联吡啶甲酸铂(Ⅱ)配合物的合成与光谱性质

Synthesis and spectroscopic properties of bipyridyl-carboxylato Pt(Ⅱ) complexes

应用2，2’-联吡啶-6-甲酸甲酯（bpym）和4，4’-二甲基-2，2’-联吡啶-6-甲酸甲酯（mbpym），制得3个铂（Ⅱ）配合物[Pt（bpyc）Cl]（bpyc=2，2’-联吡啶-6-甲酸根，1），[Pt（mbpyc）Cl]（mbpyc=4，4’-二甲基-2，2’-联吡啶-6-甲酸根，2）和[Pt（mbpyc）（PPh3）]（ClO4）（3）. 配合物3的X射线单晶衍射结果表明，Pt（Ⅱ）中心离子与mbpyc的1个氧原子和2个氮原子以及三苯基膦的1个磷原子配位，构成一个变形的N2OP平面四边形. 在紫外可见吸收光谱中，配合物1-3的乙腈溶液在320-450 nm范围内有一个弱的低能量吸收带，它会受三齿螯合配体取代基和辅助配体的影响，可归属为金属到配体的电荷转移跃迁（1MLCT）、配体到配体的电荷转移跃迁（1LLCT）和配体内的电荷转移跃迁（1ILCT），与含时密度泛函理论（TD-DFT）计算结果一致. 在室温固态荧光发射光谱中，配合物1-3均有一个荧光发射峰，它也受辅助配体和三齿螯合配体取代基的影响.

Utilizing 6-methoxycarbony-2,2＇-bipyridine and 6-methoxycarbony-4,4＇-dimethyl-2,2＇-bipyridine, three Pt（Ⅱ） complexes [Pt（bpyc）Cl] （bpyc=2.2＇-bipyridine-6-carboxglate）, [Pt（mbpyc）Cl] （mbpyc=4,4＇-dimethyl-2,2＇-bipyridine-6-carboxylate, 2）, and [Pt（mbpyc）（PPh3）]-（ClO4） （3） have been synthesized. As revealed via X-ray single-crystal diffraction, complex 3 adopts a distorted square-planar N2OP arrangement generated by one O atom and two N atoms of mbpyc and one P atom of PPh3. A weak lowest-energy absorption is observed at 320-450 nm in CH3CN solution for 1-3, which is affected by the substituents of tridentate chelating ligand and ancillary ligand and is ascribed to the metal-to-ligand charge-transfer （1MLCT） transitions mixed with the ligand-to-ligand charge-transfer （1LLCT） and intra-ligand charge-transfer （1ILCT） characters, as supported by their TD-DFT calculations. Complexes 1-3 have a solid luminescence properties at ambient temperature, which is also influenced by ancillary ligand and the substituents of tridentate chelating ligand.