Reaction of two equivalents 4-{(3-(pyridine-2-yl) 1H-pyrazole-1-yl}methyl benzonitrile (L1) and 3-{(3-(pyridine-2-yl)1H-pyrazole-1-yl}methyl benzonitrile (L2) with one equivalent of [($\eta^6$-arene)Ru(𝜇- Cl)Cl]₂ and [Cp^∗M(𝜇-Cl)Cl]₂ in methanol yielded mononuclear complexes of the formulae [($\eta^6$-arene)Ru(L1/L2)Cl]BF₄{arene =C₆H₆ (1, 6); C₁₀H₁₄ (2, 7); C₆Me₆ (3, 8)} and [Cp^∗M(L1/L2)Cl]PF₆/BF₄ {Cp^∗= $\eta^5$-C₅Me₅, M=Rh (4, 8); Ir (5, 10)}. These complexes are characterized by IR, ¹H NMR and identities of the structure are established by single crystal XRD studies of some of the representative complexes. It is confirmed from the spectral studies that the nitrile group is not taking part in complexation; instead it remains as a free pendant group only.

The chelating ligands 3-chloro-6-(3-pyridyl-1-pyrazolyl)pyridazine ($pp-Cl$) and 3,6-bis(3-pyridyl-1-pyrazolyl)pyridazine (bppp), were prepared by the condensation of pyridylpyrazole and 3,6-dichloropyridazine. The mononuclear complexes [($\eta^6$-arene)Ru($pp$-Cl)Cl]⁺ $\{\eta^6$-arene = C₆H₆ (1); 𝑝-${}^i$PrC₆H₄Me (2)}, [($\eta^5$-C₅Me₅)M($pp$-Cl)]⁺ {M = Rh (3); Ir (4)}, [($\eta^6$-arene)Ru($bppp$)Cl]⁺ $\{\eta^6$-arene = C₆H₆ (5); 𝑝-${}^i$PrC₆H₄Me (6)}, [($\eta^5$-C₅Me₅)M(bppp)]⁺ {M =Rh (7); Ir (8)} as well as the binuclear complexes [{($\eta^6$-arene)RuCl}₂(bppp)]²⁺ {$\eta^6$ -arene =C₆H₆ (9); 𝑝-$^i$PrC₆H₄Me (10)} and [{($\eta^5$-C₅Me₅)MCl}₂(bppp)]²⁺ {M = Rh (11); Ir (12)} have been synthesized from 3-chloro-6-(3-pyridyl-1-pyrazolyl)pyridazine ($pp-Cl$) or 3,6-bis(3-pyridyl-1-pyrazolyl)pyridazine (bppp) and the corresponding dimers [($\eta^6$-arene)Ru(𝜇-Cl)Cl]₂ and [Cp^∗M(𝜇-Cl)Cl]₂, respectively. All complexes were isolated as their hexafluorophosphate salts and characterized by IR, NMR, mass spectrometry and UV-visible spectroscopy. The molecular structures of [2]PF₆ and [7]PF₆ have been established by single crystal X-ray structure analysis.

Alkali metals were introduced into heavy main-group iodometallates to get two new IA/IVAheterometallic frameworks [PbI₃K(pdon)(H₂O)₂]_𝑛 (1) and {[Pb₃I₉K₂(pdon)₂(H₃O)]·H₂O} _𝑛 (2) (pdon=1,10-phenanthroline-5,6-dione), which were obtained as single phases by hydrothermal method at different pH values. Compounds 1 and 2 are three-dimensional heterometallic frameworks constructed from the linkage of pdon ligand between iodometallate chains and potassium oxides/iodide clusters. Specially, these two heterometallic frameworks exhibit broadened absorption bands at 700 and 750 nm compared with those of bulk PbI₂ and pdon ligand. The band gap of 2 is wider than that of 1, which is due to the absence of 𝜋 · · · 𝜋 interaction in 2. Their thermal stabilities are also discussed.

Pentamethylcyclopentadienyl iridium(III) and rhodium(III) complexes of formulation [(η⁵- C₅Me₅)M{(C₅H₄N) ₂C=NR)}Cl]PF₆ were prepared by the reaction of [MCl2(η⁵-C₅Me₅)] ₂ (M = Ir or Rh) with dipyridyl-N-alkylimine ligands, (C₅H₄N) ₂C=NR (R = Me or Et) in the presence of NH₄PF₆ at room temperature. The reaction also produced an unexpected dipyridyl-NH-ketimine organometallic compound

[(η⁵-C₅Me₅)M {(C₅H₄N) ₂C=NH}Cl]PF6 as minor product when the reaction was performed under refluxing acetonitrile. The NH-ketimine compounds were formed via N-C single bond cleavage of imine ligand resulting in coordination of the transformed ligand, (C5₅H₄N) ₂C=NH to the metal centre. Complexes were obtained as their hexafluorophosphate salts and characterized based on IR, NMR and ESI-MS spectroscopic data. Authenticity of NH-ketimine organometallic compound was established by single crystal X-ray analysis of a representative compound, which crystallized in orthorhombic space group Pbcn and has a pseudo-octahedral geometry around the metal ion.