Structural characterization of phosphorus-based networks and clusters: 31P MAS NMR spectroscopy and magnetic shielding calculations on Hittorf's phosphorus.

The (31)P MAS NMR spectrum of Hittorf's phosphorus has been measured and assigned to the 21 crystallographically distinct phosphorus atoms based on two-dimensional dipolar correlation spectroscopies. Application of such 2D techniques to phosphorus-based networks is particularly challenging owing to the wide chemical shift dispersions, rapid irreversible decay of transverse magnetization, and extremely slow spin-lattice relaxation in these systems. Nevertheless, a complete assignment was possible by using the combination of correlated spectroscopy (COSY) and radiofrequency-driven dipolar recoupling (RFDR).

Nb and Ta adducts: connecting d0 metal chlorides and phosphorus sulfide cages.

Phosphorus sulfide cages alpha-P(4)S(4), alpha-P(4)S(5), beta-P(4)S(5), and beta-P(4)S(6) and transition-metal chlorides TaCl(5) and NbCl(5) form molecular adducts in CS(2)/n-hexane. The crystal structures of the adducts (TaCl(5))(alpha-P(4)S(4)), (TaCl(5))(alpha-P(4)S(5)), (TaCl(5))(beta-P(4)S(5)), (NbCl(5))(beta-P(4)S(5)), and (TaCl(5))(beta-P(4)S(6)) are reported and their conformation and energetic stability are discussed on the basis of ab initio electronic structure calculations. Furthermore bond lengths of coordinated and noncoordinated phosphorus sulfide cages obtained from experiment and theory are compared, emphasizing the changes within the cages that emerge upon coordination.

Efficacy and safety of low-dose regimens of conjugated estrogens cream administered vaginally.

Objective: The aim of this study was to evaluate the efficacy and safety of low-dose conjugated estrogens (CE) cream for treatment of atrophic vaginitis.

Methods: Postmenopausal women (N = 423) with moderate-to-severe vaginal atrophy were randomized to CE cream 0.3 mg or placebo once daily (21 days on/7 days off) or twice weekly for 12 weeks, followed by open-label treatment with CE cream for 40 weeks consistent with their prior regimen.