Dalton Transactions

doi: 10.1039/c005507gpmid: N/A

doi: 10.1039/c005508ppmid: N/A

Mezzetti, Antonio

doi: 10.1039/c0dt00119hpmid: 20676450

This is a personal account of the application of ruthenium complexes containing chiral tetradentate ligands with a P2N2 ligand set (PNNP) as catalyst precursors for enantioselective “atom transfer” reactions. Therewith are meant reactions that involve bond formation between a metal-coordinated molecule and a free reagent. The reactive fragment (e.g. carbene) is transferred either from the metal to the non-coordinated substrate (e.g. olefin) or from the free reagent (e.g. F+) to the metal-bound substrate (e.g. β-ketoester), depending on the class of catalyst (monocationic, Class A; or dicationic, Class B). The monocationic five-coordinate species [RuCl(PNNP)]+ and the six-coordinate complexes [RuCl(L)(PNNP)]+ (L = Et2O, H2O) of Class A catalyse asymmetric epoxidation, cyclopropanation (carbene transfer from the metal to the free olefin), and imine aziridination. Alternatively, the dicationic complexes [Ru(L–L)(PNNP)]2+ (Class B), which contain substrates that act as neutral bidentate ligands L–L (e.g., β-ketoesters), catalyse Michael addition, electrophilic fluorination, and hydroxylation reactions. Additionally, unsaturated β-ketoesters form dicationic complexes of Class B that catalyse Diels–Alder reactions with acyclic dienes to produce tetrahydro-1-indanones and estrone derivatives. Excellent enantioselectivity has been achieved in several of the catalytic reactions mentioned above. The study of key reaction intermediates (both in the solid state and in solution) has revealed significant mechanistic aspects of the catalytic reactions.

Lobana, Tarlok S.; Sultana, Razia; Hundal, Geeta; Butcher, Ray J.

doi: 10.1039/c0dt00252fpmid: 20676416

Reactions of copper(i) halides with imidazolidine-2-thione and 1-methyl-1,3-imidazoline-2-thione in dmso involved C–S rupture in aerobic conditions and yielded a sulfate bridged polymer, [CuII{η2-N,N–(N2C3H5)2S}(μ-O,OSO2)(η1-OH2)]n1 and a sulfate chelated monomer, [CuII{η2-N,N–(N2C4H5)2S}(η2-O,OSO2)(η1-OH2)] 2 {N,N–(N2C3H5)2S = 2,2′-thio-di-2-imidazoline, N,N–(N2C4H5)2S = 1,1′-dimethyl-2,2′-di-imidazolyl sulfide}. This variable coordination behavior of in situ generated sulfate is unprecedented in the literature.

Franc, Grégory; Jutand, Anny

doi: 10.1039/c0dt00632gpmid: 20676451

CuII precursors ligated to phenanthrolines are reduced in situ by alcohols or amines in the presence of a base (Cs2CO3) to generate CuI species which are active catalysts in C–N and C–O cross-coupling reactions. The conversion CuII → CuI has been evidenced and monitored by UV-vis and NMR spectroscopy.

You, Wei; Zhu, Hao-Yu; Huang, Wei; Hu, Bin; Fan, Ying; You, Xiao-Zeng

doi: 10.1039/c0dt00101epmid: 20680215

Azo-hydrazone and cis–trans tautomerisms have been firstly observed between two disperse yellow dyes (cis/trans-HL1 and cis-HL2) and three neutral dye-metal complexes (one mononuclear NiII complex 3 and two CuII coordination polymers 4 and 5 formulated as [Ni(trans-L1)2(CH3OH)2]·2H2O, [Cu(cis-L1)2]n and [Cu(L3)(H2O)]n).

Liu, Shaofeng; Peloso, Riccardo; Pattacini, Roberto; Braunstein, Pierre

doi: 10.1039/c0dt00810apmid: 20680221

Reaction of TlPF6 with the Cr(iii) complex fac-[CrCl3(NPN)] (NPN = bis(2-picolyl)phenyl phosphine) did not lead to precipitation of TlCl but rather to addition of the Tl+ cation to the CrCl3 moiety, which resulted in a pseudo-dimeric adduct which has an unusual tetranuclear centrosymmetric structure in the solid state.

Bian, Zhao-Yong; Chi, Shao-Ming; Li, Li; Fu, Wenfu

doi: 10.1039/c0dt00310gpmid: 20683540

The photocatalytic activity for CO2 reduction and optical and electrochemical properties of two RuII–ReI binuclear complexes [Ru(dmb)2LRe(CO)3Cl]2+ (Ru–Re and RuRe, dmb = 4,4′-dimethyl-2,2′-bipyridine) with 1,2-bis(4′-methyl-2,2′-bipyridyl-4-yl)ethane and 1,2-bis(4′-methyl-2,2′-bipyridyl-4-yl)ethene as bridging ligands have been investigated. The conjugation content of the bridging ligands plays an important role in the photocatalytic behavior: a saturated linkage exhibited more efficient than the conjugated.

Lazarus, Laura L.; Brutchey, Richard L.

doi: 10.1039/c0dt00599apmid: 20625603

We report on the activity of fullerene-supported OsO4 catalysts in the achiral dihydroxylation of olefins using N-methylmorpholine N-oxide as co-oxidant. The fullerene-supported OsO4 catalysts can selectively dihydroxylate olefins with conversions up to 95% after 48 h without leaching, and the catalysts can be recovered and recycled several times.

Liu, Guohua; Liang, Xiaohui; Meetsma, Auke; Hessen, Bart

doi: 10.1039/c0dt00499epmid: 20657937

Reduction of a V(iii) complex [(η5,η1-C5H4CH2CH2NMe2)VCl2(PMe3)] in the presence of diphenylacetylene under nitrogen atmosphere yields a novel V(i) dinitrogen-bridged complex {[η5-(C5H4CH2CH2NMe2)]V(PhCCPh)(PMe3)}2(μ-N2).