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Four new water-soluble bidentate ligands, namely, (cyclopentadienyl)ethyl-1,3,5-triaza-7-phosphadamantane (1), 1,2-bis-(1,3,5-triaza-7-phosphaadamantan-6-yl) ethane (2), 1,3-bis-(1,3,5-triaza-7-phosphaaadamantan-6-yl) propane (3) and 1,4-bis-(1,3,5-triaza-7-phosphaadamantan-6-yl) butane (4) have been synthesized and characterized by multi-nuclear NMR (1H, 13C and 31P), elemental analysis and mass spectrometry. Compound 1 was synthesized by using two different synthetic routes in excellent yields and is also the first example of water-soluble chelating cyclopentadienyl ligand containing 1,3,5-triaza-7-phosphaadamantane. [ABSTRACT FROM AUTHOR]

Acceptorless dehydrogenative oxidation of primary amines into nitriles using an in situ complex derived from commercially available dichloro(1,5-cyclooctadiene) ruthenium(II) complex and simple hexamethylenetetramine has been demonstrated. The synthetic protocol is highly selective and yields the nitrile compounds in moderate to excellent yields and produces hydrogen as the sole byproduct. [ABSTRACT FROM AUTHOR]

An in situ generated catalyst were developed from readily available Ru[H.sub.2][(P[Ph.sub.3]).sub.4], an N-heterocyclic carbene (NHC) precursor, NaH, and acetonitrile. The prepared catalyst exhibited high activity for the amide synthesis directly from either alcohols or aldehydes with amines.

Ruthenium-catalyzed formation of lactones from diols in aqueous medium has been demonstrated. 1,3,5-Triazaphosphaadamantane (PTA) included water-soluble ruthenium complexes [RuCl2 (PPh3)(2,6-Py-(CH2-PTA)2 ]·2Br and [RuCl2 (PPh3)2 (2-PyCH2 PTA)]·Br in the presence of KOH were found to be efficient for the synthesis of lactones from diols. The reported synthetic protocol is green as it uses water as solvent, avoids the use of any hydrogen acceptor/oxidant, and produces hydrogen as the only side product. Mechanistic studies revealed that lactone formation involved aldehyde intermediate and followed dehydrogenative pathway. [ABSTRACT FROM AUTHOR]

The synthesis of a ruthenium complex bearing a PN-chelating ligand is described. The complex, in the presence of KOH, enabled the synthesis of ketones from secondary alcohols in the absence of a hydrogen acceptor in aqueous medium. This synthetic protocol, which uses water as the medium, is green and has a high atom economy as it avoids the use of an acceptor and produces hydrogen as the sole byproduct. Mechanistic investigations revealed that the catalytic cycle involves a phosphine dissociative pathway. [ABSTRACT FROM AUTHOR]

Our work shows that simple alkynes can be hydrated by the AuCl/MeOH catalyst system to afford the corresponding methyl ketones in moderate to high yields without any additive, ligand, or acid promoter. This methodology is simpler, milder, and operationally easier than those reported before. The reaction media significantly affects the reaction, and methanol is found to be the best solvent. Both aliphatic and aromatic terminal alkynes were able to undergo hydration, affording moderate to excellent yields under the reaction conditions used in the present work, and excellent functional-group tolerance was also observed. A plausible mechanism for the hydration reaction was proposed. [ABSTRACT FROM AUTHOR]

Ligandsubstitution is not a common procedure for the preparationof different borenium cations. This work demonstrates that the chlorideligands of several NHC-stabilized dichloroborenium cations [NHC·BCl2][X] (NHC = (R′C)2(NR)2C; 1, R = iPr, R′ = H; 2, R = iPr, R′ = Me; 3, R = tBu, R′= H; X = AlCl4, B(3,5-Cl2-C6H3)4) could be replaced with a catecholato moietyto produce [NHC·Bcat][X]. According to single-crystal X-ray analysesthis particular ligand exchange enhanced the Lewis acidity of thetarget borocations with respect to the dichloro precursors. [ABSTRACT FROM AUTHOR]

The reactivity of nucleophilic carbodiphosphorane (C(PPh3)2, 1) and carbodicarbene (C(C(NMe)2C6H4)2, 2) towards various dichlorophosphines has been explored. In most cases the expected carbone-for-chloride ligand exchange was observed. However, the use of MeN(PCl2)2 resulted in a unique P–N bond cleavage that, according to computational studies, occurred via an SN2′-like mechanism. [ABSTRACT FROM AUTHOR]