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Bulky tris(carbene)borate ligands provide access to high spin iron(ii) phosphido complexes. The complex PhB(MesIm) 3 FeP(H)Ph is thermally unstable, and [PPh] group insertion into a C-H bond of the supporting ligand is observed. An arrested α-hydride migration mechanism suggests increased nucleophilicity of the phosphorus atom facilitates [PPh] group transfer reactivity.

Anion-templated rotaxanes are a rare class of functional organic molecules capable of novel switching and mechanical behaviors. Yet, investigations of these properties are limited by existing synthetic strategies. We show a high-yielding synthesis (80%) of [3]rotaxanes using shape-persistent macrocycles, cyanostars, and anionic organo-phosphate templates catalyzed by low steric-demand click chemistry. The reaction yields correlate with the template's binding affinities. Use of longer linkers relieves steric congestion to enable a reversible acid-base response, opening the way to molecular switching.

The size-dependent recognition of large anions by shape-persistent macrocycles is poorly understood. To address this shortcoming, we created a bulky cyanostar that only forms 1 : 1 complexes and show the affinities best follow the expectations of size matching but only when solvent bias is removed.

The easy-to-prepare Nb(V) aryloxide complex [(ArO)2Nb(μ-Cl)Cl2]2 (OAr = 2,6-bis(diphenylmethyl)-4-tert-butylphenoxide) is a precursor to both Nb(IV), [trans-(ArO)2NbCl2(THF)2], and Nb(III), K3[(ArO)4Nb2(μ-Cl)3Cl2], molecules. The Nb(IV) and (V) complexes readily split atmospheric nitrogen at room temperature and 1 atmosphere, under reducing conditions, to produce the low-coordinate nitride dimer [(ArO)2Nb(μ-N)]2 and its radical anion, K[(ArO)2Nb(μ-N)]2.

Thermal Bergman cyclization of Pt(II) dialkynylporphyrins reveals a marked reduction in the cyclization temperature relative to the free base and Zn(II) derivatives. In contrast, photogenerated (3)ππ* population produces no detectable Bergman photocyclization, suggesting that the photoreactivities of the related free base and Zn(II) derivatives occurs via the (1)ππ* state.

Reduction of the dinuclear Co(II) nindigo complex dmp(2)Nin[Co(N{SiMe(3)}(2))](2), with 1 or 2 equiv. of K(0) (or KC(8)), affords the reduced complexes [dmp(2)Nin{Co(N{SiMe(3)}(2))}(2)](-) and [dmp(2)Nin{Co(N{SiMe(3)}(2))}(2)](2-), respectively. Inspection of these reduced species reveals ligand-centered reduction, with each cobalt ion retaining a formal 2+ oxidation state.

Treatment of d(1) [(nacnac)TiCl(Ntol(2))] with NaN(3) results in NaCl formation and N(2) ejection to yield the first four coordinate, parent imide [(nacnac)Ti=NH(Ntol(2))] (nacnac(-)=[ArNC(CH(3))](2)CH, Ar = 2,6-iPr(2)C(6)H(3), tol = 4-CH(3)C(6)H(4))., (This journal is © The Royal Society of Chemistry 2012)

An intimate interplay of O-H···O/C-H···F hydrogen bonds and π-π stacking interactions allows a phenyleneethynylene-based dendritic molecule to fold and self-assemble into two distinctively different molecular crystals as pseudopolymorphs.

Species (PNP)Ir(X)(Y), where PNP = N(SiMe(2)CH(2)P(t)Bu(2))(2)(-1) with X and Y halide, have a (t)Bu group C-H bond heterolytically split by addition across the Ir-N bond.

The phosphanylidene-sigma(4)-phosphorane reagents Me(3)P[double bond, length as m-dash]PAr (Ar = 2,4,6-(t)Bu(3)C(6)H(2) and 2,6-Mes(2)C(6)H(3)) are good delivery vehicles of the terminal phosphinidene moiety, PAr, to early-transition metals composed of zirconium and vanadium.

A conformationally pre-organized ligand platform allows for restricted swivelling motions of two aryleneethynylene-appended 2,2'-bipyridyl units that function as a tight bischelator as well as a ratiometric fluorescence sensor for selected metal ions.

Highly diastereo- and enantioselective additions of alpha-nitrophosphonates to imines catalyzed by a chiral Brønsted acid are described.

Reaction of 2,3-dioxochlorins with benzeneselenic anhydride (BSA) results in the formation of unusual ring-contracted azetine derivatives that further react with BSA to afford porpholactones.

Tetradentate metalloenediynes with strong imine and weaker thioether coordination serve as a geometrically non-rigid switch to drive thermal Bergman cyclization.

The air and moisture stable rhodium N-heterocyclic carbene (NHC) complex, RhCl(IMes)(COD)(IMes =N,N[prime or minute]-bis(2,4,6-trimethylphenyl)imidazole-2-ylidine; COD = 1,5-cyclooctadiene), facilitates a diastereoselective metal-catalyzed [4 + 2 + 2] carbocyclization of 1,6-enynes in the presence of silver triflate and 1,3-butadiene.

Alcoholysis of [Fe6O2(OH)2(O2CBut)10(hep)2] (1) affords ferric wheels of different nuclearities: methanol yields [Fe10(OMe)20(O2CBut)10], whereas phenol gives the structurally unprecedented wheel [Fe8(OH)4(OPh)8(O2CBut)12], and the first to contain phenoxide.

Conformationally constrained ethylene-diamine metalloenediyne compounds exhibit alkyne termini separations that are constant and independent of metal center geometry. Ancillary chloride ligand electron donation into the Bergman cyclization reaction coordinate, however, dramatically influences the observed temperatures.

Computations employing density functional theory on the reactions between ethyne and the model compounds (HE)3M identical to M(EH)3, where M = Mo and W and E = O and S, predict that the alkyne adducts M2(mu-C2H2)(EH)6 are thermodynamically favored with respect to the metathesis products HC identical to M(EH)3 except when M = W and E = O; the reaction between (tBuO)3 W identical to CPh and 2-MeC6H4SH (> 3 equiv.) yields W2(mu-PhCCPh)(SC6H4-2-Me)6 consistent with expectations based on the calculations.

The 3 MnIV title compound has been prepared and characterized by X-ray crystallography and magnetochemistry; the complex contains a [Mn(mu-O)2Mn(mu-O)2Mn]4+ core and possesses an S = 3/2 ground state.