Anion-Dependent Exocyclic Mercury(II) Coordination Polymers of Bis-dithiamacrocycle

Siewe, Arlette Deukam,Kim, Seulgi,Choi, Kyu Seong,Lee, Shim Sung Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.12

Synthesis and structural characterization of mercury(II) halides and perchlorate complexes (1-4) of bis-$OS_2$-macrocycle (L) are reported. L reacts with mercury(II) chloride and bromide to yield an isostructural 2D coordination polymers with type $[Hg(L)X_2]_n$ (1: X = Cl and 2: X = Br). In 1, each Hg atom which lies outside the cavity is six-coordinate with a distorted octahedral geometry, being bound to four adjacent ligands via monodentate Hg-S bonds and two remaining sites are occupied by two terminal chlorido ligands to form a fishnet-like 2D structure. When reacting with mercury(II) iodide, L afforded a 1D coordination polymer $\{[Hg_2(L)I_4]{\cdot}CHCl_3\}_n$ (3) in which each exocyclic Hg atom is four-coordinate, being bound to two sulfur donors from different ligands doubly bridging the ligand molecules in a head-to-tail mode. The coordination sphere in 3 is completed by two iodo terminal ligands, adopting a distorted tetrahedral geometry. On reacting with mercury(II) perchlorate, L forms solvent-coordinated 1D coordination polymer $\{[Hg_2(L)(DMF)_6](ClO_4)_4{\cdot}2DMF\}_n$ (4) instead of the anion-coordination. In 4, the Hg atom is five-coordinate, being bound to two sulfur donors from two different ligands doubly bridging the ligand molecules in a side-by-side mode to form a ribbon-like 1D structure. The three remaining coordination sites in 4 are completed by three DMF molecules in a monodentate manner. Consequently, the different structures and connectivity patterns for the observed exocyclic coordination polymers depending on the anions used are influenced not only by the coordination ability of the anions but also by anion sizes.

Preparation and Crystal Structures of Silver(I), Mercury(II), and Lead(II) Complexes of Oxathia-Tribenzo-Macrocycles

Siewe, Arlette Deukam,Ju, Huiyeong,Lee, Shim Sung Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.3

An investigation of the coordination behavior of sulfur-containing mixed-donor tribenzo-macrocycles $L^1-L^3$ ($L^1$: 20-membered $O_3S_2$, $L^2$: 20-membered $O_2S_3$, and $L^3$: 23-membered $O_4S_2$) with $d^{10}$-metal ($Ag^+$, $Hg^{2+}$, and $Pb^{2+}$) salts is reported. The X-ray structures of five complexes (1-5) with different structural types and stoichiometries, including mono- to dinuclear species have been determined. Reactions of $L^2$ and $L^3$ with the silver(I) salts ($PF_6{^-}$ and $SCN^-$) afforded two dinuclear 2:2 (metal-to-ligand) complexes with different arrangements: a sandwich-type cyclic dinuclear complex $[Ag_2(L^2)_2](PF_6)_2{\cdot}3CH_2Cl_2$ (1) and a linear dinuclear complex $[Ag_2(L^3)_2(SCN)_2]$ (2), in which two monosilver(I) complex units are linked by an Ag-Ag contact. Reactions of $L^1$ and $L^2$ with mercury(II) salts ($SCN^-$ and $Cl^-$) gave a mononuclear 1:1 complexes $[Hg(L^1)(SCN)_2]$ (3) and $[Hg(L^2)Cl_2]$ (4) with anion coordination in both cases. $L^2$ reacts with lead(II) perchlorate to yield a mononuclear sandwich-type complex $[Pb(L^2)_2(ClO_4)_2]$ (5), giving an overall metal coordination geometry of eight with a square antiprism arrangement. From these results, the effects of the donor variation and the anioncoordination ability on the resulting topologies of the soft metal complexes are discussed.

In vitro requirement for periostin in B lymphopoiesis

Siewe, Basile T.,Kalis, Susan L.,Le, Phong T.,Witte, Pamela L.,Choi, Sangdun,Conway, Simon J.,Druschitz, Laurel,Knight, Katherine L. American Society of Hematology 2011 Blood Vol.117 No.14

<B>Abstract</B><P>B lymphopoiesis arrests in rabbits by 4 months of age. To identify molecules that contribute to this arrest, cDNA-representational difference analysis on BM stromal cells from young and adult rabbits showed that expression of Postn that encodes for the extracellular matrix protein periostin dramatically reduced with age. Postn-small interfering RNA OP9 cells lost their capacity to support B-cell development from rabbit or murine BM cells, and reexpression of periostin restored this potential, indicating an in vitro requirement for periostin in B lymphopoiesis. In our system, we determined that periostin deficiency leads to increased cell death and decreased proliferation of B-lineage progenitors. Further, RGD peptide inhibition of periostin/αvβ3 interaction resulted in a marked decrease in B lymphopoiesis in vitro. Microarray analysis of the Postn-small interfering RNA OP9 cells showed decreased expression of key B-lymphopoietic factors, including IL-7 and CXCL12. In vivo, unidentified molecule(s) probably compensate periostin loss because Postn−/− mice had normal numbers of B-cell progenitors in BM. We conclude that the decline in periostin expression in adult rabbit BM does not solely explain the arrest of B lymphopoiesis. However, the interaction of periostin with αvβ3 on lymphoid progenitors probably provides both proliferative and survival signals for cells in the B-cell development pathway.</P>

Regioisomer-Dependent Endo- and Exocyclic Coordination of Bis-Dithiamacrocycles

Siewe, Arlette Deukam,Kim, Ja-Yeon,Kim, Seulgi,Park, In-Hyeok,Lee, Shim Sung American Chemical Society 2014 Inorganic chemistry Vol.53 No.1

<P>Syntheses of the regioisomers of bis-dithiamacrocycle and the regioisomer-controlled endo- and exocyclic coordination behaviors are reported. Direct bis-cyclization reaction of 1,2,4,5-tetra(bromomethyl)benzene with 3,6-dioxa-1,8-octanedithiol led to a mixture of two bis-dithiamacrocycle regioisomers (<I>ortho</I>-type; <I><B>o</B></I><B>-bis-L</B> and <I>meta</I>-type; <I><B>m</B></I><B>-bis-L</B>) which were separated by recrystallization and column chromatography. When the two isomers were reacted with AgPF<SUB>6</SUB>, <I><B>o</B></I><B>-bis-L</B> gave an endocyclic one-dimensional (1-D) coordination polymer {[Ag<SUB>3</SUB>(<I><B>o</B></I><B>-bis-L</B>)<SUB>2</SUB>(CH<SUB>3</SUB>CN)](PF<SUB>6</SUB>)<SUB>3</SUB>·2CH<SUB>3</SUB>CN}<SUB><I>n</I></SUB> (<B>1</B>) with a 3:2 (metal-to-ligand) stoichiometry, while <I><B>m</B></I><B>-bis-L</B> afforded an exocoordination-based 1-D polymeric complex {[Ag(<I><B>m</B></I><B>-bis-L</B>)](PF<SUB>6</SUB>)}<SUB><I>n</I></SUB> (<B>2</B>) with a 2:2 stoichiometry. The observed endo- and exocoordination modes depending on the isomers were discussed in terms of the S···S distances in the bis-dithiamacrocycle isomers. Due to the closer S···S distance in each macrocyclic ring, <I><B>o</B></I><B>-bis-L</B> is suitable for the endocoordination. However, <I><B>m</B></I><B>-bis-L</B> forms an exocyclic complex because the S···S distance between two macrocyclic rings is shorter than that in one macrocyclic ring. NMR experiments also revealed that <I><B>o</B></I><B>-bis-L</B> and <I><B>m</B></I><B>-bis-L</B> form the endo- and the exocyclic complexes, respectively, in solution.</P><P>Syntheses of the regioisomers of bis-dithiamacrocycle and the regioisomer-controlled endo- and exocyclic coordination behaviors are reported.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/inocaj/2014/inocaj.2014.53.issue-1/ic402346z/production/images/medium/ic-2013-02346z_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ic402346z'>ACS Electronic Supporting Info</A></P>

Anion-Dependent Exocyclic Mercury(II) Coordination Polymers of Bis-dithiamacrocycle

Arlette Deukam Siewe,Seulgi Kim,Kyu Seong Choi,이심성 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.12

Synthesis and structural characterization of mercury(II) halides and perchlorate complexes (1-4) of bis-OS2- macrocycle (L) are reported. L reacts with mercury(II) chloride and bromide to yield an isostructural 2D coordination polymers with type [Hg(L)X2]n (1: X = Cl and 2: X = Br). In 1, each Hg atom which lies outside the cavity is six-coordinate with a distorted octahedral geometry, being bound to four adjacent ligands via monodentate Hg-S bonds and two remaining sites are occupied by two terminal chlorido ligands to form a fishnet-like 2D structure. When reacting with mercury(II) iodide, L afforded a 1D coordination polymer {[Hg2(L)I4]·CHCl3}n (3) in which each exocyclic Hg atom is four-coordinate, being bound to two sulfur donors from different ligands doubly bridging the ligand molecules in a head-to-tail mode. The coordination sphere in 3 is completed by two iodo terminal ligands, adopting a distorted tetrahedral geometry. On reacting with mercury(II) perchlorate, L forms solvent-coordinated 1D coordination polymer {[Hg2(L)(DMF)6](ClO4)4·2DMF}n (4) instead of the anion-coordination. In 4, the Hg atom is five-coordinate, being bound to two sulfur donors from two different ligands doubly bridging the ligand molecules in a side-by-side mode to form a ribbon-like 1D structure. The three remaining coordination sites in 4 are completed by three DMF molecules in a monodentate manner. Consequently, the different structures and connectivity patterns for the observed exocyclic coordination polymers depending on the anions used are influenced not only by the coordination ability of the anions but also by anion sizes.

Preparation and Crystal Structures of Silver(I), Mercury(II), and Lead(II) Complexes of Oxathia-Tribenzo-Macrocycles

Arlette Deukam Siewe,주희영,이심성 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.3

An investigation of the coordination behavior of sulfur-containing mixed-donor tribenzo-macrocycles L1-L3 (L1: 20-membered O3S2, L2: 20-membered O2S3, and L3: 23-membered O4S2) with d10-metal (Ag+, Hg2+, and Pb2+) salts is reported. The X-ray structures of five complexes (1-5) with different structural types and stoichiometries, including mono- to dinuclear species have been determined. Reactions of L2 and L3 with the silver(I) salts (PF6 − and SCN−) afforded two dinuclear 2:2 (metal-to-ligand) complexes with different arrangements: a sandwich-type cyclic dinuclear complex [Ag2(L2)2](PF6)2·3CH2Cl2 (1) and a linear dinuclear complex [Ag2(L3)2(SCN)2] (2), in which two monosilver(I) complex units are linked by an Ag-Ag contact. Reactions of L1 and L2 with mercury(II) salts (SCN− and Cl−) gave a mononuclear 1:1 complexes [Hg(L1)(SCN)2] (3) and [Hg(L2)Cl2] (4) with anion coordination in both cases. L2 reacts with lead(II) perchlorate to yield a mononuclear sandwich-type complex [Pb(L2)2(ClO4)2] (5), giving an overall metal coordination geometry of eight with a square antiprism arrangement. From these results, the effects of the donor variation and the anioncoordination ability on the resulting topologies of the soft metal complexes are discussed.

Ligand Isomer Effect on the Formations of Supramolecular Lead(II), Mercury(II), and Copper(II)/Mercury(II) Complexes of Bis-O₂S₂-Macrocycle

Kim, Seulgi,Siewe, Arlette Deukam,Lee, Eunji,Ju, Huiyeong,Park, In-Hyeok,Jung, Jong Hwa,Habata, Yoichi,Lee, Shim Sung The American Chemical Society 2018 CRYSTAL GROWTH AND DESIGN Vol.18 No.4

<P>In addition to <I>ortho</I>-isomer (<I><B>o</B></I><B>-bis-L</B>) and <I>meta</I>-isomer (<I><B>m-</B></I><B>bis</B><I><B>-</B></I><B>L</B>) of bis-O<SUB>2</SUB>S<SUB>2</SUB>-macrocycle obtained previously, its <I>para</I>-isomer (<I><B>p-</B></I><B>bis</B><I><B>-</B></I><B>L</B>) was newly isolated, and the complete isomer series were structurally characterized by single crystal X-ray analysis. In complexations, borderline (Pb<SUP>2+</SUP>) and soft (Hg<SUP>2+</SUP> and Cu<SUP>+</SUP>) metal salts were employed to investigate the isomer effect on the coordination modes and topologies of the supramolecular complexes. Lead(II) perchlorate afforded an infinite one-dimensional (1-D) coordination polymer {[Pb<SUB>2</SUB>(<I><B>o</B></I><B>-bis-L</B>)(μ-ClO<SUB>4</SUB>)<SUB>2</SUB>(ClO<SUB>4</SUB>)<SUB>2</SUB>]}<SUB><I>n</I></SUB> (<B>1</B>) and a discrete complex [Pb<SUB>2</SUB>(<I><B>m</B></I>-<B>bis</B>-<B>L</B>)(CH<SUB>3</SUB>CN)<SUB>2</SUB>(H<SUB>2</SUB>O)<SUB>2</SUB>(ClO<SUB>4</SUB>)<SUB>2</SUB>](ClO<SUB>4</SUB>)<SUB>2</SUB> (<B>2</B>), both of which are based on the endocyclic binuclear complexes mainly due to the oxophilicity of the lead(II) ion. Meanwhile, mercury(II) halides showed an endocyclic dinuclear complex [Hg<SUB>2</SUB>(<I><B>o</B></I><B>-bis-L</B>)I<SUB>2</SUB>][Hg<SUB>3</SUB>I<SUB>8</SUB>] (<B>3</B>) and an exocyclic 1-D coordination polymer [Hg<SUB>3</SUB>(<I><B>m</B></I><B>-bis-L</B>)Br<SUB>6</SUB>]<SUB><I>n</I></SUB> (<B>4</B>) because the differences of sulfur-to-sulfur separation in the free ligand isomers might induce the different coordination modes. When a mixture of mercury(II) iodide and copper(I) iodide was used in the reaction with <I><B>m</B></I><B>-bis-L</B>, a heterometallic 1-D coordination polymer [Cu<SUB>2</SUB>Hg<SUB>2</SUB>(<I><B>m</B></I><B>-bis-L</B>)(μ-Cu<SUB>2</SUB>I<SUB>2</SUB>)(CH<SUB>3</SUB>CN)<SUB>2</SUB>I<SUB>6</SUB>]<SUB><I>n</I></SUB> (<B>5</B>) was obtained. In <B>5</B>, exocyclic dicopper(I) complex units are linked by −Hg-Cu<SUB>2</SUB>I<SUB>4</SUB>-Hg- segments to form an infinite zigzag chain. Consequently, unlike the borderline metal, the soft metal ions show the sulfur-to-sulfur separation dependent coordination modes. These results demonstrate how small differences in the ligand isomers impact their self-assembled coordination products in terms of coordination mode and topological structure including dimensionality.</P><P>In order to investigate the ligand isomer effect on the complexations, three regioisomers of bis-O<SUB>2</SUB>S<SUB>2</SUB>-macrocycle (<I><B>o</B></I><B>-bis-L</B>, <I><B>m-</B></I><B>bis</B><I><B>-</B></I><B>L</B>, and <I><B>p</B></I><B>-bis-L</B>) were employed. The structural characteristics of the resulting homonuclear and heteronuclear supramolecular complexes of the isomers are discussed in terms of controlling factors and coordination modes.</P> [FIG OMISSION]</BR>

Ligand-Induced Formation of Copper(I) Iodide Clusters: Exocyclic Coordination Polymers with Bis-dithiamacrocycle Isomers

Kim, Seulgi,Siewe, Arlette Deukam,Lee, Eunji,Ju, Huiyeong,Park, In-Hyeok,Park, Ki-Min,Ikeda, Mari,Habata, Yoichi,Lee, Shim Sung American Chemical Society 2016 Inorganic Chemistry Vol.55 No.5

<P>A comparative study on the formation of guest clusters induced by different shapes (or sizes) of exocyclic binding sites embedded in the bis-macrocyclic host isomers is reported. CuI reacts with two regioisomers of a bis-dithiamacrocycle, o-bis-L (W-shaped binding site) and m-bis-L (U-shaped binding site), to yield one-dimensional coordination polymers {[(mu(4)-Cu4I4)(o-bis-L)]center dot 2CH(3)CN}(n) (1a) and [(mu 4Cu2I2)(m-bis-L)](n) (2). In la, the o-bis-L ligand isomer is linked by a spacious cubane [Cu4I4] cluster, while the m-bis-L ligand in 2 is linked by a smaller rhomboid [Cu2I2] cluster because of the different exocyclic binding sites. The results observed illustrate the possibility for the metal clusters including [CunIn] (n = 2 or 4) to adopt a controlled formation through the binding site alternation or design. Because of the adaptive cluster formations, the products show different photophysical properties. Additionally, sliding of the one-dimensional chains in la was observed upon loss of the lattice solvent molecules in ambient condition.</P>

Supporting Preschool Children’s Early Writing with Self-Regulated Learning Strategies

Siew Kim Siew,Mariani Binti Md Nor 환태평양유아교육연구학회 2019 Asia-Pacific journal of research in early childhoo Vol.13 No.2

Research suggests that early writing is crucial in the development of young children’s literacy skills and links to their conventional literacy outcomes in elementary school and beyond. In order to enhance the will and the skills to express thoughts explicitly and effectively in early writing among preschool children, self-regulated learning (SRL) was suggested. This experimental study involved seventy-five preschool children, aged from five to six years old in Malaysia, aimed to investigate the effectiveness of SRL strategies on early writing performance. In this study, quantitative data collection was engaged and supported with qualitative data through interviews to obtain a deep insight of the findings results. Two-way repeated measure ANCOVA was employed and confirmed the effectiveness SRL intervention performance in early writing. In regression analyses, strategy such as planning and goal setting was confirmed as strong predictor for early writing performance. Data from the interview revealed that various SRL strategies were engaged by out-performing children from the experimental group and contributed to their early writing performance. The findings of this research provide a useful insight into early writing instructions in Malaysian context.

Inadequate vitamin D intake among pregnant women in Malaysia based on revised recommended nutrient intakes value and potential dietary strategies to tackle the inadequacy

Siew Siew Lee,Raman Subramaniam,Maiza Tusimin,King Hwa Ling,Kartini Farah Rahim,Su Peng Loh 한국영양학회 2021 Nutrition Research and Practice Vol.15 No.4

BACKGROUND/OBJECTIVES: Recently, the recommended nutrient intakes (RNI) for vitamin D for Malaysian aged 1–70 yrs has been revised from 5 μg/day to 15 μg/day. This study is aimed to assess the adequacy of vitamin D intake based on revised RNI and to recommend several dietary strategies to increase total vitamin D intake. SUBJECTS/METHODS: Vitamin D intake from both food and supplement of 217 pregnant women was assessed using a validated food frequency questionnaire. Hypothetical effect of expanded supplementation and food fortifications strategies were modelled using the consumption data. RESULTS: The results revealed that more than half (67.7%) of pregnant women had inadequate vitamin D intake (RNI < 15 μg/day). The modelling results demonstrated the potential of universal provision of 10 μg/day of multivitamins supplements in increasing vitamin D intake. Moreover, mandatory fortification of both milk and malted drink at single level of 5 μg/serving would lead to increase in vitamin D intake of Malaysians, particularly pregnant women. CONCLUSIONS: The outcome of this study can be used as a reference for public health professionals to re-evaluate the existing Malaysian food fortification policies and supplementation recommendation for vitamin D for pregnant women.