A cyclometalation reaction involving C-F bond activation at a cobalt(i) center with an aldazine-N atom as anchoring group affords ortho-chelated cobalt(iii) complexes containing a [C-Co-F] fragment [CoFMe(PMe(3))(2){(C(6)H(3)F-ortho)CH[double bond, length as m-dash]N-R}] 5-8. Under similar reaction conditions π-coordinated cobalt(0) complexes [Co(PMe(3))(3)((C(6)H(3)F-ortho)CH[double bond, length as m-dash]N-R)] 12-14 were formed when [Co(PMe(3))(4)], instead of [CoMe(PMe(3))(4)], was applied. C-F bond activation did not occur. Carbonylation of complexes 6-8 delivered novel organic fluorides 15-17. A proposed formation mechanism of the novel organic fluorides with demetallation and carbonylation of complexes 6-8 by CO is discussed with experimental support. As important intermediates, an acetyl cobalt complex, [CoFMeC[double bond, length as m-dash]O(PMe(3))(2){(C(6)H(3)F-ortho)CH[double bond, length as m-dash]N-R}] 20, and a 19-electron cobalt(0) complex, Co(CO)(3)(PMe(3))(2)21, were structurally characterized. The crystal and molecular structures of complexes 5, 6, 8, 12, 20 and 21 were determined by X-ray diffraction.

Poly(vinyl alcohol) (PVA)/poly(ethylene oxide) (PEO) hydrogels were prepared by freezing/thawing method for application as a wound dressing. The effect of PEO content on the network structure of PVA hydrogel was investigated in terms of crystalline and reological properties. It was found that a low amount of PVA crystallites were present in PVA/PEO hydrogels. With increasing content of PEO, the crstallinity of PVA hydrogel decreased, but the apparent dimensions of crystallites increased. The shear storage modulus (G 0 ) decreased slightly with the increasing temperature within 30-50 C, probably resulting from the breaking of the hydrogen bonding; while it decreased sharply within 50-70 C, probably resulting from the melt of the crystallites of PVA hydrogel. The physical crosslinking density (D pc ) increased with decreasing PEO content, while decreased more dramatically with increasing temperature, indicating that hydrogen bonding was easier to be broken at high temperature. At very low strain amplitudes, the loss modulus (G 00 ) of the hydrogel is lower than the storage modulus (G 0 ) and G 0 is independent of the strain amplitude, indicating that the deformation imposed on the network structure is entirely reversible. With increasing content of PEO, G 0 at low frequency decreased, and the mesh size (L c ) increased, indicating of the decrease of the physical crosslinking density of PVA/PEO hydrogels.

The construction of efficient artificial light-harvesting systems (ALHSs) is of vital importance in utilizing solar energy. Herein, we report the non-covalent syntheses of double helicates PCP-TPy1/2 and Rp,Rp-PCP-TPy1/2 by metal-coordination interaction and their applications in ALHSs and white light-emitting diode (LED) device. All double helicates exhibit significant aggregation-induced emission in tetrahydrofuran/water (1:9, v/v) solvent. The aggregated double helicates can be used to construct one-step or sequential ALHSs with fluorescent dyes Eosin Y (EsY) and Nile red (NiR) with the energy transfer efficiency up to 89.3%. Impressively, the PMMA film of PCP-TPy1 shows white-light emission when doped 0.075% NiR, the solid of double helicates (Rp,Rp-) PCP-TPy2 can be used as the additive of a blue LED bulb to achieve white-light emission. In this work, we provided a general method for the preparation of novel double helicates and explored their applications in ALHSs and fluorescent materials, which will promote future construction and application of helicates as emissive devices.

The title compound, [Co(C30H23O2P2)(C3H9P)2], was synthesized by the addition of a Co(PMe3)4 solution to (PPh2O)2C6H4. The CoI atom displays a trigonal-bipyramidal geometry with the two P atoms of the ‘PCP’ pincer ligand and the P atom of one of the trimethyl phosphine ligands forming the basal plane, whereas the metalated C atom and the P atom of the second phospine ligand occupy the apical sites. The Co—C distance is 1.961 (2) Å and the C—Co—P angle is 171.96 (6)°.

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