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Single-crystal-to-single-crystal (SCSC) transformation has been demonstrated to provide an ideal platform to explore the formation process of chemical bonds, which is conducive to making function-oriented crystal synthesis a reality. A solvent as a ligand or a structure-directing agent plays a significant role in the structural formation of coordination polymers (CPs), and its removal/adsorption or exchange can affect the change in metal coordination environments. In this article, we provide a brief overview of recent progress in the effect of coordinated solvent molecules on metal coordination environments of CPs in SCSC transformations. We highlight three different categories based on their stimuli conditions, heat treatment, immersion in solvent or mother liquid, and exposure to vapor. We try to discuss the criteria for CPs in which the metal coordination spheres can be affected by the coordinated solvents, which may provide new insights into the rational design and construction of CPs with the desired structures and properties. [ABSTRACT FROM AUTHOR]

Based on various comparable salen ligands, three synthesized CuIINaI-complexes present efficient catalytic activities for the coupling and cyclization reaction of 1,2-diaminopropane with nitriles towards 2-imidazolines. The catalytic results show that salen ligands with an electron-donating substituent and small steric hindrance improve the catalytic activity. [ABSTRACT FROM AUTHOR]

Reaction-determined assemblies of 6,6′-dinitrobiphenyl-2,2′,4,4′-tetracarboxylic acid (H4nbtc), various N-donor ligands and transition metal ions produce ten complexes, namely, [Zn2(nbtc)(bpa)·H2O]n (1), [Zn2(nbtc)(bpe)·H2O]n (2), [Zn2(nbtc)(2,2′-dpy)]n (3), Zn(H3nbtc)(phen)2 (4), {(H3O)2[Cd3(nbtc)2(H2O)3]·5H2O}n (5), [Cd2(nbtc)(ndpy)·0.5H2O]n (6), [Ag2(H2nbtc)(bpp)]n (7), [Co2(nbtc)(phen)2(H2O)2]n (8), [Ni2(nbtc)(phen)2(H2O)2]n (9) and Co(H2nbtc)(phen)2·2H2O (10) (bpa = 1,2-bis(4-pyridyl)ethane, bpe = 1,2-di(4-pyridyl)ethylene, bpp = 1,3-bis(4-pyridyl)propane, 2,2′-dpy = 2,2′-dipyridyl, phen = 1,10-phenanthroline, ndpy = 2-pyridinamine). Isostructural 1 and 2 feature 3D “bilayered-pillared” frameworks constructed from Zn2(μ2-COO)2(μ1-COO)2-nbtc4− wave-bilayers and bpa/bpe pillars. Unlike 1 and 2, both 3 and 6 exhibit 3D “brick-wall” frameworks constructed from nbtc4− and various SBUs (0D Zn2(μ2-COO)3(μ1-COO)1 for 3, 1D [Cd2(μ2-COO)4]n for 6). However, 3D 5 can be viewed as a combination of 2D “brick-wall” layers and 1D [Cd3-nbtc] chains. Moreover, in comparison to neutral 3 and 6 with pensile and cosmetic terminal ligands, complex 5 without an N-donor ligand is particularly interesting, containing two hydronium ions to balance the anion unit [Cd3(nbtc)2(H2O)3]2− as well as three types of coordinated Cd(ii) ions (6-, 7- and 8-). Unlike 3, complex 4 is mononuclear, despite the two complexes employing similar terminal ligands (2,2′-dpy for 3, phen for 4). In 2D layered Ag(i) 7, the 0D Ag4(μ2-COO)4 SBUs initially form Ag4(μ2-COO)4-H2nbtc2− chains before being bridged by bpp ligands. Isostructural Co(ii) 8 and Ni(ii) 9 exhibit 1D looped infinite chains. Structural comparisons indicate that the SBUs, the coordination modes of the H4nbtc ligand, the synthetic conditions and the nature of the N-donor ligands are crucial factors with respect to the structures of these compounds. Furthermore, the luminescence properties of 1–7 were investigated in the solid state at room temperature. [ABSTRACT FROM AUTHOR]

The 1D complex [(CuL0.5H2O) ⋅H2O] n ( 1) (H4L=2,2′-bipyridine-3,3′,6,6′-tetracarboxylic acid) undergoes an irreversible thermally triggered single-crystal-to-single-crystal (SCSC) transformation to produce the 3D anhydrous complex [CuL0.5] n ( 2). This SCSC structural transformation was confirmed by single-crystal X-ray diffraction analysis, thermogravimetric (TG) analysis, powder X-ray diffraction (PXRD) patterns, variable-temperature powder X-ray diffraction (VT-PXRD) patterns, and IR spectroscopy. Structural analyses reveal that in complex 2, though the initial 1D chain is still retained as in complex 1, accompanied with the Cu-bound H2O removed and new O(carboxyl)Cu bond forming, the coordination geometries around the CuII ions vary from a distorted trigonal bipyramid to a distorted square pyramid. With the drastic structural transition, significant property changes are observed. Magnetic analyses show prominent changes from antiferromagnetism to weak ferromagnetism due to the new formed Cu1-O-C-O-Cu4 bridge. The catalytic results demonstrate that, even though both solid-state materials present high catalytic activity for the synthesis of 2-imidazolines derivatives and can be reused, the activation temperature of complex 1 is higher than that of complex 2. In addition, a possible pathway for the SCSC structural transformations is proposed. [ABSTRACT FROM AUTHOR]

Seven complexes, namely, {[Co2[(R,S)-bpdado]2(CH3CN)2(H2O)2]·2H2O}n1, {Cu[(R,S)-bpdado](H2O)}n2, {[Cu2[(R,S)-bpdado]2(H2O)2]·H2O}n2′, {[Cu(R,S)-bpdado]·EtOH}n2′′, {Cu[(R,S)-bpdado](phen)}2 (phen = 1,10-phenanthroline) 3, {Cu[(R,S)-bpdado](phen)(H2O)}2·8H2O 4 and {Cu[(R,S)-bpdado](dpy)(H2O)}2·4H2O (dpy = 2,2′-pyridine) 5, have been obtained via solvothermal or layered diffusional reaction based on an axially chiral ligand, (R,S)-2,2′-bipyridyl-3,3′-dicarboxylic acid-1,1′-dioxide ((R,S)-H2bpdado). These complexes tend to form under thermodynamic control in the crystallization process of complexes. Among them, 2′ and 2′′ were reported and obtained along with the preparation of 2. Five new complexes, 1–5, are characterized by single-crystal X-ray diffraction, elemental analyses, X-ray powder diffraction, and IR and thermogravimetric analyses. Four different structural complexes, 2D achiral layers 1, 2 and 2′′ and 1D nanotubular structure 2′, are constructed by the M3[(R,S)-bpdado] tecton (M = Co(ii) or Cu(ii)) in different arrangement modes. When various N-donor ligands are used, different binuclear complexes, 3–5, are assembled by the Cu2[(R,S)-bpdado] tecton in the same arrangement mode. Apart from the arrangement modes of the tecton, some other elements are also discussed, which influence the final structures, such as the coordination modes and conformations of (R,S)-bpdado, the different metal ions, the reaction temperature, the N-donor ligand and the solvent system. [ABSTRACT FROM AUTHOR]

The abuse of antibiotics has triggered the rise of drug-resistance bacteria, which has seriously threatened public health globally. As a result, carrying out efficient and accurate antibiotic and bacteria identification are quite significant but challenge. Herein, an unprecedented Cd-MOF-based sensor, [CdL] n [ 1 , H 2 L = 4-(2-methyl-1H-benzo[ d ]imidazol-1-yl) isophthalic acid] with multiple fluorescence response behaviours towards antibiotics and bacteria was developed. Single-crystal X-ray diffraction revealed that 1 is a mesomeric 2D bilayer, which is comprised of two opposite chiral mono-layers, each assembled by left-handed or right-handed helixes. More interestingly, 1 represented multiplex detection capability towards antibiotics and bacteria through two detection behaviors: toward nitro-antibiotics and chlortetracycline (CTC) via fluorescent quenching, while toward Staphylococcus albus (S. albus) via fluorescent enhancement. Remarkably, 1 showed a low limit of detection (LOD, 47 CFU/mL) accompanied with specificity in the detection of S. albus compared to other bacteria, such as Staphylococcus aureus , Acinetobacter baumannii , Klebsiella pneumonia , Pseudomonas aeruginosa and Escherichia coli. In addition, the LOD could reach to ppm level for nitro-antibiotics and CTC. Moreover, the practical application of 1 was further reinforced through the detection of nitro-antibiotics and CTC, as well as S. albus in fetal calf serum and river water. [Display omitted] • An unprecedented highly stable Cd-MOF multiple fluorescence sensor was reported. • This sensor can rapidly and efficiently identify antibiotics or bacteria. • It can be as "turn-off" sensor towards nitro antibiotics and chlortetracycline. • It can be as "emission enhancement" sensor towards Staphylococcus albus. [ABSTRACT FROM AUTHOR]

Two luminescent coordination polymers (LCPs), namely [CdL] ( 1) and [ZnL] ( 2) based on a new ligand 2-(2-methyl-benzimidazole-1-yl)-benzoic acid (HL), have been synthesized and characterized by single crystal X-ray diffraction, powder X-ray diffraction, infrared spectroscopy, elemental analysis, and thermogravimetric analysis. 1 and 2 exhibit similar 1D looped chains with different coordination modes of L. Both LCPs show strong fluorescent emission in the visible region. The fluorescence quenching response of 1 and 2 towards Fe over other metal ions in DMF has been demonstrated by quenching titrations. Thus, 1 and 2 can be used as potential and highly selective luminescent sensors for Fe ions. Graphical Abstract: [ABSTRACT FROM AUTHOR]