Xiao-Long Feng

Three-dimensional lanthanide anionic metal-organic frameworks with tunable luminescent properties induced by cation exchange.

Three 3D lanthanide anionic metal-organic frameworks {K(5)[Ln(5)(IDC)(4)(ox)(4)]}(n) x (20H(2)O)(n) with 1D channels were synthesized under hydrothermal conditions [Ln = Gd (1), Tb (2), and Dy (3)]. The K(+) ions within the 1D channel are easily exchanged with various cations. The emission intensities of Tb(III) in 2 increased significantly upon the addition of Ca(2+) ions, while the introduction of other metal ions caused the intensities to be either unchanged or weakened.

Spontaneous resolution of a racemic nickel(II) complex and helicity induction via hydrogen bonding: the effect of chiral building blocks on the helicity of one-dimensional chains.

The reactions of a racemic four-coordinated nickel(II) complex [Ni(alpha-rac-L)](ClO4)2 (containing equal amount of SS and RR enantiomers) with l- and d-phenylalanine in acetonitrile/water gave two less-soluble six-coordinated enantiomers of {[Ni( f-SS-L)(l-Phe)](ClO4)}n (Delta-1) and {[Ni(f- RR-L)(d-Phe)](ClO4)}n (Lambda-1), respectively. Evaporation the remaining solutions gave two six-coordinated diastereomers of {[Ni 3(f- RR-L)3(l-Phe)2(H 2O)](ClO4)4}n (a-2) and {[Ni3(f- SS-L)3(d-Phe)2(H2O)](ClO4)4}n (b-2), respectively (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, Phe(-) = phenylalanine anion). The reaction of [Ni(alpha-rac-L)](ClO4)2 with dl-Phe(-) gave a conglomerate of c-1; in which, the SS and RR enantiomers preferentially coordinate to l- and d-Phe(-) respectively to give a racemic mixture of Delta-1 and Lambda-1, and the spontaneous resolution occurs during the reaction, in which each crystal crystallizes to become enantiopure. Removing Phe(-) from Delta-1 and Lambda-1 using perchloric acid gave two enantiomers of [Ni(alpha-SS-L)](ClO4)2 (S-3) and [Ni(alpha-RR-L)](ClO4)2 (R-3). Dissolving S-3 and R-3 in acetonitrile gave two six-coordinated enantiomers of [Ni( f-SS-L)(CH3CN)2](ClO4)2 (S-4) and [Ni( f- RR-L)(CH3CN)2](ClO4)2 (R-4), while dissolving [Ni(alpha-rac-L)](ClO4)2 in acetonitrile gave a racemic twining complex [Ni(f-rac-L)(CH3CN)2](ClO4)2 (rac-4). Delta-1 and Lambda-1 belong to supramolecular stereoisomers, which are constructed via hydrogen bond linking of [Ni( f-SS-L)(l-Phe)](+) and [Ni(f-RR-L)(d-Phe)](+) monomers to form 1D homochiral right-handed and left-handed helical chains, respectively. The reaction of S-3 with d-Phe(-) gave {[Ni(f-SS-L)(d-Phe)](ClO4)}n (5), which shows a motif of a 1D hydrogen bonded zigzag chain instead of a 1D helical chain. Compound a-2/ b-2 contains dimers of [{Ni(f-RR-L)}2(l-Phe)(H2O)](3+)/[{Ni( f- SS-L)}2(d-Phe)(H2O)](3+) and 1D zigzag chains of {[Ni(f-RR-L)(l-Phe)](+)}n /{[Ni(f-SS-L)(d-Phe)](+) n . The homochiral nature of Delta-1/Lambda-1, a-2/b-2, S-3/R-3, and S-4/R-4 are confirmed by the results of circular dichroism (CD) spectra measurements.

Solid-state structures of group 1 and group 2 metal 1,5-naphthalenedisulfonates: systematic investigation of lamellar three-dimensional networks constructed by metal arenedisulfonate

Seven Group 1 and Group 2 1,5-naphthalenedisulfonates (1,5-nds) have been synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectroscopy and thermal gravimetric analysis. For Group 1 metal complexes, with M = Li(+) (1), Na(+) (2) and K(+) (3), all crystallize in the same space group (P2(1)/c) with the same composition, [M(2)(1,5-nds)(H(2)O)(2)]. They adopt similar three-dimensional packing arrangements with the metal-sulfonate inorganic layers pillared by naphthalene rings. However, the coordination behavior of three metal cations toward the SO(3)(-) group and water molecule are different, resulting in different architectures for the inorganic portion. For Group 2 complexes with M = Mg(2+) (4), Ca(2+) (5), Sr(2+) (6) and Ba(2+) (7), Mg(2+) shows no direct coordination by the SO(3)(-) group while Ca(2+) is coordinated by four SO(3)(-) groups and a two-dimensional network is formed. Complexes (6) and (7) are isostructural, adopting the same three-dimensional, inorganic-organic pillared framework as seen for (1)-(3). The coordination behavior of the metal cations in these structures neatly illustrates the increase in coordination strength with decreasing charge/radius ratio for Group 1 and Group 2 metal cations with large organic anions.

The Supramolecular Isomerism Based on Argentophilic Interactions: The Construction of Helical Chains with Defined Right-Handed and Left-Handed Helicity

The reactions of racemic and enantiopure macrocyclic compounds [Ni(alpha-rac-L)](ClO(4))(2) (containing equal amounts of SS and RR enantiomers), [Ni(alpha-SS-L)](ClO(4))(2), and [Ni(alpha-RR-L)](ClO(4))(2) with K[Ag(CN)(2)] in acetonitrile/water afford three 1D helical chains of {[Ni(f-rac-L)][Ag(CN)(2)](2)}(n) (1), {[Ni(f-SS-L)](2)[Ag(CN)(2)](4)}(n) (Delta-2), and {[Ni(f-RR-L)](2)[Ag(CN)(2)](4)}(n) (Lambda-2); one dimer of [Ni(f-rac-L)][Ag(CN)(2)](2) (3); and one trimer of [Ni(f-rac-L)Ag(CN)(2)](3).(ClO(4))(3) (4) (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). Compounds 1, Delta-2, Lambda-2, and 3, which are supramolecular isomers, are constructed via argentophilic interactions. In 1, [Ni(f-RR-L)][Ag(CN)(2)](2) enantiomers alternately connect with [Ni(f-SS-L)][Ag(CN)(2)](2) enantiomers through intermolecular argentophilic interactions to form a 1D meso-helical chain, and the 1D chains are further connected through the interchain hydrogen bonds to generate a 2D network. When chiral [Ni(alpha-SS-L)](ClO(4))(2) and [Ni(alpha-RR-L)](ClO(4))(2) were used as building blocks, two supramolecular stereoisomers of Delta-2 and Lambda-2 were obtained, which show the motif of homochiral right-handed and left-handed helical chains, respectively, and the 1D homochiral helical chains are linked by the interchain hydrogen bonds to form a 3D structure. In 3, a pair of enantiomers of [Ni(f-RR-L)][Ag(CN)(2)](2) and [Ni(f-SS-L)][Ag(CN)(2)](2) connect with each other through intermolecular argentophilic interactions to form a dimer. The reaction of [Ni(alpha-rac-L)](ClO(4))(2) with K[Ag(CN)(2)] in acetonitrile gives a trimer of 4; each trimer is chiral with unsymmetrical RR, RR, and SS, or RR, SS, and SS configurations. The homochiral nature of Delta-2 and Lambda-2 was confirmed by the results of solid circular dichroism spectra measurements. The solid samples of 1-4 show strong fluorescent emissions at room temperature.

Synthesis and crystal structures of four nickel(II) 1,5-naphthalenedisulfonate compounds

AbstractFour nickle(II) 1,5-naphthalenedisulfonate (1,5nds) complexes, namely [Ni(H2O)6] (1,5nds) (1), trans-[Ni(en)2(H2O)2](1,5nds)·2H2O (2), [Ni(tren)(H2O)2](1,5nds)·H2O (3), and [Ni(dien)2](1,5nds)·2H2O (4), where en = ethylenediamine, tren = tris(2-aminoethyl)amine, and dien = diethylenetriamine, have been synthesized and structurally characterized. Compound 1 crystallizes in space group P21/c, with a = 13.200(2) Å, b = 6.6197(10) Å, c = 9.6001(14) Å, and β = 92.005(3)° compound 2 crystallizes in space group C2/c, with a = 15.698(2) Å, b = 13.006(2) Å, c = 12.845(2) Å, and β = 119.262(4) Å compound 3 crystallizes in space group P

Anion Recognition of Chloride and Bromide by a Rigid Dicobalt(II) Cryptate

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Synthesis and crystal structure of photoluminescent copper(I)–phosphine complexes with oxygen and nitrogen donor ligands

, with a = 8.8971(10) Å, b = 11.5440(13) Å, c = 11.9169(14) Å, α = 77.254(2)°, β = 74.079(2)°, and γ = 82.162(2)° compound 4 crystallizes in space group P21/c, with a = 10.3600(13) Å, b = 12.5650(16) Å, c = 9.9853(12) Å, and β = 103.599(2)°. Compound 1 crystallizes in a typical inorganic–organic layered structure adopted by metal naphthalenesulfonate, while compounds 2–4 crystallize in a hybrid inorganic–organic pattern. Unlike their Cu2+ analogue, the sulfonate does not coordinate directly to Ni2+. The hydrogen bonds formed between sulfonate and water molecules are the predominant packing forces for all structures. The inherited inversion center of the 1,5nds anion is carried into the crystal structure and results in centrosymmetric crystallization of all compounds.

Assembly chemistry of a cadmium(II) complex with cyanometalate anions [Fe(CN)5NO]2−, [Pd(CN)4]2− and [Pt(CN)6]2−

Abstract The solvothermal reaction of norfloxacin (H-Norf) with [Cu(MeCN)2(PPh3)]·ClO4 yields a mixed-ligand complex [Cu(PPh3)2(H-Norf)]·ClO4 1 which is characterized by single crystal X-ray determination, IR, far-IR and solid state 31 PNMR as well as fluorescent spectrum. Crystallographic data for 1, C52H48ClCuFN3O7P2, triclinic P-1 (No. 2), a=10.0434 (15) , b=13.5111 (17) , c=16.651 (2) A, α=97.478 (2)° , β=93.610 (2)° , γ=115.928 (2)° . Fw=1006.86, Z=2, V=2394.1 (5) A 3 , R1=0.0473, wR2=0.1155, S=0.735.