Homoconjugation/homoaromaticity in main group inorganic molecules.

Quantum chemical computations show that three groups of inorganic ions and neutral molecules, whose structures have long been known and characterized, are aromatic due to through-space homoconjugation: (i) I(4)(2+), S(6)N(4)(2+), and S(2)I(4)(2+) dications and the (O(2))(4) cluster with pericyclic transition-state-like (PTS-like) homoaromaticity; (ii) the bishomoaromatic Te(6)(2+) and 1,5-diphosphadithiatetrazocines; and (iii) the spherically homoaromatic Te(6)(4+). The S(2)I(4)(2+) dication has an unusually high S-S bond order (approximately 2.3) and dual PTS-like aromaticity arising from two separate sets of four-center, six-electron (4c-6e) in-plane through-space conjugation.

[Determination of 15 trace elements in antineoplastic traditional Chinese medicine by atomic absorption spectrometry].

Five kinds of antineoplastic traditional Chinese medicines including fufangtianxian capsule, xiaoaiping tablet, zhiling capsule, shenlian capsule and shenlinglan capsule were digested with HNO3-HCl mixed acid. The fifteen trace elements including calcium, magnesium, potassium, sodium, iron, zinc, manganese, cobalt, nickel, chromium, silver, copper, strontium, cadmium and lead in the above-mentioned drugs were determined by atomic adsorption spectrometry. The effects of the kinds of mixed acid, the ratio of HNO3 to HCl in the mixed acid, the volume of digesting solution and the digesting time were also investigated in detail.