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This paper deals with a notable halosulfite ion, (I2SO22−), which is a rare example of this inorganic anion species; the reaction of the platinum(ii) complex, [Pt(depe)2]I2with SO2afforded the complex, [Pt(depe)2](I2SO2) containing the rare anion; considering with the VSEPR concept, the structure of the anion could be interpreted as a distorted trigonal bipyramid. [ABSTRACT FROM AUTHOR]

This tutorial reviewpresents some recent examples of intramolecular Diels–Alder (IMDA) reactions as key complexity-generating steps in the total synthesis of structurally intricate natural products. The opportunities afforded by transannular (TADA) versions of the IMDA reaction in complex molecule assembly are also highlighted. The review is aimed at a wide audience, ranging from advanced undergraduates to seasoned practitioners of total synthesis; since this is an educational overview, only selected highlights from the period 2000–2009 are presented, along with chosen references to other, more comprehensive, reviews. [ABSTRACT FROM AUTHOR]

The employment of di-2-pyridyl ketone, (py)2CO, in manganese(ii) acetate chemistry is reported. The syntheses, crystal structures and magnetochemical characterisation are described for [MnII4(O2CMe)4{(py)2C(OH)O}4] (1) and [MnII10MnIII4O4(O2CMe)20{(py)2C(OH)O}4] (2), where (py)2C(OH)O−is the monoanion of the gem-diol form of the ligand. The reaction of Mn(O2CMe)2·4H2O with one equivalent of (py)2CO in Me2CO gives 1. Complex 2was obtained from the 1 : 1 reaction, in EtOH, between Mn(O2CMe)2·4H2O and (py)2CO in the presence of NEt3. The tetranuclear molecule 1has a cubane topology with the MnIIand the deprotonated oxygen atoms from the η1:η3:η1:μ3ligands occupying alternate vertices of the cube. The core of 2consists of two mixed valence cubane {MnII2MnIII2(μ3-O)2(μ3-OR″)2}4+subunits that are linked through an unusual {MnII6(η1:η2:μ-O2CMe)6(η2:η2:μ3-O2CMe)2}4+moiety viatwelve η1:η1:μ MeCO2−groups. Some suggestions have been made concerning the possible assembly of 2from 1. The magnetic properties of 1in the 300–5 K range have been modelled with two Jvalues, which reveal weak antiferromagnetic interactions within the molecule. Complex 2has a low spin ground state. This work demonstrates the flexibility, versatility and synthetic potential of combining (py)2CO with carboxylate ligands. [ABSTRACT FROM AUTHOR]

The reactions of GaX3(X = Cl, Br or I) with SMe2, SeMe2and TeMe2(L) in non-coordinating solvents produces only the pseudo-tetrahedral [GaX3L], which have been characterised by IR, Raman and multinuclear NMR (1H, 71Ga, 77Se or 125Te) spectroscopy, and by the crystal structure of [GaCl3(SeMe2)]. The 71Ga NMR resonances show small low frequency shifts for fixed halides as the neutral donors change from S → Se → Te. Bidentate ligands including MeS(CH2)2SMe, PhS(CH2)2SPh, MeSe(CH2)2SeMe, nBuSe(CH2)2SenBu and MeTe(CH2)3TeMe (L–L) also produce complexes with 4-coordinate gallium centres, [(GaX3)2(μ-L–L)], confirmed by the crystal structures of [(GaI3)2{μ-MeS(CH2)2SMe}], [(GaCl3)2{μ-PhS(CH2)2SPh}] and [(GaCl3)2{μ-nBuSe(CH2)2SenBu}]. The structural data are consistent with the weaker Lewis acidity of the gallium as the halide co-ligands become heavier. Multinuclear NMR studies suggest that in chlorocarbon solutions partial dissociation of the ligands occur, which increases with the halide co-ligand Cl < Br < I. The o-xylyl dithioether, o-C6H4(CH2SMe)2, despite being pre-organised for chelation, also forms [(GaCl3)2(μ-L–L)]. The corresponding diselenoether complex decomposes in solution with C–Se bond cleavage to form the selenonium salt [o-C6H4CH2Se(Me)CH2][GaCl4], which was structurally characterised. The ditelluroether o-C6H4(CH2TeMe)2undergoes rapid C–Te bond fission and rearrangement upon reaction with GaCl3, and the telluronium species [o-C6H4CH2Te(Me)CH2]+and [MeTe{CH2(o-C6H4)CH2TeMe}2]+have been identified by ES+mass spectrometry from their characteristic isotope patterns. [ABSTRACT FROM AUTHOR]

Three novel Re(iv) mononuclear complexes of formulae NBu4[ReCl5(pyz)] (1), NH2Me2[ReCl5(pyz)] (2) and NH4[ReCl5(pyz)]·0.75H2O (3), (pyz being pyrazine; NBu4+ = tetra-n-butylammonium cation, NH2Me2+ = dimethylammonium cation and NH4+ = ammonium cation), were synthesized by ligand substitution reaction from [ReCl6]2− anion and pyrazine in N,N-dimethylformamide (DMF). In addition, two new heterobimetallic compounds, the salt namely [ReCl5(pyz)]2[Ni(cyclam)] (4) (cyclam = 1,4,8,11-tetraazacyclotetradecane) and the heterotrinuclear [{ReCl5(μ-pyz)}2Cu(DMF)4] (5) complex, were prepared by using as precursor 1 and 3, respectively. Compounds 1–5 were characterized by single-crystal X-ray diffraction. 1–3 are made up of discrete [ReCl5(pyz)]− anions and NBu4+ (1), NH2Me2+ (2) and NH4+ (3) cations. [ReCl5(pyz)]− unit interacts toward Ni(ii) (4) and Cu(ii) (5) metal ions through different modes. In 4 two [ReCl5(pyz)]− anions weakly interact with a [Ni(cyclam)]2+ cation through chloro atoms, while compound 5 is a heterotrinuclear pyrazine-bridged ReIV2CuII complex made up of [ReCl5(pyz)]− anions and [Cu(DMF)4]2+ cations. The magnetic properties of 1–5 were investigated in the temperature range 1.9–300 K. The magnetic behaviour of 1 is that of a magnetically diluted Re(iv) complex with a large value of zero-field splitting of the ground state (|2D| is ca. 18.8(1) cm−1), whereas those of 2 and 3 are typical of antiferromagnetically coupled systems exhibiting susceptibility maxima at 10 (2) and 12 K (3). Compound 4 shows antiferromagnetic interactions between Re(iv) metal ions, Ni(ii) being diamagnetic (because of its square-planar geometry), while 5 exhibits a ferromagnetic coupling between Re(iv) and Cu(ii) metal ions across the pyrazine bridges with a JReCu value of +11.8(1) cm−1. [ABSTRACT FROM AUTHOR]