Reactions of coordinated ligands,Part III(1). Kinetics of lodination of malonate and pyruvate in malonato(pentaammine)-cobalt(III), malonato-bis-(ethylenediamine)cobalt(III) and pyruvato(pentaammine)cobalt(III) ions

Summary The kinetics of iodination of malonate and pyruvate in the title complexes are reported at 35.0 °C and I=0.3 M. The reaction is first order in substrate and zeroth order in [I₂]. This result is commensurate with rate determining enolisation of the active methylene and methyl groups of the malonate and pyruvate respectively. The reaction is catalysed by H₂O, OH^– and by the buffer anions used. The rate data suggest that the malonate methylene group in the [Co(en)₂-O₂CCH₂CO₂]²⁺ chelate is considerably more active towards electrophilic substitution than is the case in [Co(NH₃)₅O₂CCH₂CO₂]²⁺.     

Direct measurement of spreading pressures of films adsorbed on crystalline substrates

A direct reading strain gauge has been developed for the measurement of spreading pressures of films adsorbed on solid substrates. In contrast to previous instruments employing heterogeneous adsorbents, the present device, using Grafoil, has linear response to spreading pressure and displays no hysteresis. Sensitivity is adequate for studies of low coverages, down to small fractions of a monolayer. Surveys of benzene, butanol, and propanol monolayers were made with the device at room temperature. The films were found to behave as two-dimensional imperfect gases, and their second and third order virial coefficients were measured. A general theory of the dilational effect is presented, in which the strains produced by a film adsorbed on a face of a crystalline substrate are related to the elastic constants and dimensions of the crystal. The theory is applied to the case of graphite such as in Grafoil. Quantitative results consistent with the behavior of the actual device are obtained.     

Complexes of Nickel(II) Thiocyanate with Anilines

Complexes of the type NiL₂(SCN)₂ (L = aniline, o-, m-, p-toluidine, o-, m-, p-anisidine and p-phenetidine) have been prepared and characterised by room temperature magnetic moments and infra-red spectral data (down to 250 cm^?1) in the solid state. The thiocyanate is present as a bridging group and the metal atom is shown to be in a six-coordinate environment having an octahedral stereochemistry.     

Color,flavor, duality,and the pomeron

AtN _c /N _f =∞ such that quark loops are absent the Harari-Freund (HF)P+f model of diffraction can be motivated through the identification Pomeron ≈ glueball,f≈leading planar trajectory. AtN _c =3, the presence of confinement-related mass scales introduced by quark loops is a basic complication that can easily change this situation to, e.g., a dominantP?f identity structure. Aurenche and Gonzales Mestres (AGM) have argued that diffraction is essentially identical atN _c /N _f =∞ and atN _c =3. They further claim to have generated the HF scheme directly atN _c =3 through the novel mechanism of a multiperipheral iteration of daughters that becomes theP. We respond to these arguments. We give a general qualitative discussion of changes expected in theN _c /N _f =∞ toN _c =3 transition. Important hadron scattering quantities like particle multiplicities are very different in dynamics dominated by glue and atN _c =3, unlike other quantities like resonance width to mass ratios. We argue that the weak coupling dual model is not a reliable guide toN _c =3 dynamics. We criticize AGM's “daughter generated Pomeron”, and we close with a brief summary of other attempts to generate theP+f model.     

Tensor products and joint spectra

We prove that the joint spectrum of the tensor product of several operators is the cartesian product of their spectra.     

Observation of B+-->LambdaLambdaK+

We report the first observation of the charmless hyperonic B decay, B+-->LambdaLambdaK+, using a 140 fb(-1) data sample recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB (e+)(e-) collider. The measured branching fraction is B(B+-->LambdaLambdaK+) = (2.91(+0.90)(-0.70) +/- 0.38) x 10(-6). We also perform a search for the related decay mode B+-->LambdaLambdapi+, but do not find a significant signal. We set a 90% confidence-level upper limit of B(B+-->LambdaLambdapi+) < 2.8 x 10(-6).     

Evidence for B+-->omegal+nu

We have searched for the decay B+-->omegal(+)nu (l=e or mu) in 78 fb(-1) of Upsilon(4S) data (85x10(6)BB events) accumulated with the Belle detector. The final state is fully reconstructed using the omega decay into pi(+)pi(-)pi(0), combined with detector hermeticity to estimate the neutrino momentum. A signal of 414+/-125 events is found in the data, corresponding to a branching fraction of (1.3+/-0.4+/-0.2+/-0.3)x10(-4), where the first two errors are statistical and systematic, respectively. The third error reflects the estimated form-factor uncertainty.     

Inclusive measurement of the photon energy spectrum in b --> sgamma decays

We report a fully inclusive measurement of the flavor changing neutral current decay b --> sgamma in the energy range 1.8 GeV < or = E*gamma < or = 2.8 GeV, covering 95% of the total spectrum. Using 140 fb(-1), we obtain B(b --> sgamma) = (3.55+/-0.32(+0.30+0.11)(-0.31-0.07)) x 10(-4), where the errors are statistical, systematic, and from theory corrections. We also measure the first and second moments of the photon energy spectrum above 1.8 GeV and obtain (Egamma) = 2.292+/-0.026+/-0.034 GeV and (E2gamma) - (Egamma)2 = 0.0305+/-0.0074+/-0.0063 GeV2, where the errors are statistical and systematic.