Synthesis, Spectroscopic and Structural Properties of Heteropolynuclear Cyano-Bridged Complexes

Highly emissive polymorphs of anhydrous cadmium tetracyanoplatinate and their solvated coordination networks

Two anhydrous polymorphs of cadmium cyanoplatinate Cd[Pt(CN)₄] coordination polymers have been synthesized and thermally, spectroscopically, and structurally characterized. α-Cd[Pt(CN)₄] and β-Cd[Pt(CN)₄] are densely packed, highly emissive 3-D solids, with quantum yields of 0.85 (λ_em = 520 nm) and 0.79 (λ_em = 448 nm) respectively. Their mutual hydrate, Cd(H₂O)[Pt(CN)₄]·2H₂O, forms a complex 3-D coordination polymer with Cd-O-Cd bridges and Pt-Pt interactions. Additionally, exposure of solid α-Cd[Pt(CN)₄] and β-Cd[Pt(CN)₄] to several solvent vapours results in the formation of 2-D cyanometallate sheets of the adduct compounds CdL₂[Pt(CN)₄] (L = DMSO, DMF, and pyridine). Cd(pyridine)₂[Pt(CN)₄] shows a significantly lower quantum yield (0.32) in comparison to the parent Cd[Pt(CN)₄] coordination polymers. Upon heating CdL₂[Pt(CN)₄] preferentially forms the kinetic product α-Cd[Pt(CN)₄].

Synthesis, spectroscopic, thermal and structural properties of [M(3-aminopyridine)2Ni(μ-CN)2(CN)2]n (M(II)=Co and Cu) heteropolynuclear cyano-bridged complexes

Two novel cyano-bridged heteropolynuclear complexes, [Co(3-aminopyridine)2Ni(μ-CN)2(CN)2]n and [Cu(3-aminopyridine)2Ni(μ-CN)2(CN)2]n have been synthesized and characterized by elemental, thermal, FT-IR and FT-Raman spectroscopies. The structures of complexes have been determined by X-ray powder diffraction. The FT-IR and FT-Raman spectra of complexes have been recorded in the region of 3500-400cm(-1) and 3500-100cm(-1), respectively. General information was acquired about structural properties of these complexes from FT-IR and FT-Raman spectra by considering changes at characteristic peaks of the cyano group and 3AP. The splitting of the ν(CN) stretching bands in the FT-IR spectra for complexes indicates the presence of terminal and bridging cyanides. The thermal behaviors of these complexes have been also investigated in the range of 25-950°C using TG and DTG methods. Magnetic susceptibility measurements were made at room temperature using Gouy-balance.

Two dimensional cyano-bridged heteropolynuclear complex containing Pd ···π interactions

The heteronuclear complex, [Cd(NH3)2(μ-ampy)Pd(μ-CN)2(CN)2] n (1) (ampy = 4-aminomethylpyridine), was synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, elemental and thermal analyses and single crystal X-ray diffraction techniques. The complex crystallizes in the triclinic system, space group P-1. The Cd(II) ion exhibits a distorted octahedral coordination by two different N-atoms from two symmetrically equivalent ampy ligands, two ammine ligands and two bridging cyano groups, whereas the Pd(II) ion has square planar coordination and is coordinated by four cyano ligands. The tetracyanopalladate(II) anion is coordinated to the adjacent two Cd(II) ions to generate a one-dimensional chain. The adjacent 1D chains are connected by the μ-ampy bridging ligands to form a 2D network. The 2D layers are further linked by Pd···π and hydrogen bonding interactions to generate a 3D supramolecular network. The decomposition reaction takes places in the temperature range of 40–900 °C in the static air atmosphere.