Cui, Yi Wang, Suning Diboron and Triboron Compounds Based on Linear and Star-Shaped Conjugated Ligands with 8-Hydroxyquinolate Functionality:  Impact of Intermolecular Interaction and Boron Coordination on Luminescence New 8-R-quinoline functionalized linear and star-shaped conjugated molecules have been synthesized using Suzuki−Miyaura coupling methods (R = MeO, <b>L1</b>−<b>L5</b>; R = CH<sub>3</sub>OCH<sub>2</sub>O, <b>L1</b>‘−<b>L5</b>‘). When treated with HCl, <b>L1</b>‘−<b>L5</b>‘ are converted readily to the corresponding 8-hydroxyquinoline compounds <b>L</b>(OH)<b>1</b>−<b>L</b>(OH)<b>5 </b>which react readily with BPh<sub>3</sub> in refluxing THF to produce the corresponding polyboron chelate compounds <b>B1</b>−<b>B5</b> in good yields. <b>L1</b>−<b>L5 </b>and <b>B1</b>−<b>B5 </b>display similar thermal stability with <i>T</i><sub>d</sub> at ∼300 °C. Experimental and molecular orbital calculation results showed that the chelation by boron stabilizes the LUMO level of the ligand and narrows the HOMO−LUMO gap, resulting in the blue emission of the ligands and the green or orange emission of the boron compounds. Crystal structures of <b>L1</b>,<b> L3</b>, and <b>L5 </b>showed that these molecules have layered arrangements in the solid state with significant intermolecular π−π interactions. The linear diboron <b>B5 </b>displays concentration and temperature-dependent emission in solution, attributable to intermolecular interactions. The properties of a monoboron compound BPh<sub>2</sub>(5-Ph-8-MeO-q) (<b>B0</b>) and its corresponding free ligand <b>L0 </b>were investigated and compared to the closely related diboron compound <b>B1</b> and the ligand <b>L1</b>, which revealed that the increase of the number of chromophores linked by an aromatic group has a significant impact on thermal stability and the HOMO and LUMO energy levels. stability;refluxing THF;OH;Boron Coordination;L 5;L 3;diboron compound B 1;ligand L 1;interaction;LUMO level;Triboron Compounds;B 0;HOMO;CH 3 OCH 2 O;emission;ligand L 0;LUMO energy levels;crystal structures;Intermolecular Interaction;diboron B 5 displays concentration;BPh 3;L 1;molecule;boron compounds;calculation results 2006-08-18
    https://acs.figshare.com/articles/dataset/Diboron_and_Triboron_Compounds_Based_on_Linear_and_Star_Shaped_Conjugated_Ligands_with_8_Hydroxyquinolate_Functionality_Impact_of_Intermolecular_Interaction_and_Boron_Coordination_on_Luminescence/3371779
10.1021/jo060841+.s003