Figure 1. (top) Line drawing and labeled ORTEP plot of HbimDTDA (100 K; thermal ellipsoids at 50%); (bottom) singly occupied molecular orbital (SOMO) and electrostatic potential (ESP) surface calculated at uB3LYP/6-31G(d,p). Communication pubs.acs.org/JACS

A mononuclear 6-coordinate hs-Fe(ii)–radical complex exhibits single-molecule magnet behaviour.

Significantly fluorinated triarylmethyl cations have long attracted attention as potentially accessible highly reactive carbocations, but their isolation in a convenient form has proved elusive. We show that abstraction of chloride...

The Campylobacter jejuni capsule type HS1 complex is one of the most common serotypes identified worldwide, and consists of strains typing as HS1, HS1/44, HS44 and HS1/8. The capsule structure of the HS1 type strain was shown previously to be composed of teichoic-acid like glycerol-galactosyl phosphate repeats [4-)-α-D-Galp-(1–2)-Gro-(1-P-] with non-stoichiometric fructose branches at the C2 and C3 of Gal and non-stoichiometric methyl phosphoramidate (MeOPN) modifications on the C3 of the fructose. Here, we demonstrate that the capsule of an HS1/44 strain is identical to that of the type strain of HS1, and the capsule of HS1/8 is also identical to HS1, except for an additional site of MeOPN modification at C6 of Gal. The DNA sequence of the capsule locus of an HS44 strain included an insertion of 10 genes, and the strain expressed two capsules, one identical to the HS1 type strain, but with no fructose branches, and another composed of heptoses and MeOPN. We also characterize a HS1 capsule biosynthesis gene, HS1.08, as a fructose transferase responsible for the attachment of the β-D-fructofuranoses residues at C2 and C3 of the Gal unit. In summary, the common component of all members of the HS1 complex is the teichoic-acid like backbone that is likely responsible for the observed sero-cross reactivity.

Preorganization of a supramolecular unit composed of two π-radicals generates a ligand with an unusual square-shaped tetradentate binding site, ideal for coordination to early lanthanide ions. The supramolecular unit is assembled via a pairwise interaction between two neutral radicals, creating a pancake-bonded diamagnetic [π-radical]2 dimer. Synthesis and characterization of the new π-radical bitaDTDA (4-(3′-benzisothiazolyl)-1,2,3,5-dithiadiazolyl) is reported. Unlike most DTDA-based ligands in which a supramolecular [π-radical]2 pair dissociates to generate a bidentate, paramagnetic ligand, the pancake-bonded [bitaDTDA]2 unit apparently remains intact upon coordination to early lanthanide ions capable of supporting a 10-coordinate ligand sphere. The Ln­(hfac)3[bitaDTDA]2 complexes (Ln = La, Ce; hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato) are readily prepared by manual mechanochemical methods, indicating a low energy barrier to coordination. Only minor conformational changes are evident in the supramolecular [bitaDTDA]2 ligand upon coordination. A structural comparison of the free [bitaDTDA]2 ligand and Ln­(hfac)3[bitaDTDA]2 coordination complexes indicates favorable preorganization of the ligand.