Syntheses, characterization, and photochemical properties of amidate-bridged Pt(bpy) dimers tethered to Ru(bpy)3(2+) derivatives

Amidate-bridged diplatinum(II) entities [Pt(2)(bpy)(2)(μ-amidato)(2)](2+) (amidate = pivalamidate and/or benzamidate; bpy = 2,2'-bipyridine) were covalently linked to one or two Ru(bpy)(3)(2+)-type derivatives. An amide group was introduced at the periphery of Ru(bpy)(3)(2+) derivatives to give metalloamide precursors [Ru(bpy)(2)(BnH)](2+) (abbreviated as RuBnH, n = 1 and 2), where deprotonation of amide BnH affords the corresponding amidate Bn, B1H = 4-(4-carbamoylphenyl)-2,2'-bipyridine, and B2H = ethyl 4'-[N-(4-carbamoylphenyl)carbamoyl]-2,2'-bipyridine-4-carboxylate. From a 1:1:1 reaction of [Pt(2)(bpy)(2)(μ-OH)(2)](NO(3))(2), RuBnH, and pivalamide, trinuclear complexes [Pt(2)(bpy)(2)(μ-RuBn)(μ-pivalamidato)](4+) (abbreviated as RuBn-Pt(2)) were isolated and characterized. Tetranuclear complexes [Pt(2)(bpy)(2)(μ-RuBn)(2)](6+) (abbreviated as (RuBn)(2)-Pt(2)) were separately prepared and characterized in detail. The quenching of the triplet excited state of the Ru(bpy)(3)(2+) derivative (i.e., Ru*(bpy)(3)(2+)) upon tethering the Pt(2)(bpy)(2)(μ-amidato)(2)(2+) moiety is strongly enhanced in RuB1-Pt(2) and (RuB1)(2)-Pt(2), while it is only slightly enhanced in RuB2-Pt(2) and (RuB2)(2)-Pt(2). These are partly explained by the driving forces for the electron transfer from the Ru*(bpy)(3)(2+) moiety to the Pt(2)(bpy)(2)(μ-amidato)(2)(2+) moiety (ΔG°(ET)); the ΔG°(ET) values for RuB1-Pt(2), (RuB1)(2)-Pt(2), RuB2-Pt(2), and (RuB2)(2)-Pt(2) are estimated as -0.01, 0.00, +0.22, and +0.28 eV, respectively. The considerable difference in the photochemical properties of the B1- and B2-bridged systems were further examined based on the emission decay and transient absorption measurements, which gave results consistent with the above conclusions.     

Development of In-Situ/Operando Sample Cells for Soft X-ray Transmission Spectromicroscopy at UVSOR-III Synchrotron

In-situ/operando techniques have been developed for spectromicroscopic studies of heavy elements using hard X-rays with high transmittance in samples and long focal length of optical elements (i.e., long working distance) at photon energies >4 keV. On the other hand, in-situ measurements in the soft X-ray region for spectromicroscopic studies of light elements at deep inner shells and heavy elements at shallow inner shells face significant technical challenges due to several difficulties, including low transmittance and short focal lengths of optical elements. Scanning transmission X-ray microscopy (STXM) in the soft X-ray region is a promising technique for in-situ observation in comparison with other microscopic techniques using electrons and ions, considering its characteristics, such as high resolving power in energy and in space, low radiation damage, and two-dimensional (and three-dimensional) chemical state analysis using near-edge X-ray absorption fine structure.     

Ultrabroadband multiplex CARS microspectroscopy and imaging using a subnanosecond supercontinuum light source in the deep near infrared

Subnanosecond supercontinuum (SC) has been generated by a 1,064 nm microchip laser combined with a photonic crystal fiber. The ultrabroadband (>2,000 cm(-1)) SC has facilitated multiplex coherent anti-Stokes Raman scattering (CARS) microspectroscopy in the spectral range from 1,000 to 3,000 cm(-1) with lateral and depth spatial resolution of 0.9 and 4.6 microm, respectively. A clear CARS image of a Nicotiana tabacum L. cv. Bright Yellow 2 cell has been obtained with high vibrational contrast.     

More Causes Less Effect: Destructive Interference in Decision Making

We present a new experiment demonstrating destructive interference in customers’ estimates of conditional probabilities of product failure. We take the perspective of a manufacturer of consumer products and consider two situations of cause and effect. Whereas, individually, the effect of the causes is similar, it is observed that when combined, the two causes produce the opposite effect. Such negative interference of two or more product features may be exploited for better modeling of the cognitive processes taking place in customers’ minds. Doing so can enhance the likelihood that a manufacturer will be able to design a better product, or a feature within it. Quantum probability has been used to explain some commonly observed “non-classical” effects, such as the disjunction effect, question order effect, violation of the sure-thing principle, and the Machina and Ellsberg paradoxes. In this work, we present results from a survey on the impact of multiple observed symptoms on the drivability of a vehicle. The symptoms are assumed to be conditionally independent. We demonstrate that the response statistics cannot be directly explained using classical probability, but quantum formulation easily models it, as it allows for both positive and negative “interference” between events. Since quantum formalism also accounts for classical probability’s predictions, it serves as a richer paradigm for modeling decision making behavior in engineering design and behavioral economics.     

Halogenated cladosporols produced by the sodium halide-supplemented fermentation of the plant-associated fungus Cladosporium sp. TMPU1621

A new cladosporol derivative, 2-chloro-cladosporol D (6), was isolated together with known cladosporol (1), cladosporols B–D (2–4), and cladosporol F (5) from the culture broth of plant-associated Cladosporium sp. TMPU1621. The structure of 6 was elucidated from spectroscopic analyses including NMR and MS data. The productivity of 6 increased in 3% NaCl-supplemented medium; therefore, fermentation of the producing fungus TMPU1621 with 3% NaBr was investigated, leading to the induced production of a new halogenated cladosporol, 2-bromo-cladosporol D (7). Compound 2 showed the lowest MIC values of 3.13 and 12.5?μg/mL against two MRSA strains, ATCC43300 and ATCC700698, respectively.     

Catalytic enantioselective conjugate reduction of lactones and lactams

A dramatic acceleration of the enantioselective copper-catalyzed conjugate reduction of alpha,beta-unsaturated lactones, lactams, and esters is reported upon addition of alcohol additives. Good to excellent yields and enantioselectivities were realized using a catalyst generated in situ from CuCl(2).H(2)O, t-BuONa, p-tol-BINAP, and PMHS, and this methodology was applied to the synthesis of (-)-Paroxetine.     

Pd-catalyzed nucleophilic allylic alkylation of aliphatic aldehydes by the use of allyl alcohols

Under catalysis of Pd(OAc)₂-(P-n-Bu)₃, Et₂Zn promotes a variety of allyl alcohols to undergo nucleophilic allylation of aliphatic aldehydes and ketones at room temperature and provides homoallyl alcohols in 60-90 and ca. 60% isolated yield, respectively. The reaction is irreversible and kinetically controlled, and unique regio- and stereoselectivities observed for the allylation with unsymmetrically substituted allyl alcohols are discussed.     

Nickel-catalyzed addition of dimethylzinc to aldehydes across alkynes and 1,3-butadiene: an efficient four-component connection reaction

In the presence of 10 mol % of Ni(acac)(2), four components comprising Me(2)Zn, alkynes, 1,3-butadiene, and carbonyl compounds combine in this order in 1:1:1:1 ratio to furnish (3E,6Z)-octadien-1-ols 1 in good yields. Similarly, the coupling reaction of Me(2)Zn, 1,omega-dienynes 5, and carbonyls furnishes 1-alkylidene-2-(4'-hydroxy-(1'E)-alkenyl)cyclopentanes and -cyclohexanes 6 and their oxygen and nitrogen heterocycle derivatives in good yield and an excellent level of 1,5-diastereoselectivity with respect to the cycloalkane methine carbon and the OH-bearing carbon of the C2 side chain. The reaction is completed in most cases within 1 h at room temperature under nitrogen, tolerates an ester, a hydroxy, an allyl and propargyl ethers, an allylamino, and a pyridyl functionalities, and accommodates a variety of aromatic and aliphatic alkynes and carbonyls (aldehydes and ketones).     

Nickel catalyzed stereoselective conjugate addition of dimethylzinc upon aldimines across 1,3-dien-8-ynes and 1,3-dien-9-ynes

Ni(acac)2 catalyzes the five-component connection reaction of Me2Zn, alkynes, diene (of 1,3-dien-8-ynes and 1,3-dien-9-ynes), aldehydes and anisidine to furnish cyclic dienyl amines anti-2 with high remote 1,5-diastereoselectivity.