We report a method for the fabrication of phthalocyanine particles with dimensions in the nanoscale regime. Phthalocyanines are of particular interest as reversed saturable absorption-based optical limiters. By fabricating phthalocyanine particles of nanometer sizes, we found intermolecular effects to strongly influence the linear and nonlinear optical properties. Linear optical studies, including absorption and emission spectroscopy, were used to investigate the interactions between the molecules inside the particles. The Z-scan technique was employed to examine the optical limiting effects in phthalocyanine nanoparticles compared to solutions of the corresponding molecules. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) studies were performed to further investigate the particle structure. Furthermore, X-ray diffraction measurements were made to probe the molecular alignment in the nanoparticle.

The reaction of tetracyanidoboronic acid, H[B(CN)4], with CoCO3 or Co(OH)2 in aqueous solution leads after slow evaporation of water to single crystals of Co[B(CN)4]2·2H2O. The compound has been characterized by single crystal X‐ray diffraction ($I {\bar 4} \mathit{2}d$, a = 12.2922(9), c = 9.2235(7) Å, Z = 4). The Co2+ ion is octahedrally coordinated by four nitrogen atoms of four different tetracyanidoborate CN groups occupying the four equatorial positions and two molecules of water occupying the remaining corners of the octahedron. The single crystal X‐ray structure, the vibrational spectra, and the thermal properties are compared with other known tetracyanidoborates with divalent cations.

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The reaction of Fe(OH)(3) with tetracyanidoboronic acid, H[B(CN)(4)]·xH(2)O, in water leads to the first examples of tetracyanidoborates with a triply charged metal cation, [Fe(III)(H(2)O)(6)][B(CN)(4)](3) (1). Using elemental iron powder as starting material, [Fe(II)(H(2)O)(2){κ(2)ΝB(CN)(4)]}(2)] (2) is obtained. Anhydrous iron(II) tetracyanidoborate, which is synthesized by heating of 2, is soluble in dry dimethylformamide. After evaporation of the DMF solvent, single crystals of the third title compound, [Fe(II)(DMF)(6)][B(CN)(4)](2) (3), are obtained. Compound 3 is the first metal tetracyanidoborate soluble in nonpolar solvents. The title compounds have been characterized by single-crystal X-ray diffraction (1 rhombohedral, R3c (no. 167), a = 14.9017(7) Å, c = 20.486(1) Å, Z = 6; 2 tetragonal, I42d (no. 122), a = 12.3662(3) Å, c = 9.2066(4) Å, Z = 4; 3 triclinic, P1 (no. 2), a = 8.6255(3) Å, b = 11.0544(4) Å, c = 12.2377(5) Å, Z = 1). The metal ions in all three compounds are octahedrally coordinated. Whereas 1 and 3 are built up from isolated complex ions, 2 comprises a coordination polymer, in which the Fe(II) ion is coordinated by two oxygen atoms of two water molecules in a trans orientation and four nitrogen donor atoms of the [B(CN)(4)](-) groups, which bridge between neighboring iron ions. The iron(III) ion in 3 is in a perfect octahedral environment, which is formed by the O atoms of 6 molecules of water. The single-crystal X-ray structures, vibrational spectra, thermal properties, solubilities, and electrochemical characteristics are reported and compared with those of other known tetracyanidoborates.