Jan C. J. Bart

X-ray crystal structure of the dye 2-bromo-4-cyano-4′-N,N-diethylaminoazobenzene

Abstract The crystal structure of 2-bromo-4-cyano-4′-N,N-diethylaminoazobenzene has been determined from X-ray diffraction data: C17H17N4Br, mol. wt = 357·1. Triclinic, PĪ (No. 2), α = 13·162(5) A, b = 7·516(3) A, c = 8·496(4) A, α = 101·63(4)°, β = 95·79(4)°, γ = 91·49(4)°, V = 818·10 A3, Z = 2, Dc = 1·45 g cm−3, F(000) = 378, λ(MoKz) = 0·7107 A, μ(MoKα) = 26·70 cm−1. The structure was solved by direct methods and refined by full-matrix least-squares to R = 0·053 for 2081 independent reflexions. The molecule possesses an essentially planar azobenzene skeleton. The effects of substituents on the geometry of the azo group are discussed. Significant molecular parameters are: NN, 1·264(6) A; 1BrC, 1·904(5) A; mean NC, 1·410(7) A; NNC, 115·7(2)° and 113·0(2)°; NCC (cis relative to NN), 125·4(3)° and 123·1(2)°; CC(Br)C, 123·0(2)°.

Structure of the dye 2,6-dichloro-4′-N,N-diethylaminoazobenzene

Abstract The structure of 2,6-dichloro-4′- N , N -diethylaminoazobenzene has been determined from X-ray diffractometer data: C 16 H 17 Cl 2 N 3 , MW = 322·2, monoclinic, P 2 1 / n , a = 11·160 (2), b = 12·066 (2), c = 13·633 (3) A, β = 116·46 (2)°, V = 1643·5 A 3 , Z = 4, D c = 1·30 g cm −3 , F (000) = 672, λ(MoKα) = 0·71069 A, μ(MoKα) = 3·94 cm −1 . The structure was solved by direct methods and refined to R = 0·073 for 1495 independent reflexions. The molecule is non-planar with a dihedral angle of 87·8° between the phenyl rings. The effects of substituents on the aromatic ring geometry are discussed. Significant molecular parameters are: NN, 1·164 (9) A; mean ClC, 1·741 (6) A; mean CN(azo), 1·487 (9) A; NNC, 112·4 (2)° and 109·1 (2)°; NCC ( cis relative to NN), 125·5 (3)° and 122·4 (2)°; NCC ( trans relative to NN) 114·0 (3)° and 119·5 (3)°; mean CC(Cl)C, 122·3 (3)°.

Synthesis and structure of new arylnickel(II) malonato-complexes

SummaryInteraction of malonate anions with chloro(aryl)bis(organophosphine)nickel(II) complexes leads to the formation of stable (aryl)(malonato)(organophosphine)nickel(II) species, as shown by i.r. and1H n.m.r. data. The crystal and molecular structure of (diethylmalonato-O,O)(α-naphthyl)(triphenylphosphine)nickel(II), determined by x-ray methods (space group P¯1,a=10.767(9),b=16.253(16),c=9.835(13)Å, α=108.97(10)0, β=106.08(10)0, γ=89.11(7)0,Z= 2;R= 0.070 for 3650 independent observed reflections), shows distorted square-planar O2PC coordination about the nickel with bond distances: Ni-P, 2.142(2)Å; Ni-O, 1.888(5) and 1.936(5)Å; Ni-C, 1.887(8)Å. The parameters and bonding of the triphenylphosphine-nickel and naphthyl moieties in the complex are normal, whereas considerable electron-delocalisation occurs in the planar ethylmalonate moiety. The σ-naphthyl ligand is oriented almost perpendicularly to the NiO2CP core-malonate plane.

Fluorescence EXAFS of MgCl2-Supported Titanium Trichloride

Ziegler-Natta catalyst components, prepared by co-milling of MgCl2 with TiCl3 (ARA, HRA) in dry inert atmosphere, together with the model compounds δ-TiCl3 (a form of TiCl3 with disorder in the stacking of the Cl-Ti-Cl sheets) and TiCl4, were studied by means of fluorescent EXAFS /1/ in order to improve the signal-to-noise ratio with respect to conventional transmission measurements. In fact, in spite of the relatively high concentration of titanium in the samples, the presence of over 75% strongly absorbing element (Cl) in the region of interest and the dishomogeneity of the catalyst samples make collection of reliable data in transmission mode impossible.

Human and Environmental Impact Assessment for a Soybean Biodiesel Production Process Through the Integration of LCA and RA

Biodiesel is one of the most important global renewable fuels produced by vegetable biomass. It is the main green fuel produced and utilized in Europe (in this context Italy is the 4th producer country) and the result of national biofuel mandates. The EU Renewable Energy Directive imposes to reach a minimum threshold of 10 % diesel blending with biodiesel by 2020 in order to reduce global warming. Biodiesel has many positive aspects, it is a renewable, non-ecotoxic and obtained from vegetable oils and animal fats with a favorable balance in terms of GWP (Global Warming Potential) and EROI (Energy Return On Investment), but its production has also some critical aspects mainly related to its impacts on the environment and health. The aim of this chapter is to demonstrate how an approach for the assessment of these impacts, by means of the integration of LCA (Life Cycle Assessment) and RA (Risk Assessment) methodologies, helps in evaluating the acceptability of the process.

Structure of the larvicideN-(2-chlorobenzoyl)-N′-[4-(2-chloro-3,3,3-trifluoroprop-1-enyl)phenyl]urea, C17H11Cl2F3O2N2

Mw=403,2 amu,P21/c,a 18.944(8) Å,b=8.540(4) Å,c=10.794(7) Å,β=98.11(4)°,V=1729(2) Å3,Z=4,Dx=1.548 g·cm−3,μ (MoKα)=4.26 cm−1; m.p. 202–204°C. FinalR=0.083 for 1632 independent observed reflections having 2θ (Mo Kά)<50° andI>2 σ(I). The molecule has an extended overall nonplanar conformation with onecis and twotrans-C(O)-NH- units and intramolecular hydrogen bridges. The relatively highR factor is on account of conformational disorder of the trifluoromethyl and chloro substituents of the 2-chloro-3,3,3-trifluoropropenyl moiety.

Studies of systemic acylanilide fungicides. Part III. Crystal structure and molecular conformation ofN-(2-methoxyacetyl)-N-(2,6-xylyl)-3-amino-1,3-oxazolidin-2-one

The crystal structure of the title compound (C14H18N2O4) was determined by three-dimensional X-ray analysis from diffractometer data. Crystal data are: monoclinic,P21/n,a=9.363(1) Å,b=12.715(1) Å,c=12.360(1) Å,β=102.64(10)°,Z=4,Dx=1.288 Mg m−3,μ(MoKα)=0.10 mm−1. FinalR=0.062 for 1175 observed reflections. The dimethylphenyl group and the planar portion of the oxazolidinone ring are steeply inclined to the amidic plane of the molecule (76.0° and 66.5°, respectively); the oxazolidinone ring is in a half-chain form.

Studies of systemic acylanilide fungicides: Part V. Crystal structure and molecular conformation ofDL-methylN-(2,6-dimethylphenyl)-N-(2-phenylacetyl) alaninate

A crystalline modification of the title compound (C17H19NO4) was determined by three-dimensional X-ray analysis from diffractometer data. Crystal data: monoclinic,Cc,a=15.997(12) Å,b=7.929(7) Å,c=14.664(11) Å,β=118.70(5)°,Z=4;Dx=1.227 Mg m−3,μ(MoKα)=0.094 mm−1. FinalR=0.068 for 852 observed reflections. The dimethylphenyl ring is strongly twisted (94.9°) with respect to the amidic plane of the molecule, which almost coincides with the furan ring (6.9°).

X-ray crystal structure of the dye 2-cyano-4-bromo-4′-N,N-diethylaminoazobenzene

Abstract The crystal structure and molecular conformation of 2-cyano-4-bromo-4′-N,N-diethylaminoazobenzene (C17H17N4Br, mol. wt. = 357·2 a.m.u) has been determined from X-ray diffraction data; triclinic, P 1 (No. 2), a = 10·132(11) A, b = 12·216(16) A, c = 6·966(11) A, α = 104·21(9)°, β = 92·67(12)°, γ = 97·22(7)°, V = 826·5(9) A3, Z = 2, Dc = 1·436 g cm−3, F(000) = 378, λ(MoKα) = 0·71069 A, μ(MoKα) = 26·0 cm−1. The structure was solved by the multiple solution direct method and refined by full-matrix least-squares to R = 0·059 for 1538 independent observed reflections. The azobenzene skeleton is planar to within 0·06 A. Most significant bonding data are: NN, 1·290(8) A; BrC, 1·866(6) A; mean CN (azo) 1·380(8) A; NNC, 113·6(4) and 115·3(4)°; NCC (cis relative to NN) 125·9(4)° and 126·7(4)°; NCC (trans) 116·8°(5)° and 116·1(4)°.

Colour prediction of organic dye molecules on a microcomputer—a readily available form of the PPP-MO method for teaching and research

Abstract The Pariser-Parr-Pople molecular orbital (PPP-MO) method, which provides a way of calculating electronic absorption spectroscopic properties of organic dye molecules, such as the position of the absorption maximum in the visible spectrum, its intensity and polarisation direction, has been implemented in PASCAL language on a 64 kB Apple 11 computer. The system consists of two modes: (1) Graphic mode and (2) PPP mode, which are controlled separately or successively. The system occupies up to 32 kB of memory, needs 1 minifloppy disk in the entire execution of the program, and handles up to 30 atoms routinely with configuration interaction.