The Synthesis Of NCN Ligands And Binuclear-Pt(â…¡) Pincer Compounds

In the thesis, a series of NCN binuclear-Pt(II) pincer compounds were synthesized containing 1,3-bis(1H-benzo[d]imidazol-2-yl)benzene, or 1,3-di(pyridin-2-yl)benzene, with the 2-bromopyridine, 2-bromo-4-methylpyridine or isophthalic acid as the starting materials. And the photophysical behavior of the bi-Pt(II) pincer compounds is also preliminary studied. The main research contents were as follows: 1. The synthesis of boric acid and borateThe boric acid or borate 1, 4a-c, or 5(Scheme 1) bearing different substituents were synthesized from 1,4-dibromobenzene, hydroquinone, and 1,3-dibromobenzene, respectively.Scheme 1 2. The synthesis of NCN 1,3-di(pyridin-2-yl)benzene ligands and binuclear-Pt(II) pincer compounds.First, the 1,3-di(pyridin-2-yl)benzene 6a-6b were synthesized through Negishi coupling reaction with 2-bromopyridine and 2-bromo-4-methylpyridine as the starting materials. Then, the NCN ligands 7, 9a-f, 11 installing 1,3-di(pyridin-2-yl)benzene were yielded with the homocoupling reaction of 6, and Suzuki coupling reaction of 1, 4a-c, 5. Finally, the NCN ligands 7, 9a-f, and 11 were reacted with K2 Pt Cl4 in anhydrous HOAc, affording the corresponding NCN binuclear-Pt(II) pincer compounds 8, 10a-f, 12(Scheme 2).Scheme 2 3. The synthesis of NCN 1,3-bis(1H-benzo[d]imidazol-2-yl)benzene and binuclear-Pt(II) pincer compounds.First, the 2,2’-(5-bromo-1,3-phenylene)bis(benzo[d]imidazole) 15a-b were synthesized via the reaction sequence of NBS bromination, amination of o-phenylenediamine, and alkylation reaction, in the condition of isophthalic acid as the starting material. Then, the NCN ligands 16a-c, 18a-b installing 1,3-bis(1H-benzo[d]imidazol-2-yl)benzene were achieved on the use of Suzuki VII coupling reaction. Finally, the Metalation reaction of NCN ligands16a-c, 18a-b afforded the corresponding NCN binuclear-Pt(II) pincer compounds17a-c, 19a-b(Scheme 3).Scheme 3 4. The photophysical and spectroscopic behavior of NCN binuclear-Pt(II) pincer compoundsThe photophysical and spectroscopic behavior of NCN binuclear-Pt(II) pincer compounds 10 e, 10 f, 17 a, 17 c, 19 a were studied.