The reaction of aqueous solutions of K2PdCl4 and K3Co(CN)6 results in gellike polymeric materials, characterized by bridging cyanides between the central metals of the adducts. These materials tend to be rigid in nature but contain in excess of 95% water by weight. We refer to these novel transition metal based hydrogels as cyanogels. In contrast to classic inorganic hydrogels these materials are not based on an oxide network. Dehydration of the cyanogels results in amorphous xerogels which maintain the initial polymeric structure of the cyanogel. Thermal processing of gels containing palladium and cobalt centers under an inert atmosphere at temperatures between 200 and 500 °C, produces a new metastable material. Sintering between 500 and 1000 °C produces ferromagnetic alloys, while processing under oxygen in the same temperature region gives the ceramic mixed oxide material PbCoO2, having the delafossite structure.

Adenosine 5'-diphosphoribose (ADPR) and a second compound, which may be nicotinamide, are the newly discovered photoproducts resulting from irradiation of beta-nicotinamide adenine dinucleotide (beta-NADH) in the wavelength range of 300-400 nm under oxygen-poor conditions. Both products emerge there even exclusively, whereas, at higher oxygen concentrations, the oxidized form of nicotinamide adenine dinucleotide (NAD+) is additionally formed, although still as a minor product. The development of ADPR and NAD+ is clearly oxygen-dependent, while, for the formation of the second photoproduct, small quantities of oxygen appear to be sufficient.

The reaction of aqueous solutions of SnCl 4 ‚5H 2 O and K 4 Fe(CN) 6 in a 2/1 Sn/Fe atomic ratio results in a hydrogelled polymeric material, characterized by bridging cyanides between the central metals of the adducts. Materials of this type have previously been noted upon reaction of PdCl 4 2with cyanometalates in aqueous solution and have been referred to as cyanogels. Dehydration of Sn/Fe cyanogels results in xerogels that maintain the initial polymeric structure of the hydrogel. Thermal processing of such gels under an air atmosphere at 900 °C produces a solid homogeneous mixture of microcrystalline SnO 2 and Fe 2 O 3 .

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The reaction of a wide variety of cyanometalate complexes of the general form [M(CN)x]n- (where M= a transition metal ion) with square planar [PdCl4]2- in aqueous solution leads to the formation of linear polymers. Polymerization occurs via substitution of chloride ligands on the Pd(II) centers, by the nitrogen end of the cyanide ligand to generate extended bridging cyanide structures. Upon generation at room temperature polymer solutions of this type under go a sol-gel transition to generate robust hydrogels having water content in excess of 95%. In the case of the cyanocobaltate/tetrachloropalladate gel, pyrolysis at 900°C produces ferromagnetic Pd/Co metallic alloys having novel morphological character. Materials formed with a hydrogel having a 2:1 Pd to Co stoichiometry are found to be “sponge-like”. When placed in water, the metallic matrix swells becoming pliable and holding up to seven equivalents of water per metal site. The conductivity and magnetic properties of this material are maintained in the swollen state. Sintering of the Pd/Co hydrogel in air generates the layered oxide, PbCoO2 having a delafossite structure.