MULTICUBE: Multi-objective design space exploration of multi-core architectures

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Iron Pentacarbonyl Promoted Addition of CO and MeOH to 1,4-Disubstituted-1,3-butadiyne and Formation of Vinylallyl and Butatriene Ligand Systems

Photochemical reaction of methanol solution containing 1,4-diferrocenyl- or 1,4-diphenyl-1,3-butadiynes and iron pentacarbonyl into which CO was constantly bubbled, yielded diiron hexacarbonyl complexes of cumulene ligand systems, [eta(1):eta(3)-{RCHC(2)CR(COOMe)}Fe(2)(CO)(6)] (1; E, R = Fc, 2; Z, R = Fc, 5; E, R = Ph, 6; Z, R = Ph) and [eta(3):eta(3)-{RCHC(2)CR(COOMe)}Fe(2)(CO)(6)] (3; E, R = Fc, 7; E, R = Ph), formed by 1,4-addition of -COOMe and -H to the butadiynes. Additionally, diferrole, [Fe(CO)(4){C(O)CC(Fc)C(O)}(2)], 4 was obtained in minor quantity. Compounds 1, 2, 5 and 6 contain vinylallyl carbon framework which is stabilized by MeOC=O -> Fe bond along with eta(1):eta(3) coordinated Fe(2)(CO)(6) unit. Compounds 3 and 7 contain butatriene units which are stabilized by eta(3):eta(3) coordinated Fe(2)(CO)(6) unit. Characterization of the new compounds was carried out by IR and (1)H and (13)C NMR spectroscopy and by mass spectrometry. Molecular structures of 2-7 were established by single crystal X-ray diffraction methods

Ni(COD)(2)-Catalyzed ipso-Silylation of 2-Methoxynaphthalene: A Density Functional Theory Study

Density functional theory has been used for the systematic investigation of the mechanism involved in Ni(COD)(2)-catalyzed ipso-silylation of 2-methoxynaphthalene. The two fundamental mechanistic pathways, internal nucleophilic substitution and a nonclassical oxidative addition, have been studied. In both pathways, the first equivalent of KOtBu directly reacts with the silyl boronate (Et3SiBpin) to generate the silyl anion surrogate Et3SiK or silylborate [Et3Si-Bpin(OtBu)]K (IN3), which further reacts with Ni(COD)(2) to form a substrate catalyst complex, [(eta(2)-COD)(2)NiSiEt3]K. The internal nucleophilic substitution reaction pathway proceeds through eta(2) complexation of nickel with the C(1)=C(2) bond of 2-methoxynaphthalene. Later, nickel connects to =C(1) through sigma-bond formation and coordinates with oxygen of the -OMe group. Simultaneously, the -SiEt3 group approaches =C(2) possessing -OMe followed by rearomatization which is facilitated by coordination of K+ with nickel and methoxy oxygen. In a nonclassical oxidative addition, the chelation of K+ with -OMe as well as -SiEt3 from [(eta(2)-COD)(2)NiSiEt3] is the key step which promotes the insertion of NiSiEt3 to the =C(2) carbon of 2-methoxynaphthalene. We also observed that the activation energy barrier in the non-pi-extended aromatic systems is higher than that of the pi-extended aromatic systems. The overall study manifests that Ni(COD)(2)-catalyzed ipso-silylation of 2-methoxynapthalene operates through an internal nucleophilic substitution pathway

Analysis of Plastic Optical Fiber Based Daylight System Suitable for Building Applications

In the scenario of world energy crisis, building energy efficiency has become a mainstream research focus; since buildings take up a large share of the world energy consumption. Lighting plays an integral part in the buildings operationality through providing indoor visual comfort; and the much-needed daylight harnessing in building structures can be achieved through various strategies. This paper aims to evaluate the amount of plastic optical fiber (POF) required for achieving optimum indoor illumination through light transport and study the advantage of two dimensional solar tracking and light concentration on indoor daylight enhancement through POF as a trade-off for the amount of POF required in a static system. Illumination attained inside a representative closed chamber due to light transported by POF via various mechanisms was experimentally compared with outdoor direct illumination and the amount of POF required for achieving comfortable indoor illumination was calculated for a proposed system involving tracking and light concentration. A microcontroller based dual-axis solar tracker was designed for tracking sunlight on the POF collector node every 10 seconds and opaque internally reflective plastic containers acted like sample rooms in a building. Calculations for the representative day normalized for the flooring area in an office building showed a promising payback period of around 5 years through partial replacement of electric lighting. Additionally, reduction in heat conduction through window glazing further reduces the cooling costs

<i>Syn-</i>Aminoauration versus <i>Anti-</i>Aminoauration of Alkynes in Au(I)/Au(III) Catalysis: Understanding the Origin of Selectivity

There is no experimental evidence of whether such gold-catalyzed aminoauration reactions follow the anti- and/or syn-pathway, and hence, to understand the origin of the selectivity in Au(I)- and Au(III)-catalyzed reactions of alkynes, a thorough mechanistic study was performed using DFT methods. The NBO and ASM analyses provided significant information about the structure–stability–reactivity of the pathway-determining states (PDS). This study further reveals that the oxidation states and geometries of gold, the steric bulk, and the dihedral angles of the PDS direct the mechanistic pathways and control the turnover frequency