Structural Diversity of Mercury(II) Halide Complexes Containing Bis-pyridyl-bis-amide with Bulky and Angular Backbones: Ligand Effect and Metal Sensing

Abstract

Hg(II) halide complexes [HgCl2] 2L1 [L1 = N,N’-bis(3-pyridyl)bicyclo(2,2,2,)oct-7-ene-2,3,5,6-tetracarboxylic diamide), 1, [HgBr2(L1)]n, 2, [HgI2(L1)], 3, [Hg2X4(L2)2] [X = Cl, 4, Br, 5, and I, 6; L2 = N,N’-bis(4-pyridylmethyl)bicyclo(2,2,2,)oct-7-ene-2,3,5,6-tetracarboxylic diamide] and {[HgX2(L3)]×H2O}n [X = Cl, 7, Br, 8 and I, 9; L3 = 4,4′-oxybis(N-(pyridine-3-yl)benzamide)] are reported and structurally characterized using single-crystal X-ray diffraction analyses. The linear HgCl2 units of complex 1 are interlinked by the L1 ligands through Hg---N and Hg---O interactions, resulting in 1D supramolecular chains. Complex 2 shows 1D zigzag chains interlinked through the Br---Br interactions to form 1D looped supramolecular chains, while the mononuclear [HgI2L2] molecules of 3 are interlinked through Hg---O and I---I interactions, forming 2D supramolecular layers. Complexes 4–6 are isomorphous dinuclear metallocycles, and 7–9 form isomorphous 1D zigzag chains. The roles of the ligand type and the halide anion in determining the structural diversity of 1–9 is discussed and the luminescent properties of 7–9 evaluated. Complexes 7–9 manifest stability in aqueous environments. Moreover, complexes 7 and 8 show good sensing towards Fe3+ ions with low detection limits and good reusability up to five cycles, revealing that the Hg-X---Fe3+ (X = Cl and Br) interaction may have an important role in determining the quenching effect of 7 and 8.

Formation of entangled Co(ii) coordination polymers based on bis-pyridyl-bis-amide and angular dicarboxylate ligands: a structural comparison

“…The reagents 4,4′-sulfonyldibenzoic (H 2 SDA) and 4,4-(hexafluoroisopropylidene)-bis(benzoic acid) (H 2 HFIPBB) were purchased from Aldrich Chemistry Co., 4,4′-oxybis(benzoic acid) (H 2 OBA) and Co(OAc) 2 ·4H 2 O from Alfa Aesar Co., and diphenylmethane-4,4′-dicarboxylic acid (H 2 MBA) from Matrix Scientific Co. The ligands N , N ′-di(4-pyridyl)sebacoamide ( L 1 ), 11 N , N ′-bis(4-pyridylmethyl)bicyclo(2,2,2,)oct-7-ene-2,3,5,6-tetracarboxylic diamide ( L 2 ), 12,13 and N , N ′-di(4-pyridyl)adipoamide ( L 3 ) 11 were prepared according to published procedures.…”

Flexible Co(II)-and Ni(II)-Based Cationic 2D Metal–Organic Frameworks Based on a Charge-Neutral (O,O)-Donor Bridge

“…Electroneutrality is a rather rare feature of polytopic (O,O)-donor bridges in polymeric coordination networks. Such uncharged bridging ligand classes as polyethers [11], carbohydrates [12,13], cyclodextrins [14,15], and different type polyamides [16,17], including cucurbit[n]urils [18], are mainly represented by alkali and alkaline earth metal-based cationic networks in MOF chemistry, with an accordingly limited range of functional properties.…”

Synthesis, Structural Versatility, Magnetic Properties, and I− Adsorption in a Series of Cobalt(II) Metal–Organic Frameworks with a Charge-Neutral Aliphatic (O,O)-Donor Bridge

“…The typical design of positively charged porous MOFs involves the connection of metal cations by charge-neutral organic molecule linkers. The vast majority of such linkers is represented by N-donor heterocycles, such as 4,4 -bipyridyl or dabco [27][28][29], whereas the O-donor neutral carbohydrate molecules [30][31][32], polyethers [33], and amide derivatives [34][35][36] rarely afford stable MOF structures except for the those based on strongly oxophilic metal cations. N-oxide molecules feature a substantial negative charge on oxygen atoms [37,38], which makes them stronger than N-donor ligands and attractive linkers for the design of chemically stable and robust cationic frameworks based on metal cations of different natures [39][40][41][42].…”