Synthesis and Properties of Bis-Porphyrin Molecular Tweezers : Effects of Spacer Flexibility on Binding and Supramolecular Chirogenesis

• Abstract: Ditopic binding of various dinitrogen compounds to three bisporphyrin molecular tweezers with spacers of varying conformational rigidity, incorporating the planar ene-diyne (1), the helical stiff stilbene (2), or the semirigid glycoluril motif fused to  the porphyrins (3) are compared. Binding constants Ka = 10^4 to 10^6 M^-1 reveal subtle  differences between these tweezers, that are discussed in terms of porphyrin dislocation  modes. Exciton coupled circular dichroism (ECCD) of complexes with chiral dinitrogen  guests provides experimental evidence for the conformational properties of the tweezers. The results are further supported and rationalized by conformational analysis.

Subject headings

NATURVETENSKAP  -- Kemi -- Organisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Organic Chemistry (hsv//eng)

Keyword

Bisporphyrin tweezers

metalloporphyrins

porphyrinoids

host-guest chemistry

supramolecular chemistry

chirogenesis

chirality transfer

exciton coupled circular dichroism

conformational analysis

Chemistry with specialization in Organic Chemistry

Kemi med inriktning mot organisk kemi

Teknisk fysik med inriktning mot nanoteknologi och funktionella material

Engineering Science with specialization in Nanotechnology and Functional Materials

Publication and Content Type

ref (subject category)

art (subject category)