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Mixed ruthenium(II) nitrosyls have been synthesized in yields larger than 60% by a general reaction of [Ru(η5-C5H5)(PPh3)L]+X−(L = 2,2′-bipyridine or 1,10-phenanthroline, X = Cl or Br) or [Ru(η5-C5,H5)(PPh3)(L)X] (L = PPh3, pyridine, 3-picoline, 4-picoline, , or ; X− = Cl−, Br−, I−, CN−, NCS−, H−, or SnCl3−) with NOBr3and N2O3. In these complexes NO seems to bind with the metal ion as NO+. The reactions of N2O3gave either nitrito or nitrosyl dinitrito complexes. The reactions of NOBr3with trichlorostannate complexes did not yield nitrosyl complexes, instead nitrito complexes were isolated in which spectroscopic evidence (ir, 1H nmr) suggest π-interaction of one of the phenyl rings of the triphenylphosphine ligand to the ruthenium center. All products are characterised by elementary microanalyses, conductivity, magnetic moment measurements, electronic, ir, and 1H nmr spectral data.

Complexes of 2-mercaptopyrimidin-4-ol with RhIII, PdII, PdIV, PtII and PtIV have been prepared. Their tentative structures have been assigned on the basis of infrared and electronic spectra and magnetic and analytical data. The ligand behaves as a bidentate bridging ligand towards metal ions except for PtII. Crystal field parameters have also been calculated.

Complexes of RuIII, RuII, RhIII, PdIV, IrIII and PtIV with 1,3,4-thiadiazole- 2,5-dithiol have been prepared. Probable structures for the complexes have been proposed on the basis of chemical analyses, magnetic susceptibility and electronic and infrared spectral data. Crystal field parameters have been calculated which are in accordance with the structures proposed. In every complex the ligand behaves as a unidentate towards two metal ions.

The complexes of 2-mercaptopyrimidin-4-ol with Cu11, Ni11, Co11 and Fe111 have been synthesized. Their structures have been assigned on the analytical, spectral (i.r, and visible), magnetic and d.t.a. data. It has been shown that there is a possibility of the Fe-O-Fe bond in the iron complex.

The complexes [CpRuL2Cl] (L=PPh3, AsPh3, SbPh3) react with the phenylacetylene,γ-hydroxyacetylenes HC≡CCR1R2OH (R1=R2=H, Me, and R1=Me, R2=Et; CR1R2OH=1-hydroxycyclohexanol) and NaBF4in methanol, to yield complexes of the typeη1-vinylidenes [CpL2Ru+(=C=CHR)],η1- allenylidene [CpL2Ru+(=C=C=CR1R2)], and dimeric allenylidene-vinyl and vinylidene-alkylidene complexes. Theseη1-vinylidene andη1-allenylidene complexes are reversibly deprotonated by sodium borohydride in methanol to yield the correspondingη1-alkynyl complexes [CpL2Ru(C≡CR)].

The Mössbauer effect in a number of europium (III) complexes with ligands having nitrogen or oxygen as donor atoms has been studied at room temperature. A comparison of the resonance effects indicates significant differences between several of the complexes. High resonance effects are correlated with the polymeric nature of the complexes. The isomer shifts of the complexes have also been interpreted on the basis of the participation of 6s or/and 4f or 5p orbitals in the bond formation.

NOX (X = Cl, Br, Br3) reacts with χ5-cyclopentadienyl ruthenium(II) complexes of the type [Ru(χ5-C5H5)SnCl3(EPh3)L] and [Ru(χ5-C5H5)(EPh3)(L-L)]SnCl3 (where E = As, Sb; L = AsPh3, SbPh3, PPh3, pyridine, χ-picoline; L-L = 2,2'-bipyridine, 1,10-phenanthroline) to give nitrito complexes, in which spectroscopic evidence (ir, 1H nmr) suggest π-interaction of one of the phenyl rings of the triphenylarsine or triphenylstibine ligand to the ruthenium center. All the products were characterized by microanalyses, electronic, ir and 1H nmr spectral data.

Some Europium(III) dibenzoylmethide and benzoylacetonate complexes have been subjected to Mössbauer studies at liquid nitrogen temperature. An attempt is made to discuss covalency in these complexes in terms of 6s, 4f and/or 5d orbital participation in the bond formation. Small linewidths are correlated to less symmetric structures. Resonance effects reflect the polymeric nature of these chelates.

Complexes of Co(II), Ni(II), Cu(II), Ru(II), Rh(III), Pd(II), Pt(II), and Au(I) with 2H-1,2,4-triazole3-thiol have been prepared. Probable structures have been proposed for the complexes on the basis of visible and infrared spectra, magnetic susceptibility, and chemical analysis. Crystal field parameters have been calculated wherever possible.

Complexes of Ni(II), Rh(I) Pd(II), Pt(II), Au(III) and Cu(II) with 5-Amino-1,3,4-thiadiazole-2-thiol have been prepared. Probable structures have been proposed for the complexes on the basis of visible and infrared spectral and magnetic susceptibility data and results of chemical analysis. Crystal field parameters have been calculated wherever possible.

A series of mono and binuclear cyanodithioformate (cdf) complexes with [RuIICpL2] [L = PPh3, AsPh3, SbPh3, (dppe)1/2, (dppm)1/2], exploiting its different coordination modes have been synthesized. Various physical and electrochemical methods have been used to characterize them. cdf by virtue of its vacant p*orbital introduces a low laying energy state in the compounds that facilitates Ru ? cdf (dp ? p*) MLCT transition. MLCT band, upon dimerizaion shows red shift, whose magnitude depends upon site of attachment of second ruthenium moiety [, 3750 cm-1for µ(?1–S; ?1–S') and 1010 cm-1for µ(?1–S; ?1–N) cdf complexes]. All complexes exhibit anodic oxidation peaks except binuclear µ(?1–S, ?1–S') cdf complex which exhibits reversible oxidation wave E1/2, -0.20 V vs. SCE in acetonitrite. Their spectral and electrochemical behavior are correlated with the s, p characterstics of cdf and ruthenium moieties.