Connecting π-Chromophores by σ-P−P Bonds:  New Type of Assemblies Exhibiting σ−π-Conjugation

Abstract

To study the ability of sigma-P-P skeleton to mediate interaction between pi-chromophores, 1,1'-biphospholes bearing phenyl or thienyl substituents at the 2,2' and 5,5'-position have been prepared and studied. These air-stable derivatives are readily available via a "one-pot" synthesis starting from diynes. Theoretical studies and UV-vis data clearly establish that the two pi-systems interact via the sigma-P-P bridge. This through-bond interaction results in a lowering of the optical HOMO-LUMO gap of the assemblies. The nucleophilic sigma(3)-P centers of these 1,1'-biphospholes allow chemical modifications of the sigma-bridge. These modifications offer further tuning of the optical properties of the assembly. Electrooxidation of the thienyl-substituted 1,1'-biphosphole results in electroactive materials characterized by low optical band gap and reversible p-doping.

Mechanistic Studies on a Novel, Highly Potent Gold-Phosphole Inhibitor of Human Glutathione Reductase

“…GoPI Synthesis-The synthesis of [1-phenyl-2,5-di(2-pyridyl)-phosphole}AuCl] was carried out in analogy to the synthesis of [{1-phenyl-2,5-di(2-thienyl)phosphole}AuCl] (18,19) and [{1-phenyl-2,5-di(2-pyridyl)phosphole}W(CO) 5 ] (20). The reactant 1-phenyl-2,5-di(2-pyridyl)phosphole was synthesized as described previously (16).…”

Dendrimeric Oligo(phenylenevinylene)‐Extended Dithieno[3,2‐b:2′,3′‐d]phospholes—Synthesis, Self‐Organization, and Optical Properties

“…In addition, the phosphole system exhibits a peculiar electronic structure, with a low-lying LUMO energy level that is particularly attractive for organic electronics. [13] RØau and co-workers were among the first to incorporate the phosphole moiety in extended p-conjugated materials [14] and to utilize these in phosphole-based OLED devices. [15] A few years ago, we introduced the dithieno[3,2-b:2',3'-d]phos-A C H T U N G T R E N N U N G phole system (1, Scheme 1) to this field of research.…”

Organophosphorus π-conjugated materials: the rise of a new field

“…While the spectrum of (3a) shows only one absorption due to a p-p* transition (412 nm), several bands are recorded for (12) with one red shifted broad shoulder (k onset = 560 nm) (Fig. 2) [20]. The TD-DFT simulated absorptions of (12) (vertical lines, Fig.…”

“…We anticipated that P-P bridges could be potentially good candidates to mediate through-bond conjugation since they possess a low rr* gap. Compound (12) (Scheme 4) [20], assembling two di(2-thienyl)phosphole chromophores via a P-P bond, was prepared according to the classical route to 1,1 0 -biphospholes, implying a coupling of the corresponding phospholyl anion upon oxidation with iodine [21]. An X-ray diffraction study performed on (12) revealed a P-P single bond [2.224(1) Å ] [22] and showed that the P atoms are strongly pyramidalised [(R)bond angles, 293.7°].…”

“…An X-ray diffraction study performed on (12) revealed a P-P single bond [2.224(1) Å ] [22] and showed that the P atoms are strongly pyramidalised [(R)bond angles, 293.7°]. The bond lengths and valence angles of the organophosphorus frame of (12) compare with those of the 2,5-dithienylphosphole (3a) [20]. The absorption spectrum of 1,1 0 -biphosphole (12) differs notably from that of the corresponding phosphole (3a).…”