Department of Chemistry, R. K. Mission Residential College, Narendrapur, Kolkata-700103, India.
Dalton Trans. 2013 Nov 14;42(42):15028-42. doi: 10.1039/c3dt51771c. Epub 2013 Sep 2.
Reactions of benzoyl pyridine, o-phenylenediamine and anhydrous ZnX2 in methanol afford imine complexes [Zn(L1)X2] (X = Cl, 1; X = Br, 2) in good yields (L1 = (E)-N(1)-(phenyl(pyridin-2-yl)methylene)benzene-1,2-diamine). The reduction of 1 with NaBH4 affords (E)-N(1)-(phenyl(pyridine-2-yl)methylene)benzene-1,2-diamine (L2H). The reaction of L2H with [Ru(II)(PPh3)3Cl2] results in the oxidative dehydrogenation to L1 generating cis-[Ru(II)(L1)(PPh3)Cl2] (3). The reaction of L2H with salicylaldehyde affords (E)-2-(((2-((phenyl(pyridin-2-yl)methyl)amino)phenyl)imino)methyl)phenol (L3H2). The reaction of L3H2 with anhydrous FeCl3 in CH3OH affords cis-[Fe(III)(L3H(-))Cl2] (4). Reaction of L3H2 with [Ru(II)(PPh3)3Cl2] results in the oxidative dehydrogenation to diimine, L4H, affording trans-Ru(II)(L4(-))(PPh3)2, which is isolated as trans-[Ru(II)(L4(-))(PPh3)2]PF6 (5(+)PF6(-)) (L4H = 2-((E)-(2-((E)-phenyl(pyridin-2-yl)methyleneamino)phenylimino)methyl)phenol). The reduction of L3H2 with NaBH4 produces 2-(((2-((phenyl(pyridin-2-yl)methyl)amino)phenyl)amino)methyl)phenol (L5H3). With iron(III) L5H3 undergoes oxidative dehydrogenation to L3H2 affording 4, while with [Ru(II)(PPh3)3Cl2], L5H3 undergoes 4e + 4H(+) transfer giving 5(+). A fluid solution of L3H2 at 298 K exhibits an emission band at 470 nm (λ(ex) = 330 nm, τ1 = 3.70 ns) and a weaker band at 525 nm (λ(ex) = 330, 390 nm, τ1 = 1.1 ns) at higher concentrations due to molecular aggregation, which are temperature dependent. 4 is brightly emissive (λ(ex) = 330 nm, λ(em) = 450 nm, Φ = 0.586, τ1 = 3.70 ns). Time resolved emission spectra (TRES) and lifetime measurements confirm that the lower energy absorption band of L3H2 at 390 nm, which is absent in complex 4, has a larger non-radiative rate constant (k(nr)). The redox innocent Al(III) adduct of L3H2 is fluorescent (λ(ex) = 330 nm, λ(em) = 450 nm, τ1 = 3.70 ns). On the contrary, the cis-Fe(II)(L3H(-))Cl2 and cis-Co(L3H(-))Cl2 analogues are non emissive. Density function theory (DFT) calculations, redox potentials and the near infra-red (NIR) absorption data prove that 4 is emissive due to the stable [Fe(III)(L3H(-))] state, while 3, 5(+), cis-Fe(II)(L3H(-))Cl2 and cis-Co(L3H(-))Cl2 are non-emissive due to transformations of the [M(II)(L)] to [M(III)(L˙(-)*)] states.
苯甲酰吡啶、邻苯二胺和无水 ZnX2 在甲醇中的反应以良好的产率得到亚胺配合物[Zn(L1)X2]（X = Cl，1；X = Br，2）（L1 = (E)-N(1)-(苯（吡啶-2-基）亚甲基）苯-1,2-二胺）。1 用 NaBH4 还原得到(E)-N(1)-(苯（吡啶-2-基）亚甲基）苯-1,2-二胺（L2H）。L2H 与[Ru(II)(PPh3)3Cl2]反应导致氧化脱氢生成 L1，生成顺式-[Ru(II)(L1)(PPh3)Cl2]（3）。L2H 与水杨醛反应得到(E)-2-(((2-((苯（吡啶-2-基）甲基）氨基）苯基）亚氨基）甲基）苯酚（L3H2）。L3H2 与无水 FeCl3 在 CH3OH 中反应得到顺式-[Fe(III)(L3H(-))Cl2]（4）。L3H2 与[Ru(II)(PPh3)3Cl2]反应导致氧化脱氢生成二亚胺 L4H，生成反式-Ru(II)(L4(-))(PPh3)2，其作为反式-[Ru(II)(L4(-))(PPh3)2]PF6（5(+)PF6(-)）（L4H = 2-((E)-(2-((E)-苯（吡啶-2-基）亚甲基氨基）苯基亚氨基）甲基）苯酚）分离。L3H2 用 NaBH4 还原生成 2-(((2-((苯（吡啶-2-基）甲基）氨基）苯基）氨基）甲基）苯酚（L5H3）。Fe(III)与 L5H3 发生氧化脱氢反应生成 L3H2，生成 4，而与[Ru(II)(PPh3)3Cl2]反应，L5H3 发生 4e + 4H(+)转移，生成 5(+)。在 298 K 的液态 L3H2 溶液在较高浓度下由于分子聚集而在 470 nm 处显示发射带（λ(ex) = 330 nm，τ1 = 3.70 ns）和在 525 nm 处显示较弱的带（λ(ex) = 330、390 nm，τ1 = 1.1 ns），这是温度依赖性的。4 是明亮的发光体（λ(ex) = 330 nm，λ(em) = 450 nm，Φ = 0.586，τ1 = 3.70 ns）。时间分辨发射光谱（TRES）和寿命测量证实，L3H2 在 390 nm 处较低能量的吸收带，其在配合物 4 中不存在，具有更大的非辐射速率常数（k(nr)）。L3H2 的氧化惰性 Al(III)加合物是荧光的（λ(ex) = 330 nm，λ(em) = 450 nm，τ1 = 3.70 ns）。相反，顺式-Fe(II)(L3H(-))Cl2和顺式-Co(L3H(-))Cl2类似物是非发光的。密度泛函理论（DFT）计算、氧化还原电位和近红外（NIR）吸收数据证明，4 是发光的，因为稳定的[Fe(III)(L3H(-))]态，而 3、5(+)、顺式-Fe(II)(L3H(-))Cl2和顺式-Co(L3H(-))Cl2是非发光的，因为[M(II)(L)]态转化为[M(III)(L˙(-)*)]态。
