The development of nonbleachable colorants made of safe and inexpensive materials is a scientifically important task in view of future environmental and biological impacts. In this study, the conditions under which spherical colloidal crystals (photonic balls) formed mainly of sub-micron-sized monodispersed silica fine particles and carbon black exhibit vivid structural coloring were systematically investigated. The (111) plane of the face-centered cubic colloidal crystal formed by the silica particles is mainly oriented on the surface of the photonic balls formed from monodispersed silica particles. As a result, light in a specific wavelength region is reflected from the photonic balls according to the Bragg condition. When silica particles with diameters of 221, 249, and 291 nm are used, the peaks of the Bragg reflections generated from the photonic balls occur at 495, 562, and 647 nm, respectively; each photonic ball exhibits the ability to produce blue, green, and red colors. In particular, when a black background is used, a vivid structural color is observed from each photonic ball, and it is possible to reproduce all colors using the three primary colors of light by changing the mixture ratio of these photonic balls. The introduction of a small amount of carbon black into the photonic balls makes it possible to reproduce the additive color mixture by the three primary colors of light even when the background color is white. We report that safe and nonbleachable coloring materials with controlled nanosized periodic structures and micrometer-sized geometric structures can be developed using three types of photonic balls consisting of safe and inexpensive silica fine particles with/without carbon black.

Nickel(II) complexes bearing a  3 SNS pincer ligand, 2,5-bis(benzylaminothiocarbonyl)pyrrolyl (L1) and a  3 SCS pincer ligand, 2,6-bis(benzylaminothiocarbonyl)phenyl (L2), were synthesized, and their structures and electrochemical properties were elucidated. The crystal structures of [Ni(SNS)Br] (2) and [Ni(SCS)Br] (5) were determined by X-ray crystallography. The electrochemical and crystallographic data obtained from the complexes revealed that the  3 SCS ligand has a stronger electron donating ability than the  3 SNS ligand. Keywords: Nickel / pincer complex / X-ray crystal structures / electron donating ability *Manuscript Click here to view linked References CIF Data Files (if paper contains X-ray crystal structures) Click here to download CIF Data Files (if paper contains X-ray crystal structures): CIF_complex-2.cif CIF Data Files (if paper contains X-ray crystal structures) Click here to download CIF Data Files (if paper contains X-ray crystal structures): CIF_complex-5.cif CIF Data Files Validation Report (if paper contains X-ray crystal structures) Click here to download CIF Data Files Validation Report (if paper contains X-ray crystal structures): checkcif_complex-2.pdf CIF Data Files Validation Report (if paper contains X-ray crystal structures) Click here to download CIF Data Files Validation Report (if paper contains X-ray crystal structures): checkcif_complex-5.pdf

Regioregulated poly(aminopyridine)s were synthesized by a Pd-catalyzed CN coupling reaction. The polymerization using Pd(0) and a bulky monodentate phosphine ligand distinctively produced the para-linked and meta-linked poly(aminopyridine)s, without the need for a protection process. The regioregularity of the polymer was confirmed by (1) H NMR spectroscopy. Model reactions were studied to evaluate the possibility of crosslinkage in the polymer. A large difference in reactivity was observed between 5-amino-2-bromopyridine and 2-amino-5-bromopyridine, which should have afforded same product. Density functional theory (DFT) calculations indicated that electron densities of the Br-bound carbon atom and the pyridine-nitrogen atom determine the reactivity of the monomers.

New pincer ruthenium complexes, [Ru(SCS)(tpy)]PF(6) (1) (SCS = 2,6-bis(benzylaminothiocarbonyl)phenyl), tpy = 2,2':6',2''-terpyridyl) and [Ru(SNS)(tpy)]PF(6) (2) (SNS = 2,5-bis(benzylaminothiocarbonyl)pyrrolyl), having κ(3)SCS and κ(3)SNS pincer ligands with two secondary thioamide units were synthesized by the reactions of [RuCl(3)(tpy)] with N,N'-dibenzyl-1,3-benzenedicarbothioamide (L1) and N,N'-dibenzyl-2,5-1H-pyrroledicarbothioamide (L2), respectively, and their chemical and electrochemical properties were elucidated. The structure of 1 was determined by X-ray crystallography. The complexes 1 and 2 showed a two-step deprotonation reaction by treatment with 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU), and the addition of DBU led to a shift of the metal-centered redox couples to a lower potential by 720 and 550 mV, respectively. The di-deprotonated complexes were also studied by (1)H-NMR and UV-vis spectroscopy. The addition of methanesulfonic acid (MSA) to the di-deprotonated complexes enabled the recovery of 1 and 2, indicating that the thioamide moiety underwent a reversible deprotonation-protonation process, which resulted in regulating the redox potentials of the metal center. The Pourbaix diagram of 1 revealed that 1 underwent a one-proton/one-electron transfer process in the pH range of 5.83-10.35, and a two-proton/one-electron process at a pH of over 10.35, indicating that the deprotonation/protonation process of the complexes is related to proton-coupled electron transfer (PCET).