Effect of Different Carboxylates on a Series of Ag(I) Coordination Compounds with Benzoguanamine Ligand

The ultrasonic reactions of Ag2O with benzoguanamine and ancillary carboxylate ligands under the ammoniacal condition gave eight new coordination compounds (CCs), namely, [Ag4(bga)6(mal)2] (1), [Ag4(bga)6(mlc)2] (2), [Ag(bga)2(tpa)0.5]n (3), {[Ag(bga)(suc)0.5]·C2H5OH}n (4), {[Ag(bga)(pta)0.5]·CH3OH}n (5), {[Ag(bga)(ox)0.5]·C2H5OH·H2O}n (6), {[Ag2(bga)2(dnb)2]·DMF}n (7), and [Ag2(bga)2(pma)0.5(H2O)]n (8) (bga = benzoguanamine, H2mal = malonic acid, H2mlc = maleic acid, H2tpa = terephthalic acid, H2suc = succinic acid, H2pta = phthalic acid, H2ox = oxalic acid, Hdnb = 3,5-dinitrobenzoic acid, H4pma = pyromellitic acid, and DMF = N,N′-dimethylformamide). All CCs have been characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction. Compounds 1 and 2 are 0D discrete molecules and contain centrosymmetric [Ag2(mal)]2 and [Ag2(mlc)]2 units, respectively, which are extended to 1D supramolecular chains through intermolecule N–H···N complementary hydrogen bonds. Compounds 3 and 4 contain similar 1D [Ag2(tpa)]n and [Ag2(suc)]n infinite chains incorporating monodentate bga ligand as an ornament. It is noteworthy that the Ag···Ag interaction was exclusively observed in the 1D chain of compound 4, which may be caused by different coordination environments of the Ag(I) center between 3 and 4. The Ag···π interactions further extend the 1D chains into 2D sheet in 4. In 5 and 6, the μ2-bga ligands link Ag(I) ions to form 1D helical chains, which are further extended by μ2-dicarboxylate to 2D 63-hcb net incorporating different dimensions of hexagonal grids. Compound 7 is a 1D chain containing [Ag2(dnb)2] subunits, to which the monodentate and bidentate bga ligands as well as DMF coordinate. Compound 8 is a 2D sheet structure incorporating μ6-η1:η1:η1:η1:η1:η0:η1:η0 pma, monodentate and bidentate bga ligands. The results show that the structural diversity (0D–2D) of the CCs is mainly attributed to the usage of diverse ancillary carboxylate ligands as well as diverse coordination modes of bga ligand. Moreover, the photoluminescence properties of the CCs 1–6 were also investigated in the solid state at room temperature

Effect of Different Carboxylates on a Series of Ag(I) Coordination Compounds with Benzoguanamine Ligand

The ultrasonic reactions of Ag2O with benzoguanamine and ancillary carboxylate ligands under the ammoniacal condition gave eight new coordination compounds (CCs), namely, [Ag4(bga)6(mal)2] (1), [Ag4(bga)6(mlc)2] (2), [Ag(bga)2(tpa)0.5]n (3), {[Ag(bga)(suc)0.5]·C2H5OH}n (4), {[Ag(bga)(pta)0.5]·CH3OH}n (5), {[Ag(bga)(ox)0.5]·C2H5OH·H2O}n (6), {[Ag2(bga)2(dnb)2]·DMF}n (7), and [Ag2(bga)2(pma)0.5(H2O)]n (8) (bga = benzoguanamine, H2mal = malonic acid, H2mlc = maleic acid, H2tpa = terephthalic acid, H2suc = succinic acid, H2pta = phthalic acid, H2ox = oxalic acid, Hdnb = 3,5-dinitrobenzoic acid, H4pma = pyromellitic acid, and DMF = N,N′-dimethylformamide). All CCs have been characterized by elemental analyses, IR spectra, and single-crystal X-ray diffraction. Compounds 1 and 2 are 0D discrete molecules and contain centrosymmetric [Ag2(mal)]2 and [Ag2(mlc)]2 units, respectively, which are extended to 1D supramolecular chains through intermolecule N–H···N complementary hydrogen bonds. Compounds 3 and 4 contain similar 1D [Ag2(tpa)]n and [Ag2(suc)]n infinite chains incorporating monodentate bga ligand as an ornament. It is noteworthy that the Ag···Ag interaction was exclusively observed in the 1D chain of compound 4, which may be caused by different coordination environments of the Ag(I) center between 3 and 4. The Ag···π interactions further extend the 1D chains into 2D sheet in 4. In 5 and 6, the μ2-bga ligands link Ag(I) ions to form 1D helical chains, which are further extended by μ2-dicarboxylate to 2D 63-hcb net incorporating different dimensions of hexagonal grids. Compound 7 is a 1D chain containing [Ag2(dnb)2] subunits, to which the monodentate and bidentate bga ligands as well as DMF coordinate. Compound 8 is a 2D sheet structure incorporating μ6-η1:η1:η1:η1:η1:η0:η1:η0 pma, monodentate and bidentate bga ligands. The results show that the structural diversity (0D–2D) of the CCs is mainly attributed to the usage of diverse ancillary carboxylate ligands as well as diverse coordination modes of bga ligand. Moreover, the photoluminescence properties of the CCs 1–6 were also investigated in the solid state at room temperature

Solvent-Controlled Rare Case of a Triple Helical Molecular Braid Assembled from Proton-Transferred Sebacic Acid

A novel triple helix based on proton-transferred sebacic acid was observed in a 1:1 organic salt of [(Hambtz)+(Hsba)−·2H2O] (1, ambtz = 2-amino-6-methoxybenzothiazole, H2sba = sebacic acid) incorporating a zigzag water chain. Changing the solvent system, another simple 1D zigzag chain, cocrystal [(ambtz)2(H2sba)] (2), was obtained. The structural dissimilarity between them was dependent on different conformations of ambtz and H2sba modulated by solvent systems. The photoluminescence behaviors of 1 and 2 were also discussed

Solvent-Controlled Rare Case of a Triple Helical Molecular Braid Assembled from Proton-Transferred Sebacic Acid

A novel triple helix based on proton-transferred sebacic acid was observed in a 1:1 organic salt of [(Hambtz)+(Hsba)−·2H2O] (1, ambtz = 2-amino-6-methoxybenzothiazole, H2sba = sebacic acid) incorporating a zigzag water chain. Changing the solvent system, another simple 1D zigzag chain, cocrystal [(ambtz)2(H2sba)] (2), was obtained. The structural dissimilarity between them was dependent on different conformations of ambtz and H2sba modulated by solvent systems. The photoluminescence behaviors of 1 and 2 were also discussed

Probing Hydrogen Bond Energies by Mass Spectrometry

Mass spectrometry with desorption electrospray ionization (DESI) is demonstrated to be useful for probing the strength of hydrogen bonding, exemplified by various complexes of benzothiazoles and carboxylic acids in the solid state. Efficiencies for fragmentation of the complexes, quantified by collision-induced dissociation (CID) technology, correspond well with energies of the hydrogen bonds of O–H···N and N–H···O bridging each pair of benzothiazole and carboxylic acid. Linear correlations (with correlation factors of 0.8953 and 0.9928) have been established for the calibration curves of normalized collision energy at 100% fragmentation rate vs the length between donor and acceptor (in the hydrogen bond of O–H···N) as well as the slope of the fragmentation efficiency curve vs the average length difference between O–H···N and N–H···O in the complex. The mechanism responsible for determination of the hydrogen bonds is proposed on the basis of the experiments starting from the mixtures of the complexes as well as labeling with deuterium. As a complement of previously available methods (e.g., X-ray diffraction analysis), expectably, the proposed mass spectrometric method seems to be versatile for probing hydrogen bond energies

Probing Hydrogen Bond Energies by Mass Spectrometry

Mass spectrometry with desorption electrospray ionization (DESI) is demonstrated to be useful for probing the strength of hydrogen bonding, exemplified by various complexes of benzothiazoles and carboxylic acids in the solid state. Efficiencies for fragmentation of the complexes, quantified by collision-induced dissociation (CID) technology, correspond well with energies of the hydrogen bonds of O–H···N and N–H···O bridging each pair of benzothiazole and carboxylic acid. Linear correlations (with correlation factors of 0.8953 and 0.9928) have been established for the calibration curves of normalized collision energy at 100% fragmentation rate vs the length between donor and acceptor (in the hydrogen bond of O–H···N) as well as the slope of the fragmentation efficiency curve vs the average length difference between O–H···N and N–H···O in the complex. The mechanism responsible for determination of the hydrogen bonds is proposed on the basis of the experiments starting from the mixtures of the complexes as well as labeling with deuterium. As a complement of previously available methods (e.g., X-ray diffraction analysis), expectably, the proposed mass spectrometric method seems to be versatile for probing hydrogen bond energies