Vicinal13C-13C coupling via nn,nno and cn paths

From the vicinal ¹³C-¹³C coupling constants determined for a series of bi(poly) cyclic azo-, azoxy- and imino-compounds an independent increment for the NN-, NNO- and NC units of ca. 15, 3–4 and ca.8 Hz resp. was deduced.     

Synthesis of alpha-P-modified nucleoside diphosphates with ethylenediamine

This report describes a one-pot synthesis of alpha-P-borano-, alpha-P-thio-, and alpha-P-seleno-modified nucleoside diphosphate analogues that are otherwise difficult to obtain. The key step involves the intramolecular nucleophilic attack by an amino group in 5 to remove the gamma-phosphate. The absolute configurations of P-diastereomers were confirmed by analysis of their 1H NMR. Affinity studies revealed that the nucleoside boranodiphosphates are potentially useful in antiviral research.     

Formation of the magic cluster Na8 in noble gas matrixes

The sodium molecules Na(2), Na(4), and Na(8) have been isolated in argon matrixes at 15 K and characterized for the first time by Raman spectroscopy. The vibrational frequencies are compared with density functional (DFT) calculations. The Na(4) cluster possesses a rhombic structure (D(2h)) with calculated d(Na-Na) = 307.2 and 347.4 pm, respectively. For octasodium, a hypertetrahedral structure (T(d)) is predicted in which each side of an inner tetrahedron with d(Na-Na) = 331.5 pm is capped by sodium atoms with a distance of d(Na-Na) = 348.7 pm. The green octasodium cluster is the first example of a matrix-isolated magic number cluster. Its formation from blue tetrasodium is discussed on the basis of the observed sequence of cluster growth.