Displaying publications 1 - 20 of 88 in total

Abstract:
Sort:
  1. Fulltext (2-{[1,1-Bis(hy-droxy-meth-yl)-2-oxidoeth-yl]imino-meth-yl}-4-chloro-phenolato-κO,N,O')dibutyl-tin(IV)
    Lee SM, Mohd Ali H, Lo KM
    Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 7):m793.
    PMID: 21587717 DOI: 10.1107/S1600536810021872
    In the title compound, [Sn(C(4)H(9))(2)(C(11)H(12)BrNO(4))], the Schiff base ligand chelates to the Sn(IV) atom through the two deprotonated hy-droxy groups, as well as through the N atom, to confer an overall cis-C(2)SnNO(2) trigonal-bipyramidal geometry at the Sn(IV) atom [C-Sn-C = 129.92 (9)°]. The remaining methyl-enehy-droxy groups engage in O-H⋯O hydrogen bonding with the O atoms of adjacent mol-ecules, leading to infinite supra-molecular chains propagating in [001].
  2. (Tris{2-[(5-chloro-2-oxido-benzyl-idene-κO)amino-κN]eth-yl}amine-κN)-ytterbium(III): crystal structure and Hirshfeld surface analysis
    Lee SM, Lo KM, Tan SL, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2016 Oct 1;72(Pt 10):1390-1395.
    PMID: 27746926
    The Yb(III) atom in the title complex, [Yb(C27H24Cl3N4O3)] [systematic name: (2,2',2''-{(nitrilo)-tris-[ethane-2,1-di-yl(nitrilo)-methylyl-idene]}tris-(4-chloro-phenolato)ytterbium(III)], is coordinated by a trinegative, hepta-dentate ligand and exists within an N4O3 donor set, which defines a capped octa-hedral geometry whereby the amine N atom caps the triangular face defined by the three imine N atoms. The packing features supra-molecular layers that stack along the a axis, sustained by a combination of aryl-C-H⋯O, imine-C-H⋯O, methyl-ene-C-H⋯π(ar-yl) and end-on C-Cl⋯π(ar-yl) inter-actions. A Hirshfeld surface analysis points to the major contributions of C⋯H/ H⋯C and Cl⋯H/H⋯Cl inter-actions (along with H⋯H) to the overall surface but the Cl⋯H contacts are at distances greater than the sum of their van der Waals radii.
  3. 1-Chloro-4-[2-(4-chloro-phen-yl)eth-yl]benzene and its bromo analogue: crystal structure, Hirshfeld surface analysis and computational chemistry
    Jotani MM, Lee SM, Lo KM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2019 May 01;75(Pt 5):624-631.
    PMID: 31110800 DOI: 10.1107/S2056989019004742
    The crystal and mol-ecular structures of C14H12Cl2, (I), and C14H12Br2, (II), are described. The asymmetric unit of (I) comprises two independent mol-ecules, A and B, each disposed about a centre of inversion. Each mol-ecule approximates mirror symmetry [the Cb-Cb-Ce-Ce torsion angles = -83.46 (19) and 95.17 (17)° for A, and -83.7 (2) and 94.75 (19)° for B; b = benzene and e = ethyl-ene]. By contrast, the mol-ecule in (II) is twisted, as seen in the dihedral angle of 59.29 (11)° between the benzene rings cf. 0° in (I). The mol-ecular packing of (I) features benzene-C-H⋯π(benzene) and Cl⋯Cl contacts that lead to an open three-dimensional (3D) architecture that enables twofold 3D-3D inter-penetration. The presence of benzene-C-H⋯π(benzene) and Br⋯Br contacts in the crystal of (II) consolidate the 3D architecture. The analysis of the calculated Hirshfeld surfaces confirm the influence of the benzene-C-H⋯π(benzene) and X⋯X contacts on the mol-ecular packing and show that, to a first approximation, H⋯H, C⋯H/H⋯C and C⋯X/X⋯C contacts dominate the packing, each contributing about 30% to the overall surface in each of (I) and (II). The analysis also clearly differentiates between the A and B mol-ecules of (I).
  4. Fulltext 2-{1-[2-((2-Ammonio-ethyl){2-[1-(5-chloro-2-hydroxy-phen-yl)ethyl-idene-amino]eth-yl}amino)ethyl-iminio]eth-yl}-4-chloro-phenolate trifluoro-acetate
    Lee SM, Ali HM, Lo KM, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 2):o410.
    PMID: 21582002 DOI: 10.1107/S1600536809002943
    In the title ion-pair, C(22)H(29)Cl(2)N(4)O(2) (+)·C(2)F(3)O(2) (-), ammonium-carboxyl-ate N-H⋯O hydrogen bonds link two cations and two anions about a centre of inversion to generate a hydrogen-bonded tetramer. In the cation, one of the imino N atoms is protonated and donates a hydrogen bond to the O atom of the adjacent chloro-phenyl ring. The other imino N atom acts as a hydrogen-bond acceptor from a phenolate O atom.
  5. Fulltext 2-{1-[2-(Bis{2-[1-(5-chloro-2-hydroxy-phen-yl)ethyl-ideneamino]eth-yl}amino)-ethyl-iminio]eth-yl}-4-chloro-phenolate toluene hemisolvate
    Lee SM, Ali HM, Lo KM, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 2):o409.
    PMID: 21582001 DOI: 10.1107/S1600536809002906
    In the toluene hemisolvated tripodal tris-(2-amino-ethyl)amine Schiff base, C(30)H(33)Cl(3)N(4)O(3)·0.5C(7)H(8), one of the three imino N atoms is protonated, forming a hydrogen bond with the O atom at an adjacent benzene ring. The other two imino N atoms act as hydrogen-bond acceptors from phenolate OH groups. The toluene solvent mol-ecule is disordered about a centre of inversion.
  6. Fulltext 3-Hydr-oxy-N'-isopropyl-idene-2-naphthohydrazide
    Lee SM, Lo KM, Ali HM, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 12):o3282.
    PMID: 21578975 DOI: 10.1107/S1600536809050661
    The title Schiff base, C(14)H(14)N(2)O(2), is close to being planar (r.m.s. deviation for the non-hydrogen atoms = 0.052 Å) and an intra-molecular N-H⋯O hydrogen bond generates an S(6) ring. In the crystal, the moleucles are linked by O-H⋯O hydrogen bonds, giving rise to helical chains propagating along the c axis of the tetra-gonal unit cell.
  7. A 6-year safety surveillance of 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) in South Korea
    Lee SM, Lee JH, Song ES, Kim SJ, Kim JH, Jakes RW, et al.
    Hum Vaccin Immunother, 2018 Aug 07.
    PMID: 30084702 DOI: 10.1080/21645515.2018.1502525
    In 2010, Korea introduced 10-valent pneumococcal conjugate vaccine for children aged 6 weeks to 5 years against invasive disease caused by Streptococcus pneumoniae serotypes 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, 23F and cross-reactive 19A. The aim of this 6-year real-world study of 646 healthy Korean children from 16 centers vaccinated in routine practice is to monitor vaccine safety, as per Ministry of Food and Drug Safety regulations. Around 50% had a past or existing medical condition, 19.3% an existing condition and 7.6% received concomitant medication). Total of 489 recorded adverse events (AEs) were reported in 274 infants; 86% were mild and the rest moderate, only three were reported as serious. Most AEs (97.8%) were not related to vaccination; one case of injection-site swelling and of fever was related, two cases of fever were probably related, five cases of fever and one case each of diarrhea and coughing were possibly related. None of the serious AEs were related to vaccination. Of 11 adverse drug reactions (ADRs) in 10 subjects, none were serious. Overall, 263 subjects (40.7%) received medication (mainly antibiotics or antipyretics) for the treatment of an AE, of which 6 subjects were treated for an ADR. There was no difference in the incidence of AEs according to age, sex or concomitant vaccination. Subjects with an existing medical condition had significantly more AEs than those without any conditions (p = 0.03), but no differences regarding ADRs. Four-dose vaccination with PHiD-CV appears to have a clinically-acceptable safety profile for Korean children. ClinicalTrials.gov identifier: NCT01248988.
  8. Fulltext A novel CT-emphysema index/FEV1 approach of phenotyping COPD to predict mortality
    Loh LC, Ong CK, Koo HJ, Lee SM, Lee JS, Oh YM, et al.
    Int J Chron Obstruct Pulmon Dis, 2018;13:2543-2550.
    PMID: 30174423 DOI: 10.2147/COPD.S165898
    Background: COPD-associated mortality was examined using a novel approach of phenotyping COPD based on computed tomography (CT)-emphysema index from quantitative CT (QCT) and post-bronchodilator (BD) forced expiratory volume in 1 second (FEV1) in a local Malaysian cohort.

    Patients and methods: Prospectively collected data of 112 eligible COPD subjects (mean age, 67 years; male, 93%; mean post-BD FEV1, 45.7%) was available for mortality analysis. Median follow-up time was 1,000 days (range, 60-1,400). QCT and clinicodemographic data were collected at study entry. Based on CT-emphysema index and post-BD FEV1% predicted, subjects were categorized into "emphysema-dominant," "airway-dominant," "mild mixed airway-emphysema," and "severe mixed airway-emphysema" diseases.

    Results: Sixteen patients (14.2%) died of COPD-associated causes. There were 29 (25.9%) "mild mixed," 23 (20.5%) "airway-dominant," 15 (13.4%) "emphysema-dominant," and 45 (40.2%) "severe mixed" cases. "Mild mixed" disease was proportionately more in Global Initiative for Chronic Obstructive Lung Disease (GOLD) Group A, while "severe mixed" disease was proportionately more in GOLD Groups B and D. Kaplan-Meier survival estimates showed increased mortality risk with "severe mixed" disease (log rank test, p=0.03) but not with GOLD groups (p=0.08). Univariate Cox proportionate hazard analysis showed that age, body mass index, long-term oxygen therapy, FEV1, forced volume capacity, COPD Assessment Test score, modified Medical Research Council score, St Georges' Respiratory Questionnaire score, CT-emphysema index, and "severe mixed" disease (vs "mild mixed" disease) were associated with mortality. Multivariate Cox analysis showed that age, body mass index, and COPD Assessment Test score remain independently associated with mortality.

    Conclusion: "Severe mixed airway-emphysema" disease may predict COPD-associated mortality. Age, body mass index, and COPD Assessment Test score remain as key mortality risk factors in our cohort.
  9. A statistical approach for modelling the physical process of bacterial attachment to abiotic surfaces
    Wang Y, Lee SM, Gentle IR, Dykes GA
    Biofouling, 2020 11;36(10):1227-1242.
    PMID: 33412938 DOI: 10.1080/08927014.2020.1865934
    A statistical approach using a polynomial linear model in combination with a probability distribution model was developed to mathematically represent the process of bacterial attachment and study its mechanism. The linear deterministic model was built based on data from experiments investigating bacterial and substratum surface physico-chemical factors as predictors of attachment. The prediction results were applied to a normal-approximated binomial distribution model to probabilistically predict attachment. The experimental protocol used mixtures of Streptococcus salivarius and Escherichia coli, and mixtures of porous poly(butyl methacrylate-co-ethyl dimethacrylate) and aluminum sec-butoxide coatings, at varying ratios, to allow bacterial attachment to substratum surfaces across a range of physico-chemical properties (including the surface hydrophobicity of bacterial cells and the substratum, the surface charge of the cells and the substratum, the substratum surface roughness and cell size). The model was tested using data from independent experiments. The model indicated that hydrophobic interaction was the most important predictor while reciprocal interactions existed between some of the factors. More importantly, the model established a range for each factor within which the resultant attachment is unpredictable. This model, however, considers bacterial cells as colloidal particles and accounts only for the essential physico-chemical attributes of the bacterial cells and substratum surfaces. It is therefore limited by a lack of consideration of biological and environmental factors. This makes the model applicable only to specific environments and potentially provides a direction to future modelling for different environments.
  10. A three-dimensional (3D) printing approach to fabricate an isolation chip for high throughput in situ cultivation of environmental microbes
    Goh CBS, Goh CHP, Wong LW, Cheng WT, Yule CM, Ong KS, et al.
    Lab Chip, 2022 Jan 18;22(2):387-402.
    PMID: 34935836 DOI: 10.1039/d1lc00723h
    The full plethora of environmental bacteria is often poorly represented in vitro as the majority remain difficult, if not impossible, to culture under standard laboratory settings. These bacteria often require native conditions for the formation of cell masses that collectively have higher chances of survival. With that, a 3D-printed version of the isolation chip (iChip) was used to cultivate bacteria from a tropical peat swamp in situ prior to growth and maintenance in vitro. Briefly, plates made from either acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), or epoxy resin were tested in terms of their usability and durability under acidic conditions similar to those of peat matter. The epoxy resin plates were then found to be most optimal for the sampling conditions. Peat soil samples were collected from the base of a Koompassia malaccensis tree and reconstituted in molten 10% (wt/vol) tryptone soy agar (TSA) prior to inoculation. The iChips were subsequently assembled and buried in the site of origin. As a comparison, bacteria from the same soil sample were cultivated directly on TSA and incubated at 28 °C for two weeks. Thereafter, agar plugs from the iChip were transferred to TSA plates to allow microcolonies within each plug to grow. Each pure isolate from both cultivation approaches that grew was then pooled and extracted for total DNA prior to 16S rRNA gene amplification and sequencing via Illumina MiSeq. Taxonomic abundance comparison revealed that the bacterial taxa at the level of order were significantly different between the two approaches, particularly in the orders, Burkholderiales, Xanthomonodales, Enterobacteriales, and Actinomycetales (differences of 12.0, 7.1, 8.0, and 4.2%, respectively). This indicated that the 3D-printed iChips present a possible low-cost tool for the isolation of bacterial genera that may not be able to grow on media directly in vitro.
  11. Acetic acid induces pH-independent cellular energy depletion in Salmonella enterica
    Tan SM, Lee SM, Dykes GA
    Foodborne Pathog Dis, 2015 Mar;12(3):183-9.
    PMID: 25562466 DOI: 10.1089/fpd.2014.1853
    Weak organic acids are widely used as preservatives and disinfectants in the food industry. Despite their widespread use, the antimicrobial mode of action of organic acids is still not fully understood. This study investigated the effect of acetic acid on the cell membranes and cellular energy generation of four Salmonella strains. Using a nucleic acid/protein assay, it was established that acetic acid did not cause leakage of intracellular components from the strains. A scanning electron microscopy study further confirmed that membrane disruption was not the antimicrobial mode of action of acetic acid. Some elongated Salmonella cells observed in the micrographs indicated a possibility that acetic acid may inhibit DNA synthesis in the bacterial cells. Using an ATP assay, it was found that at a neutral pH, acetic acid caused cellular energy depletion with an ADP/ATP ratio in the range between 0.48 and 2.63 (p<0.05) that was apparent for the four Salmonella strains. We suggest that this effect was probably due solely to the action of undissociated acid molecules. The antimicrobial effect of acetic acid was better under acidic conditions (ADP/ATP ratio of 5.56 ± 1.27; p<0.05), where the role of both pH and undissociated acid molecules can act together. We concluded that the inhibitory effect of acetic acid is not solely attributable to acidic pH but also to undissociated acid molecules. This finding has implication for the use of acetic acid as an antimicrobial against Salmonella on food products, such as chicken meat, which can buffer its pH.
  12. Fulltext Antioxidant Content, Antioxidant Activity, and Antibacterial Activity of Five Plants from the Commelinaceae Family
    Tan JB, Yap WJ, Tan SY, Lim YY, Lee SM
    Antioxidants (Basel), 2014 Nov 17;3(4):758-69.
    PMID: 26785239 DOI: 10.3390/antiox3040758
    Commelinaceae is a family of herbaceous flowering plants with many species used in ethnobotany, particularly in South America. However, thus far reports of their bioactivity are few and far between. The primary aim of this study was to quantify the antioxidant and antibacterial activity of five Commelinaceae methanolic leaf extracts. The antioxidant content was evaluated by the total phenolic content (TPC), total tannin content (TTC), and total flavonoid content (TFC) assays. The antioxidant activities measured were DPPH free radical scavenging (FRS), ferric reducing power (FRP), and ferrous ion chelating (FIC); of the five plants, the methanolic leaf extract of Tradescantia zebrina showed the highest antioxidant content and activity, and exhibited antibacterial activity against six species of Gram-positive and two species of Gram-negative bacteria in a range of 5-10 mg/mL based on the broth microdilution method.
  13. Fulltext Antioxidant and antibacterial activity of Rhoeo spathacea (Swartz) Stearn leaves
    Tan JB, Lim YY, Lee SM
    J Food Sci Technol, 2015 Apr;52(4):2394-400.
    PMID: 25829624 DOI: 10.1007/s13197-013-1236-z
    The decoction and infusion of Rhoeo spathacea (Swartz) Stearn leaves have been recognized as a functional food particularly in South America, but has not yet gained international popularity as a beverage. The primary aim of this study was to establish the viability of R. spathacea aqueous leaf extracts as a beverage, in terms of its antioxidant activity and antibacterial activity. The antioxidant contents of aqueous and methanol leaf extracts were evaluated by the total phenolic content (TPC) and total flavonoid content (TFC) assays. The antioxidant activities measured were DPPH radical scavenging activity (FRS), ferric reducing power (FRP) and ferrous ion chelating (FIC) activity. The aqueous leaf extracts in the forms of decoction and infusion, were found to have comparable TPC and antioxidant activity with other herbal teas previously reported by our research group. Both decoction and infusion also exhibited antibacterial activity against six species of Gram positive and four species of Gram negative bacteria, notably methicillin-resistant Staphylococcus aureus and Neisseria gonorrhoeae. A total of four different known phenolic compounds were identified by HPLC and MS, three of which have not been previously reported to be found in this plant. Both the decoction and infusion of the leaves R. spathacea have potential to be popularized into a common beverage.
  14. Fulltext Aqua-{6,6'-dimeth-oxy-2,2'-[ethane-1,2-diylbis(nitrilo-methyl-idyne)]diphenolato-κO,N,N',O'}(formato-κO)manganese(III) dihydrate
    Lee SM, Lo KM, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2011 Jun 01;67(Pt 6):m746.
    PMID: 21754637 DOI: 10.1107/S1600536811017648
    The Mn(III) atom in the title complex, [Mn(C(18)H(18)N(2)O(4))(CHO(2))(H(2)O)]·2H(2)O, is O,N,N',O'-chelated by the deproton-ated Schiff base; the four chelating atoms form an approximate square, with the O atoms of the water mol-ecule and the formate ion in axial positions above and below the square plane. Two metal-bearing mol-ecules are linked by an O-H(water)⋯O hydrogen bond about a center of inversion, generating a hydrogen-bonded dinuclear species; adjacent dinuclear units are linked through the lattice water mol-ecules, forming a three-dimensional network.
  15. Fulltext Association of some Campylobacter jejuni with Pseudomonas aeruginosa biofilms increases attachment under conditions mimicking those in the environment
    Teh AHT, Lee SM, Dykes GA
    PLoS One, 2019;14(4):e0215275.
    PMID: 30970009 DOI: 10.1371/journal.pone.0215275
    Campylobacter jejuni is a microaerophilic bacterial species which is a major food-borne pathogen worldwide. Attachment and biofilm formation have been suggested to contribute to the survival of this fastidious bacteria in the environment. In this study the attachment of three C. jejuni strains (C. jejuni strains 2868 and 2871 isolated from poultry and ATCC 33291) to different abiotic surfaces (stainless steel, glass and polystyrene) alone or with Pseudomonas aeruginosa biofilms on them, in air at 25°C and under static or flow conditions, were investigated using a modified Robbins Device. Bacteria were enumerated and scanning electron microscopy was carried out. The results indicated that both C. jejuni strains isolated from poultry attached better to Pseudomonas aeruginosa biofilms on abiotic surfaces than to the surfaces alone under the different conditions tested. This suggests that biofilms of other bacterial species may passively protect C. jejuni against shear forces and potentially oxygen stress which then contribute to their persistence in environments which are detrimental to them. By contrast the C. jejuni ATCC 33291 strain did not attach differentially to P. aeruginosa biofilms, suggesting that different C. jejuni strains may have alternative strategies for persistence in the environment. This study supports the hypothesis that C. jejuni do not form biofilms per se under conditions they encounter in the environment but simply attach to surfaces or biofilms of other species.
  16. Bactericidal and cytotoxic activity of a diarylheptanoid (etlingerin) isolated from a ginger (Etlingera pubescens) endemic to Borneo
    Daniel-Jambun D, Ong KS, Lim YY, Tan JBL, Yap SW, Lee SM
    J Appl Microbiol, 2019 Jul;127(1):59-67.
    PMID: 31006174 DOI: 10.1111/jam.14287
    AIMS: The aim of this study was to investigate the antimicrobial activities of Etlingera pubescens, and to isolate and identify the antimicrobial compound.

    METHODS AND RESULTS: The crude extracts of E. pubescens were obtained through methanol extraction, and evaluated for antimicrobial activities. From this extract, 1,7-bis(3,4-dihydroxyphenyl)heptan-3-yl acetate (etlingerin) was isolated. When compared to curcumin (a compound with a similar chemical structure), etlingerin showed twofold lower minimum inhibitory concentration values while also being bactericidal. Through time kill assay, etlingerin showed rapid killing effects (as fast as 60 min) against the Gram-positive bacteria (Staphylococcus aureus ATCC 43300 and Bacillus subtilis ATCC 8188). Further assessment revealed that etlingerin caused leakage of intracellular materials, therefore suggesting alteration in membrane permeability as its antimicrobial mechanism. Cytotoxicity study demonstrated that etlingerin exhibited approximately 5- to 12-fold higher IC50 values against several cell lines, as compared to curcumin.

    CONCLUSIONS: Etlingerin isolated from E. pubescens showed better antibacterial and cytotoxic activities when compared to curcumin. Etlingerin could be safe for human use, though further cytotoxicity study using animal models is needed.

    SIGNIFICANCE AND IMPACT OF THE STUDY: Etlingerin has a potential to be used in treating bacterial infections due to its good antimicrobial activity, while having potentially low cytotoxicity.

  17. Biofilm inhibiting activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms
    Yong YY, Dykes G, Lee SM, Choo WS
    J Appl Microbiol, 2019 Jan;126(1):68-78.
    PMID: 30153380 DOI: 10.1111/jam.14091
    AIMS: To investigate the biofilm inhibitory activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms.

    METHODS AND RESULTS: The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by subfractionation to obtain betacyanin fraction. The anti-biofilm activity was examined using broth microdilution assay on polystyrene surfaces and expressed as minimum biofilm inhibitory concentration (MBIC). The betacyanin fraction from red spinach showed better anti-biofilm activity (MBIC: 0·313-1·25 mg ml-1 ) against five Staph. aureus strains while the betacyanin fraction from red pitahaya showed better anti-biofilm activity (MBIC: 0·313-0·625 mg ml-1 ) against four P. aeruginosa strains. Both betacyanin fraction significantly reduced hydrophobicity of Staph. aureus and P. aeruginosa strains. Numbers of Staph. aureus and P. aeruginosa attached to polystyrene were also reduced without affecting their cell viability.

    CONCLUSION: Betacyanins can act as anti-biofilm agents against the initial step of biofilm formation, particularly on a hydrophobic surface like polystyrene.

    SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to investigate the use of betacyanin as a biofilm inhibitory agent. Betacyanin could potentially be used to reduce the risk of biofilm-associated infections.

  18. Fulltext Bis(μ2-N-methyl-N-phenyl-dithio-carbamato)-κ(3)S,S':S;κ(3)S:S,S'-bis-[(N-methyl-N-phenyl-dithio-carbamato-κ(2)S,S')cadmium]: crystal structure and Hirshfeld surface analysis
    Suwardi SA, Lee SM, Lo KM, Jotani MM, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2017 Mar 01;73(Pt 3):429-433.
    PMID: 28316825 DOI: 10.1107/S2056989017002705
    The title compound, [Cd2(C8H8NS2)4], is a centrosymmetric dimer with both chelating and μ2-tridentate di-thio-carbamate ligands. The resulting S5 donor set defines a Cd(II) coordination geometry inter-mediate between square-pyramidal and trigonal-bipyramidal, but tending towards the former. The packing features C-H⋯S and C-H⋯π inter-actions, which generate a three-dimensional network. The influence of these inter-actions, along with intra-dimer π-π inter-actions between chelate rings, has been investigated by an analysis of the Hirshfeld surface.
  19. Fulltext Bis[4-(dimethyl-amino)pyridinium] tetra-bromidobis(4-chloro-phen-yl)stannate(IV)-4-bromo-chloro-benzene (1/1)
    Lee SM, Lo KM, Mohd Ali H, Robinson WT
    Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 9):m1039.
    PMID: 21577402 DOI: 10.1107/S1600536809030232
    In the title compound, (C(7)H(11)N(2))(2)[SnBr(4)(C(6)H(4)Cl)(2)]·C(6)H(4)BrCl, the Sn(IV) atom in the tetra-bromidobis(4-chloro-phen-yl)stannate(IV) anion lies on a centre of inversion. The distances between the 4-(dimethyl-amino)pyridinium N atom and the Br atoms of the anion are 3.450 (2) and 3.452 (2) Å, suggesting weak hydrogen bonding. The 4-bromo-chloro-benzene solvent mol-ecule, which is a bromination by-product from the reaction, is disordered about a twofold rotation axis with approximately equal occupancy.
  20. Fulltext Bis[4-(dimethyl-amino)pyridinium] tetra-bromidobis(4-methyl-phen-yl)stannate(IV)
    Lee SM, Lo KM, Mohd Ali H, Robinson WT
    Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 9):m1040.
    PMID: 21577403 DOI: 10.1107/S1600536809030323
    In the title compound, (C(7)H(11)N(2))(2)[SnBr(4)(C(7)H(7))(2)], the tetra-bromidobis(4-methyl-phen-yl)stannate(IV) anion possesses a centre of inversion located at the Sn(IV) atom. In the crystal structure, two inversion-related cations are linked to the anion via weak N-H⋯Br hydrogen bonds.
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links