Poly­sulfonyl­amines. CXLV.

The prominent features in the molecular structure of the title compound (alternative name: 2‐diethyl­carbamoyl‐1,1,3,3‐tetraoxo‐1,3,2‐benzodi­thia­zole), C₁₁H₁₄N₂O₅S₂, arise in the urea moiety S₂N—C(O)—N′C₂: the sum of the angles at N is 332.3 (1)°, the N—C(O)—N′C₂ unit is planar, and distances N—C(O) = 1.494 (3) Å, N′—C(O) = 1.325 (2) Å and C—O = 1.215 (2) Å. The mol­ecules are associated via five C—H?O hydrogen bonds to form layers parallel to the yz plane. This compound and its di­methyl homologue, which were synthesized by treating the silver salt of o‐benzene­disulfon­imide with carbamoyl chlorides, are prone to rapid hydro­lysis at the weak N—C(O) bond. For both mol­ecules, the rotational barrier about the partial N′—C(O) double bond is ca 50 kJ mol^?1 at 250 K (from dynamic ¹H NMR experiments).     

Glenn T. Seaborg; discoveries; and the capital of knowledge

Ten years from Glenn T. Seaborg’s death we remember his achievements; his teaching about the importance of basic research is as timely as ever.     

Mechanochemistry of the 5f-elements compounds. 5. Influence of the reaction medium on the mechanochemically induced reduction of U<Subscript>3</Subscript>O<Subscript>8</Subscript>

The structure changes and the degree of reduction of U₃O₈ after mechanoactivation in agate and stainless steel vessels in different media are studied. Clearly expressed reduction of U(IV, VI) oxide, accompanied by oxygen release as a result of mechanochemical activation is observed. The highest degree of reduction is reached when mechanoactivation is performed in suspension with nonpolar organic solvents. The presence of acetaldehyde as a reducing agent did not cause valuable increase of the reduction process. Quantitative evaluation of the mechanochemically induced changes in the crystal structure of U₃O₈ is done. Decrease of the crystallite sizes of both the U₃O₈ and the reduced form, provoked by the mechanochemical treatment is observed for all the samples. No other uranium-contained compounds, formed during the mechanoactivation in the different media and mixtures were found.     

Automatized Parameterization of the Density‐functional Tight‐binding Method. II. Two‐center Integrals

We present an efficient numerical integration scheme (TWOCENT) to be used in the context of automatized parameterization of the density‐functional tight‐binding (DFTB) method. The accuracy of the integration process is assessed and its range of applicability is discussed. The functionality of the developed code is tested by reproducing the electronic portion of the existing mio parameter sets and by reproducing a series of reference DFT band structures of elemental solids.     

1,7-Trimethylenenorbornane. A novel member of the ‘adamantaneland’. Preliminary communication

A synthesis of the novel C₁₀H₁₆ hydrocarbon 1,7-trimethylenenorbornane ( 13 ), one of the 19 members of the adamantane family, is described.     

Polymerization of o‐quinodimethanes. IV. Radical polymerization of 1‐cyano‐o‐quinodimethane in the presence of TEMPO

The radical polymerization behavior of 1‐cyano‐o‐quinodimethane generated by thermal isomerization of 1‐cyanobenzocyclobutene in the presence of 2,2,6,6‐tetramethylpiperidine‐N‐oxide (TEMPO) and the block copolymerization of the obtained polymer with styrene are described. The radical polymerization of 1‐cyanobenzocyclobutene was carried out in a sealed tube at temperatures ranging from 100 to 150 °C for 24 h in the presence of di‐tert‐butyl peroxide (DTBP) as a radical initiator and two equivalents of TEMPO as a trapping agent of the propagation end radical to obtain hexane‐insoluble polymer above 130 °C. Polymerization at 150 °C with 5 mol % of DTBP in the presence of TEMPO resulted in the polymer having a number‐average molecular weight (M_n ) of 2900 in 63% yield. The structure of the obtained polymer was confirmed as the ring‐opened polymer having a TEMPO unit at the terminal end by ¹H NMR, ¹³C NMR, and IR analyses. Then, block copolymerization of the obtained polymer with styrene was carried out at 140 °C for 72 h to give the corresponding block copolymer in 82% yield, in which the unimodal GPC curve was shifted to a higher molecular weight region. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3434–3439, 2000