The crystal structure of (2,3-dioxo-5,6:13,14-dibenzo-9,10-benzo-1,4,8,11-7, 11-diene-κ4N,N′,N′′,N′′′)-nickel(II), Ni(C22H14N4O2)

Crystal structure of tetra­aqua­bis­(1,3-dimethyl-2,6-dioxo-7H-purin-7-ido-κN 7)cobalt(II)

The title complex, [Co(C7H7N4O2)2(H2O)4], comprises mononuclear mol-ecules consisting of a CoII ion, two deprotonated theophylline ligands (systematic name: 1,3-dimethyl-7H-purine-2,6-dione) and four coordinating water mol-ecules. The CoII atom lies on an inversion centre and has a slightly distorted octa-hedral coordination environment, with two N atoms of two trans-oriented theophylline ligan...

Crystal structure of 12-benzyl­sulfanyl-2,9-di­bromo-6H-dibenzo[b,g][1,8]naphthyridin-11-one

The hetero-tetra-cene skeleton of the title mol-ecule, C23H14Br2N2OS, is defined by linear annulation of four six-membered rings, including two N heteroatoms. This moiety is nearly planar (r.m.s. deviation = 0.055 Å), with a slight twist of 4.1 (2)° between the two halves of the aromatic system. The dihedral angle between the least-squares plane of the skeleton and the benzyl group is 24.5 (3)°...

the underlying structure of language proficiency and the proficiency level

هدف از انجام این تخقیق بررسی رابطه احتمالی بین سطح مهارت زبان خارجی (foreign language proficiency) و ساختار مهارت زبان خارجی بود. تعداد 314 زبان آموز مونث و مذکر که عمدتا دانشجویان رشته های زبان انگلیسی در سطوح کارشناسی و کارشناسی ارشد بودند در این تحقیق شرکت کردند. از لحاظ سطح مهارت زبان خارجی شرکت کنندگان بسیار با هم متفاوت بودند، (75 نفر سطح پیشرفته، 113 نفر سطح متوسط، 126 سطح مقدماتی). کلا ...

Crystal structure of dimethyl 3,4,5,6-tetra­phenyl­cyclo­hexa-3,5-diene-1,2-di­carboxyl­ate

In the title compound, C34H28O4, the cyclo-hexa-diene ring has a screw-boat conformation with a torsion angle between the double bonds being on average ca 15° [15.2 (3) and -15.3 (3) in the two independent mol-ecules]. All four phenyl rings in both mol-ecules are arranged in a propeller-like conformation. The two mol-ecules exhibit S,R- and R,S- chirality, respectively, and are connected via C-...

Exposure-risk relationship for benzo[a]pyrene in BekGS 910