised on the basis of elemental analyses, electrical conductance, magnetic susceptibility measurements and spectral (electronic and infrared) data. The parent dipicolinic acid complexes are found to have a six-coordinate pseudooctahedral structure, whereas for mixed ligand complexes, a polymeric six-coordinate structure has been assigned. Various ligand field and nephelauxetic parameters have also been evaluated.

Oxovanadium(IV) complexes of macrocyclic ligands derived from 2,6-dipicolinoyl dihydrazine and β-diketones

Abstract The reactions of oxovanadium(IV) complexes of 2,6-dipicolinoyl dihydrazine (DPH) with β-diketones, viz. , acetylacetone, propionylacetone and benzoyl-acetone have been studied. The reaction products, five-coordinate oxo-vanadiun(IV) complexes of the type [VO(L)(H 2 O)] (where L = macrocyclic ligand derived from 2,6-dipicolinoyl dihydrazine (DPH) and a β-diketone), have been characterized on the basis of elemental analyses, electrical conductance, magnetic susceptibility and spectral (infrared and electronic) data.

ZINC(II), CADMIUM(II) AND MERCURY(II) COMPLEXES OF MACROCYCLIC LIGANDS DERIVED FROM 2,6-DIACETYLPYRIDINE

Abstract A novel series of complexes, of the type [M(DAPCH)X2(M=Zn(II), Cd(II) or Hg(II); DAPCH =planar pentadentate ligand derived from 2,6-diacetylpyridine and carbohydrazide, X=Cl, Br, I, NO3, CH3COO) have been synthesized and characterized by elemental analyses, conductance measurements and infrared spectral data. The ligand DAPCH appears to behave as a pentadentate ligand, having coordination sites at one pyridine nitrogen, two azomethine nitrogen and two amide oxygen atoms. Possible structures are proposed for these complexes. All the complexes contain terminal hydrazinic nitrogen atoms with an unshared electron pair and may take part in nucleophilic condensations. Therefore, the reactions of these complexes (X=Cl, Br, NO3) with 2,6-diacetylpyridine have also been studied viz., ring closure and formation of macrocyclic ligand complexes. Two types of cyclic products viz., mononuclear [M(L′)X2] and binuclear [M2(L′)X4] (M=Zn(II), Cd(II) or Hg(II); L=macrocyclic ligand derived from DAPCH and 2,6-diacet...

Ruthenium(III), Platinum(IV), Shodium(III), Palladium(II) and Platinum(II) Completes op Triazoline Thiones

Abstract Complexes of ruthenium(III), platinum(IV), rhodium(III), palladium(II) and platinum(II) with 3-(o-hydroxyphenyl)-1,2, 4-triasoline-5-thione (pttH) and 3-(o-hydroxyphenyl)-4-(o-hydroxy-benzylidine)-1,2, 4-triasoline-5-thione (HO-bttH) have been Synthesised aad oharaoterised on the basis of elemental analyses and infrared and electronic spectra and magnetic susceptibility measurements. The pslladium(II) and platinum(II) Complexee are square planar, Whereas ruthenium(III), platinum(IV) and rhodium (III) Complexes possees pseudooctahedral stereo chemistry. Various ligand field and nephelauxetic parameters have been evaluated wherever possible.

Mixed Ligand Uranyl(VI) Complexes of 2,6-Dipicolinic Acid

Abstract The mixed ligand uranyl(VI) complexes of pyridine-2,6-dicarboxylic acid (H2PDC) of the type [UO2(PDC) (N-N)], where N-N stands for a bidentate ligand, such as ethylenediamine, 2,2′-bipyridyl, 1,10-phenanthroline, o- and m-phenylenediamines, have been described. The complexes have been characterised on the basis of elemental analysis, electrical conductance and spectral (infrared and electronic) data.

Zirconyl(IV) Complexes of Macrocyclic Ligands Derived from 2,o-Dipicolinoyl Dihydrazine and its Reactions with β-Diketones

Abstract The zirconyl(IV) complex of 2,6-dipicolinoyl dihydrazine (DPH2), [ZrO(DP)(H2O)2] or [Zr(DP)(OH)2(H2O)], and its reactions with β-diketones have been described. The complexes so obtained have been characterised on the basis of elemental analyses, electrical conductance and spectral (infrared and electronic) data. The parent complex [ZrO(DP)(H2O)2] or [Zr(DP)(OH)2(H2O)] reacts with β-diketones to form complexes of the type [ZrO(DPM)(H2O)2] or [ZrO(DPM)(H2O)], where DPM is a macrocyclic ligand derived by the condensation of DPH2 and a β-diketone in the presence of the metal ion. All these complexes are six-coordinated.

Oxovanadium(IV) Complexes of N, N′-Diacetyl- 2, 6 -Diaminopyridine

Abstract The oxovanadium(IV) complexes of the formulae VOLX2 and VO(L)2 (ClO4)2, where L is N,N′-diacetyl-2, 6-diamino-pyridine and X = Cl, Br, I, NCS, or NO3, have been synthesised and characterised by elemental analysis and by infrared, electronic spectral, conductance and magnetic studies. The halo and pseudohalo complexes are six-coordinate and have tetragonally distorted structures, whereas the perchlorate complex appears to be seven-coordinate. Various ligand field (Dq, Ds, Dt) and NSH Hamiltonian (DQ, DS and DT) parameters have been calculated and the degrees of distortion (determined in terms of the ratio DT/DQ) lie inthe range 0.17 – 0.19, indicating that the complexes are slightly distorted, In the far infrared region3 (M-py), d (M-0) and d(M[sbnd]X) have been assigned and discussed.

Mixed Ligand Complexes of Chromium(III), Manganese(III), Iron(III) And Cobalt(III) With Dipicolinic Acid and Some Monobasic Bidentate Nitrogen, Oxygen Donor Ligands

Abstract The mixed-ligand complexes of trivalent chromium, manganese, iron and cobalt of type [M(dipic)(N-O)] nH2O (Where dipicH2 = pyridine-2, 6-dicarboxylic acid or dipicolinic acid; N-OH represents different nitrogen, oxygen donor ligands viz., picolinic acid, nicotinic acid, isonicotinic acid, glycine, aminophenol, o-aminobenzoic acid or p-aminobenzoic acid) have been prepared and characterized on the basis of elemental analyses, magnetic susceptibility measurements and spectral (electronic and infrared) data. A polymeric six-coordinate structure has been assigned for these complexes.

Reactions of uranyl(VI) complexes of acid dihydrazides with ?-diketones

SummaryUranyl(VI) complexes of malonic acid dihydrazide (MDH2) and phthalic acid dihydrazide (PDH2) and the products of their reactions with four β-diketones have been characterised by elemental analysis and by electrical conductance, and spectral (i.r. and electronic) measurements. The MDH2 and PDH2 complexes UO2(L)2(H2O)2 are eight coordinate whereas the macrocyclic UO2(L′)(H2O)2 complexes are six coordinate. In each complex MDH2 and PDH2 act as bidentate liglands having the coordination sites at secondary amide-nitrogen atoms.

Alkyl Thioglycolates of Aluminium, Titanium and Zirconium

Abstract Alkyl thioglycolates of the type Al(OR)G (R = Pri, But); M(OR)2G (M = Ti, Zr; R = Pri, But); MG2 (M = Ti, Zr), Al2G3 and Al(GH)G where GH2 is methyl or ethyl thioglycolate have been prepared. The isopropoxy derivatives were obtained by carrying out the reaction between the isopropoxide of the corresponding metal with methyl or ethyl thioglycolate in anhydrous benzene in different molar ratios, whereas the tertiary butoxy derivatives were prepared from the respective isopropoxy derivatives by alcohol interchange technique. Molecular weights of soluble titanium and zirconium derivatives show them to be dimeric in nature. Structures have been suggested on the basis of infrared spectral and molecular weight studies.