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Polycrystalline CsBi2Ti2NbO10, an n = 3 member of the Dion—Jacobson (DJ) family, is prepared by solid state reaction of a stoichiometric mixture of Cs2CO3, Bi2O3, La2O3, TiO2, and Nb2O5 (alumina boat, 1.

Reactions of bis(pentafluorophenyl)mercury with piperidine, sodium iso-propoxide or sodium tert-butoxide have yielded the corresponding 4-substituted tetrafluorophenylmercurials, [Hg(C6F4X-4)2] (X = cyclo-C5H10N (1), OCH(CH3)2 (2), OC(CH3)3 (3)), in reasonable yields but the bulkier nucleophiles, cis-2,6-dimethylpiperidine and 2,6-di-iso-propylphenolate (from sodium 2,6-di-iso-propylphenolate) decomposed the mercurial into pentafluorobenzene. Treatment of bis(pentafluorophenyl)mercury with another bulky nucleophile, 2,6-diphenylphenolate (from sodium 2,6-diphenylphenolate), in methanol, resulted in the unexpected formation of [Hg(C6F4(OMe)-4)2] (4). The structures of all the mercurials have linear C–Hg–C stereochemistry with two coplanar aryl rings. Amongst a complex series of supramolecular interactions, Hg⋯O bonding is observed for the alkoxy substituted mercurials but there are no Hg⋯N interactions in the structure of bis(2,3,5,6-tetrafluoro-4-piperidinophenyl)mercury.

Small cyano anions, and their derivatives, have proved to be remarkably versatile building blocks for coordination polymers. They have led to magnetically ordered materials, structures with new entangled motifs or novel topologies, and a significant structural diversity, including polymorphism, induced by subtle changes in anion, cation, co-ligands, preparative conditions, or even desolvation.

A combination of sulfenylation and Wittig-type olefination gives enantioenriched allyl sulfides of type (IV).

The chemistry of the anions dicyanamide and tricyanomethanide (dca and tcm, respectively) has produced a plethora of discoveries over the past few decades, particularly in relation to transition-metal coordination polymers with magnetic coupling. Over recent years there have been an increasing number of reports of heterofunctionalised cyano-containing anions, typically derivatives of dicyanomethanide. Our own group has been particularly concerned with the amide- and nitroso-functionalised anions carbamoyldicyanomethanide (cdm) and dicyanonitrosomethanide (dcnm), respectively. This feature article examines the fascinating diversity of materials and complexes that can be obtained using small cyano anions, ranging from coordination polymers to heterometallic clusters and hydrogen bonding networks. In particular, we focus on results from our own laboratories in the past few years. The magnetic properties of these materials are briefly discussed.

Single crystals of the title compound (Db18c6: dibenzo-18-crown-6) are grown by reaction of Lu metal with I2 in THF (25 °C, ≈12 h) followed by addition of the crown ether.

The reaction between [Mn(Ch2Ph)(CO)5] and TePEt3 results in the insertion of tellurium into the Mn–CH2 bond, producing the first known monomeric σ-bonded alkyltelluriomanganese complex [Mn(TeCH2Ph)(CO)3(PEt3)2]2; pyrolysis of 2 yields polycrystalline manganese telluride.

Prolonged reaction of manganese metal with bis(pentafluorophenyl)mercury in thf or 1,2-dimethoxyethane (dme) yields Mn(C 6 F 5 ) 2 (thf) 2 or Mn(C 6 F 5 ) 2 (dme). The latter reacts with N,N,N′,N′-tetramethylethane-1,2-diamine(tmen) in toluene to give Mn(C 6 F 5 ) 2 (tmen). Mass spectra indicate the complexes have associated structures. Impure Mn( p -HC 6 F 4 ) 2 (dme) was obtained from manganese metal and Hg( p -HC 6 F 4 ) 2 .

Pentafluorobenzoic acid reacts with YbCp 2 (dme) to yield, after hydrolysis, 2,3,4,5-tetrafluorobenzoic acid. Conversion is near quantitative with activated magnesium as a coreductant and there is evidence for catalytic turnover in ytterbium on addition of a cyclopentadiene source. Reduction of 2,6-F 2 C 6 H 3 CO 2 H to o -FC 6 H 4 CO 2 H and of o -FC 6 H 4 CO 2 H to PhCO 2 H has also been achieved.

The title compound has an infinite three-dimensional structure that contains eight-coordinate bismuth(III), five- and six-coordinate copper(II) and four-coordinate vanadium(V). The mean bond distances are: Bi-O 2.57 (31) A, Cu-O 1.956 (27) (in the square planes), 2.64 (10) A (out-of-plane distances), and V-O 1.713 (29) A. The shortest Cu-Cu distance is 3.063 (3) A

The crystal structure of (NH4)(2)[Cd(NH3)(2)(CrO4)(2)] is reported. Below about 300 K the compound changes from a monoclinic cell (space group C2/m, Z = 2, a = 12.8380(11) Angstrom, b = 6.0308(6) Angstrom, c = 7.5890(6) Angstrom, beta = 110.154(14)degrees) in which all four Cd-O bonds of the trans-Cd(NH3)(2)O-4 coordination sphere are crystallographically equivalent to a triclinic cell (space group P ($) over bar 1, Z = 1, a = 6.0210(4) Angstrom, b = 7.0363(4) Angstrom, c = 7.5714(8) Angstrom, alpha = 106.802(18); beta = 93.032(12); gamma = 114.079(11)degrees) in which the only symmetry element of the Cd complex is an inversion center. It is shown that the previously reported temperature dependence of the EPR spectrum of similar to 0.3% Cu2+ doped into this compound is consistent with the change in crystal structure. The spectra may be explained using a model of dynamic vibronic coupling in which the effects of Jahn-Teller coupling and a ''strain'' due to the inequivalence of the ligands are applied to the e(g) vibrational and E(g) electronic wave functions of the Cu2+ ion. The balance between the ligand field asymmetry and the natural tendency of Cu2+ to adopt a tetragonally elongated octahedral coordination geometry results in a complex with an orthorhombic coordination geometry having short bonds to the ammine groups and intermediate and long bonds to the chromate oxygen atoms. However, the long Cu-O bonds may occur to either pair of trans chromate oxygen atoms. In the high-temperature monoclinic unit cell, the EPR spectrum confirms that these two conformations are energetically equivalent, but in the low-temperature triclinic cell this is no longer the case, and the EPR spectrum is consistent with a temperature-dependent equilibrium between the two possible structural isomers. However, the model suggests that significant delocalization of the vibronic wave functions may occur, so that it is difficult to define precisely the bond lengths and electronic wave function parameters of the guest copper(II) complexes.

The synthesis, structures and reactions of lanthanoid complexes with alkenes, alkynes and arenes have been reviewed. Whilst the discussion is centred on neutral π donors, including intramolecular π-arene-lanthanoid bonding, some formal [Sm III (C 5 Me 5 ) 2 (π-donor) − ] complexes, derived from Sm(C 5 Me 5 ) 2 and neutral π donors, have been included, especially examples which readily dissociate into the reactants. Metal-carbon bond lenghts for lanthanoid(II or III) complexes have been convenientljy analysed and compared by subtraction of the appropriate lanthanoid ionic radius for the formal coordination number. Derived values in the approximate range 1.70–2.10 A are typical, with higher values often associated with intramolecular π-areneLn coordination or dimerization through intermolecular π-areneLn bonding. Lower values, 1.40–1.70 A, can carry implications of charge transfer, e.g. Ln II L 0 → Ln III (L) −1 or may be partly a geometric consequence of other bonding in the molecule. The significantly covalent arene-lanthanoid(0) complexes have stronger bonding than in Ln(II or III)-(π donor) derivatives and occupy a unique place in organolanthanoid chemistry.

The tris(formamidinato)lanthanum(III) complexes [La(o-TolForm)3(thf)2] [1; o-TolForm = N,N′-bis(o-tolyl)formamidinate], [La(XylForm)3(thf)] [2; XylForm = N,N′-bis(2,6-dimethylphenyl)formamidinate], and [La(EtForm)3] [3, EtForm = N,N′-bis(2,6-diethylphenyl)formamidinate] are a new class of precatalysts for the Tishchenko reaction. Their catalytic activity is a result of their high Lewis acidity and the ease with which the ligand spheres can be interchanged. For the dimerization of benzaldehyde to give benzyl benzoate, which is a benchmark reaction, compound 1 is, to the best of our knowledge, the most active catalyst ever reported. On a preparative scale, the reaction can be performed in the absence of solvent. A range of aromatic, heteroaromatic, and aliphatic aldehydes was rapidly converted into the corresponding esters by using catalysts 1–3.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

The design, development and initial operation of a new type of fluorine microreactor are described. Its use in agrochemical discovery chemistry is illustrated with simple examples of electrophilic fluorination.

Reaction of primary aromatic amines, mercuric acetate, and ethylene in tetrahydrofuran under pressure (ca. 40 atm) yields the organomercurials ArN(CH 2 CH 2 -HgOAc) 2 (Ar = Ph, 2-ClC 6 H 4 , 3-ClC 6 H 4 , or 4-ClC 6 H 4 ) or, after treatment of the crude products with sodium halide, ArN(CH 2 CH 2 HgX) 2 (Ar = 4-MeC 6 H 4 , 4-MeOC 6 H 4 , or 2,4,6-Me 3 C 6 H 2 , X = Cl; Ar = 2,4-Cl 2 C 6 H 3 , 2,6-Cl 2 C 6 H 3 , or 2,4,6-Br 3 C 6 H 2 , X = Br). The X-ray diffraction study of 2,4,6-Me 3 C 6 H 2 N(CH 2 CH 2 HgCl) 2 shows the molecules to have near linear C-Hg-Cl stereochemistry, and to be arranged in centrosymmetric dimers with weak Hg ··· Cl intermolecular bonding.