Satoru Tsukada

Expanding Family of π-Conjugated Trinuclear Dithiolenes: The Cases of Group 8 (RuII) and 10 (NiII and PtII) Metals

New π-conjugated trinuclear dithiolenes with group 8 (6, Ru(II)) and 10 (7 and 8, Ni(II) and Pt(II)) metals were synthesized. Compounds 6 and 7 exhibited intense electronic communication through the phenylene bridge among the three dithiolene moieties during oxidation of the metalladithiolene rings, which has not been confirmed in the analogous family of group 9 metals, 1-5. Compound 8 exhibited an intense absorption band across the visible and near-IR regions, which was assigned as a charge transfer to the diimine and was red-shifted and broadened compared to the corresponding band of the mononuclear complex.

Ir3Co6 and Co3Fe3 Dithiolene Cluster Complexes: Multiple Metal-Metal Bond Formation and Correlation between Structure and Internuclear Electronic Communication

π-Conjugated trinuclear iridium and cobalt dithiolenes undergo multiple metal-metal bond formation with Co(2)(CO)(8) and Fe(CO)(5), giving rise to Ir(3)Co(6) nonanuclear and Co(3)Fe(3) hexanuclear cluster complexes 5 and 6, respectively. 5 retains a planar framework and intense π conjugation across the three iridadithiolenes and the phenylene bridge, which results in intense electronic communication among the three Co(2)(CO)(5) units in reduced mixed-valent states.

π-Conjugated Trinuclear Group-9 Metalladithiolenes with a Triphenylene Backbone

Previously, we synthesized π-conjugated trinuclear metalladithiolene complexes based on benzenehexathiol (J. Chem. Soc., Dalton Trans.1998, 2651; Dalton Trans.2009, 1939; Inorg. Chem.2011, 50, 6856). Here we report trinuclear complexes with a triphenylene backbone. A reaction with triphenylenehexathiol and group 9 metal precursors in the presence of triethylamine gives rise to trinuclear complexes 9-11. The planar structure of 11 is determined using single crystal X-ray diffraction analysis. The ligand-to-metal charge transfer bands of 9-11 move to longer wavelengths compared with those of mononuclear 12-14. Electrochemical measurements disclose that the one-electron and two-electron reduced mixed-valent states are stabilized thermodynamically. UV-vis-NIR spectroscopy for the reduced species of 9 identifies intervalence charge transfer bands for 9(-) and 9(2-), substantiating the existence of electronic communication among the three metal nuclei. These observations prove that the triphenylene backbone transmits π-conjugation among the three metalladithiolene units.

Alkynylation of benzotriazole with silylethynyliodonium triflates. Regioselective synthesis of 2-ethynyl-2H-benzotriazole derivatives.

Phenyl(trimethylsilylethynyl)iodonium and tert-butyldimethylsilylethynyl(phenyl)iodonium triflates were applied to alkynylation of benzotriazole. Treatment of the silylethynyliodonium triflates with the potassium salt of benzotriazole ion in (t)BuOH and CH(2)Cl(2) gave 2-(trimethylsilylethynyl)-2H-1,2,3-benzotriazole and 2-(tert-butyldimethylsilylethynyl)-2H-1,2,3-benzotriazole in 74% and 76% yields, respectively. The regioisomers, 1-silylethynyl-1H-1,2,3-benzotriazole derivatives, were minor. In both cases of the silyl-substitued ethynyliodonium salts, novel regioselective alkynylation of benzotriazole at the 2 position was observed.

Carbon Monoxide Addition to Ruthenium–Dithiolene Complex and Polysiloxane Hybrid Film Formation

The addition of carbon monoxide to the ruthenium center of [(η(6) -C6 Me6 )Ru(S2 C6 H4 )] (1) has been investigated. [(η(6) -C6 Me6 )Ru(CO)(S2 C6 H4 )] (2) was obtained by the addition of CO gas to the ruthenium center of 1 in both solution and solid states. 1 was reproduced by treating 2 with an oxidant. A 1/polysiloxane self-standing hybrid film was also prepared and showed a dramatic color change upon transformation of 1 to 2 in polysiloxane hybrid film.

Syntheses of cage octasilicate polymers

Octakistetramethylammonium octasilsesquioxane (Q8TMA) was synthesized from water glass (No. 3) by neutralization, extraction with tetrahydrofuran, and condensation reaction using tetramethylammonium hydroxide. Octakisdimethylsilyl octasilsesquioxane (Q8DMS) was synthesized by the reaction of Q8TMA with chloro(dimethyl)silane. An all-siloxane-type cage-containing polymer was synthesized by the reaction of Q8DMS with water by using diethylhydroxylamine as a catalyst. The reaction of Q8DMS with diphenylsilanediol was carried out to provide oligomers. This reaction was carried out by the addition of Q8DMS twice to isolate a cage-containing polymer with a weight-average molecular weight of 18,000.Graphical Abstract

Preparation and properties of a fullerene/polysiloxane hybrid from chemically modified fullerene and polymethoxysiloxane

An organic–inorganic hybrid was prepared by simply mixing a fullerene derivative with polymethoxysiloxane. First, C60 was subjected to a radical addition reaction with 4,4′-azobis(4-cyanovaleric acid) to provide a C60 derivative. Polymethoxysiloxane was prepared by a controlled hydrolytic condensation of tetramethoxysilane. These two compounds were mixed and heated to provide hybrid bulk body. The hybrid bulk body showed high mechanical strength and elastic modulus compared with polymethoxysiloxane or the C60/polymethoxysiloxane hybrid. The formation of a dense siloxane network was established by a homogeneous mixing of the C60 derivative with polymethoxysiloxane.

Properties and surface morphologies of organic–inorganic hybrid thin films containing titanium phosphonate clusters

AbstractOrganic–inorganic hybrid thin films containing [Ti4(μ3-O)(OiPr)5(μ-OiPr)3(O3PPh)3]·THF (TiOPPh) were prepared via the hybridization of TiOPPh with poly(vinyl phenol) (PVP), poly(styrene-co-allyl alcohol) (PSA), and poly(bisphenol A-co-epichlorohydrin) (PBE) using spin coating. These thin films were characterized in terms of their transmittance, pencil hardness, and surface morphologies. The transmittance values of the PVP hybrid thin films decreased with the addition of TiOPPh because of the formation of Ti–O–Ph bonds. The pencil hardness values of the hybrid thin films were in the order PVP > PBE > PSA hybrids. Using confocal laser scanning microscopy and atomic force microscopy, the pencil hardness values were determined to be strongly dependent on the surface morphology, such as the roughness and presence of pin holes. The model cluster was synthesized by the reaction of TiOPPh with excess ethanol to study the structures of the TiOPPh in hybrids. From the nuclear magnetic resonance spectroscopy and single-crystal X-ray structure analyses, the main core structure of the model cluster was found to retain the core structure of TiOPPh.Organic–inorganic hybrid thin films containing [Ti4(μ3-O)(OiPr)5(μ-OiPr)3(O3PPh)3]·THF (TiOPPh) as element blocks were prepared via hybridization with the hydroxyl-substituted organic polymers (PVP, PSA, or PBE) by spin-coating. The hybrid thin films were characterized by AFM, DSC, and pencil hardness. The pencil hardness values of the PVP hybrid thin films were in the order 20 > 40 > 0 wt% and were dependent on the surface smoothness. When TiOPPh was reacted with excess ethanol, the core was retained. Therefore, the core of TiOPPh will be retained in the hybrid polymers.

Preparation of Ruthenium Dithiolene Complex/Polysiloxane Films and Their Responses to CO Gas

To develop advanced materials using metal complexes, it is better to prepare metal complexes contained in composite or hybrid films. To achieve this purpose, we synthesized ruthenium complexes with dihalogen-substituted benzendithiolate ligands, [(η6-C6Me6)Ru(S2C6H2X2)] (X = F, 3,6-Cl, Br, 4,5-Cl), 1b–1e. We also investigated preparation of 1c or 1e containing polysiloxane composite films and their reactivity to CO gas. All ruthenium complexes 1b–1e reacted with CO gas, and carbonyl ligand adducts 2b–2e were generated. Ruthenium complexes 1b–1e show two strong absorption peaks around 550 and 420 nm. After exposure to CO gas, these absorption peaks were immediately decreased without a peak shift. A similar trend was observed in 1c or 1e containing polysiloxane composite films. These results indicate that 1c and 1e were easily converted into 2c and 2e, both in the solution and the polysiloxane film during CO gas exposure.

Zinc–diethanolamine complex: synthesis, characterization, and formation mechanism of zinc oxide via thermal decomposition

AbstractZn(OAc)2(H2DEA) was synthesized by the reaction of zinc acetate dihydrate (Zn(OAc)2•2H2O) with diethanolamine (H2DEA), and was characterized using single-crystal X-ray structural analysis, nuclear magnetic resonance spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and elemental analysis. Zn(OAc)2(H2DEA) had a trigonal bipyramidal geometry comprised of one zinc atom, two acetate groups, and one H2DEA as a neutral tridentate ligand to form two five-membered rings. The states of Zn(OAc)2(H2DEA) heated at various temperatures were determined by FT-IR spectroscopy. At 270 °C, the H2DEA ligand dissociated and was removed. The absorption bands assigned to Zn–O stretching vibration of Zn4O core such as the zinc-oxo cluster appeared. When heated at 500 °C, the absorption bands of μ4-oxozincate and the acetate group disappeared completely and hexagonal wurtzite structural ZnO was formed at 550 °C. A possible thermal decomposition pathway from Zn(OAc)2(H2DEA) to ZnO was proposed. The ZnO film was highly transparent and formed by the deposition of ZnO nanoparticles with size ~40 nm. Zn(OAc)2(H2DEA) was synthesized and characterized. The states of Zn(OAc)2(H2DEA) heated at various temperatures were determined by FT-IR spectroscopy, and the formation mechanism of ZnO was estimated.HighlightsZinc–diethanolamine complex was synthesized by the reaction of zinc acetate with diethanolamine.Zinc–diethanolamine complex was isolated and characterized.The formation mechanism of ZnO was estimated by FT-IR spectra.