Man-Sheng Chen

Reversible Single-Crystal-to-Single-Crystal Transformation and Highly Selective Adsorption Property of Three-Dimensional Cobalt(II) Frameworks

A three-dimensional (3D) coordination polymer, [Co(3)(L)(2)(BTEC)(H(2)O)(2)]·2H(2)O [1, HL = 3,5-di(imidazol-1-yl)benzoic acid, H(4)BTEC = 1,2,4,5-benzenetetracarboxylic acid], with tfz-d topology has been hydrothermally synthesized. The framework of 1 has high thermal stability and exhibits single-crystal-to-single-crystal (SCSC) transformations upon removing and rebinding the noncoordinated and coordinated water molecules. X-ray crystallographic analyses revealed that the coordination geometry of Co(II) changes from octahedral to square pyramid upon dehydration, accompanying the appearance of one-dimensional (1D) open channels with dimensions of 2.0 × 2.8 Å. The dehydrated form [Co(3)(L)(2)(BTEC)] (2) exhibits highly selective adsorption of water molecules over N(2), CH(3)OH, and CH(3)CH(2)OH, which could be used as sensors for water molecules. Furthermore, the magnetic properties of 1 and 2 were investigated, showing the existence of ferromagnetic interaction between the Co(II) atoms within the trinuclear subunit.

Spontaneous resolution of two homochiral ferroelectric cadmium(II) frameworks and an achiral framework from a one-pot reaction involving achiral rigid ligands

Unprecedented two homochiral Cd(II) enantiomers and one achiral Cd(II) complex obtained from one pot reaction with achiral mixed rigid ligands 1,3,5-tris(1-imidazolyl)benzene (tib) and 1,4-benzenedicarboxylate (BDC2−) feature interesting entangled structures in which the ligands display huge distortion, and the homochiral enantiomers show ferroelectric property.

Cadmium(II) complexes with 3,5-di(1H-imidazol-1-yl)benzoate: topological and structural diversity tuned by counteranions

Four new coordination polymers [Cd(L)(OAc)]·H2O (1), [Cd(L)(µ2-OH)]·H2O (2), [Cd2(L)2(µ3-SO4)(H2O)2]·5H2O (3) and [Cd(L)2]·H2O (4) with different structures and topologies were obtained by solvo/hydrothermal reactions of varied Cd(II) salts with 3,5-di(1H-imidazol-1-yl)benzoic acid (HL) and 1,3-bis(4-pyridyl)propane (bpp). The structures of 1–4 were characterized by single-crystal X-ray diffraction analysis and the results showed that no bpp ligands were incorporated in the resulting complexes, and more interestingly, complexes 1–3 were obtained by reactions of metal to ligand ratio of 1:1, however, when the reactions were carried out with a metal to ligand ratio of 1:2, the resulting complexes had the same structure, namely [Cd(L)2]·H2O (4). In contrast to the 2D network with 63-hcb topology of complex 1 with acetate as terminal ligand, complex 2 is a 3D (4,6)-connected net with µ2-hydroxyl bridging group. Complex 3 is an unprecedented 3D self-penetrating (3,4,5)-connected net with each sulfate as a µ3-bridge to link three Cd(II) atoms, and complex 4 is a 3D self-penetrating (3,5)-connected net formed by two alternate chiral helical chains linking 2-fold interpenetrating 2D (4,82) nets. The results showed that the L− ligand has varied coordination modes and the counteranions have a great impact on the structure of the complexes.

Metal–organic frameworks with six- and four-fold interpenetration and their photoluminescence and adsorption property

Three-dimensional interpenetrated metal–organic frameworks (MOFs) {[ZnL2]·4H2O}n (1) and {[Cu(HL)2(H2O)2]Cl2}n (2) were synthesized by reactions of the corresponding metal salt and 1-(imidazol-1-yl)-4-(imidazol-4-yl)benzene (HL) with and without addition of sodium hydroxide, respectively. Complex 1 is a 6-fold interpenetrated porous 66dia framework filled with water molecules, in which the metal atom has distorted tetrahedral coordination geometry and the ligand was deprotonated. While complex 2 with octahedral Cu(II) is a 4-fold interpenetrated dia framework with chloride as counteranions and no deprotonation of the ligand occurred. In addition, the stability, photoluminescence and the adsorption properties of the complexes were studied.

Synthesis and characterization of metal complexes with a mixed 4-imidazole-containing ligand and a variety of multi-carboxylic acids

Six new metal–organic coordination polymers [Ni(L)(adip)(H2O)] (1), [Co(L)(adip)]·H2O (2), [Cd2(L)(adip)2] (3), [Ni(L)(oxba)]·H2O (4), [Co(L)(obea)]·H2O (5) and [Mn3(L)2(bta)2]·2H2O (6) were synthesized by reactions of the corresponding metal salt with the rigid ligand 1,4-di(1H-imidazol-4-yl)benzene (L) and different multi-carboxylic acids of adipic acid (H2adip), 4,4′-oxybis(benzoic acid) (H2oxba), 1,2-phenylenediacetic acid (H2obea), benzene-1,3,5-triacetic acid (H3bta), respectively. The structures of the complexes were determined by single crystal X-ray diffraction analysis. Complexes 1–4 have entangled structures with different topologies: 1 is a 2-fold interpenetrating two-dimensional (2D) network with (4,4) topology containing rare meso-helical chains; 3 is a three-dimensional (3D) uninodal 8-connected self-penetrating net; 2 and 4 are a 3-fold interpenetrating dmp 3D net. Complex 5 is a 2D network with (4,4) topology, while 6 is a typical (3,8)-connected tfz-d 3D net based on the trinuclear Mn(II) subunits. Complex 3 exhibits intense light blue emission in the solid state at room temperature and the results of magnetic measurements show that there are antiferromagnetic interactions in 6.

A series of silver(I)–lanthanide(III) heterometallic coordination polymers: syntheses, structures and photoluminescent properties

A series of new 4d–4f heterometallic coordination complexes based on 5-(4H-1,2,4-triazol-4-yl)benzene-1,3-dicarboxylic acid (H2L), namely [AgLn(L)2(H2O)4] [Ln = Nd (1), Eu (2) and Tb (3)], [AgLn(L)2] [Ln = Nd (4), Eu (5) and Tb (6)] and [AgLn(L)2(H2O)]·H2O [Ln = Er (7) and Yb (8)] were successfully synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR, elemental and thermogravimetric analyses. Complexes 1–3 consist of two-dimensional (2D) networks, which are further connected by hydrogen bonding and π–π interactions to give three-dimensional (3D) frameworks. Complexes 4–6 display a 3D (4,6)-connected framework containing 2D heterometallic bilayers. Complexes 7 and 8 are 3-fold interpenetrated (3,4,6)-connected 3D frameworks. The results show that the reaction temperature and the lanthanide have great influence on the structure of the complexes. Luminescent measurements revealed that 2, 3, 5 and 6 exhibit the characteristic emission bands of the lanthanide in the visible region with lifetimes in the range of 0.24–1.81 ms and the strongest emissions are 5D0 → 7F2 for 2 and 5, and 5D4 → 7F5 transitions for 3 and 6.

Three-dimensional lanthanide–silver heterometallic coordination polymers: syntheses, structures and properties

Assembly reactions of 5-(isonicotinamido)isophthalic acid (H2INAIP) with Ln2O3 or Ln(NO3)3·6H2O together with NaOH in the presence of AgNO3 result in formation of two series of new 4d–4f heterometallic coordination polymers {[LnAg(INAIP)2]·3H2O}n [Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5)] and {[LnAg(INAIP)2(H2O)]·xH2O}n [Ln = La (6), Pr (7), Nd (8), x = 0; Dy (9), Er (10), x = 1]. The results of single-crystal X-ray diffraction analysis indicate that 1–5 are isomorphous and have 2-fold interpenetrated 3D structure with 3-nodal net Point (Schlafli) symbol for net: (4·62)4(44·66·815·103), while 6–10 are isostructural with similar non-interpenetrating 3D frameworks containing 2D lanthanide–carboxylate bilayers. The results indicate that the reaction conditions have great influence on the structure of the resulting complexes in this system. Furthermore, 3 and 5 show intense red and green fluorescent emissions, respectively, and the emission bands of Nd(III) were observed in the near IR region for 1. The magnetic properties of 1–5, 9 and 10 were investigated.

Metal–organic frameworks with pyridyl- and carboxylate-containing ligands: syntheses, structures and properties

Assembly reactions of pyridyl- and carboxylate-containing ligand 5-(isonicotinamido)isophthalic acid (H2INAIP) with corresponding metal salts result in formation of six new coordination polymers, namely {[Mn(INAIP)(DMF)]·0.5DMF}n (1), {[Mn(INAIP)(H2O)2]·4H2O}n (2), {[Co(INAIP)(H2O)]·2H2O}n (3), {[Co(INAIP)(bpy)0.5]}n (4), {[Co(INAIP)(Him)(H2O)]·H2O}n (5), and {[Cu(INAIP)(Him)(H2O)]·H2O}n (6) (DMF = N,N-dimethylformamide, bpy = 4,4′-bipyridine, Him = imidazole). The results of single-crystal X-ray diffraction analysis indicate that 1 is a two-fold interpenetrated three-dimensional (3D) framework with sra topology, complexes 2, 5 and 6 have two-dimensional (2D) network structure with (6,3) topology, while 3 and 4 have infinite 2D bi-layer structure with different topologies. Complex 3 exhibits a 4-connected network with the Schlafli symbol (43·63), and 4 displays a (4,5)-connected net with Schlafli symbol (43·52·6)(43·55·62). The magnetic and adsorption properties of the complexes were investigated.

Three-dimensional 3d-4f heterometallic coordination polymers: syntheses, structures and properties

Six new 3d-4f heterometallic coordination polymers, {[Ln4Cu2(INAIP)8(H2O)15]·14H2O}n [Ln = La (1), Pr (2), Nd (3)] and {[LnCo0.5(INAIP)2(H2O)2]·2H2O}n [Ln = Tb (4), Dy (5), Yb (6), H2INAIP = 5-(isonicotinamido)isophthalic acid] have been synthesised and characterised by single crystal X-ray diffraction analysis. The results of structural analyses showed that 1–3 are isomorphous showing two-fold interpenetrated three-dimensional (3D) coordination framework, while 4–6 have the same non-interpenetrated 3D structure with 2D (4, 4) lanthanide-carboxylate layers. The results revealed that the different transition metal centres have great influence on the structures of the resulted complexes in this system. In addition, thermogravimetric and magnetic properties of 1–6, and photoluminescence of 4 were investigated.

Syntheses and crystal structures of two supramolecular isomers of manganese(II) with 3,5-bis(isonicotinamido)benzoate

Two new supramolecular isomeric complexes [Mn(BBA)2(H2O)2] n · 4nH2O (1) and [Mn(BBA)2(H2O)2] · 4H2O (2) were obtained by hydrothermal reactions of MnCl2 · 4H2O with 3,5-bis(isonicotinamido)benzoic acid (HBBA) under different ratio of NaOH/HBBA. Complex 1 is a 1-D zigzag chain in which the Mn(II) is six-coordinate with distorted octahedral geometry. The 1-D chains are further connected by hydrogen bonds to give a 3-D supramolecular framework. Complex 2 is a monomeric molecular complex, assembled through intermolecular hydrogen bonds into a 3-D supramolecular network. Reaction conditions have remarkable influence on the structures of the complexes. The thermal and non-linear optical properties of the complexes were studied.