ABSTRACT
The Cave of Giant Crystals in the Naica mine (Mexico) is one of the most amazing displays of mineral beauty ever created in nature. In addition to the colossal crystals of gypsum, which in some cases exceed eleven meters in length and one meter in thickness, the scenery fashioned by the crystalline beams that thrust through the darkness of the cave from floor to ceiling with a luster like moonlight is a unique example of harmony based on crystal symmetry. We review the crystallogenesis of this remarkable and challenging phenomenon of mineralization near equilibrium that can be used to teach the basics of nucleation and crystal growth.
ABSTRACT
Single crystals of the title compound, C(39)H(43)N(3)O(11)S.2C(3)H(8)O, have been obtained from 2-propanol/water solutions. ET-743 belongs to the group of ecteinascidins (ETs), which is a family of novel marine tetrahydroisoquinoline derivatives characterized by a monobridged pentacyclic skeleton. Three large principal planar groups are observed in the three-dimensional structure of the ET-743 molecule, corresponding to three aromatic units which are nearly perpendicular to each other. In the crystal, the methoxy group on the large fused ring system adopts an anti conformation with respect to the S atom, thus presenting the same conformation as that found in solution.
