Synthesis of an (NHC)2Pd(SiMe3)2 (NHC = N-Heterocyclic Carbene) Complex. Catalytic, cis-Bis-Silylations of Internal Alkynes with Unactivated Disilanes

The novel complex cis-[(ITMe)2Pd(SiMe3)2 (ITMe =1,3,4,5-tetramethylimidazol-2-ylidene) has been synthesised by mild oxidative cleavage of Me3SiSiMe3 using (ITMe)2Pd(0). The use of this complex as precatalyst for the cis-bis-silylation of internal alkynes using unactivated disilanes is reported

Ligand-Free Copper-Catalyzed Cyano- and Alkynylstannylation of Arynes

A carbon–carbon triple bond of arynes was found to undergo cyanostannylation with a tin cyanide under CuCN catalysis to afford diverse ortho-cyanoarylstannanes in high yield. The copper catalyst was also effective for alkynylstannylation of arynes, and the resulting alkynylstannylated products were demonstrated to be convertible into biologically active compounds and a dye for dyesensitized solar cell.This work was financially supported by JSPS KAKENHI Grant Number JP16H01031 in Precisely Designed Catalysts with Customized Scaffolding and by ACT-C, JST

Lyotropic Liquid Crystallinity of Linear and Star Poly(quinoxaline-2,3-diyl)s: Isotropic-Liquid Crystal Phase Equilibria in Tetrahydrofuran

Hasegawa H., Terao K., Sato T., et al. Lyotropic Liquid Crystallinity of Linear and Star Poly(quinoxaline-2,3-diyl)s: Isotropic-Liquid Crystal Phase Equilibria in Tetrahydrofuran. Macromolecules, 52(9), 3158-3164, April 16, 2019. Copyright © 2019, American Chemical Society. https://doi.org/10.1021/acs.macromol.9b00460

Predictive Calculation for Deflections of Reinforced Concrete Floor Slab Systems ―Part 1 Procedure―

In this report, we incorporate equations for a respective estimation of causally different types of deflection for r.c. beams and one-way slabs into our system for the deflection calculation of two-way floor structures, so that, after the system has been suitably modified, it may be of extended and generalized use for examining such structures. This permits us to express chronic (or longtime) deflection as the total effect of a variety of agents. Then, we examine whether and how the actually observed chronic transition of slab behaviors is consistent overall with their follow-up predictions established by our procedure, and we test its utility by resorting to some available previous test examples of slab models under sustained service loading. We note that our system can be maintained in practice

Auxiliary Schemes for Axonometric Drawing to Add to its Practical Utility

The present report is intended to help enhance practical utility of axnometric manual drawing techniques. As a pertinent aid，a simple geometrical scheme is introduced to make transformation easier of a trimetric system into its dimetric equivalent，and v.v.; specifically concerning rotation of both systems about anynormal to a coordinate/principal plane they have in common. The above subscheme coupled with now reconsidered auxiliary views to the main drawing and/or the customary resorts serves to make it easier in drawing to account for angular relations between the line of sight and the considered axonometric coordinate system and to address oblique or non-axonometric linear elements and circular segments of an object than only with those resorts，e. g. scale ratios for axonometric lines and coordinate plane revolution to deal with non-axonometric portions (with the known method ofintersections as a generalization thereof). Utility of the customary drawing routine combined with introduced partial alternatives thereto，notably in drawing to meet compound geometrical conditions，is noted in an example to show the agency of our present procedureand others to clarify relatedly conceived additional use of the conventional ellipse guides

Predictive Calculation for Deflections of Reinforced Concrete Floor Slabs Part 2: Application of the Proposed Prediction System

In Part 2 we initially examine how our method tolerably predicts r. c. floor deflections in practice. In an effort then needed to set measurement against prediction, as we earlier used test data on slab models, we here employ a field set of data which is rare but justifiably representative record of in-situ observation of chronic floor deflection progress, toward sagging damage, taken over several years on a spacious multistorey r. c. building having floor systems with a number of slab panels. And for the purpose of further similar comparison the same set of data is used by our method and by two others both proposed in major r. c. design codes. The results of thus trying our procedure being substantially comparable to the measured set of data, we likewise examine several other reported cases of buildings with floor sagging injuries: whereupon partially in accurate construction is rated as the main of their common causes. Also by our method we review the formula for limiting slab thickness prescribed in the domestic r. c. design code. Finally we suggest partial reconsideration of the equation

A Procedure for the Analysis of Long-Team Deflection of Reinforced Concrete Members and Its Adaptability

For deformation analysis of partially cracked floor members of reinforced concrete, a procedure with some modifications to our earlier system is proposed. Instead of its having relied on that concept of average for the oft-cited effective member stiffness long used thus far at least in ancillary form by the ACI Code, the present system can afford to account for the detail of steel arrangement along a member by treating all its sections assumed attendant on finite difference subdivision for beam analysis. In a consistent attempt, the whole lengthwise sectional variation is considered as well in the long-time case of analysis. Then, a long standing notion of increased modular ratio is adopted, alternatively to the ACI\u27s time-dependent multiplier which is given also in average form by way of direct inclusion of the effect of the creep resistant compression steel. Relative adequacy of the proposed procedure is discussed in comparison of many cases of earlier test results in the literature with deflection estimates by our method and commonly available code methods

Admissible Sectional Dimensions of R/C Floor Elements to be Designed without Deflection Check Part 2: Floor Slabs

We review the adequacy of the slab thickness equation in the r/c design code by the Architectural Institute of Japan, in comparison with the related data obtained by our recently renovated method which employs the known effective stiffness and an experimentally estimated time-dependent reduced elastic modules and whose practical accuracy to tolerable degrees has been observed in our earlier reports. Using this method we try series of deflection estimate for slab models of graduated dimensions in a practically chosen wide range, for the purpose of examining the subject matter of defined possibility for rational slab sections to be designed without deflection check

Admissible Sectional Dimensions of R/C Floor Elements to be Designed without Deflection Check Part 1: Transverse Beams

By use of our proposed modified method, a parametric deflection analysis is attempted for transverse beam models with their dimensions varied within a major practical range in typical cases of their end condition depending on whether or not they have, at one end and/or both, adjoining beams in a slab-beam-girder floor system; the analysis being interested to result in necessary criteria for beam section sizes admissible in floor design without intricacy of deflection check. Some other design criteria needed for maintained serviceability are derived at the same time

Transition metal catalyzed element–element′ additions to alkynes

The efficient and stereoselective synthesis of, or precursors to, multi-substituted alkenes has attracted substantial interest due to their existence in various industrially and biologically important compounds. One of the most atom economical routes to such alkenes is the transition metal catalyzed hetero element–element′ π-insertion into alkynes. This article provides a thorough up-to-date review on this area of chemistry, including discussions on the mechanism, range of Esingle bondE′ bonds accessible and the stoichiometric/catalytic transition metal mediators employed