Synthesis and Applications of Tricarbonyliron Complexes of Dendralenes

[3]Dendralene and [4]dendralene are converted smoothly into tricarbonyliron complexes. The structures of four complexes analyzed by DFT and single‐crystal X‐ray analysis show that, in contrast to free hydrocarbons, complexed dendralenes prefer a roughly in‐plane conformation. The complexes are stable towards Fe(CO)₃ group migration up to 150 °C. The synthetic value of Fe(CO)₃ complexation in the dendralene series is demonstrated through a variety of selective synthetic manipulations (Diels–Alder reaction, dipolar cycloaddition, Simmons–Smith cyclopropanation, dihydroxylation, olefin cross metathesis) that are not achievable by direct transformation of the free hydrocarbons. Application to the synthesis of a previously unreported, highly reactive linear/cross‐conjugated hydrocarbon is also described.     

Metastable States and CDW Conductivity in NbSe3

A study of the response of niobium triselenide to pulsed currents shows that the field-induced motion of the charge-density waves (CDWs) leaves them in long-lived metastable states in which, presumably, some distortion is stabilised by pinning. Evidence of this is provided by a reduction in Ohmic conductivity after current flows non-linearly through a specimen originally in thermal equilibrium, and by a transient increase in the non-linear conductivity on subsequent reversals of the current. A gradual increase in the non-linear conductivity during pulses applied repeatedly in the same sense is found to arise from a thermally-induced change in the strength of the pinning. The possible origin of this change is discussed.     

Synthesis and application to asymmetric allylic amination of substituted monodonor diazaphospholidine ligands

The synthesis of a series of substituted monodonor diazaphospholidine ligands is described. A regioselective lithiation process is a key step in one of these syntheses. The compounds are designed to be incorporated into soluble polymer and other solid phase supports. Enantiomeric excesses of up to 88% were observed when these compounds were employed in palladium-catalysed asymmetric amination reactions.     

Insights into the Binding Sites of Organometallic Ruthenium Anticancer Compounds on Peptides Using Ultra-High Resolution Mass Spectrometry

The binding sites of two ruthenium(II) organometallic complexes of the form [(η⁶-arene)Ru(N,N)Cl]⁺, where arene/N,N = biphenyl (bip)/bipyridine (bipy) for complex AH076, and biphenyl (bip)/o-phenylenediamine (o-pda) for complex AH078, on the peptides angiotensin and bombesin have been investigated using Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Fragmentation was performed using collisionally activated dissociation (CAD), with, in some cases, additional data being provided by electron capture dissociation (ECD). The primary binding sites were identified as methionine and histidine, with further coordination to phenylalanine, potentially through a π-stacking interaction, which has been observed here for the first time. This initial peptide study was expanded to investigate protein binding through reaction with insulin, on which the binding sites proposed are histidine, glutamic acid, and tyrosine. Further reaction of the ruthenium complexes with the oxidized B chain of insulin, in which two cysteine residues are oxidized to cysteine sulfonic acid (Cys-SO₃H), and glutathione, which had been oxidized with hydrogen peroxide to convert the cysteine to cysteine sulfonic acid, provided further support for histidine and glutamic acid binding, respectively.

Construction of some quantum stochastic operator cocycles by the semigroup method

A new method for the construction of Fock-adapted quantum stochastic operator cocycles is outlined, and its use is illustrated by application to a number of examples arising in physics and probability. The construction uses the Trotter-Kato theorem and a recent characterisation of such cocycles in terms of an associated family of contraction semigroups. In celebration of Kalyan Sinha’s sixtieth birthday     

Two remarks on equivelar manifolds

It has been pointed out that a construction for equivelar polyhedral manifolds described in an earlier paper by the present authors may possibly not be performed; an alternative construction is given here. Further, it is shown that certain equivelar polyhedra cannot have equiangular (and hence regular) faces.