Nanomaterials have been used in the development of active, smart, or intelligent packaging presenting special chemical and electrooptical properties mostly due to their high surface-to-volume ratio compared to macroscale materials and some of these properties are enhanced surface reactivity, electrical conductivity, and magnetic properties. Another important characteristic of nanoparticles is that their properties can be manipulated by changing their size, shape, their composition, and adjusting their surface by suitable functionalization, to maximize their benefit. Various nanotechnology-based techniques have been implemented in different sections of the food industry to enhance food quality and safety, and to increase sensitivity and speed of analysis and quality control measurements. Food packaging based on nanotechnology has progressed rapidly, although of limited social acceptance. Commercially, this direction has its concerns because of the mindset of the consumers. More commercials probably will aid the social acceptance of nanotechnology in the food industry.

Evaluation of diazonium salts in forensic chemistry will vastly benefit in the design of novel developers for latent fingerprints on metal surfaces used as crime tools. We used the easily reducible aryldiazonium salt stabilized with tetrachloroaurate anion of the formula [NO2-4-C6H4N NI]AuCl4. Localized elemental analysis, after 2 h of contact with the aryldiazonium salt, using X-ray fluorescence (XRF) and energy dispersive spectroscopy (EDS) showed the deposition of gold on the fingerprints collected on copper, lead and aluminum. Poor development obtained from the non-gold aryldiazonium salt [NO2-4-C6H4N N]BF4, in addition the temporal evolution of the deposition over 24 h showed images of poor contrast and scattered minor deposits. It can be noticed from the images collected using scanning electron microscopy (SEM) and stereomicroscope that the grafted film was not filling the grooves but selectively adhered to the eccrine prints on copper and lead however showed indiscriminate deposition on aluminum surface at high concentrations. Obliteration of developed fingerprints was not observed on all surfaces. The degraded contrast on aluminum after the visible overflow of the trenches is a limitation of diazonium on highly reactive metal surfaces according to the electrochemical series. It can be concluded that copper surface is the most successful among the three metals. The gold film aided to visualize the three levels of primary, secondary and tertiary fingermarks at high level of details. Reduced gold on fingerprints can be beneficial in archiving and future analysis.

We report the synthesis of aryldiazonium tetrachloroaurate(III) salts [X-4-C6H4N=N]AuCl4 (X = F, Cl, Br, I, CN, NO2) and their mild reduction to covalently functionalized nanoparticles. The synthesis of the salts was carried out by the oxidation of anilines, dissolved in HCl, using sodium nitrite followed by the exchange of the counter anion with [AuCl4](-) in water. In another procedure, the anilines were protonated with H[AuCl4] in acetonitrile followed by one-electron oxidation using nitrosonium salt [NO] X (X = BF4-, PF6-). Raman and ATR-FTIR spectroscopy displayed the diazonium nu(N N) and Raman showed the tetrachloroaurate nu(Au-Cl) stretching frequencies. X-ray crystal structure of [NO2-4-C6H4N N]AuCl4 salt showed N N bond distance typical of a triple bond. Gold-aryl nanoparticles were constructed by the mild chemical reduction of the diazonium gold(III) salts using 9-borabicyclo[3.3.1] nonane (9-BBN). Nanoparticles hydrodynamic diameter, elemental composition, dynamics information, and stability data were determined. Transmission electron microscopy (TEM) measurements showed limited aggregation due to the small suppressing organic shell. However, dynamic light scattering (DLS) measurements showed considerable aggregation in acetonitrile. X-ray photoelectron spectrometry (XPS) showed the gold core in zero oxidation state and manifested the gold-organic shell connectivity. The eN 1/4 N-aryl interfacial formation on the gold surface can be ruled out since the N1s peak assigned to the diazonium moiety showed no sign in the XPS nitrogen area in addition to its absence in the ATR-FTIR spectra. Raman spectroscopy measurements showed a peak assigned to gold-carbon bonding supported by density functional calculations (DFT) on Au-20-C6H4-CN model. (c) 2018 Elsevier B.V. All rights reserved.

Developed fingerprints imaging was achieved by dusting using doped polyaniline (PANI) nanocomposites. Substituted anilines of 2,6-dimethyl, 2,6-diisopropyl, 3-nitro, and 2-carboxyl were used in the synthesis of the nanocomposites by oxidative polymerization using gold acid and ammonium persulfate (APS). The nanocomposites were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray fluorescence (XRF), X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). Au-PANI developed latent fingerprints showed better results than APS-PANI developed fingerprints on paper, glass, and stainless steel; better adhesion and good contrast ridge details. Developed fingerprints were imaged using optical microscopy and further studied using EDS and XRF. Latent fingerprints developed with Au-PANI were studied using XRF based on the map of gold and chloride elements. This approach is beneficial for faint or partial fingerprints. Fingerprint ridges were obvious in the chloride and gold images acquired from any position of the developed fingerprints. Novelty and significance of this work comprise the ability to visualize the three levels of fingerprint details of primary, secondary, and tertiary, enhanced contrast, less labor intensive, applicable to porous and non-porous surfaces, and cost effective.

Gold is emerging as a potential therapeutic agent in the treatment of arthritis, cancer and AIDS. The therapeutic mechanism of arthritic gold drugs and their modification in the presence of stomach hydrochloric acid, in the joints, and in the presence of mild and strong oxidizing agents is a matter of debate. It is believed that gold affects the entire immune response and reduces its potency and limits its oxidizing nature. DNA apparently is not the main target of gold in cancer treatment. Rheumatoid arthritis, cancer, heart diseases and recently AIDS have all been targeted with gold nanoparticles therapy. The era of gold nanoparticles started with cancer imaging and treatment studies. Gold nanoparticles have emerged as smart drug vehicles.

Tetranuclear gold(I) fluorinated amidinate complexes have been synthesized and their photophysical properties and structures described. DFT calculations were carried out to illustrate how a minor change in the ligand resulted in a loss of emission in the perfluorophenyl amidinate complex compared with nonfluorinated phenyl amidinate complexes reported previously. The fluorinated complexes reported here [Au(ArN)(2)C(H)](4) (1, Ar = 4-FC(6)H(4); 2, 3,5-F(2)C(6)H(3); 3, 2,4,6-F(3)C(6)H(2); 4, 2,3,5,6-F(4)C(6)H) emit in the blue-green region at 470, 1, 478, 2, 508, 3, and 450 nm, 4, by excitation at ca. 375 nm at room temperature with nanosecond lifetimes. The emissions observed at 77 K in the solid state show structured emission for complexes 1 and 2, with a vibrational spacing of ca. 1200 and 1500 cm(-1), corresponding to the vibrational modes of the amidinate ligand. The pentafluorophenyl derivative 5, Ar = C(6)F(5,) shows no photoluminescence in the solid state nor in the solution. This result is different from results in which the pentafluorophenyl group is attached to a phenylpyridine ligand in an Ir(III) complex and other organics. This quenching appears to be related to a nonradiative de-excitation process caused by the ππ*-πσ* crossover in the excited state of the pentafluorophenyl amidinate ligand. With increasing numbers of fluorine atoms, there is a progressive decrease in the contribution of the amidinate ligands to the corresponding HOMO orbital. There also is a slight decrease in the ligand contribution to the LUMO with increased numbers of fluorine atoms and an exchange of the character of the orbitals of the gold centers.

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Various reagents such as Cl2, Br2, I2, benzoyl peroxide and CH3I add to the dinuclear gold(I) amidinate complex [Au2(2,6-Me2Ph-form)2] to form oxidative-addition gold(II) metal–metal bonded complexes. The gold–gold distance in the dinuclear complex decreases upon oxidative-addition with halogens from 2.7 to 2.5Å, similar to observations made with dithiolate and ylide ligands. The sodium salt of the guanidinate Hhpp ligand, Hhpp=1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine reacts with (THT)AuCl in THF or CH2Cl2 to form a Au(II) complex, [Au2(hpp)2Cl2], either by solvent oxidation or disproportionation of the Au(I) to Au(II) and the metal. Density functional theory (DFT) and MP2 calculations on [Au2(hpp)2Cl2] find that the highest occupied molecular orbital (HOMO) is predominately hpp and chlorine-based with some Au–Au δ* character. The lowest unoccupied molecular orbital (LUMO) has metal-to-ligand (M–L) and metal-to-metal (M–M) σ* character (approximately 50% hpp/chlorine, and 50% gold). The charge-transfer character of the deeply colored solutions is observed in all the oxidative-addition products of the dinuclear gold(II) nitrogen ligands. This contrasts with the colors of the gold(II) ylide oxidative-addition products which are pale yellow. The colors of the crystalline gold(II) nitrogen complexes are dark orange to brown. This review will focus on the chemistry of gold(II) with nitrogen ligands and compare this with the well reviewed chemistry of gold(II) thiolate and ylide complexes.