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With the introduction of 2,2′-bipyridine (2,2′-bipy) agent, two new zinc coordination polymers (CPs), {[Zn6(HL-H)4(2,2′-bipy)4]·¼H2O}n 1 and {[Zn3(HL-H)2(H2O)4]·6H2O}n 2, have been hydrothermally obtained derived from diphosphonic acid, 1-hydroxy-2-(3-pyridyl)ethylidene-1,1-diphosphonic acid (H5L = (H4C5N)CH2C(OH)(PO3H2)2, HL-H = (H4C5N–H)CH2C(OH)(PO3)2), and determined by single-crystal X-ray diffractions, elemental analysis, IR, powder X-ray diffractions (PXRD). The single-crystal X-ray diffractions reveal that compound 1 owns a novel 1-D fishbone-like inorganic chain structure built from binuclear building blocks [Zn2(O–P–O)2]n via [ZnO4]n tetrahedron linkers. It is the first example that N-heterlcyclic amine 2,2′-bipy is used as the second ligand to construct the compound 1 with the diphosphonic acid ligand H5L. Both hydrogen bonding and π–π stacking interactions further extend the 1-D chain to the 3-D supramolecular network. Compound 2 exhibits a 2-D reticulate layer structure containing 4-, 8- and 16-membered rings created from 1-D ladder-like inorganic chain, and the organic pyridine rings in the structure point to voids defined by the 16-membered rings. Moreover, the room-temperature fluorescence measurements show that both the compounds display two fluorescent emissions centered at 379, 424 nm for 1 and 380, 424 nm for 2, respectively, caused by intraligand π*–π emission state of organic pyridine ring (λex = 235 nm). With the introduction of 2,2′-bipyridine (2,2′-bipy) agent, two new Zn(II)-phosphonate CPs, 1-D {[Zn6(HL-H)4(2,2′-bipy)4]·¼H2O}n 1 and 2-D {[Zn3(HL-H)2(H2O)4]·6H2O}n 2 (H5L = (H4C5N)CH2C(OH)(PO3H2)2, HL-H = (H4C5N–H)CH2C(OH)(PO3)2), have been hydrothermally obtained and characterized. The thermal stabilities and fluorescent properties of them have been investigated.

Two 2-D diphosphonate coordination polymers (CPs), {[Co3(HL1-H)2(H2O)4]·2H2O}n 1 and {[Fe3(HL2-H)2(H2O)4]·6H2O}n 2, (H5L1 = (1-hydroxy-2-(imidazo[1,2-a]pyridin-3-yl)ethane-1,1-diyl)diphosphonic acid, H5L2 = 1-hydroxy-2-(3-pyridyl)ethylidene-1,1-diphosphonate acid), have been hydrothermally isolated and determined by single-crystal X-ray diffractions, elemental analysis, IR, powder X-ray diffractions (PXRD), TG-DSC. Both two compounds possess 2-D inorganic layer structures containing 1-D ladder-like inorganic chains with building blocks [M2O2]n and [MO6]n. Compound 1 is the first example of Co(II)-H5L1 diphosphonate. The photoluminescence studies show that both compounds display fluorescent emissions, 378.5, 431.5 nm for 1 and 321.5, 390 nm for 2 (λex = 235 nm), respectively. Magnetic results show that both 1 and 2 present ferro- (FM) and antiferro- (AFM) metamagnetic behavior aroused by spin canted antiferromagnetic coupling between metal(II) centers. Moreover, the studies on the zero-field alternating current (ac) magnetic susceptibility suggest that compound 2 displays slow magnetic relaxation property, being promising potential as magnetic materials.

Three examples of M(II)-diphosphonates, [Cu 3 (H 3 L H) 4 ]·2(OH)·2H 2 O 1 , [Cu 3 (H 2 L) 2 (H 2 O) 2 ] 2 , and [Cd(H 2 L H)]·H 2 O 3 based on 1-hydroxy-2-(3-pyridyl)ethylidene-1,1-diphosphonic acid (H x L/H x L H: x = 0–5, H 5 L = (H 4 C 5 N)CH 2 C(OH)(PO 3 H 2 ) 2 , H 5 L-H = (H 4 C 5 N H)CH 2 C(OH)(PO 3 H 2 ) 2 ), have been hydrothermally obtained and characterized by powder X-ray diffraction, elemental analysis, TG-DSC and IR. The single-crystal X-ray diffractions reveal that compounds 1 and 3 are one-dimensional chain structures (linear for 1 and ladderlike for 3 ) constructed by binuclear units [M 2 O 2 ] n , simultaneously organic pyridine-ring suspending both sides, and compound 2 shows a two-dimensional inorganic-organic alternate arrangement layer built from 1-D ladderlike inorganic chain with trinuclear units [Cu 3 (OPO) 4 ] n via pyridine-ring linker. The results of electrochemical measurements indicate that both 2 and 3 are significant negatively shifted by 0.17 V and 0.13 V (0.33 V for 2 and 0.37 V for 3) , respectively, while 1 was red-shifted by 0.87 V (1.37 V), compared with the ligand H 5 L (0.50 V). Moreover fluorescent measurements reveal that compounds 1 – 3 display fluorescent emission bands, 383 nm and 425 nm for 1 , 382 nm and 425 nm for 2 and 311 nm, 378 nm and 422.5 nm for 3 (λ ex = 235 nm), caused by intraligand π *– π emission state of the ligand H 5 L ( λ ex = 233 nm). Magnetic data indicate that compound 1 exhibits weak ferromagnetic interactions within 1-D linear chain, but compound 2 gives an antiferromagnetic behavior within 1-D ladderlike chain. The energy levels of the frontier molecular orbitals of 1 ∼ 3 are obtained from DFT calculations ( E HOMO 1 : −15.23 eV, 2 : = −9.74 eV, 3 : −11.5 eV ), and the low HOMO–LUMO gaps of 1 (0.38 eV), 2 (0.20 eV) and 3 (0.38 eV) mean that high chemical reactivity for three compounds.

Two examples of CuII/CaII-diphosphonate coordination polymers, [Cu2(L)(H2O)2]n 1 and {[Ca(L-H2)]2·2H2O}n 2 (H4L = H2O3PCH2N(C4H8)NCH2PO3H2), L-H2 = O3PCH2HN(C4H8)NHCH2PO3), N,N′-piperazinebis(methylenephosphonic acid)), have been hydrothermally synthesized and characterized by elemental analysis, FT-IR, PXRD, TGA and single-crystal X-ray diffractions. Compound 1 possesses a 2-D inorganic-organic alternate arrangement layer structure, in which ligand H4L shows a never reported multi-dentate coordination mode. Compound 2 possesses a 3-D open-framework structure with 1-D channel built from 44-atom rings. Results of fluorescent measurements indicate the maximum emission band centered at 435 nm of 1 should be due to the coordination effect with metal(II) ions, and the high energy emission peaks (383, 298 nm for 1 and 378, 300 nm for 2) could be derived from the intraligand π*→n transition station of H4L (382, 310 nm, λex = 235 nm). Magnetism analysis of 1 indicated antiferromagnetic interactions being from the 1-D magnetic chain with the binuclear unit [Cu2O2].

Two examples of Co(II)-N-heterocyclic coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L=CH3C(OH)(PO3H2)2), namely 0.5(H3NCH2CH2NH3)·[Co6(Cl2)(H3L)2(H2L)(HL)(2,2'-bipy)6] 1 and 2(NH4)·[Co3(HL)2(H2O)2(phen)2]·2(H2O) 2, have been solvothermally obtained by introducing the second ligands 2,2'-bipyridine/1,10-phenanthroline (2,2'-bipy/phen) and characterized by powder X-ray diffraction (PXRD), elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that compound 1 possesses a 0-D structure with hexa-nuclear cluster [Co6(O-P-O)8] built through single/double O-P-O bridges and compound 2 displays a 1-D ladder-like chain structure with magnetic topology building blocks [Co4(O-P-O)4]n. Then H-bonding and π-π stacking interactions further expand the two low-dimensional structures into three-dimensional supramolecular frameworks. Fluorescent measurements reveal that both the maximum emission peaks of 1-2 are centered at 423nm, mainly deriving from intraligand π*-π transition state of N-heterocyclic ligand 2,2'-bipy/phen, respectively. Magnetism data indicate that 1 exhibits antiferromagnetic behavior within hexa-nuclear Co(II) clusters, while 2 shows weak ferromagnetic interactions in 1-D topology Co(II)-chain, showing promising potential as magnetic materials.

By introducing the second ligand 1,10-phenanthroline (phen), three low-dimensional examples of CdII/ZnII diphosphonates based on 1-hydroxyethylidenediphosphonic acid (H5L = CH3C(OH)(PO3H2)2), [Cd2(H3L)2(phen)2(H2O)2] 1, {[Zn3(H2L)2(phen)2]·2H2O}n 2 and [Zn2(H3L)2(phen)2]·(HOCH2CH2OH) 3, have been hydro- or solvo-thermally obtained and characterized by powder X-ray diffraction (PXRD), elemental analysis, IR, TG-SDTA. The single-crystal X-ray diffractions show that both compounds 1 and 3 display zero-dimensional structures built from binuclear units [M2(OPO)2] n (M = CdII/ZnII) via a double O–P–O bridge, and compound 2 possesses one-dimensional fish-bone inorganic chain structure with three types of coordination modes of Zn(II) ions. Then H-bond or/and π–π stacking interactions further expand the low-dimensional structures into the three-dimensional supramolecular frameworks. Fluorescent measurements reveal that the maximum emission peaks (371.5, 391.5 nm for 2 and 376.5, 392.5 nm for 3) of 2–3 have a significant increase in intensity compared to those of the phen ligand (λ em = 362.5, 379 nm, λ ex = 335 nm), which are mainly caused by intraligand π*–π emission state of the phen ligand. The results of electrochemical measurements indicate the donor ability of 1–3 has gone up, compared with the ligands (H5L and phen). Three examples of CdII/ZnII diphosphonates have been hydro- or solvo-thermally obtained. Two Zn(II) diphosphonates with 1,10-phenanthroline indicate a significant increase in intensity of fluorescence. The results of electrochemical measurements indicate the donor ability of CdII/ZnII diphosphonates increase, compared with the ligands H5L and phen.

Two new supramolecular architectures, [Co(dafo)2(H2O)2]·1,5-nds 1 and [Co(phen)2(H2O)(1,5-nds)] 2 (1,5-nds = 1,5-naphthalenedisulfonate; dafo = 4,5-diazafluoren-9-one; phen = 1,10-phenanthroline), were synthesized and characterized by element analysis, IR, XRD, TG-DSC and single-crystal X-ray diffraction. Compounds 1 and 2 exhibit 2D and 3D supramolecular structures via O–H∙∙∙O hydrogen bond interactions and π–π interactions, respectively. The compound 1 represents the first example of the Co(II)-1,5-nds-dafo system, in which the [Co(dafo)2(H2O)2]2+ chains and the counter anions 1,5-nds appear alternately. In addition, luminescent properties of 1 and 2 were discussed. The emission band at 422 nm of 1 is attributed to intraligand transitions. 2 shows two emission bands centered at 420 nm which may be originated from the intraligand emission from the phen ligand and at 459 nm assigned to the combined interaction of intraligand π* → π transitions of the phen ligand and ligand-to-metal charge-transfer (LMCT) transitions (λ ex = 254 nm).

A novel bisphosphonic-trimesic acid adduct, 2H3 BTC·H4 L·2H2O 1 (H4 L = N,N′-piperazinebis(methylenephosphonic acid), H3 BTC = 1,3,5-benzenetricarboxylic acid) was obtained by solvothermal technique. It was characterized by elemental analysis, IR, TGA, PXRD, and single-crystal X-ray diffraction analysis. The compound 1 possesses a 3-D supramolecular network with a double chain built from H4 L and a double zigzag supramolecular chain derived from H3 BTC. We also studied quantum chemistry calculation of spectrum (UV–Vis spectra) using the B3LYP/6-31G* method. The result reveals that 1 has small (HOMO-7)–LUMO energy gap (1.395 eV) and high chemical reactivity. Results of electrochemical studies indicate a higher donor ability of 1. The maximum of the fluorescent emission bands of 1 is located at 458 nm (λ ex = 365 nm).

Two novel 1,3-dithiole-2-ylidene derivatives with a push–pull structures, 3-(4,5-dicarbomethoxy-1,3-dithiol-2-ylidene)naphthopyranone 1 and 3-(4,5-dimethylthio-1,3-dithiol-2-ylidene)naphthopyranone 2, have been synthesized and characterized by 1H NMR, IR, MS. The UV–vis spectra of 1, 2 in CH2Cl2, the lowest-energy absorption bands, are centered at 280, 316, and 430 nm for 1 and 284, 317, and 450 nm for 2, respectively, which are caused by the HOMO LUMO single electron promotion. Furthermore, the steady-state fluorescence originating states of 1, 2 from the excited charge-transfer were observed. To estimate the position and energies of frontier orbitals for 1, 2, DFT calculations were performed using the Gaussian 03 program at the B3LYP/6-31 G* level. The calculated vertical excitation energies are in good agreement with the experimental data. The high HOMO–LUMO gaps of 1 (3.08 eV) and 2 (3.00 eV) indicate high kinetic stability of the title compounds.

Vibrational and electronic spectral measurements were performed for 3-(2-chloro-1,3-thiazol-5-ylmethyl)-5-methyl-1,3,5-oxadiazinan-4-ylidene(nitro) amine (thiamethoxam). Optimized geometrical structure and harmonic vibrational frequencies were calculated with ab initio RHF and DFT (B3LYP, CAMB3LYP, M06 and PBE1PBE) methods with 6-311++G (d, p) basis set. Complete assignments of the observed spectra were proposed. The absorption spectra of the compound were computed in gas-phase using TD-B3LYP/6-311++G (d, p) approach and H2O solution using PCM-TD-B3LYP/6-311++G (d, p) approach. The calculated results matched well with the experimental values. Temperature dependence of thermodynamic parameters in the range of 100-1000 K were determined. The bond orbital occupancies, contribution from parent natural bond orbital (NBO), the natural atomic hybrids was discussed.

By introducing the second organic N-heterocyclic ligands 2,2′-bipyridine (2,2′-bipy)/1,10-phenanthroline (phen), two mono-/bi-nuclear examples of Cu(II)-diphosphonate coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L = CH3C(OH)(PO3H2)2), [Cu(H4L)2(2,2′-bipy)]·H2O 1 and [Cu(H3L)(phen)]2·(HOCH2CH2OH)0.5 2, have been solvothermally obtained and characterized by powder X-ray diffraction, elemental analysis, IR, TG–DSC. The single-crystal X-ray diffractions show that both the two compounds possess zero-dimensional structures, built from mononuclear unit [CuO4N2]n for 1 and binuclear unit [–Cu–O–P–O–]2n with a double O–P–O bridge for 2 in syn-anti fashion. Then H-bond or/and π–π interactions further expand the two zero-dimensional structures into the three-dimensional supramolecular frameworks. Fluorescent measurements reveal that the maximum emission peaks of 1–2 centered at 433.5 nm for 1 and 434.5 nm for 2, respectively, are mainly caused by intraligand π*–π emission state of N-heterocyclic ligands (λex = 235 nm). The further magnetic study shows the two coordination polymers exhibit antiferromagnetic behavior for 1 between the mononuclear units, while ferromagnetic behavior for 2 derived from double O–P–O bridges in syn-anti mode between the metal centers.

A novel D-A compound, [Cu(L)2Cl2]·2CH2Cl2 ML, has been synthesized based on 4′,5′-diaza-9′-(4,5-bis(benzylthio)-1,3-dithiole-2-ylidene)-fluorene ((C11N2H6)(C3S2)(SCH2C6H5)2, L). Both ML and L are further characterized by elemental analysis, IR, 1H and 13C NMR. Single-crystal X-ray diffraction shows ML displays a 3-D supramolecular network built by the neutral mononuclear unit [Cu(L)2Cl2] via hydrogen bonds, π–π stacking and S⋯S interactions. The UV–Vis spectra show the lowest-energy absorption band (431 nm) of ML is red-shifted compared to that of L (415 nm). The electrochemistry behavior shows that while the HOMO level of the ML is lowered by L coordinating with the Cu2+ ion, the oxidative potentials are increased (1.19 to 1.37 V). Photocurrent measurements show the intramolecular charge transfer (ICT) of L should be easier than that of ML. The results of the reorganization energy obtained from DFT calculations (λi: 0.25 eV for L, 0.82 eV for ML) reveal the lower reorganization energy is of great benefit to carrier transport within L. These results are in good agreement with those experimentally obtained by CV, UV–Vis, fluorescence and photocurrent measurements.

Three new divalent metal organic frameworks (MOFs) derived from diphosphonate coordination polymers, [Ni 3 (H 2 L) 2 (H 2 O) 4 ]·3H 2 O 1 , [Fe(H 3 L)(H 2 O)] 2 and [Mg 3 (H 2 L) 2 (H 2 O) 4 ]·2H 2 O 3 , (H 5 L = 1-hydroxy-2-(3-pyridyl)ethylidene-1,1-diphosphonate acid, (H 4 C 5 N)CH 2 C(OH)(PO 3 H 2 ) 2 ), have been hydrothermally obtained and determined by single-crystal X-ray diffractions, elemental analysis, IR, PXRD, TG–DTA. The single-crystal X-ray diffractions reveal that compound 1 owns a novel 2-D layer structure constructed by 1-D ladder-like inorganic chain with magnetic topology building blocks [Ni 4 (O–P–O) 4 ] n via pyridine moieties linkage. Compounds 2 and 3 are the first examples of Fe(II) and Mg(II) phosphonates based on ligand H 5 L, respectively. Compound 2 exhibits a 3-D supramolecular network built from 1-D ladder-like inorganic chain with 4- and 8-membered rings through hydrogen bonds, the organic pyridine ring holding close to both sides of the chain. Compound 3 displays a reticulate 2-D layer structure containing 8- and 16-membered rings built from novel 1-D right-handed helical chain. Moreover the room-temperature fluorescent measurements reveal that all the compounds display two fluorescent emissions centered at 377 nm and 422 nm for 1 , 382 nm and 424 nm for 2 as well 383 nm and 425 nm for 3 , respectively, caused by intraligand π *– π emission state of organic pyridine ring ( λ ex = 234 nm). Magnetism data indicate that compound 1 exhibits spin canted antiferromagnetic exchange coupling between Ni(II) centers, while compound 2 shows alternating ferromagnetic and antiferromagnetic interactions within 1-D topology Fe(II)-chain, showing promising potential as magnetic materials.

Under hydrothermal conditions, reaction of Cu(II)/Cd(II) salts with 1,5-naphthalenedisulfonate (1,5-NDS) and 4,5-diazafluoren-9-one (dafo) afforded [Cu(dafo)2(1,5-NDS)]n (1) and [Cd(dafo)2(1,5-NDS)]n (2), respectively. The compounds were characterized by elemental analysis, IR, PXRD, TG-DSC, and single-crystal X-ray diffraction. Both 1 and 2, which are the first M(II)-1,5-NDS-dafo systems, exhibit 3-D supramolecular structures generated by 1-D chains via C–H⋯O hydrogen bonds and π–π interactions. Solid-state photoluminescence properties of both 1 and 2 were investigated with emission bands at 426–496 nm (λ ex = 280, 270 nm for 1 and 2, respectively).

Two new supramolecular transition metal compounds, [Zn(phen)2(1,5-NDS)(H2O)] and [Cd(phen)2(1,5-NDS)]n (1,5-NDS = 1,5-naphthalenedisulfonate, phen = 1,10-phenanthroline), were obtained under hydrothermal/solvothermal conditions and structurally characterized by elemental analysis, IR, PXRD, TG-DSC, and single-crystal X-ray determination. They represent the first examples of Zn(II)/Cd(II) supramolecular compounds based on the 1,5-NDS/phen system. The Zn compound exhibits a 3D supramolecular structure via hydrogen bond (O–H⋯O and C–H⋯O) and π–π interactions. The Cd compound is a 3D supramolecular framework generated by 1D coordinated chains through a hydrogen bond (C–H⋯O) and π–π interactions. In addition, photoluminescence properties for both have been discussed. [Zn(phen)2(1,5-NDS)(H2O)] shows an emission peak at 420 nm (λ ex = 342 nm), and [Cd(phen)2(1,5-NDS)] n displays a strong emission peak at 388 nm with a shoulder peak at 369 nm (λ ex = 332 nm). .

The first examples of two d 10 metal coordination polymers based on 1,5-naphthalenedisulfonic acid and benzimidazole, namely, [Cd(bim)4(1,5-nds)] 1 and [Ag(bim)2]·½1,5-nds 2 (bim = benzimidazole, 1,5-nds = 1,5-naphthalenedisulfonic acid) were synthesized successfully under solvothermal conditions. Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR, TG-DSC, PXRD, UV–Vis, and DFT. 1 exhibits a 3D supramolecular structure which started from 1D helical chain. 2 also shows a 3D architecture which was assembled via π–π interactions and hydrogen bonds. The hydrogen bonds formed by 1,5-nds play an important role in increasing the dimensionality of architectures of 1 (from 1D to 3D) and 2 (from 0D to 1D). Moreover, both 1 and 2 show excellent luminescent properties, 335 nm for 1 (λ ex = 286 nm) and 341 nm and 389 nm for 2 (λ ex = 234 nm), and may be the suitable candidates of fluorescent materials. From UV–Vis spectra, the remarkable absorption peaks can be found at 276 nm for 1 and 271 nm for 2. The simulated UV–Vis spectra (290.30 nm for 1 and 271.64 nm for 2) by Gaussian 09 DFT correspond well with the experimental results. From the electron density distribution of frontier molecular orbitals, it is known that the two absorption bands are attributed to the intra-ligand electron transition from HOMO−26 to LUMO and from HOMO−3 to LUMO+1 for 1, from HOMO−1 to LUMO+18 and LUMO+19 for 2.

By introducing the second organic N-heterocyclic ligand 2,2′-bipyridine (2,2′-bipy), two binuclear examples of Cu(II)-diphosphonate coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L=CH3C(OH)(PO3H2)2), [Cu2(H4L)2(H3L)(2,2′-bipy)2] 1 and [Cu(H3L)(2,2′-bipy)] 2, have been hydrothermally obtained and characterized by powder X-ray diffraction, elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that both the two compounds possess zero-dimensional binuclear structures built through a single O–P–O bridge for 1 and a double O–P–O bridge for 2 in syn–anti fashion. Then H-bond and π–π interactions further expand the two zero-dimensional binuclear structures into three-dimensional supramolecular frameworks. Fluorescent measurements reveal that the maximum emission peaks of 1–2 centered at 423.5 nm for 1 and 423 nm for 2, respectively, are mainly caused by intraligand π*–π emission state of N-heterocyclic ligand 2,2′-bipy (λ ex = 233 nm). The further magnetic study shows the two coordination polymers exhibit ferromagnetic behaviors derived from O–P–O bridges in syn–anti mode between the metal centers.

By introducing the second bridging ligand, 4,4′-bipyridyl (4,4′-bipy), the first 3D example of a Cu(II)-diphosphonate-4,4′-bipy metal organic framework (MOF), [Cu3(L)(4,4-bipy)(OH)2] 1 (H4L = H2O3P(C6H4)2PO3H2) was hydrothermally obtained and characterized through powder X-ray diffraction, elemental analysis, IR, and TG-DSC. Single-crystal X-ray diffraction revealed that compound 1 has a 3D MOF structure which is created by a 2D inorganic layer [Cu3O6P2]n through 4,4′-bipy and an organic biphenyl moiety of H4L linkages. In the structure, an inorganic layer and two organic pillars were alternately arranged. The results of fluorescence measurements revealed two decayed emission bands centered at 442 and 374 nm (λex = 236 nm) may be caused by the intraligand π∗–π emission states of the 4,4′-bipy ligand (λem = 442 and 381.5 nm, λex = 236 nm). Magnetism analysis indicated antiferromagnetic interactions between the metal centers within the 1D magnetic chain {–Cu(1)–Cu(2)–Cu(2)–Cu(1)–}n.

Two metal compounds, 1 and 2, have been obtained by incorporating 1,10-phenanthroline (phen) and 5-sulfoisophthalic acid monosodium salt () ligands under hydrothermal conditions. Meanwhile, the two compounds were characterized by element analysis, IR, XRD, TG-DTA and single-crystal X-ray diffraction. Both 1 and 2 present 3D supramolecular structures via O-HO hydrogen bond interactions. Luminescent properties for 1 and 2 were also studied. The compound 1 has two fluorescence emission peaks centered at 398 nm attributed to the intraligand emission from the SIP ligand and at 438 nm assigned to the combined interaction of intraligand transitions of the phen ligand and ligand-to-metal-charge-transfer (LMCT) transitions ( = 233 nm). The compound 2 shows one emission band centered at 423 nm with a shoulder peak at 434 nm which may be originated from the intraligand transitions of the phen ligand ( = 266 nm).

The first example of cadmium complex containing methyl orange [MO, (CH 3 ) 2 NC 6 H 4 N = NC 6 H 4 SO 3 Na], formulated as [Cd(en) 2 (H 2 O) 2 ](MO) 2 1 (en = ethylenediamine) was synthesized hydrothermally and characterized by single-crystal X-ray diffraction, IR, XRD, elemental analysis and Raman spectroscopic analysis. Compound 1 display a two-dimensional supramolecular layer structure with ladder-like supramolecular chain by X-ray crystallographic analysis. MO anion immobilized by H-bonds, as acid–base indicator, shows a similar behavior in comparison with its solution counterpart in terms of response to pH.

In situ lead-MOF derived from 2-Methyl-3-acetylnaphtho[2,3-b]furan-4,9-dione (MAFD), [Pb7O2(OH)2(1,2-BDC)4(H2O)] 1, 1,2-BDC = C6H4(COOH)2, phthalic acid, has been synthesized and characterized by elemental analysis, IR, TG-DTA, powder X-ray diffraction (XRD) and single crystal X-ray diffraction. Compound 1 possesses 2-D inorganic layer structure built from rare tetranuclear unit [(μ 4-O)Pb4]. In 1, both crystallographic distinct Pb(1) and Pb(4) ions adopt six-coordination geometry, and the other two crystallographic distinct Pb(2) and Pb(3) ions display eight-coordination geometry under the condition of Pb–O bond length extended to 3.10 A. A 3-D supramolecular network is also formed by hydrogen bonds (C–H···O). Result of photoluminescence measurement indicates an emission band at 385 nm (λ excitation = 209 nm).

The first example of lead compound from and N-heterocyclic ligand , 1 (L' = OOC, has been obtained under hydrothermal condition by decarboxylation, and characterized by elemental analysis, IR, TGDTA, and single-crystal X-ray diffraction. Compound 1 possesses a rare two-dimensional upper-lower offset terrace-like layer structure. In 1, crystallographic distinct Pb(II) ion adopts five-coordination geometry, and two lattice water molecules occupy the voids between 2-D layers. Results of solid state fluorescence measurement indicate that the emission band 458 nm may be assigned to and electronic transitions within the aromatic systems of the ligand L', however, the emission bands centred at 555 nm, 600 nm and 719 nm may be derived from phosphorescent emission ( = 390 nm).

A novel three-dimensional barium metal–organic framework [Ba3(btc)2(H2O)4]·0.5H2O (H3btc = 1,3,5-benzenetricarbox-ylic acid) has been synthesised under hydrothermal conditions, and characterised by single-crystal X-ray structure determination, thermogravimetric analysis, X-ray powder diffraction, IR, and photoluminescence studies. The volume of the tunnel formed by the two-dimensional layers is 341.9 Å3 per unit cell using PLATON based on the crystal structures, comprising 14.3% of the crystal volume 2387.2 Å3. The solid-state fluorescence measurement of this compound at room temperature reveals a fluorescent emission band at 454.5 nm under the excitation of 337 nm, assigned to a charge-transfer transition.

The crystal structure of adduct of 6-benzylaminopurine and 5-sulfosalicylic acid C19H25N5O10S 1 is studied using single-crystal diffraction (R = 0.0482 for 2852 reflections with I > 2σ(I)). The asymmetric unit of 1 contains one 6-benzylaminopurine molecule and one 5-sulfosalicylic acid molecule, as well as four lattice water molecules. Hydrogen bonds, formed by 6-benzylaminopurine and 5-sulfosalicylic acid, link the two molecules into one-dimensional chain (omitting four water molecules), further joined to two-dimensional layer network. Short ring-interactions with intra-chain π-π stacking are observed. The data of IR spectroscopy confirm the formation of the two-dimensional supramolecular layer structure. At last, a 3D supramolecular network constructs via hydrogen bonds.

Hydrothermal reaction of zinc(II) salts with 5-sulfoisophthalic acid monosodium salt (NaO 3 SC 6 H 3 -1,3-(COOH) 2, NaH 2 -SIP) and 1,10-phenanthroline (phen) led to two new compounds, [Zn(phen) 3 ]·2H 2 SIP·4H 2 O (1) and [Zn(phen) 2 (H 2 O) 2 ]· 2H 2 SIP·2H 2 O (2). They were characterized by element analysis, IR spectroscopy, thermalgravimetric analysis (TGA), X-ray powder diffraction (XRD), and single-crystal X-ray diffraction. Both compounds 1-2 represent the first example ofZn/phen/SIP system. The Zn (II) ion in 1 is six-coordinated by six nitrogen atoms from three phen molecules, and the H 2 SIP - ligands engage in the formation of hydrogen bond. The Zn(II) ion in 2 is coordinated by four nitrogen atoms from two phen molecules and two oxygen atoms from two water molecules. Moreover, both 1 and 2 are assembled into 3 D supramolecular architectures by hydrogen bonds (O-H···O) and π-π interactions. Solvent water molecules occupying voids of the compounds serve as receptors or donors of the extensive O-H···O hydrogen bonds.

Two novel conjugated imino-π-extended tetrathiafulvalenes with p-iminobenzene, N,N′-bis(4,5-bis(methylthio)-1,3-dithiol-2-ylidene)benzene-1,4-diamine (1) and N,N′-bis(4,5-bis(ethylenedithio)-1,3-dithiolo-2-ylidene)benzene-1,4-diamine (2), have been synthesized and characterized by NMR, IR, MS and X-ray single-crystal diffraction. Both the two targets adopt chair-like conformation, and the central rings of p-iminobenzene moieties of the two molecules are severely twisted from the planarity of two dithiole rings, respectively. The UV–vis spectra of 1 and 2 show the lowest-energy absorption bands caused by the HOMO–LUMO one-electron promotion. Cyclic voltammetry (CV) measurements show only one, two-electron irreversible oxidation picks. These experimentally estimated energy levels of the frontier orbital of 1 and 2 (EHOMO 1: = −5.45, 2: −5.47 eV) are in good agreement with those obtained from DFT calculations (EHOMO 1: = −5.5, 2: = −5.3 eV). The high HOMO–LUMO gaps of 1 (4.05 eV) and 2 (4.00 eV) indicate high kinetic stability of the title compounds.

The crystal structure of hydrate adduct of 6-benzylaminopurine and 5-sulfosalicylic acid [(C12H12N5)(C7H5O6S)·H2O] 1 is studied. It crystallizes in monoclinic system space group P21/n with a = 6.2128(9) A, b = 20.762(3) A, c = 15.675(2) A, β = 92.040(2)°, V = 2,020.6(5) A3, Z = 4, R gt(F) = 0.0494, wR ref(F 2) = 0.1112, and T = 173(2) K. Single-crystal X-ray diffraction analysis reveals that the asymmetric unit of 1 contains one 6-benzylaminopurine molecule and one 5-sulfosalicylic acid molecule, as well as one lattice water molecule. In 1, hydrogen bonds link the two monomers into one-dimensional double chain, two-dimensional layer network, and further a 3-D supramolecular network. Short ring-interactions with intra-chain π–π stacking are observed (distances between ring centroids are 3.964, 3.796 and 3.571 A, and the dihedral angle between planes are 6.97°, 5.55°, and 5.66°, respectively). A novel hydrate adduct [(C12H12N5)(C7H5O6S)·H2O] 1, has been synthesized and consists of 6-benzylaminopurine and 5-sulfosalicylic acid molecules with one lattice water molecule. The monomers connect with each other via intermolecular hydrogen bonds C(N, O)–H···O(N) to form double chain, further two-dimensional layer, at last 3-D supramolecular structure network, along with π–π interactions within 4 A.

A novel 3-D metal–organic framework Nd(2,5-pydc)(nic)(H2O) (1, 2,5-pydc = pyridine-2,5-dicarboxylic acid, nic = nicotinic acid) has been hydrothermally synthesized and characterized by elemental analyses, IR, and X-ray single-crystal diffraction. Compound 1 is the first MOF based on mixed 2,5-pydc/nic ligands. The title compound displays an interseting 3-D (6,3)-connected network with the topology of (4.62)2(42 × 610 × 83). Magnetic susceptibility measurements show that compound1 presents a rare ferromagnetic interaction between two adjacent Nd(III) ions.

A novel 2-D hemidirected metal-organic framework [Pb(HIDC)]n (1, H3IDC = imidazole-4,5-dicarboxylic acid) has been hydrothermally synthesized and characterized by elemental analyses, IR, TGA, and X-ray single-crystal diffraction. Compound 1 is the first MOF based on Pb(II) and imidazole-4,5-dicarboxylic acid ligand. The 2-D (3,3)-net architecture with a rare (4 · 82) topology is built from alternately arranged left- and right-handed helical chains bridged by HIDC2− ligand.

The example of Co(II)-N-heterocyclic complex based on 1-hydroxyethylidenediphosphonic acid (H5L = CH3C(OH)(PO3H2)2), namely [Co2(H3L)2(2,2′-bipy)2] 1, has been solvothermally isolated using the second ligand 2,2'-bipyridine (2,2'-bipy) and characterized by powder X-ray diffraction (PXRD), elemental analysis, IR, and thermal gravimetric analyses. The single-crystal X-ray diffractions show that complex 1 possesses a 0-D structure built from binuclear unit [Co2(O–P–O)2] by μ2-(O–P–O) bridge. Then, H-bonding and π–π stacking interactions further expand this 0-D structure into a 3-D supramolecular framework. Fluorescent measurements reveal that the maximum emission peak is centered at 421.5 nm, mainly deriving from intraligand π*–π transition state of the second ligand 2,2'-bipy (λem = 419.5 nm, λex = 235 nm). Magnetism data indicate that 1 exhibits ferromagnetic behavior within binuclear Co(II) unit via μ2-(O–P–O) bridge in syn-anti mode.

A novel 3-D magnesium metal–organic framework [Mg1.5(μ5-btec) (H2O)2] · [H2N(CH3) 2] · H2O (btec = 1,2,4,5-benzenetetracarboxylic acid) has been synthesized under solvothermal conditions, and characterized by single-crystal X-ray structure determination, thermogravimetric analysis, X-ray powder diffraction, IR, and photoluminescent studies.

The crystal structure of indolizine derivative C22H12O2NBr (1) is studied using X-ray diffraction. The crystals are monoclinic, a = 12.888(3), b = 8.6250(2), c = 15.479(3)A, β = 101.6(3)°, V = 1685.5(6) A3, Z = 4, space group P21/c and R = 0.0722 for 1292 reflections with I > 2σ(I). Single-crystal X-ray diffraction analysis reveals that the molecule 1 is monomeric and contains four six-membered rings and one five-membered ring. The fused four rings are in the same plane, giving rise to conjugative effect. Hydrogen bonds link the monomers into double chain. Short ring interactions with intranhain π-π stacking are observed (distance between ring centroids is 3.85 A, and the dihedral angle between their planes is −8.7°). The data of IR spectroscopy confirm the formation of the structure.

Two new nickel(II) phosphonates (H4PMIDA = N-(phosphonomethyl)iminodiacetic acid, H4L), one-dimensional zigzag chain (NH4)2[Ni(PMIDA)(H2O)] (1) and tetramer (H3O)8[Ni4O2(HPMIDA)4(H2O)2] (2), have been solvothermally synthesized and characterized by elemental analyses, IR, TGA and X-ray single-crystal diffraction, and their magnetic and fluorescent properties are also reported. Compound 1 is the first chain phosphonate linked by carboxyl group in anti–anti mode based on Ni(II) and H4PMIDA ligand, and compound 2 with tetranuclear units is the first example of showing the spin-canting antiferromagnetic coupling between Ni(II) centers.

A new complex, [Pb2(H2O)2(HBTC)2] · 3H2O (H3BTC = 1,3,5-Benzenetricarboxylic acid) (1), has been synthesized under hydrothermal condition. The single-crystal analysis shows that 1 consists of 1-D double-chains with Pb(II) six-coordinated by three H3BTC and one H2O molecule with the Pb–O bond distances in the range of 2.56–2.76 A. When the Pb–O bonding limit extends from 2.76 to 2.90 A, the potential weak bonds of Pb–O can be found and the coordination number of Pb will increase from six to nine. As a result, the coordination geometry of Pb(II) transforms from hemidirected to holodirected and an infinite 3-D framework is obtained by the connection of the double-chains. The IR spectrum and the TGA–DTA curve of 1 are also reported in this paper.

A novel 3D [La2(C2O4)2(NO3) (OH)(H2O)] · 3H2O 1 has been synthesized under hydrothermal conditions and characterized by elemental analyses, IR, TGA, X-ray powder diffraction, X-ray single crystal diffraction and photoluminescence. The bridging modes of both nitrates and oxalates in compound 1 are uncommon. We have unexpectedly generated an unusual compound by using the simplest ligands, oxalates and nitrates in the presence of nicotinate (HIN).

The compound 9-p-tolyl-9H-carbazole-3-carbaldehyde (HCCD) was synthesized and characterized by X-ray diffraction, FT-IR, FT-Raman and UV-Vis spectra. The X-ray diffraction study showed that HCCD has a Z-configuration. The benzene ring including methyl is twisted from the mean plane of the carbazole group by 59.7(3)°, which is comparable with the calculated result 65° for B3LYP/6-311++G(d, p) method. Vibrational spectra and electronic spectra measurements were made for the compound. Optimized geometrical structure and harmonic vibrational frequencies were computed with B-based DFT (BLYP, B3LYP and cam-B3LYP) methods, and WB-based DFT (WB97, WB97X and WB97XD) methods and ab initio RHF method using 6-311++G(d, p) basis set. Assignments of the observed spectra were proposed. The equilibrium geometries computed by all of the methods were compared with X-ray diffraction results. The absorption spectra of the title compound were computed both in gas phase and in DMF solution using TD-(cam)B3LYP/6-311++G(d, p) and PCM-(cam)B3LYP/6-311++G(d, p) approaches, respectively. The calculated results provide good descriptions of the bands maxima in the observed electronic spectrum. Temperature dependence of thermodynamic parameters in the range of 100-1000 K was determined. The natural atomic hybrids were calculated and discussed.

The crystal structure of a new coordination compound tri(2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) Co(II) complex ([Co(dcpip)3]Cl2) was measured with X-ray diffraction measurements. The compound is crystallizes triclinic, Pī space group. The ligand, 2-(2,6-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline(dcpip), binds to Co(II) ions with a bis-dentate mode, and each Co(II) ion with a distorted octahedral coordination geometry. The calculated interaction energies of Co(II) with coordination atoms N are between 101.7-206.5 kJ/mol and 115.3-230.9 kJ/mol for B3LYP/6-31+G(∗) and PBE1PBE/6-31+G(∗) theoretical methods, respectively. The experimental Fourier transform infrared spectrum was assigned. The calculated IR based on B3LYP/6-31+G(∗) and PBE1PBE/6-31+G(∗) methods were performed and compared with experimental results. The UV-Vis experimental spectrum of [Co(dcpip)3]Cl2 was measured in methanol solution. The calculated electronic spectrum was performed with TD/B3LYP and TD/PBE1PBE methods with 6-31+G(∗) basis set. The first and second order hyperpolarizability for the compound was calculated. The calculated values of γtot are -1.5551344 × 10(-33) esu for B3LYP method and -1.3323259 × 10(-33) esu for PBE1PBE method. The nature bond orbital analysis and temperature dependence of the thermodynamic properties were calculated with the same methods.

2-Amino-3-((E)-(9-p-tolyl-9H-carbazol-3-yl) methyleneamino) maleonitrile (ACMM) was synthesized and characterized by X-ray diffraction, FT-IR, FT-Raman and UV-Vis spectra. The X-ray diffraction study showed that ACMM has a Z-configuration, due to the intramolecular C18H18A⋯N2, N3H3A⋯N2 and C20H20A⋯N4 hydrogen bonds and intermolecular C10H10A⋯N4, N3H3B⋯N9 (2-x, 2-y, 2-z) and N3H8C⋯N4 (2-x, 1-y, 2-z) hydrogen bonds. The benzene ring including methyl is twisted from the mean plane of the carbazole group by 59.7(3)°. Vibrational spectra and electronic spectra measurements were made for the compound. Optimized geometrical structure and harmonic vibrational frequencies were computed with DFT (B3-based B3P86, B3LYP, B3PW91 and B-based BP86, BLYP, BPW91) methods and ab initio RHF method using 6-311++G(d, p) basis set. Assignments of the observed spectra were proposed. The equilibrium geometries computed by all of the methods were compared with X-ray diffraction results. The absorption spectra of the title compound were computed both in gas phase and in DMF solution using TD-B3LYP/6-311++G(d, p) and PCM-B3LYP/6-311++G(d, p) approaches, respectively. The calculated results provide a good description of positions of the bands maxima in the observed electronic spectrum. Temperature dependence of thermodynamic parameters in the range of 100-1000K were determined. The bond orbital occupancies, contribution from parent natural bond orbital (NBO), the natural atomic hybrids was calculated and discussed.

The two examples of alkaline-earth M(II)-phosphonate coordination polymers, [Ba2(L)(H2O)9]·3H2O (1) and [Mg1.5(H2O)9]·(L-H2)1.5·6H2O (2) (H4L = H2O3PCH2N(C4H8)NCH2PO3H2),N,N′-piperazinebis(methylenephosphonic acid), (L-H2= O3PH2CHN(C4H8)NHCH2PO3) have been hydrothermally synthesized and characterized by elemental analysis, FT-IR, PXRD, TG-DSC, and single-crystal X-ray diffraction. Compound1possesses a 2D inorganic-organic alternate arrangement layer structure built from 1D inorganic chains through the piperazine bridge, in which the ligand L−4shows two types of coordination modes reported rarely at the same time. In1, both crystallographic distinct Ba(1) and Ba(2) ions adopt 8-coordination two caps and 9-coordination three caps triangular prism geometry structures, respectively. Compound2possesses a zero-dimensional mononuclear structure with two crystallographic distinct Mg(II) ions. Free metal cations [MgO6]n2+and uncoordinated anions(L-H2)n2-are joined together by static electric force. Results of photoluminescent measurement indicate three main emission bands centered at 300 nm, 378.5 nm, and 433 nm for1and 302 nm, 378 nm, and 434.5 nm for2(λex=235 nm), respectively. The high energy emissions could be derived from the intraligandπ∗-ntransition stations ofH4L(310 nm and 382 nm,λex=235 nm), while the low energy emission (>400 nm) of1-2may be due to the coordination effect with metal(II) ions.

Vibrational and electronic spectral measurements were made for 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). Optimized geometrical structure and harmonic vibrational frequencies were computed by DFT(B3LYP, CAMB3LYP, B3P86, M062X, mPW3PBE and PBE1PBE) using 6-311++G(d,p) basis set. Complete assignments of the observed spectra were proposed. The absorption spectra of the compound were computed both in gas-phase and in CH2Cl2 solution using TDCAMB3LYP/6-311++G(d,p) and PCM-TDCAMB3LYP/6-311++G(d,p) approaches, respectively, the calculated results provide a good description of positions of the bands maxima in the observed electronic spectrum.

Four new cyano-substituted styryl derivatives based on carbazole and phenothiazine were facilely synthesized by conventional Knoevenagel condensation and well characterized. The UV-vis spectra of these dyes showed the lowest-energy absorption bands were mainly caused by the HOMO-LUMO one-electron promotion as conformed by TD-DFT calculations. The thermogravimetric analysis showed these dyes were thermally stable up to 350 °C. The UV-vis absorption and fluorescence emission spectra were also studied in solvents of different polarity, these dyes exhibited unusual large Stokes shift.

By introducing the second organic N-heterocyclic ligands 4'-(4-pyridyl)-4,2':6',4''-terpyridine (pyterpy) and 4,4'-bipyridyl (4,4'-bipy), two examples of Cu(II)-diphosphonates, [Cu(3)(HL)(2)(Hpyterpy)(2)]·2H(2)O 1 and [Cu(4)(HL)(2)(4,4'-bipy)(H(2)O)(5)] 2 based on 1-hydroxyethylidenediphosphonic acid (H(5)L = CH(3)C(OH)(PO(3)H(2))(2)), have been hydrothermally obtained and characterized by powder X-ray diffraction, elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions reveal that compound 1 has a one-dimensional fishbone-like chain constructed by anions [Cu(3)(HL)(2)(2-)](n) while simultaneously organic cations [Hpyterpy(+)](n) suspending both sides, and compound 2 exhibits two-dimensional inorganic-organic alternate arrangement layer built from 1-D ladder-like inorganic chain with tetranuclear cluster [Cu(4)O(10)] via 4,4'-bipy linkage. The results of electrochemical measurements indicate half-wave potential of 1 (E(1/2)(1) = 1.01 V) is less than that of 2 (E(1/2)(2) = 1.20 V), indicating a good D-A system in ICT for 1. Moreover fluorescent measurements reveal that emission intensity of 1 centered at 422 nm is larger than that of 2 emitted at 420 nm, caused by intraligand π*-π emission state of organic N-heterocyclic amine (λ(ex) = 233 nm). Magnetism data indicate that compound 1 exhibits ferrimagnetic interactions between metal centers, while compound 2 has antiferromagnetic property.

A novel organic–inorganic coordination polymer [CdCl3(CH3)3NH] 1 was synthesized by the reaction of CdCl2 with trimethylamine (TMA) at 170 °C for 5 days in ethanol and structurally characterized by means of X-ray single diffraction. The title compound affords a one-dimensional chain structure. It crystallizes in hexagonal system space group P 6 ( 3 ) / m with a = 9.1401 ( 13 ) A , b = 9.1401 ( 13 ) A , c = 6.7313 ( 13 ) A , γ = 120.00 ° , V = 487.00 ( 14 ) A 3 , Z = 2 , D C = 1.895 Mg / m 3 , F ( 000 ) = 266 , M r = 277.86 , μ ( Mo K α ) = 2.99 mm −1 , the final R = 0.0420 and ω R = 0.1020 for 355 observed reflections with I > 2 σ ( I ) . The title compound consists of cation [(CH3)3NH]+ and anion chain [ ( CdCl 3 ) ] n − , and they are combined by static attracting forces in the crystal. TG–DTA, XRD and IR data for the title compound are reported and discussed. The photoluminescent properties of the compound 1 were also investigated.

A new method was developed to separate epinephrine enantiomers derivatized with fluorescent chiral reagent, R-(-)/S-(+)-4-(N, N-dimethylaminosulfonyl)-7-(3-iso-thiocyanatopyrrolidino)-2, 1, 3-benzoxadiazole (DBD-PyNCS), by reversed-phase high performance liquid chromatography, on a Diamonsil C18 column(150 mm x 4.6 mm i.d., 5 microns), with a mobile phase of water-acetonitrile(72:28, volume ratio) and a fluorescent detector at the excitation wavelength of 460 nm and the emission wavelength of 550 nm. The column was eluted at 40 degrees C, with a flow rate of 1 mL/min. At first, let the fluorescent chiral reagent(36 mmol/L, 10 microL) react with epinephrine enantiomers(1 mmol/L, 10 microL), and then 10 microL 20% pyridine acetonitrile solution was added. The resulting mixture was stirred for 1 min and kept at 65 degrees C for 35 min and then a 10 microL aqueous of the diastereomeric derivatives was injected directly into the chromatograph. The diastereomeric compounds were efficiently separated. The Rs value was 2.6 with alpha of 1.07. The k's of L-epinephrine and D-epinephrine were 17.11 and 18.13 respectively. The retention times of L-epinephrine and D-epinephrine were 30.24 min and 31.94 min respectively. The linear range was 0.07 g/L -0.50 g/L (r = 0.9995). The RSD was 4.3%(n = 7). The detection limit was 12 g/L(S/N = 3).

A novel lead-phosphonate, [Pb2(HL)]·(NO3)·2(H2O) 1 (H4L = H2O3PCH2N(C4H8)NCH2PO3H2 N,N′-piperazinebis(methylenephosphonic acid), so HL = O3PCH2NH(C4H8)NCH2PO3), has been hydrothermally synthesized and characterized by elemental analysis, IR, TG-DTA, and X-ray single-crystal diffraction. Compound 1 possesses a 2D cationic layer structure built from inorganic chains with three types of eight-membered rings arranged in an ABAC manner. In 1, both crystallographic distinct Pb(II) ions adopt three-coordination geometry, and a counter anion NO3 – and two lattice water molecules occupy the voids between 2D layers. After the removal of solvent, the size of tunnel formed by 2D layers is 137.9 Å3 per unit cell, comprising 17.0% of the crystal volume based on the crystal structure. When the bond length of Pb–O(N) extended to 3.10 Å, a 3D metal–organic framework was constructed via long Pb–O(N) contacts, simultaneously accompanied by the hemi- to holo-directed transition in coordination geometry of Pb(II). Except for the long Pb–O contacts, a 3D supramolecular network is also formed by hydrogen bonds (N–H···O, O–H···O, and C–H···O), van der Waals forces as well as electrostatic interactions. The result of fluorescence measurements indicates that 1 shows a fluorescent emission band at 465 nm (λexcitation = 215 nm).

Three compounds have been isolated from solvothermal reactions of a transition metal(II) (Ni(II), Co(II)) with N,N-bis(phosphonomethyl)aminoacetic acid [(HO2CCH2)N(CH2PO3H2)2] (H5L), namely [NH3(CH2)3NH3](NH4)4[Ni(L)(H2O)]2 (1), (H3O)3[Ni(L)(H2O)2]·4H2O (2) and (H3O)[Co(H2L)(H2O)2]·2H2O (3). These compounds were characterized by single crystal and powder X-ray diffraction, infrared spectroscopy, thermal analysis, elemental analysis, fluorescent spectroscopy and magnetic measurements. The structure of compound 1 is composed of binuclear [Ni2O6N2]n4− units, which are further interconnected into a 3D supramolecular network by hydrogen bonds. Compounds 2 and 3 are both mononuclear and consist of similar octahedral [MO5N] units. A 1D dendritic water chain is formed by hydrogen bond interactions in the supramolecular network of compound 2. Compounds 1 and 2 show ferromagnetic properties, while weak antiferromagnetic properties are observed in compound 3. Compounds 1 and 2 also display fluorescent emission excited at 235 nm.