Synfacts 2011(8): 0840-0840  
DOI: 10.1055/s-0030-1260701
Synthesis of Materials and Unnatural Products
© Georg Thieme Verlag Stuttgart ˙ New York

Selective NIR-Absorbing Dyes

Contributor(s):Timothy M. Swager, Jan M. Schnorr
G. M. Fischer, E. Daltrozzo, A. Zumbusch*
Universität Konstanz, Germany
Selective NIR Chromophores: Bis(pyrrolopyrrole) Cyanines
Angew. Chem. Int. Ed.  2011,  50:  1406-1409  
Further Information

Publication History

Publication Date:
20 July 2011 (online)


Significance

Near-infrared (NIR) dyes that do not absorb in the visible range have potential as heat-blocking window coatings, laser-protecting glasses or as antiforgery markers. The authors present the synthesis of a series of NIR-absorbing bis(pyrrolo­pyrrole) cyanine dyes (4 and 5 as well as derivatives with different side and end groups) that meet these criteria.

Comment

Rigidifying the conjugated system of 4 by introduction of BPh2 groups (leading to 5) ­results in a red shift of the absorption maximum by 65 nm as well as in narrowing the absorption bands and in an increase of the extinction coefficient (ε = 277’000 M cm for 4 to ε = 571’000 M cm for 5).