ABSTRACT
The asymmetric unit of the title compound, 2C31H28N2O4S·C2H6O, contains a parent mol-ecule and a half mol-ecule of ethanol solvent. The main compound stabilizes its mol-ecular conformation by forming a ring with an R 1 2(7) motif with the ethanol solvent mol-ecule. In the crystal, mol-ecules are connected by C-Hâ¯O and O-Hâ¯O hydrogen bonds, forming a three-dimensional network. In addition, C-Hâ¯π inter-actions also strengthen the mol-ecular packing.
ABSTRACT
The reaction of 4'-(2-thienyl)-2,2':6',2,2''-terpyridine (S-terpy) with the heterometallic complexes [Au2Ag2R4(OEt2)2]n (R = C6F5, C6Cl5) leads to the compounds [{Au(C6X5)2}Ag(S-terpy)]n (X = F (1), Cl (2)). The X-ray diffraction analysis of the complexes shows an alternating disposition of the metals -Au-Ag-Au-Ag- in 1D infinite polymeric chains. Despite the fact of having the same metallic sequence, the spatial arrangement observed for both complexes is very different, since for [{Au(C6F5)2}Ag(S-terpy)]n (1) the metals adopt a zigzag disposition, whereas an helicoidal distribution of the interacting metals is observed for the complex [{Au(C6Cl5)2}Ag(S-terpy)]n (2). These different arrangements are related to the perhalophenyl ligands present in the complexes, which appear with different spatial dispositions, being staggered in the case of C6F5 (1) and almost eclipsed in the case of C6Cl5 (2). In order to explain the reasons for these different structural arrangements, we performed a DFT-D3 computational analysis and a subsequent study of the qualitative characterization of the noncovalent interactions (NCIs) in real space.
ABSTRACT
The title compound, C22H33N3O4, crystallizes in the triclinic space group P with two mol-ecules in a unit cell. The two pyrrole rings are essentially planar (r.m.s. deviation = 0.002â Å) and they form a dihedral angle of 81.24â (10)° with each other. The crystal packing is stabilized by C-Hâ¯π inter-actions and π-π stacking inter-actions, forming a three-dimensional network. The Hirshfeld surface analysis and two-dimensional fingerprint plots reveal that the most important contributions for the crystal packing are from Hâ¯H (74.3%), Câ¯H/Hâ¯C (11.5%) and Oâ¯H/Hâ¯O (9.1%) contacts.
ABSTRACT
A rare example of chemospecificity in the tandem Diels-Alder reaction of activated alkynes and bis-dienes has been revealed. The reaction between bis-furyl dienes and DMAD occurs at 25-80 °C and leads to kinetically controlled "pincer" adducts, 4a,8a-disubstituted 1,4:5,8-diepoxynaphthalenes. On the contrary, only thermodynamically controlled "domino" adducts (2,3-disubstituted 1,4:5,8-diepoxynaphthalenes) are formed in the same reaction at 140 °C. The "pincer" adducts can be transformed to the "domino" adducts at heating. The rate constants for reactions of both types were calculated using dynamic 1H NMR spectroscopy.
