Zheng-Zhi Zhang

A highly luminescent tetranuclear copper(I) cluster: Structure and photophysical properties

Abstract A tetranuclear copper(I) cluster Cu4(CCPh)4L2 (1) [L=Ph2PCH2(CH2OCH2)2CH2PPh2] prepared by self assembly reaction of [Cu(CCPh)]n with the bridging diphosphine ligand L comprises a Cu2(L)2 metallomacrocycle with two phenylethynyl copper(I) units encapsulated in the host site. The four Cu(I) are coplanar and arranged as a zigzag chain and the complex displays an intense emission at 522 nm with a lifetime of 9.8 μs and a quantum yield of 0.42 in dichloromethane.

Synthesis and crystal structures of heterobimetallic 2-(diphenylphosphino)-pyridine complexes containing an Fe→M (M = CuI, AgI or HgII) donor–acceptor bond and a mononuclear iron(II) complex bearing a pair of planar strained four-membered chelate rings

Four heterobimetallic Fe–M (M = CuI, AgI or HgII) complexes and a mononuclear iron(II) complex containing a pair of strained planar four-membered chelate rings have been synthesized via the reaction of a neutral organometallic trans-Fe(CO)3(dppy)2 L [dppy = 2-(diphenylphosphino)pyridine] with the corresponding metal perchlorates. Their structures have been determined by single-crystal X-ray analysis. In [CuL(Me2CO)]ClO4·1.75Me2CO 1, [CuL(H2O)]ClO4·CH2Cl22, [AgL(dppy)]ClO4·0.5MeOH 3, [HgL(H2O)(OClO3)]ClO4· 2.5H2O·0.5MeOH 4 and cis-[Fe(CO)2(dppy-P,N)2][ClO4]2·CH2Cl25, the Fe–M (M = Cu, Cu, Ag or Hg) distances are 2.501(2), 2.512(2), 2.760(1) and 2.545(1)A, respectively, unequivocally indicating the existence of a dative Fe→M bond. To our knowledge, 3 is the first binuclear iron(0)–silver(I) donor–acceptor complex to be fully characterized by single-crystal X-ray analysis, and 5 provides the first example of a first-row transition-metal complex which incorporates two planar four-membered chelate rings involving P and N donor atoms.

Binuclear silver(I) complexes with polydentate phosphine ligands 2-(diphenylphosphino)-6-[3-(2′-pyridyl)pyrazol-1-yl]pyridine and 2-(diphenylphosphino)-6-(pyrazol-1-yl)pyridine

The new polydentate, pyridine-based phosphine ligand 2-(diphenylphosphino)-6-[3-(2′-pyridyl)-pyrazol-1-yl]pyridine (L2) has been synthesized. The reaction of L2 with [Ag(MeCN)4][ClO4] resulted in the formation of the binuclear silver(I) complex [Ag2(µ-L2)2(ClO4)2], which is stabilized by significant π–π stacking interactions between its inter-ligand pyridyl fragments. In contrast, the reaction of 2-(diphenylphosphino)-6-(pyrazol-1-yl)pyridine (L1) with [Ag(MeCN)4][ClO4] gave the binuclear complex [Ag2(µ-L1)2(MeCN)2][ClO4]2, which exhibits a weak metal–metal interaction.

Synthesis and reactivity of binuclear copper(I) complexes of 2-(diphenylphosphino)-6-(pyrazol-1-yl)pyridine (L1). Crystal structures of [Cu2(µ-L1)2(MeCN)2][ClO4]2, [Cu2(µ-L1)2(µ-η1-CCPh)][ClO4]· CHCl3·H2O and [Cu2(µ-L1)2(µ-Cl)][ClO4]·H2O

Reaction of 2-(diphenylphosphino)-6-(pyrazol-1-yl)pyridine (L1) with 1 equivalent of [Cu(MeCN)4][ClO4] resulted in the formation of [Cu2(µ-L1)2(MeCN)2][ClO4]2 1. Complex 1 reacted with Li(CCPh) to give [Cu2(µ-L1)2(µ-η1-CCPh)][ClO4] 2, which underwent an alkynyl ligand-transfer reaction with [Pd(PBun3)2Cl2] to give [Cu2(µ-L1)2(µ-Cl)][ClO4] 3 and [Pd(PBun3)2(CCPh)Cl]. Reaction of 1 with dimethyl acetylenedicarboxylate yielded [Cu2(µ-L1)2(µ-MeO2CCCCO2Me)][ClO4]2 4, the alkynyl ligand of which can easily be displaced by bis(diphenylphosphino)methane (dppm) to give [Cu2(µ-L1)2(µ-dppm)][ClO4]2 5. The crystal structures of 1, 2·CHCl3·H2O and 3·H2O have been determined.

Self-assembly of coordination polymeric chains: crystal structures of silver(I) complexes with 3,6-bis(diphenylphosphino)pyridazine and 2,6-bis(diphenylphosphino)pyridine

Site-specific metal–ligand interactions lead to self-assembly of coordination polymeric chains in the crystal structures of silver(I) complexes with 3,6-bis(diphenylphosphino)pyridazine and 2,6-bis(diphenylphosphino)pyridine.