Molecular Structure, Optical, and Magnetic Properties of Free-Base Naphthalocyanine Dianions
Molecular Structure, Optical, and Magnetic Properties of Free-Base Naphthalocyanine Dianions
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游离碱萘酞菁双阴离子的分子结构、光学和磁性
DOI：
10.1002/ejoc.201800364
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
R. N. Lyubovskaya
中科院分区：
文献类型：
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作者：
D. V. Konarev;S. S. Khasanov;Y. Nakano;A. F. Shestakov;M Ishikawa;A. Otsuka;H. Yamochi;H. Kitagawa;R. N. Lyubovskaya
用氟酮酮基钠和过量的二（三苯基磷酰亚胺）氯化铵（PPN+）（Cl -）还原游离碱萘菁（H2Nc），意外地合成了（PPN+）2（H2Nc2 -）盐(1)。由于氟酮酮酮钠只能生成H2Nc·-自由基阴离子，因此H2Nc2的形成很可能是通过H2Nc·-与h2nc0和H2Nc2 -歧化来实现的。h2n2 -离子沿平面间距为3.30 Å， HOMO - HOMO （HOMO =最高占据分子轨道）重叠积分为3.1 × 10-3的方向形成π -π层。h2n_2 -大环由于形成了长、短交替的C-N（亚胺）键而发生扭曲。由于占据了最低的未占据分子轨道（LUMO）， H2Nc上的负电荷越多，大环的畸变越大。计算表明，这种畸变在h2nc2的三重态中消失，因为LUMO和LUMO+1轨道的占用平均了它们对大环几何结构的影响。1的光谱显示出最低的能量吸收带atλ= 1230 nm，这归因于HOMO→LUMO+1激发和H2Nc Q‐带的蓝移。电子顺磁共振（EPR）沉默值为1表示h2nc2 - diions的反磁单线态。DFT计算表明，开壳破对称单重态的能量低于相应的闭壳单重态和三重态。大的单重态-三重态能隙表明相应的三重态是热不可达的。
The reduction of free‐base naphthalocyanine (H2Nc) with sodium fluorenone ketyl and an excess of bis(triphenylphosphoranylidene)ammonium chloride (PPN+)(Cl–) unexpectedly results in the synthesis of the (PPN+)2(H2Nc2–) salt (1). As sodium fluorenone ketyl can generate only H2Nc·–radical anions, the formation of H2Nc2–is most probably realized through the disproportionation of H2Nc·–to H2Nc0and H2Nc2–. The H2Nc2–dianions in1form layers in which π–π stacks of H2Nc2–are formed along theadirection with a short interplanar distance of 3.30 Å and a HOMO–HOMO (HOMO = highest occupied molecular orbiatl) overlap integral of 3.1 × 10–3. The H2Nc2–macrocycle is distorted owing to the formation of alternate short and long C–N(imine) bonds. The distortion of the macrocycle increases with the negative charge on H2Nc owing to the occupation of the lowest unoccupied molecular orbital (LUMO). Calculations indicate that the distortion disappears in the triplet state of H2Nc2–as the occupation of the LUMO and LUMO+1 orbitals averages their effects on the geometry of the macrocycle. The optical spectrum of1shows a lowest energy absorption band atλ= 1230 nm, which is attributed to the HOMO → LUMO+1 excitation and a blueshift of the Q‐band of H2Nc. The elecron paramagnetic resonance (EPR) silence of1indicates the diamagnetic singlet state of the H2Nc2–dianions. The DFT calculations indicate that the open‐shell broken‐symmetry singlet state is lower in energy than the corresponding closed‐shell singlet and triplet states. The large singlet–triplet energy gap indicates that the corresponding triplet state is thermally inaccessible.