title: Synthesis, characterization, and UV-vis linear absorption of centrosymmetric pi-systems incorporating closo-dodecaborate clusters.
abstract: Single- and multibranched centrosymmetric derivatives incorporating B12 clusters [B12H11-N(H)=C(H)-C6H4-C6H4-C(H)=(H)N-B12H11]2- (3) and [1,3,5-(4-(B12H11-N(H)=C(H))-C6H4)-C6H3]3- (5) have been synthesized. Both derivatives were characterized by multinuclear NMR and ESI-MS analyses. To the best of our knowledge, compound 5 is the first example of a multicage derivative bearing three B12 units. Compounds 3 and 5 are only slightly yellowish colored. The UV-vis absorption curves of 3 and 5 show intense absorption bands at 360 and 314 nm, respectively. This result permits us to confirm the strong donor effect of the B12 cluster. The hypsochrome effect observed for compound 5 compared to that of compound 3 confirms the interest in multibranched derivatives for the preparation of two-photon absorption materials active in the visible range.
authors.affiliation: Laboratoire des Multimatériaux et Interfaces, UMR 5615 CNRS-Université Claude Bernard Lyon 1, 43 Boulevard du 11 Novembre 1918, F-69622 Villeurbanne Cedex, France.
authors.forename: Rémy
authors.initials: R
authors.lastname: Bernard
authors.forename: David
authors.initials: D
authors.lastname: Cornu
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Scharff
authors.forename: Rodica
authors.initials: R
authors.lastname: Chiriac
authors.forename: Philippe
authors.initials: P
authors.lastname: Miele
authors.forename: Patrice L
authors.initials: PL
authors.lastname: Baldeck
authors.forename: Josef
authors.initials: J
authors.lastname: Caslavský