Adamantane-type clusters: compounds with a ubiquitous architecture but a wide variety of compositions and unexpected materials properties.

The research into adamantane-type compounds has gained momentum in recent years, yielding remarkable new applications for this class of materials. In particular, organic adamantane derivatives (AdR4) or inorganic adamantane-type compounds of the general formula [(RT)4E6] (R: organic substituent; T: group 14 atom C, Si, Ge, Sn; E: chalcogenide atom S, Se, Te, or CH2) were shown to exhibit strong nonlinear optical (NLO) properties, either second-harmonic generation (SHG) or an unprecedented type of highly-directed white-light generation (WLG) - depending on their respective crystalline or amorphous nature. The (missing) crystallinity, as well as the maximum wavelengths of the optical transitions, are controlled by the clusters' elemental composition and by the nature of the organic groups R. Very recently, it has been additionally shown that cluster cores with increased inhomogeneity, like the one in compounds [RSi{CH2Sn(E)R'}3], not only affect the chemical properties, such as increased robustness and reversible melting behaviour, but that such 'cluster glasses' form a conceptually new basis for their use in light conversion devices. These findings are likely only the tip of the iceberg, as beside elemental combinations including group 14 and group 16 elements, many more adamantane-type clusters (on the one hand) and related architectures representing extensions of adamantane-type clusters (on the other hand) are known, but have not yet been addressed in terms of their opto-electronic properties. In this review, we therefore present a survey of all known classes of adanmantane-type compounds and their respective synthetic access as well as their optical properties, if reported.

AgONO-assisted direct C-H arylation of heteroarenes with anilines.

A novel copper-catalyzed C-H arylation of heteroarenes with anilines by an in situ diazonium reaction is established by using silver nitrite (AgONO) as an unconventional nitrosating reagent under acid-free conditions. It provides a complementary approach for the C-H arylation of electron-rich heteroarenes with aromatic amines affording a variety of heterobiaryls in moderate to good yields.

(η(6)-Benzene)-dichlorido-(chloro-dicyclo-hexyl-phosphane-κP)ruthenium(II) chloro-form monosolvate.

The title compound, [RuCl2(η(6)-C6H6)(C12H22ClP)]·CHCl3, was prepared by reaction of [RuCl2(η(6)-C6H6)]2 with chloro-dicyclo-hexyl-phosphane in CHCl3 at 323 K under argon. The Ru(II) atom is surrounded by one arene ligand, two Cl atoms and a phosphane ligand in a piano-stool geometry. The phosphane ligand is linked by the P atom, with an Ru-P bond length of 2.3247 (4) Å. Both cyclo-hexyl rings at the P atom adopt a chair conformation. In the crystal, the Ru(II) complex mol-ecule and the chloro-form solvent mol-ecule are linked by a bifurcated C-H⋯(Cl,Cl) hydrogen bond. Intra-molecular C-H⋯Cl hydrogen bonds are also observed.

(η(6)-Benzene)(carbonato-κ(2) O,O')[di-cyclohex-yl(naphthalen-1-ylmeth-yl)phosphane-κP]ruthenium(II) chloro-form tris-olvate.

The title compound, [Ru(CO3)(η(6)-C6H6){(C6H11)2P(CH2C10H7)}]·3CHCl3, was synthesized by carbonation of [RuCl2(η(6)-C6H6){(C6H11)2P(CH2C10H7)}] with NaHCO3 in methanol at room temperature. The Ru(II) atom is surrounded by a benzene ligand, a chelating carbonate group and a phosphane ligand in a piano-stool configuration. The crystal packing is consolidated by C-H⋯O and C-H⋯Cl hydrogen-bonding inter-actions between adjacent metal complexes and between the complexes and the solvent mol-ecules. The asymmetric unit contains one metal complex and three chloro-form solvent mol-ecules of which only one was modelled. The estimated diffraction contributions of the other two strongly disordered chloro-form solvent mol-ecules were substracted from the observed diffraction data using the SQUEEZE procedure in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155].

A convenient and selective palladium-catalyzed aerobic oxidation of alcohols.

An efficient procedure for the oxidation of primary and secondary alcohols to aldehydes and ketones, respectively, with molecular oxygen under ambient conditions has been achieved. By applying catalytic amounts of Pd(OAc)2 in the presence of tertiary phosphine oxides (O=PR3) as ligands, a variety of substrates are selectively oxidized without formation of ester byproducts. Spectroscopic investigations and DFT calculations suggest stabilization of the active palladium(II) catalyst by phosphine oxide ligands.

Synthesis of stable phosphomide ligands and their use in Ru-catalyzed hydrogenations of bicarbonate and related substrates.

New benzoyl- and naphthoyl-substituted phosphines have been synthesized, which are stable to air and moisture. Testing these so-called phosphomide ligands in the presence of different ruthenium precursors, the hydrogenation of sodium bicarbonate (NaHCO(3)) to sodium formate (NaHCO(2)) proceeded with good catalyst turnover numbers in the range of 1300-1600 at 80°C and a total pressure of hydrogen of 60 bar in the absence of amines or other additives. Similarly, catalytic hydrogenations of carbon dioxide, cinnam-, and benzaldehyde were possible with these new ruthenium complexes. As an intermediate of the catalytic cycle the defined ruthenium complex [(η(6)-C(6)H(6))-RuCl(2)(Cy(2)P(1-naphthoyl)] (Cy=cyclohexyl) was prepared and characterized by X-ray crystallography.

Dicyclo-hexyl-bis-(naphthalen-1-ylmeth-yl)phospho-nium chloride chloro-form disolvate.

In the title solvated phosphonium salt, C34H40P(+)·Cl(-)·2CHCl3, the two cyclo-hexyl and two 1-naphthyl-methyl groups at the P atom are in a distorted tetra-hedral arrangement [105.26 (6)-113.35 (6)°]. Both cyclo-hexyl rings adopt a chair conformation. The dihedral angle between the naphthyl ring systems is 74.08 (3)°.

A general and efficient catalyst for palladium-catalyzed C-O coupling reactions of aryl halides with primary alcohols.

An efficient procedure for palladium-catalyzed coupling reactions of (hetero)aryl bromides and chlorides with primary aliphatic alcohols has been developed. Key to the success is the synthesis and exploitation of the novel bulky di-1-adamantyl-substituted bipyrazolylphosphine ligand L6. Reaction of aryl halides including activated, nonactivated, and (hetero)aryl bromides as well as aryl chlorides with primary alcohols gave the corresponding alkyl aryl ethers in high yield. Noteworthy, functionalizations of primary alcohols in the presence of secondary and tertiary alcohols proceed with excellent regioselectivity.