Chun-Wei Yeh

Adjusting the frameworks of polymeric silver(I) complexes with 2-aminopyrimidyl ligands by changing the counterions

The complexes [Ag2(L)2(SO4)]∞, (L = 2-aminopyrimidine) 1, [Ag(L)1.5(ClO4)]∞, 2, and [Ag(L)(OAc)·2H2O]∞, 3, were prepared by layering the aqueous solution of the corresponding Ag(I) salt with L in ethanol, while [Ag(L′)(NO3)]∞, 4, and [Ag(L′)(ClO4)·H2O]∞, 5, were prepared by refluxing AgNO3 and AgClO4, respectively, with 2-amino-4,6-dimethylpyrimidine (L′) in H2O. Reaction of Ag2SO4 with L′ in methanol afforded the complex [Ag4(L′)2(SO4)2(H2O)4]∞, 6. In complex 1, the L ligands are coordinated to the Ag(I) metal centers in new tridentate fashions, forming 2-D pleated molecular sheets which are interlinked by the SO42− anions to form a 3-D layer structure. Complex 2 forms a pleated molecular sheet consisting of twenty four-membered metallocycles, involving six Ag ions which are bridged by six L ligands through the pyrimidyl nitrogen atoms. Complex 3 forms linear chains with sinusoidal geometry, which are interlinked through extensive Ag⋯Ag interactions (Ag⋯Ag = 3.102 A) to form 2-D wavy rectangular grids. Complex 4 forms single-strained helical coordination polymers, which are interlinked through a series of Ag⋯O interactions (2.667 and 2.699 A) to form 2-D chair like grids. The silver atoms of 5 are bound to the nitrogen atoms of two symmetry-related L′ ligands in a distinctly non-linear geometry, forming zigzag chains. The structure of 6 consists of clusters of the formula [Ag8(L′)4(SO4)4(H2O)8], which are interlinked through L′ ligands to form 2-D sheets. The μ1-O, μ2-O′- bonding mode of the SO42− anion in complex 6 is unique for Ag(I) complexes. Their thermal properties have been investigated by using differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA)

Ligand isomerism-controlled structural diversity of cadmium(II) perchlorate coordination polymers containing dipyridyladipoamide ligands

The syntheses, structures and ligand conformations of three Cd(II) coordination polymers [Cd(L1)(ClO4)2]∞ [L1 = N,N′-di(2-pyridyl)adipoamide], 1, {[Cd(L2)2(CH3OH)2](ClO4)2·2CH3OH}∞ [L2 = N,N′-di(3-pyridyl)adipoamide], 2 and [Cd(L3)2(ClO4)2(CH3CH2OH)2]∞ [L3 = N,N′-di(4-pyridyl)adipoamide], 3, are reported. Their structures have been characterized by X-ray crystallography. Complex 1 forms 1D zigzag chains, while complex 2 forms 2D pleated sheets which are positioned in an ABAB manner. Complex 3 shows a rare 3D entanglement from parallel polycatenation of 3-fold interpenetrated square layers. While the L1 ligands in 1 adopt AAAtrans conformations and the L2 ligands in 2 adopt GAGtrans conformations, the L3 ligands in 3 adopt AAAtrans and AGAtrans conformations. The structural types of the Cd(II) coordination polymers can be directed by ligand isomerism.

Interpenetrated and polycatenated nets of Cd(II) coordination networks from mixed N,N′-dipyridyladipoamide and dicarboxylate ligands

The synthesis, structures and properties of five Cd(II) coordination networks: [Cd(bpdc)(L1)]n [L1 = N,N′-di(4-pyridyl)adipoamide; H2bpdc = 4,4′-biphenyldicarboxylic acid], 1; {[Cd2(1,4-ndc)2(L1)2(H2O)]·H2O·2DMF}n (1,4-H2ndc = naphthalene-1,4-dicarboxylic acid), 2; {[Cd(OBA)(L1)]·2H2O}n [H2OBA = 4,4′-oxybis(benzoic acid)], 3; {[Cd(SDA)(L1)]·1.5H2O}n (H2SDA = 4,4′-sulfonyldibenzoic acid), 4; and {[Cd(1,4-ndc)(L2)(H2O)]·2H2O}n [L2 = N,N′-di(3-pyridyl)adipoamide], 5, are reported. Complexes 1 and 2 show the pcu and fsd topologies with 2- and 3-fold interpenetrating modes, respectively, and complex 4 exhibits a 2-fold 2D → 2D parallel interpenetration network containing a rotaxane-like motif. Complex 3 is a 1D → 2D polycatenane derived from the helical channels, and the 2D layers are further mutually interdigitated, whereas complex 5 is a 2D → 3D polycatenane based on the undulating sql sheets. These five complexes show different thermal and luminescent properties and the CO2 capture is preferable to N2 in the gas sorption for the desolvated product of 1.

Roles of I⋯I and Ag⋯I interactions on the self-assembly of Ag(I) complexes containing 2-amino-5-iodopyrimidine; formation of the unique Ag⋯I⋯I⋯Ag interaction

A series of silver(I) complexes [Ag(L)(NO3)]4, (L = 2-amino-5-iodopyrimidine), 1, [Ag(L)(PF6)]∞, 2, and [Ag(L)(ClO4)]∞, 3, have been prepared by the reactions of AgX (X = NO3−, PF6− and ClO4−, respectively) with L. All the complexes have been structurally characterized by X-ray crystallography, confirming that complex 1 forms sixteen–membered metallocycles interlinked by I⋯I and Ag⋯O interactions to create a porous structure. Complexes 2 and 3 form helical chains, with different periods of 22.584 and 11.465 A, respectively. In addition to the Ag⋯O interaction and hydrogen bonds, the unique discrete Ag⋯I⋯I⋯Ag and linear ⋯(Ag⋯I⋯I⋯Ag)n⋯ interactions with short I⋯I and Ag⋯I contacts were found in complexes 2 and 3, respectively, to support their supramolecular structures.

Roles of halide anions in the structural diversity of Zn(II) complexes containing the flexible N,N′-di(4-pyridyl)adipoamide ligand

A series of Zn(II) complexes with N,N′-di(4-pyridyl)adipoamide ligands, {[ZnX2(L)]·H2O}∞ (X = Cl, 1, Br, 2 and I, 3; L = N,N′-di(4-pyridyl)adipoamide), [Zn2X4(L)2]·2DMF (X = Cl, 4 and Br, 5) and [Zn2I4(L)2]·4DMF·C4H10O, 6, were prepared and their structures determined by X-ray crystallography. Complexes 1 and 2 form double-stranded helical chains which are supported by the N–H⋯O and O–H⋯X hydrogen bonds involving the guest water molecules and the halide anions, whereas 3 shows sinusoidal chains which are interlinked by the N–H⋯O hydrogen bonds and π–π interactions. Complexes 1–3 represent a unique example that the halide anions show significant effect on folding and unfolding of the Zn(II) double-stranded helical coordination polymers. Complexes 1–3 can be transformed to the corresponding complexes 4–6, which are dinuclear with 34-membered metallocycles. In these complexes, the chloride and bromide anions play the same role in the crystal structures, while the iodide anion is distinct.

Diverse Ag(I) complexes constructed from asymmetric pyridyl and pyrimidyl amide ligands: roles of Ag⋯Ag and π–π interactions

Reactions of silver(I) salts with the isomeric pyridyl amide ligands methyl-4-(pyridin-2-ylcarbamoyl)benzoate (L1), methyl-4-(pyridin-3-ylcarbamoyl)benzoate (L2) and methyl-4-(pyridin-4-ylcarbamoyl)benzoate (L3) and the pyrimidyl amide ligand methyl-4-(pyrimidin-2-ylcarbamoyl)benzoate (L4) afforded the complexes Ag4(L1)4(NO3)4, 1, [Ag(L2)2][Ag(NO3)2], 2, [Ag(L2)2](ClO4), 3, [Ag(L2)2](ClO4)·2CH3CN, 4, [Ag(L3)2](NO3), 5, [Ag(L3)2](ClO4)·CH3CN, 6, and [Ag(L4)2](X) (X = ClO4−, 7; BF4−, 8; PF6−, 9), which were structurally characterized by X-ray crystallography. The L1–L3 ligands in 1–6 adopt monodentate bonding modes, which coordinate to the metal centers through the pyridyl nitrogen atoms, whereas the L4 ligands of 7–9 adopt a bidentate mode, featuring chelation through one pyrimidyl nitrogen atom and the amide oxygen atom. All nine complexes adopt discrete structures with 1 being tetranuclear and 2–9 being mononuclear. Moreover, Ag⋯Ag short contacts, π⋯π stacking interactions and/or Ag⋯O interactions are found in these complexes which extend the dimensionalities of the structures. The changes of the donor atom positions and counteranions significantly affect the supramolecular structures of these complexes and the L1–L4 ligands are sufficiently flexible to adopt the cis and/or trans conformations.

Self-assembly of two-dimensional coordination polymers from AgX (X = BF4−, ClO4−, NO3− and PF6−) and 2,6-dimethyl-3,5-dicyano-4-(6-methyl-2-pyridyl)-1,4-dihydropyridine

Novel supramolecules of Ag(I) complexes of the type [Ag(2-ddph)][X] (2-ddph = 2,6-dimethyl-3,5-dicyano-4-(6-methyl-2-pyridyl)-1,4-dihydropyridine; X = BF4−, 1, ClO4−, 2, NO3−, 3 and PF6−, 4) have been prepared by self-assembly of AgX with 2,6-dimethyl-3,5-dicyano-4-(6-methyl-2-pyridyl)-1,4-dihydropyridine (2-ddph) in MeOH–H2O. The elemental analyses and IR have been recorded and all the complexes have been structurally characterized by X-ray crystallography confirming that complexes 1–4 are two-dimensional coordination polymers. The anions BF4− and PF6− in complexes 1 and 4 are not coordinated to the Ag(I) atoms while the ClO4− and NO3− anions in 2 and 3 are coordinated to the metal centers through a monodentate oxygen atom. Complexes 1–3 show 2-D brick-wall structures, while complex 4 shows square grids.

Silver(I) supramolecular complexes generated from polydentate ligands containing cyano and pyridyl groups

A series of silver(I) complexes of the type {[Ag(L1)][X]}∞ (L1 = 2,6-dimethyl-3,5-dicyano-4-(4-pyridyl)-1,4-dihydropyridine; X = BF4−, 1; ClO4−, 2; and NO3−, 3); {[Ag2(L2)4][SO4]}n, 4; and [Ag2(L2)2(NO3)2]n, 5 (L2 = 2,6-dimethyl-3,5-dicyano-4-(3-pyridyl)-1,4-dihydropyridine) have been prepared by reactions of various Ag(I) salts with L1 or L2 in MeOH–H2O. All the complexes have been structurally characterized by X-ray crystallography confirming that complexes 1–3 are two-dimensional coordination polymeric nets, while complexes 4 and 5 are one-dimensional coordination polymeric chains. All the L1 ligands in complexes 1–3 act as tridentate ligands to bridge Ag(I) ions. The anions BF4− and ClO4− in complexes 1 and 2 are not coordinated to the Ag(I) atoms while the NO3− anions in complex 3 are coordinated to the metal centers through one of the three oxygen atoms. The tridentate L2 ligands in complex 4 bind soft acid Ag(I) ions through the cyano and pyridyl groups forming the 1-D polymeric chain, while in complex 5, the L2 ligands bind to Ag(I) centers in bi- and tri-dentate coordination modes. The SO42− anions in complex 4 are not coordinated to the Ag(I) atoms whereas the NO3− anions in complex 5 are coordinated to the metal centers through one of the three oxygens. The anions in complexes 4–5 play important roles in linking cationic chains or layers into 3-D supramolecular structures.

Poly[[μ(2)-1,4-bis-(4,5-dihydro-1,3-oxazol-2-yl)benzene-κN:N']di-μ(2)-chlorido-cadmium].

In the title coordination polymer, [CdCl2(C12H12N2O2)]n, the CdII ion, situated on an inversion center, is coordinated by four bridging Cl atoms and two N atoms from two 1,4-bis(4,5-dihydro-1,3-oxazol-2-yl)benzene (L) ligands in a distorted octahedral geometry. Each L ligand also lies across an inversion center and bridges two CdII ions, forming infinite two-dimensional rectangular layers running parallel to (010).

Structural diversity in the self-assembly of Ag(I) complexes containing 2,6-dimethyl-3,5-dicyano-4-(3-pyridyl)-1,4-dihydropyridine

A series of silver(I) complexes of the type [Ag(L)2][PF6], 1, {[Ag(L)2][PF6]}∞, 2, {[Ag(L)(CH3CN)][BF4]}∞, 3, {[Ag(L)(CH3CN)][CF3SO3]}∞, 4, and {[Ag2(L)2(ClO4)][ClO4]}∞, 5 [L = 2,6-dimethyl-3,5-dicyano-4-(3-pyridyl)-1,4-dihydropyridine] have been prepared by reactions of various Ag(I) salts with L in different solvent systems. All the complexes have been structurally characterized by X-ray crystallography confirming that complex 1 is a 0-D molecular complex, while complexes 2–5 are one-dimensional coordination polymeric chains. The L ligands in complex 1 act as new unidentate ligands to bond Ag(I) ions, while the L ligands in complexes 2–5 act as bi- and tri-dentate ligands to bridge Ag(I) ions. The anions PF6−, BF4− and CF3SO3− in complexes 1–4 are not coordinated to the Ag(I) atoms while the ClO4− anions in complex 5 are coordinated to the metal centers through one of the four oxygen atoms. The resulting structural types of complexes 1–5 are affected by factors such as counteranions and solvents, the anions in complexes 1–5 play important roles in linking cationic chains or layers to form 3-D supramolecular structures.