Addendum to “On natural monomial characters of Sn”

It is shown that the natural monomial characters of the symmetric group introduced in the above article are well-behaved with respect to π-elements.     

Photochromism and Metal Complexation of a Macrocyclic Styryl Naphthopyran

A macrocyclic benzo‐15‐crown‐5 ether unit tethered to a photochromic naphthopyran by a styryl spacer ( MEN ) is shown to form a 1:1 complex with magnesium(II). The structure and dynamics of the specific host–metal interactions were investigated by PFG‐NMR analysis. A combination of UV/Vis and variable temperature multi‐dimensional ¹H NMR photokinetic analysis of the crown‐containing styryl naphthopyran and its metal complex was used to probe the effect of metal complexation on the photochromism.     

The New High‐Pressure Sodium Tetraborate HP‐Na2B4O7

The new polymorph of sodium tetraborate HP‐Na₂B₄O₇ was synthesized under high‐pressure / high‐temperature conditions of 6 GPa and 1000 °C in a multianvil apparatus with a Walker‐type module. HP‐Na₂B₄O₇ crystallizes with nine formula units per cell in the trigonal chiral space groups P3₂21 or P3₁21. The parameters are a = 765.5(2), c = 2142.3(4) pm, V = 1.0872(3) nm³, R₁ = 0.0581, and wR₂ = 0.0809 (all data). The crystal structure of HP‐Na₂B₄O₇ is built up from interconnected “sechser” rings of alternating corner‐sharing BO₃ and BO₄ groups.     

Characterization of Tetracyanopyridine (TCNPy)‐Based Magnets: V[TCNPy]2⋅z (CH2Cl2) (Tc=111 K) and V[TCNPy]3⋅z (CH2Cl2) (Tc=90 K)

The reaction of 2,3,5,6‐tetracyanopyridine (TCNPy) with V(CO)₆ in CH₂Cl₂ forms new organic‐based magnets of V[TCNPy]_x?z (CH₂Cl₂) (x=2, 3) composition. Analysis of the IR spectra suggests that the TCNPy is reduced and coordinated to V^II sites through the nitriles. V[TCNPy]_x order as ferrimagnets with 111 and 90 K T_c values for V[TCNPy]₂ and V[TCNPy]₃, respectively. Their respective remanent magnetizations and coercive fields are 1260 and 250 emuOe mol^?1 and 9 and 6 Oe at 5 K, and they exhibit some spin‐glass behavior.     

Synthesis and characterization of colored EUDRAGIT® as enteric coating material

The synthesis of novel polymeric dyes by directly attaching toluidine blue O and MPPD via EDC and CDI coupling is described for polymers with enteric properties [poly(methacrylic acid‐co‐ethyl acrylate)]. The polymeric dyes are analyzed by SEC and UV/Vis measurements as well as investigated regarding their dissolution and permeation characteristics. Almost no changes between the modified and nonmodified polymer could be observed by conventional drug studies and a self‐established method for dissolution rates. Also no influence on the film formation properties was observed by SEM measurements. In vitro toxicity studies showed no increase of toxicity compared to the non modified polymer. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2386–2393     

Synthesis and Photoisomerization of Substituted Dibenzofulvene Molecular Rotors

The synthesis, spectral and structural characterization, and photoisomerization of a family of 2‐substituted dibenzofulvene molecular actuators based on (2,2,2‐triphenylethylidene)fluorene (TEF) are reported. The 2‐substituted species investigated are nitro (NTEF), cyano (CTEF), and iodo (ITEF). X‐ray structures of these three compounds and three intermediates were determined to assign alkene configuration and investigate the effects of the 2‐substituents on steric gearing. The addition–elimination reaction of Z‐ 9 with trityl anion to form Z‐ 10 proceeded with complete retention of configuration. Rates of photoisomerization were measured at irradiation wavelengths between 266–355 nm in acetonitrile/dioxane solutions at room temperature. Photoisomerization quantum yields (φ) were calculated by means of a mathematical model that accounts for a certain degree of photodecomposition in the cases of CTEF and ITEF. Quantum yields vary significantly with substituent, having maximum values of φ=0.26 for NTEF, 0.39 for CTEF, and 0.50 for ITEF. NTEF is photochemically robust and has a large quantum yield for photoisomerization in the near‐UV, making it a particularly promising drive rotor moiety for light‐powered molecular devices.     

The Influence of Radical Stability of Organomagnesium Halide Reagents on the Direction of Addition to an α-β-Unsaturated Phosphoryl Group

The addition of Grignard reagents with increasing radical character to α,β-unsaturated phosphoryl groups was found to occur with a corresponding increase in the yield of the aromatic substitution products. Molecular modelling was used to determine that the radical character has a greater role in determining the degree of aromatic substitution than does steric parameters.