Designing a visible light-mediated double photoswitch: a combination of biradical and azobenzene structural motifs that can be switched independently.

A new molecular switch is presented that combines both biradical and azobenzene motifs to perform visible light-induced constitutional and stereo-isomerisation within the same molecule. The insertion of isonitrile-functionalised azobenzenes into the four-membered biradical [˙P(μ-NTer)P˙] (1), yielding a phosphorus-centred cyclopentane-1,3-diyl (-4B and -5B), represents a straightforward method to generate the desired double switches (-4B and -5B) in excellent yields (>90%). The switching properties are demonstrated for the fluorinated species -5B and, interestingly, can occur either stepwise or simultaneously, depending on the order in which the sample is irradiated with red and/or green light.

Neurocognitive Functioning is Impaired in Perinatally HIV-Infected Youth.

Background: The present study examined neurocognitive differences between Perinatally HIV (PHIV)-infected-youth and age and gender matched healthy controls. Despite early, long-term anti-viral treatment (ART), significant neurocognitive deficiencies remain for PHIV-infected-youth reaching adulthood compared to controls.

Methods: Participants were assessed with a comprehensive neuropsychological battery.

Tricyanomethane or Dicyanoketenimine-Silylation makes the Difference.

Pseudohalides such as tricyanomethanide, [C(CN)], are well known in chemistry, biochemistry and industrial chemistry. The protonated species HC(CN), a classic hydrogen pseudohalide Brønsted acid, is a very strong acid with a pK value of -5. However, HC(CN) is difficult to handle as it tends to decompose rapidly or, more precisely, to oligo- and polymerize.

A Phosphorus-Centred, Zirconocene-Bridged Tetraradical: Synthesis, Structure and Application as Molecular Double Switch.

Biradicals are important intermediates in the formation and breaking of a chemical bond. Their use as molecular switches is of particular interest. Much less is known about tetraradicals, which can, for example, consist of two biradical(oid) units.