Coordination-driven self-assembly of 2D-metallamacrocycles using a new carbazole-based dipyridyl donor: synthesis, characterization, and C60 binding study.

Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore-560 012, India.
Inorganic Chemistry (Impact Factor: 4.79). 04/2012; 51(8):4817-23. DOI: 10.1021/ic300199j
Source: PubMed

ABSTRACT A new carbazole-based 90° dipyridyl donor 3,6-di(4-pyridylethynyl)carbazole (L) containing carbazole-ethynyl functionality is synthesized in reasonable yield using the Sonagashira coupling reaction. Multinuclear NMR, electrospray ionization-mass spectrometry (ESI-MS), including single crystal X-ray diffraction analysis characterized this 90° building unit. The stoichiometry combination of L with several Pd(II)/Pt(II)-based 90° acceptors (1a-1d) yielded [2 + 2] self-assembled metallacycles (2a-2d) under mild conditions in quantitative yields [1a = cis-(dppf)Pd(OTf)(2); 1b = cis-(dppf)Pt(OTf)(2); 1c = cis-(tmen)Pd(NO(3))(2); 1d = 3,6-bis{trans-Pt(C≡C)(PEt(3))(2)(NO(3))}carbazole]. All these macrocycles were characterized by various spectroscopic techniques, and the molecular structure of 2a was unambiguously determined by single crystal X-ray diffraction analysis. Incorporation of ethynyl functionality to the carbazole backbone causes the resulted macrocycles (2a-2d) to be π-electron rich and thereby exhibit strong emission characteristics. The macrocycle 2a has a large internal concave aromatic surface. The fluorescence quenching study suggests that 2a forms a ~1:1 complex with C(60) with a high association constant of K(sv) = 1.0 × 10(5) M(-1).

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    ABSTRACT: Bi(iii) ions are capable of reversible, multicomponent self assembly with suitable tris-coordinate ligands. The nature of the self-assembled structures observed are dependent on the ligand coordination geometry, ligand protonation state and Bi concentration. These assemblies can exploit the maximum number of coordination sites at the Bi vertices (nine), and the self-assembly process has been studied by 1D NMR, Diffusion NMR, ESI-MS and X-ray crystallographic analysis. V-shaped coordinating ligands reversibly form discrete M2L4, M2L3, and M2L2 complexes dependent on ligand/bismuth concentration, whereas a linear coordinating ligand forms a single discrete M3L3 assembly.
    Dalton Transactions 04/2013; · 4.10 Impact Factor


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