Low-Nuclearity Alkynyl d10 Clusters Supported by Chelating Multidentate Phosphines

The coordination chemistry of the tri- and tetradentate chelating phosphines (2-PPh2C6H4)2P­(O)­Ph (P3O) and (2-PPh2C6H4)3P (P4) with respect to d10 copper subgroup metal ions has been investigated. Depolymerization of (MC2R)n (M = Cu, Ag) with P4 affords the series of mono- and trinuclear complexes (P4)­CuC2Ph (1), (P4)­Cu3(C2Ph)3 (2), (P4)­Ag3(C2Ph) (Hal)2 (Hal = Cl (3), Br (4), I (5)). Reactions of the M+ (M = Cu, Ag) ions with (M′C2R)n (M′ = Cu, Ag, Au) acetylides in the presence of P4 yield the family of dinuclear species [(P4)­MM′(C2R)]+ (6–12), which comprise the Cu2/Ag2 (6, 7; R = Ph), AuCu (8–10; R = Ph, C­(OH)­Me2, C­(OH)­Ph2), and AuAg (11, 12; R = Ph, C­(OH)­Ph2) metal cores. A related triphosphine, (2-PPh2C6H4)2PPh (P3), applied in a similar protocol undergoes partial oxidation and leads to the heterotrimetallic clusters [{(P3O)­M}2Au­(C2R)2]+ (M = Cu, R = C­(OH)­Ph2, 13; M = Ag, R = C­(OH)­Ph2, 14; M = Ag, R = Ph, 15), which can be prepared more efficiently starting from the oxidized ligand P3O. The structures of the complexes 1–4 and 6–15 were established by single-crystal X-ray crystallography. According to the variable-temperature 1H and 31P­{1H} NMR experiments, compounds 1–12 demonstrate fluxional behavior in solution. The title complexes do not show appreciable luminescence in solution at 298 K, and the photophysical properties of 1–15 were studied in the solid state. The observed phosphorescence (Φem up to 0.46, λem from 440 to 635 nm) is assigned to cluster-centered transitions mixed with some MLCT d → π*­(alkynyl) character.本研究针对三齿、四齿螯合膦配体(2-PPh₂C₆H₄)₂P(O)Ph（简写为P3O）与(2-PPh₂C₆H₄)₃P（简写为P4），围绕d¹⁰族铜副族金属离子的配位化学展开了系统探究。通过P4对(MC₂R)ₙ（M=Cu、Ag）进行解聚反应，得到一系列单核及三核配合物：(P4)CuC₂Ph（1）、(P4)Cu₃(C₂Ph)₃（2）、(P4)Ag₃(C₂Ph)(Hal)₂（Hal=Cl(3)、Br(4)、I(5)）。在P4存在下，M⁺（M=Cu、Ag）离子与(M′C₂R)ₙ（M′=Cu、Ag、Au）炔化物发生反应，得到一系列双核物种[(P4)MM′(C₂R)]⁺（6~12），其金属核分别为Cu₂/Ag₂（6、7；R=Ph）、AuCu（8~10；R=Ph、C(OH)Me₂、C(OH)Ph₂）以及AuAg（11、12；R=Ph、C(OH)Ph₂）。采用相似实验方案时，相关三膦配体(2-PPh₂C₆H₄)₂PPh（P3）会发生部分氧化，生成异三金属团簇[{(P3O)M}₂Au(C₂R)₂]⁺（M=Cu、R=C(OH)Ph₂，13；M=Ag、R=C(OH)Ph₂，14；M=Ag、R=Ph，15）；该类团簇可通过氧化配体P3O更高效地制备。配合物1~4与6~15的分子结构均通过单晶X射线衍射法得以解析。结合变温¹H与³¹P{¹H}核磁共振（NMR）实验结果，配合物1~12在溶液中表现出流变行为。本研究涉及的标题配合物在298 K的溶液中未表现出显著发光特性，故针对1~15的光物理性质开展了固态测试。实验观测到的磷光（发光量子产率Φem最高可达0.46，发射波长λem范围为440~635 nm）可归因为簇中心跃迁与少量金属到配体电荷转移（MLCT）型d→π*（炔基）电荷转移特征的混合。