Displaying publications 1 - 20 of 46 in total

  1. Tan SL
    Med J Malaysia, 1980 Dec;35(2):162-3.
    PMID: 7266411
    A 103 year old patient was admitted with pain in the right iliac fossa. There was no response to conservative treatment. Subsequent laparatomy showed the presence of a perforated ulcer in the pyloric region. The condition improved gradually after the surgical management.
  2. Harith S, Tan SL
    Ann Geriatr Med Res, 2020 Jun;24(2):115-124.
    PMID: 32743332 DOI: 10.4235/agmr.20.0005
    Background: This study aimed to translate and validate the comprehensive geriatric assessment (CGA) questionnaire among older adult patients in Malaysia in the Malay language.

    Methods: The questionnaire contained items on the socio-demographic characteristics, medical condition, quality of life (QOL), nutritional status, functional capacity, and depression status. The forward and backward translation processes of the original English language version of the questionnaire were undertaken by three independent linguistic translators, while its content was validated by an expert team consisting of seven geriatricians, physicians, dietitian, and lecturers. The Malay version of the questionnaire was tested for face validity in 10 older adult patients over 65 years of age. The internal consistency reliability and construct validity were evaluated among 166 older adult patients (mean age, 71.0 years; 73.5% male). The questionnaire was administered through face-to-face interviews with the patients. Minor amendments were made after the content and face validity tests.

    Results: The internal consistency reliability was good, as the Cronbach's alpha for most of the scales surpassed 0.70, ranging from 0.70 to 0.98, with only one exception (Mini Nutritional Assessment Short-Form, Cronbach's alpha=0.62). The factor loadings for all scales were satisfactory (>0.40), ranging from 0.45 to 0.90.

    Conclusion: The Malay-version CGA showed evidence of satisfactory internal consistency reliability and construct validity in Malaysian geriatric patients.

  3. Tan SL, Juliana S, Sakinah H
    Malays J Nutr, 2011 Dec;17(3):287-99.
    PMID: 22655451 MyJurnal
    Compliance with medical nutrition therapy is important to improve patient outcomes. The purpose of this study was to determine dietary compliance and its association with glycemic control among outpatients with poorly controlled type 2 diabetes mellitus (T2DM) in Hospital Universiti Sains Malaysia (HUSM).
  4. Ng SF, Tan SL
    Int J Pharm, 2015 Nov 30;495(2):798-806.
    PMID: 26434999 DOI: 10.1016/j.ijpharm.2015.09.057
    Topical chemotherapy is the application of cancer drugs directly onto the skin, which has become a standard treatment for basal cell carcinoma. Due to the promising results in the treatment of skin cancer, topical chemotherapy has recently been applied to breast cancer patients because some breast cancer tissues are only superficial. Hydroxytyrosol, a phenolic compound from olives that is present in high amounts in Hidrox(®) olive extract, has been shown to have a protective effect on normal cells and selective antitumor activities on cancerous cells. The aims of the present study were to develop an alginate bilayer film containing Hidrox(®) and to investigate its potential use as a topical chemotherapeutic agent. Alginate films were characterized for swelling and for physical, thermal, rheological, and mechanical properties. Drug content uniformity and in vitro drug release tests were also investigated. The alginate bilayer films containing Hidrox(®), HB2, showed controlled release of hydroxytyrosol at a flux of 0.094±0.009 mg/cm(2)/h. The results of the cytotoxic assay showed that the HB2 films were dose-dependent and could significantly reduce the growth of breast cancer cells (MCF-7) at 150 μg/mL for a cell viability of 29.34±4.64%. In conclusion, an alginate bilayer film containing Hidrox(®) can be a potential alternative for topical chemotherapeutic agent for skin and breast cancer treatment.
  5. Tan SL, Tiekink ERT
    PMID: 31161060 DOI: 10.1107/S205698901900375X
    The asymmetric unit of the three-component title compound, 2,2'-di-thiodi-benzoic acid-2-chloro-benzoic acid-N,N-di-methyl-formamide (1/1/1), C14H10O4S2·C7H5ClO2·C3H7NO, contains a mol-ecule each of 2,2'-di-thiodi-benzoic acid (DTBA), 2-chloro-benzoic acid (2CBA) and di-methyl-formamide (DMF). The DTBA mol-ecule is twisted [the C-S-S-C torsion angle is 88.37 (17)°] and each carb-oxy-lic group is slightly twisted from the benzene ring to which it is connected [CO2/C6 dihedral angles = 7.6 (3) and 12.5 (3)°]. A small twist is evident in the mol-ecule of 2CBA [CO2/C6 dihedral angle = 4.4 (4)°]. In the crystal, the three mol-ecules are connected by hydrogen bonds with the two carb-oxy-lic acid residues derived from DTBA and 2CBA forming a non-symmetric eight-membered {⋯HOCO}2 synthon, and the second carb-oxy-lic acid of DTBA linked to the DMF mol-ecule via a seven-membered {⋯HOCO⋯HCO} heterosynthon. The three-mol-ecule aggregates are connected into a supra-molecular chain along the a axis via DTBA-C-H⋯O(hydroxyl-2CBA), 2CBA-C-H⋯O(hydroxyl-DTBA) and DTBA-C-H⋯S(DTBA) inter-actions. Supra-molecular layers in the ab plane are formed as the chains are linked via DMF-C-H⋯S(DTBA) contacts, and these inter-digitate along the c-axis direction without specific points of contact between them. A Hirshfeld surface analysis points to additional but, weak contacts to stabilize the three-dimensional architecture: DTBA-C=O⋯H(phenyl-DTBA), 2CBA-Cl⋯H(phenyl-DTBA), as well as a π-π contact between the delocalized eight-membered {⋯HOC=O}2 carb-oxy-lic dimer and the phenyl ring of 2CBA. The latter was confirmed by electrostatic potential (ESP) mapping.
  6. Tan SL, Tiekink ERT
    PMID: 30574371 DOI: 10.1107/S205698901801544X
    The asymmetric unit of the title co-crystal, 2,2'-thiodi-benzoic acid-tri-phenyl-phosphane oxide (1/2), C14H10O4S·2C18H15OP, comprises two mol-ecules of 2,2'-thiodi-benzoic acid [TDBA; systematic name: 2-[(2-carb-oxy-phen-yl)sulfan-yl]benzoic acid] and four mol-ecules of tri-phenyl-phosphane oxide [TPPO; systematic name: (di-phenyl-phosphor-yl)benzene]. The two TDBA mol-ecules are twisted about their di-sulfide bonds and exhibit dihedral angles of 74.40 (5) and 72.58 (5)° between the planes through the two SC6H4 residues. The carb-oxy-lic acid groups are tilted out of the planes of the rings to which they are attached forming a range of CO2/C6 dihedral angles of 19.87 (6)-60.43 (8)°. Minor conformational changes are exhibited in the TPPO mol-ecules with the range of dihedral angles between phenyl rings being -2.1 (1) to -62.8 (1)°. In the mol-ecular packing, each TDBA acid mol-ecule bridges two TPPO mol-ecules via hy-droxy-O-H⋯O(oxide) hydrogen bonds to form two three-mol-ecule aggregates. These are connected into a three-dimensional architecture by TPPO-C-H⋯O(oxide, carbon-yl) and TDBA-C-H⋯(oxide, carbon-yl) inter-actions. The importance of H⋯H, O⋯H/H⋯O and C⋯H/H⋯C contacts to the calculated Hirshfeld surfaces has been demonstrated. In terms of individual mol-ecules, O⋯H/H⋯O contacts are more important for the TDBA (ca 28%) than for the TPPO mol-ecules (ca 13%), as expected from the chemical composition of these species. Computational chemistry indicates the four independent hy-droxy-O-H⋯O(oxide) hydrogen bonds in the crystal impart about the same energy (ca 52 kJ mol-1), with DTBA-phenyl-C-H⋯O(oxide) inter-actions being next most stabilizing (ca 40 kJ mol-1).
  7. Tan SL, Tiekink ERT
    PMID: 32071755 DOI: 10.1107/S2056989020000572
    The asymmetric unit of the title 1:2 co-crystal, C14H14N4O2·2C7H5ClO2, comprises two half mol-ecules of oxalamide (4LH2), as each is disposed about a centre of inversion, and two mol-ecules of 4-chloro-benzoic acid (CBA), each in general positions. Each 4LH2 mol-ecule has a (+)anti-periplanar conformation with the pyridin-4-yl residues lying to either side of the central, planar C2N2O2 chromophore with the dihedral angles between the respective central core and the pyridyl rings being 68.65 (3) and 86.25 (3)°, respectively, representing the major difference between the independent 4LH2 mol-ecules. The anti conformation of the carbonyl groups enables the formation of intra-molecular amide-N-H⋯O(amide) hydrogen bonds, each completing an S(5) loop. The two independent CBA mol-ecules are similar and exhibit C6/CO2 dihedral angles of 8.06 (10) and 17.24 (8)°, indicating twisted conformations. In the crystal, two independent, three-mol-ecule aggregates are formed via carb-oxy-lic acid-O-H⋯N(pyrid-yl) hydrogen bonding. These are connected into a supra-molecular tape propagating parallel to [100] through amide-N-H⋯O(amide) hydrogen bonding between the independent aggregates and ten-membered {⋯HNC2O}2 synthons. The tapes assemble into a three-dimensional architecture through pyridyl- and methyl-ene-C-H⋯O(carbon-yl) and CBA-C-H⋯O(amide) inter-actions. As revealed by a more detailed analysis of the mol-ecular packing by calculating the Hirshfeld surfaces and computational chemistry, are the presence of attractive and dispersive Cl⋯C=O inter-actions which provide inter-action energies approximately one-quarter of those provided by the amide-N-H⋯O(amide) hydrogen bonding sustaining the supra-molecular tape.
  8. Tan SL, Tiekink ERT
    PMID: 31921447 DOI: 10.1107/S2056989019016153
    The mol-ecular structure of the title bis-pyridyl substituted di-amide hydrate, C14H14N4O2·H2O, features a central C2N2O2 residue (r.m.s. deviation = 0.0205 Å) linked at each end to 3-pyridyl rings through methyl-ene groups. The pyridyl rings lie to the same side of the plane, i.e. have a syn-periplanar relationship, and form dihedral angles of 59.71 (6) and 68.42 (6)° with the central plane. An almost orthogonal relationship between the pyridyl rings is indicated by the dihedral angle between them [87.86 (5)°]. Owing to an anti disposition between the carbonyl-O atoms in the core, two intra-molecular amide-N-H⋯O(carbon-yl) hydrogen bonds are formed, each closing an S(5) loop. Supra-molecular tapes are formed in the crystal via amide-N-H⋯O(carbon-yl) hydrogen bonds and ten-membered {⋯HNC2O}2 synthons. Two symmetry-related tapes are linked by a helical chain of hydrogen-bonded water mol-ecules via water-O-H⋯N(pyrid-yl) hydrogen bonds. The resulting aggregate is parallel to the b-axis direction. Links between these, via methyl-ene-C-H⋯O(water) and methyl-ene-C-H⋯π(pyrid-yl) inter-actions, give rise to a layer parallel to (10); the layers stack without directional inter-actions between them. The analysis of the Hirshfeld surfaces point to the importance of the specified hydrogen-bonding inter-actions, and to the significant influence of the water mol-ecule of crystallization upon the mol-ecular packing. The analysis also indicates the contribution of methyl-ene-C-H⋯O(carbon-yl) and pyridyl-C-H⋯C(carbon-yl) contacts to the stability of the inter-layer region. The calculated inter-action energies are consistent with importance of significant electrostatic attractions in the crystal.
  9. Tan SL, Tiekink ERT
    PMID: 31921461 DOI: 10.1107/S2056989019016840
    The crystal and mol-ecular structures of the title 1:2 co-crystal, C14H14N4O2·2C7H6O2, are described. The oxalamide mol-ecule has a (+)-anti-periplanar conformation with the 4-pyridyl residues lying to either side of the central, almost planar C2N2O2 chromophore (r.m.s. deviation = 0.0555 Å). The benzoic acid mol-ecules have equivalent, close to planar conformations [C6/CO2 dihedral angle = 6.33 (14) and 3.43 (10)°]. The formation of hy-droxy-O-H⋯N(pyrid-yl) hydrogen bonds between the benzoic acid mol-ecules and the pyridyl residues of the di-amide leads to a three-mol-ecule aggregate. Centrosymmetrically related aggregates assemble into a six-mol-ecule aggregate via amide-N-H⋯O(amide) hydrogen bonds through a 10-membered {⋯HNC2O}2 synthon. These are linked into a supra-molecular tape via amide-N-H⋯O(carbon-yl) hydrogen bonds and 22-membered {⋯HOCO⋯NC4NH}2 synthons. The contacts between tapes to consolidate the three-dimensional architecture are of the type methyl-ene-C-H⋯O(amide) and pyridyl-C-H⋯O(carbon-yl). These inter-actions are largely electrostatic in nature. Additional non-covalent contacts are identified from an analysis of the calculated Hirshfeld surfaces.
  10. Tan SL, Tiekink ERT
    PMID: 32523767 DOI: 10.1107/S2056989020006829
    The title di-substituted thio-urea, C12H16N2O3S, has the hy-droxy-lethyl and ethyl benzoate substituents bound to the same amine-N atom, and is twisted, having a (+)syn-clinal conformation with the Namine-C-C-O(hydroxyl, carbon-yl) torsion angles of 49.39 (13) and 59.09 (12)°, respectively; the dihedral angle between the almost planar CN2S core and the pendent benzene ring is 69.26 (4)°. In the crystal, supra-molecular layers propagating in the ac plane are formed via a combination of hydroxyl-O-H⋯S(thione), amine-N-H⋯O(hydroxyl, carbon-yl) hydrogen-bonds. The layers stack along the b axis with inter-digitation of the benzene rings allowing the formation of π-π stacking [inter-centroid separation = 3.8722 (7) Å] and parallel C=O⋯π inter-actions. A computational chemistry study shows the conventional hydrogen bonding in the crystal leads to significant electrostatic stabilization but dispersion terms are also apparent, notably through the inter-actions involving the benzene residue.
  11. Tan SL, Tiekink ERT
    PMID: 32523755 DOI: 10.1107/S2056989020006568
    The asymmetric unit of the title 1:2 co-crystal, C14H14N4O2·2C7H5ClO2, comprises a half-mol-ecule of oxalamide (4LH2), being located about a centre of inversion, and a mol-ecule of3-chloro-benzoic acid (3-ClBA) in a general position. From symmetry, the 4LH2 mol-ecule has a (+)anti-periplanar conformation with the 4-pyridyl residues lying to either side of the central, planar C2N2O2 chromophore with the dihedral angle between the core and pyridyl ring being 74.69 (11)°; intra-molecular amide-N-H⋯O(amide) hydrogen bonds are noted. The 3-ClBA mol-ecule exhibits a small twist as seen in the C6/CO2 dihedral angle of 8.731 (12)°. In the mol-ecular packing, three-mol-ecule aggregates are formed via carb-oxy-lic acid-O-H⋯N(pyrid-yl) hydrogen bonding. These are connected into a supra-molecular tape along [111] through amide-N-H⋯O(carbon-yl) hydrogen bonding. Additional points of contact between mol-ecules include pyridyl and benzoic acid-C-H⋯O(amide), methyl-ene-C-H⋯O(carbon-yl) and C-Cl⋯π(pyrid-yl) inter-actions so a three-dimensional architecture results. The contributions to the calculated Hirshfeld surface are dominated by H⋯H (28.5%), H⋯O/O⋯H (23.2%), H⋯C/C⋯H (23.3%), H⋯Cl/Cl⋯H (10.0%) and C⋯Cl/C⋯Cl (6.2%) contacts. Computational chemistry confirms the C-Cl⋯π inter-action is weak, and the importance of both electrostatic and dispersion terms in sustaining the mol-ecular packing despite the strong electrostatic term provided by the carb-oxy-lic acid-O-H⋯N(pyrid-yl) hydrogen bonds.
  12. Tan SL, Tiekink ERT
    PMID: 30713723 DOI: 10.1107/S2056989018017097
    The asymmetric unit of the title 1:2 co-crystal, C14H10O4S2·2C7H6O2, comprises half a mol-ecule of di-thiodi-benzoic acid [systematic name: 2-[(2-carb-oxy-phen-yl)disulfan-yl]benzoic acid, DTBA], as the mol-ecule is located about a twofold axis of symmetry, and a mol-ecule of benzoic acid (BA). The DTBA mol-ecule is twisted about the di-sulfide bond [the C-S-S-C torsion angle is -83.19 (8)°] resulting in a near perpendicular relationship between the benzene rings [dihedral angle = 71.19 (4)°]. The carb-oxy-lic acid group is almost co-planar with the benzene ring to which it is bonded [dihedral angle = 4.82 (12)°]. A similar near co-planar relationship pertains for the BA mol-ecule [dihedral angle = 3.65 (15)°]. Three-mol-ecule aggregates are formed in the crystal whereby two BA mol-ecules are connected to a DTBA mol-ecule via hy-droxy-O-H⋯O(hydroxy) hydrogen bonds and eight-membered {⋯HOC=O}2 synthons. These are connected into a supra-molecular layer in the ab plane through C-H⋯O inter-actions. The inter-actions between layers to consolidate the three-dimensional architecture are π-π stacking inter-actions between DTBA and BA rings [inter-centroid separation = 3.8093 (10) Å] and parallel DTBA-hy-droxy-O⋯π(BA) contacts [O⋯ring centroid separation = 3.9049 (14) Å]. The importance of the specified inter-actions as well as other weaker contacts, e.g. π-π and C-H⋯S, are indicated in the analysis of the calculated Hirshfeld surface and inter-action energies.
  13. Tan SL, Tiekink ERT
    PMID: 32695471 DOI: 10.1107/S2056989020008257
    The title 1:1 solvate, C14H10O4S2·C3H7NO, features a twisted mol-ecule of 2,2'-di-thiodi-benzoic acid (DTBA), with the central C-S-S-C torsion angle being -88.57 (6)°, and a mol-ecule of di-methyl-formamide (DMF). The carb-oxy-lic acid groups are, respectively, close to co-planar and twisted with respect to the benzene rings to which they are connected as seen in the CO2/C6 torsion angles of 1.03 (19) and 7.4 (2)°. Intra-molecular, hypervalent S←O inter-actions are noted [S⋯O = 2.6140 (9) and 2.6827 (9) Å]. In the crystal, four-mol-ecule aggregates are formed via DTBA-O-H⋯O(DMF) and DTBA-O-H⋯O(DTBA) hydrogen bonding, the latter via an eight-membered {⋯OHCO}2 homosynthon. These are linked into supra-molecular layers parallel to (011) via benzene-C-H⋯O(DTBA) and DTBA-C=O⋯π(benzene) inter-actions, with the connections between these, giving rise to a three-dimensional architecture, being of the type benzene-C-H⋯π(benzene). An analysis of the calculated Hirshfeld surfaces indicates, in addition to the aforementioned inter-molecular contacts, the presence of stabilizing inter-actions between a benzene ring and a quasi-π-system defined by O-H⋯O hydrogen bonds between a DTBA dimer, i.e. the eight-membered {⋯OCOH}2 ring system, and between a benzene ring and a quasi-π(OCOH⋯OCH) system arising from the DTBA-O-H⋯O(DMF) hydrogen bond. The inter-centroid separations are 3.65 and 3.49 Å, respectively.
  14. Tan SL, Neoh CY, Tan HH
    Singapore Med J, 2012 Feb;53(2):e24-7.
    PMID: 22337196
    Rhinoscleroma is a chronic, slowly progressive, inflammatory disease of the upper respiratory tract. It is associated with Klebsiella rhinoscleromatis infection. We present the clinical and pathological features of four patients diagnosed with rhinoscleroma at the National Skin Centre, Singapore between 1997 and 2010. All four patients presented with only cutaneous involvement, and the diagnosis was clinched via histological examination. The patients were treated with a combination of antibiotics. Two patients who were on follow-up at the time of this writing responded positively to the antibiotic treatment, while two were lost to follow-up. Rhinoscleroma is a diagnostic challenge, as it is an uncommon disease in Singapore and Malaysia. We highlight this condition to raise awareness of the disease in order to aid in early diagnosis of patients. Without treatment, this condition can result in significant complications, including involvement of the lower airways. Early diagnosis and appropriate treatment help to reduce morbidity.
  15. Low YS, Tan SL, Wan AS
    J Pediatr Pharmacol Ther, 2015 Mar-Apr;20(2):119-27.
    PMID: 25964729 DOI: 10.5863/1551-6776-20.2.119
    OBJECTIVE: To evaluate the usefulness of extended-interval gentamicin dosing practiced in neonatal intensive care unit (NICU) and special care nursery (SCN) of a Malaysian hospital.
    METHODS: Cross-sectional observational study with pharmacokinetic analysis of all patients aged ≤28 days who received gentamicin treatment in NICU/SCN. Subjects received dosing according to a regimen modified from an Australian-based pediatric guideline. During a study period of 3 months, subjects were evaluated for gestational age, body weight, serum creatinine concentration, gentamicin dose/interval, serum peak and trough concentrations, and pharmacokinetic parameters. Descriptive percentages were used to determine the overall dosing accuracy, while analysis of variance (ANOVA) was conducted to compare the accuracy rates among different gestational ages. Pharmacokinetic profile among different gestational age and body weight groups were compared by using ANOVA.
    RESULTS: Of the 113 subjects included, 82.3% (n = 93) achieved therapeutic concentrations at the first drug-monitoring assessment. There was no significant difference found between the percentage of term neonates who achieved therapeutic concentrations and the premature group (87.1% vs. 74.4%), p = 0.085. A total of 112 subjects (99.1%) achieved desired therapeutic trough concentration of <2 mg/L. Mean gentamicin peak concentration was 8.52 mg/L (95% confidence interval [Cl], 8.13-8.90 mg/L) and trough concentration was 0.54 mg/L (95% CI, 0.48-0.60 mg/L). Mean volume of distribution, half-life, and elimination rate were 0.65 L/kg (95% CI, 0.62-0.68 L/kg), 6.96 hours (95% CI, 6.52-7.40 hours), and 0.11 hour(-1) (95% CI, 0.10-0.11 hour(-1)), respectively.
    CONCLUSION: The larger percentage of subjects attaining therapeutic range with extended-interval gentamicin dosing suggests that this regimen is appropriate and can be safely used among Malaysian neonates.
    KEYWORDS: aminoglycosides; extended-interval; gentamicin; neonate; pharmacokinetics
  16. Ko SM, Tan SL, Leong B
    Singapore Med J, 1996 Apr;37(2):168-71.
    PMID: 8942256
    In a prospective study of fifty consecutive outpatients (30 men and 20 women) attending the Behaviour Therapy Clinic at a general hospital, the commonest conditions were obsessive compulsive disorders (n = 16), phobic disorders (n = 11) and generalised anxiety disorders (n = 9). Three-quarters of the referrals were from psychiatrists and family physicians. The patients received between 2 to 10 sessions of behaviour treatment; most had 4 to 6 sessions with a mean of 4.7, SD 1.82. The commonest behavioural techniques administered were exposure therapy with response prevention and relaxation therapy. Initially, treatment was therapist-aided, but subsequently self-help was encouraged with regular reviews of the patient's homework. After one month, 42 patients (84%) were assessed to have improved somewhat, with 20 (40%) showing moderate improvement. After three months, 41 (82%) continued to improve, with 33 (66%) showing moderate to great improvement. Nine patients were considered to have failed in therapy-six defaulted and three were non-responders. The reasons for defaulting treatment were unwillingness to bear with the discomfort involved in exposure therapy, lack of motivation or returning to own hometown in Malaysia. Sixteen patients (n = 32%) were treated solely with behavioural techniques while the rest had a combination of behaviour therapy and drugs, especially anxiolytics and antidepressants. However, at the end of treatment, the dosages of most medications were reduced or else discontinued completely.

    Study site: Behavior therapy clinic at a general hospital
  17. Chan YQ, Lee ZM, Tan SL
    Med J Malaysia, 2020 07;75(4):433-435.
    PMID: 32724010
    Intracranial haemorrhage (ICH) in a patient with relapse of idiopathic thrombocytopaenic purpura (ITP) can be lethal. The site of haemorrhage, compounded by low platelets in this disease, makes its management extremely challenging, especially when a neurosurgical procedure is warranted. We report a case report of an unconventional way of increasing platelet counts in ITP rapidly in an emergency setting.
  18. Lee SM, Lo KM, Tan SL, Tiekink ER
    PMID: 27536419 DOI: 10.1107/S2056989016012159
    In the solid state, the title compound, C12H16BrNO5 [systematic name: 4-bromo-2-((1E)-{[1,3-dihy-droxy-2-(hy-droxy-meth-yl)propan-2-yl]iminium-yl}meth-yl)-6-meth-oxy-benzen-1-olate], C12H16BrNO5, is found in the keto-amine tautomeric form, with an intra-molecular iminium-N-H⋯O(phenolate) hydrogen bond and an E conformation about the C=N bond. Both gauche (two) and anti relationships are found for the methyl-hydroxy groups. In the crystal, a supra-molecular layer in the bc plane is formed via hy-droxy-O-H⋯O(hy-droxy) and charge-assisted hy-droxy-O-H⋯O(phenolate) hydrogen-bonding inter-actions; various C-H⋯O inter-actions provide additional cohesion to the layers, which stack along the a axis with no directional inter-actions between them. A Hirshfeld surface analysis confirms the lack of specific inter-actions in the inter-layer region.
  19. Yeo CI, Tan SL, Tiekink ER
    PMID: 27536384 DOI: 10.1107/S2056989016010781
    The title compound, [Au(C8H7ClNOS)(C18H15P)], is a monoclinic (P21/n, Z' = 1; form β) polymorph of the previously reported triclinic form (P-1, Z' = 1; form α) [Tadbuppa & Tiekink (2010 ▸). Acta Cryst. E66, m664]. The mol-ecular structures of both forms feature an almost linear gold(I) coordination geometry [P-Au-S = 175.62 (5)° in the title polymorph], being coordinated by thiol-ate S and phosphane P atoms, a Z conformation about the C=N bond and an intra-molecular Au⋯O contact. The major conformational difference relates to the relative orientations of the residues about the Au-S bond: the P-Au-S-C torsion angles are -8.4 (7) and 106.2 (7)° in forms α and β, respectively. The mol-ecular packing of form β features centrosymmetric aggregates sustained by aryl-C-H⋯O inter-actions, which are connected into a three-dimensional network by aryl-C-H⋯π contacts. The Hirshfeld analysis of forms α and β shows many similarities with the notable exception of the influence of C-H⋯O inter-actions in form β.
  20. Lee SM, Lo KM, Tan SL, Tiekink ER
    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.
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