We report two new helicenes derived from the double fusion of an acene with two perylene diimide (PDI) subunits. These PDI-helicene homologs exhibit very different structural and electronic properties, despite differing by only a single ring in the link between the PDI units. The shorter inter-PDI link brings the two PDI subunits closer together, and this results in the collision of their respe...

Aromaticity is a key concept in organic chemistry. Even though this concept has already been theoretically extrapolated to three dimensions, it usually still remains restricted to planar molecules in organic chemistry textbooks. Stacking of antiaromatic π-systems has been proposed to induce three-dimensional aromaticity as a result of strong frontier orbital interactions. However, experimental ...

In the title compound, C(7)H(11)N(2) (+)·C(7)H(7)O(3)S(-), the cation is protonated at the N atom of the heterocyclic ring. The dimethyl-amino group lies close to the pyridinium ring plane with a dihedral angle between the pyridinium and the dimethyl-amine CNC planes of 3.82 (17)°. The N-C bond linking the dimethyl-amino substituent to the pyridinium ring is characteristically short [1.3360 (19...

In the crystal structure of the title Ni(II) complex, [Ni(C(6)H(4)NO(3))(2)(C(3)H(4)N(2))(2)], the Ni(II) atom is located on a twofold rotation axis and is chelated by two oxidopyridiniumcarboxyl-ate anions and further cis-coordinated by two imidazole ligands in a distorted cis-N(2)O(4) octa-hedral geometry. The C-O bond distance of 1.2573 (19) Å found for the non-coordinating O atom of the car...

Covalent organic frameworks (COFs) are an emerging class of highly ordered porous polymers with many potential applications. They are currently designed and synthesized through hexagonal and tetragonal topologies, limiting the access to and exploration of new structures and properties. Here, we report that a triangular topology can be developed for the rational design and synthesis of a new cla...

In the title compound, C(11)H(14)ClNO, the herbicide propachlor, there are significant differences between the three N-C bond lengths [N-C(carbon-yl) = 1.354 (3) Å, N-C(phen-yl) = 1.444 (2) Å and N-C(isoprop-yl) = 1.496 (3) Å], indicating the presence of π delocalization involving the carbonyl group. The N atom lies 0.074 (2) Å from the plane defined by the the three bonded C atoms.

In the title compound, (C(16)H(36)N)(2)[Pd(C(4)N(2)S(2))(2)], the Pd(II) center adopts a distorted square-planar geometry due to the four-membered chelate rings formed by coordination of the 2,2-dicyano-ethyl-ene-1,1-dithiol-ate (i-mnt) ligands [bite angle 75.0159 (17)°]. The bond distances in the coordinated i-mnt ligands indicate some delocalization of the π-system.

Stereoelectronic effects modulate molecular structure, reactivity, and conformation. We find that the interaction between the ester and carboxyl moieties of aspirin has a previously unappreciated quantum mechanical character that arises from the delocalization of an electron pair (n) of a donor group into the antibonding orbital (π*) of an acceptor group. This interaction affects the physicoche...

In the title compound, (C(16)H(36)N)(2)[Pt(C(4)N(2)S(2))(2)], the Pt(II) center adopts a distorted square-planar geometry due to the 4-membered chelate rings formed by coordination to the S atoms of the 1,1-dicyano-ethyl-ene-2,2-dithiol-ate (i-mnt) ligands [bite angle 74.35 (4)°]. The bond distances in the coordinated i-mnt ligands indicate some delocalization of the π-system.