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Wei QH, Yin GQ, Zhang LY, Shi LX, Mao ZW, Chen ZN: Luminescent Ag i-Cu i heterometallic hexa-, octa-, and hexadecanuclear alkynyl complexes. Inorg Chem. 2004 May 31;43(11):3484-91.
A series of Ag (I)-Cu (I) heteronuclear alkynyl complexes were prepared by reaction of polymeric (MCCC (6) H (4) R-4)(n)() (M = Cu (I) or Ag (I); R = H, CH (3), OCH (3), NO (2), COCH (3)) with [M'(2)(mu-Ph (2) PXPPh (2))(2)(MeCN)(2)](ClO (4))(2) (M' = Ag (I) or Cu (I); X = NH or CH (2)). Heterohexanuclear complexes [Ag (4) Cu (2)(mu-Ph (2) PNHPPh (2))(4)(CCC (6) H (4) R-4)(4)](ClO (4))(2) (R = H, 1; CH (3), 2) were afforded when X = NH, and heterooctanuclear complexes [Ag (6) Cu (2)(micro-Ph (2) PCH (2) PPh (2))(3)(CCC (6) H (4) R-4)(6)(MeCN)](ClO (4))(2 ) (R = H, 3; CH (3), 4; OCH (3), 5; NO (2), 6) were isolated when X = CH (2). Self-assembly reaction between (MCCC (6) H (4) COCH (3)-4)(n) and [M'(2)(mu-Ph (2) PCH (2) PPh (2))(2)(MeCN)(2)](ClO (4))(2), however, gave heterohexadecanuclear complex [Ag (6) Cu (2)(micro-Ph (2) PCH (2) PPh (2))(3)(CCC (6) H (4) COCH (3)-4)(6)](2)(ClO (4) )(4) (7). The heterohexanuclear complexes 1 and 2 show a bicapped cubic skeleton (Ag (4) Cu (2) C (4)) consisting of four Ag (I) and two Cu (I) atoms and four acetylide C donors. The heterooctanuclear complexes 3-6 exhibit a waterwheel-like structure that can be regarded as two Ag (3) Cu (CCC (6) H (5))(3) components put together by three bridging Ph (2) PCH (2) PPh (2) ligands. The heterohexadecanuclear complex 7 can be viewed as a dimer of heterooctanuclear complex [Ag (6) Cu (2)(micro-Ph (2) PCH (2) PPh (2))(3)(CCC (6) H (4) COCH (3)-4)(6)](ClO (4))(2 ) through the silver and acetyl oxygen (Ag-O = 2.534 (4) A) linkage between two waterwheel-like Ag (6) Cu (2) units. All of the complexes show intense luminescence in the solid states and in fluid solutions. The microsecond scale of lifetimes in the solid state at 298 K reveals that the emission is phosphorescent in nature. The emissive state in compounds 1-5 is likely derived from a (3) LMCT (CCC (6) H (4) R-4 --> Ag (4) Cu (2) or Ag (6) Cu (2)) transition, mixed with a metal cluster-centered (d --> s) excited state. The lowest lying excited state in compounds 6 and 7 containing electron-deficient 4-nitrophenylacetylide and 4-acetylphenylacetylide, respectively, however, is likely dominated by an intraligand (3)[pi --> pi] character. |
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