Crystal and molecular structure of 3-methoxy-8β-methyloestradiol 17-monobromoacetate

Abstract

The crystal structure of 3-methoxy-8@-methyioestradiol 17-rnonobromoacetate, Cz2HzpO3Br, has been determined by a three-dimensional X-ray analysis. The crystals are monoclinic with a = 11.84, b = 8.08, c = 10.47 8, and @ = 96" 39', in space group P2,. The crystal structure was solved by the heavy-atom method and refined by the least-squares method. The final value of R over the 715 independent reflexions was 0.094. The ring c of the steroid skeleton has a normal chair form, and ring D is represented by the slightly deformed P-envelope conformation.

On the stability of noble-metal nanoclusters protected with thiolate ligands

“…ii) Large energy gap between homo-lumo states. iii) Highly symmetric and compact atomic structure of the metallic core; iv) which is protected with capping units, −SR−[M−SR] y , composed by the metal atoms attached to the thiolate ligands [25]. Two other elements have been added to the discussion: v) Strong electrostatic interactions of the different atomic shells [26].…”

“…Thiolate NCs have been described as a metallic core capped with an external layer composed with ligands and metal atoms that form −SR−[M−SR] y oligomers. This capping layer has been proposed as an additional condition to explain the NCs stability [25,47]. The stability of [M 25 (SR) 18 ] − , with M = Au or M = Ag, has been attributed to a combination of a closed electron shell and a symmetric atomic structure [25].…”

“…This capping layer has been proposed as an additional condition to explain the NCs stability [25,47]. The stability of [M 25 (SR) 18 ] − , with M = Au or M = Ag, has been attributed to a combination of a closed electron shell and a symmetric atomic structure [25]. This NC is composed by an icosahedral metal core, M 13 (fig.…”