[Au(PH3)]^＋修饰的芳香基炔基配合物发光机制的从头计算研究

Ab initioStudy on Luminescent Mechanism of [Au(PH_3)]^+ Complexes with Aryl and Alkynyl Ligands

用从头计算法研究H3PAuC≡CPh(a),H3PAu(C≡C-1,4-C6H4)Ph(b)和H3PAu(C≡C-1,4-C6H4)C≡CPh(c)3种Au(Ⅰ)配合物的磷光发光性质,使用MP2和CIS方法分别优化配合物的基态和激发态的几何结构.计算结果表明,激发态的电子跃迁减弱了Au与配体的成键作用.由计算得出3种Au(Ⅰ)配合物的最低能量磷光发射光谱分别为530,610和615nm,皆由A3A′→1A′产生,属于Au(6p)→C(2p)的电荷转移(MLCT)修饰下的pπ*(C≡C,■)→pπ(C≡C,■)跃迁本质,并伴有Au(6p)→Au(5d)的金属中心电荷转移(MCCT)性质.随着分子增长,其激发态轨道中Au的p轨道成分减少,相应的最低能量磷光发射的波长红移.

Abstract The structures of Au（Ⅰ） complexes, H3PAuC≡CPh （a）, H3Pau （C≡C-1,4-C6H4 ） Ph （b） and H3PAu（ C≡C-1,4-C6H4） C-C Ph（c） were optimized by the ab initio MP2 and CIS methods for the ground states and excited states, respectively. It was shown that the electron transitions weaken the bonding between Au and ligands. The lowest-energy phosphorescent emissions from A^3A′→^1A′ were predicted at 530,610, and 615 nm for complexes a-c, respectively, agreeing well with experimental data. The emissions were attributed to the pπ. （Ph）→pπ （Ph） transition nature modified by the Au→C charge transfer（MLCT） and the Au （6p）→Au （Sd） transition （MCCT）. With the increase of conjugated lengths of complexes, the participation of Au（p） orbital decreases in the excited state. Consequently, the corresponding emission wavelength redshifts.