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James A Ibers - One of the best experts on this subject based on the ideXlab platform.

  • synthesis and characterization of the silver maleonitrilediselenolates and silver maleonitriledithiolates k 2 2 2 Cryptand 4 ag4 se2c2 cn 2 4 na 2 2 2 Cryptand 4 ag4 s2c2 cn 2 4 0 33mecn nbu4 4 ag4 s2c2 cn 2 4 k 2 2 2 Cryptand 3 ag se2c2 cn 2 2 2mecn
    Inorganic Chemistry, 2001
    Co-Authors: Craig C Mclauchlan, James A Ibers
    Abstract:

    Reaction of AgBF(4), KNH(2), K(2)Se, Se, and [2.2.2]-Cryptand in acetonitrile yields [K([2.2.2]-Cryptand)](4)[Ag(4)(Se(2)C(2)(CN)(2))(4)] (1). In the unit cell of 1 there are four [K([2.2.2]-Cryptand)](+) units and a tetrahedral Ag(4) anionic core coordinated in mu(1)-Se, mu(2)-Se fashion by each of four mns ligands (mns = maleonitrilediselenolate, [Se(2)C(2)(CN)(2)](2)(-)). Reaction of AgNO(3), Na(2)(mnt) (mnt = maleonitriledithiolate, [S(2)C(2)(CN)(2)](2)(-)), and [2.2.2]-Cryptand in acetonitrile yields [Na([2.2.2]-Cryptand)](4)[Ag(4)(mnt)(4)].0.33MeCN (2). The Ag(4) anion of 2 is analogous to that in 1. Reaction of AgNO(3), Na(2)(mnt), and [NBu(4)]Br in acetonitrile yields [NBu(4)](4)[Ag(4)(mnt)(4)] (3). The anion of 3 also comprises an Ag(4) core coordinated by four mnt ligands, but the Ag(4) core is diamond-shaped rather than tetrahedral. Reaction of [K([2.2.2]-Cryptand)](3)[Ag(mns)(Se(6))] with KNH(2) and [2.2.2]-Cryptand in acetonitrile yields [K([2.2.2]-Cryptand)](3)[Ag(mns)(2)].2MeCN (4). The anion of 4 comprises an Ag center coordinated by two mns ligands in a tetrahedral arrangement. Reaction of AgNO(3), 2 equiv of Na(2)(mnt), and [2.2.2]-Cryptand in acetonitrile yields [Na([2.2.2]-Cryptand)](3)[Ag(mnt)(2)] (5). The anion of 5 is analogous to that of 4. Electronic absorption and infrared spectra of each complex show behavior characteristic of metal-maleonitriledichalcogenates. Crystal data (153 K): 1, P2/n, Z = 2, a = 18.362(2) A, b = 16.500(1) A, c = 19.673(2) A, beta = 94.67(1) degrees, V = 5941(1) A(3); 2, P4, Z = 4, a= 27.039(4) A, c = 15.358(3) A, V = 11229(3) A(3); 3, P2(1)/c, Z = 6, a = 15.689(3) A, b = 51.924(11) A, c = 17.393(4) A, beta = 93.51(1) degrees, V = 14142(5) A(3); 4, P2(1)/c, Z = 4, a = 13.997(1) A, b = 21.866(2) A, c = 28.281(2) A, beta = 97.72(1) degrees, V = 8578(1) A(3); 5, P2/n, Z = 2, a = 11.547(2) A, b = 11.766(2) A, c = 27.774(6) A, beta = 91.85(3) degrees, V = 3772(1) A(3).

  • facile syntheses and structures of new metal maleonitrilediselenolates k 2 2 2 Cryptand 3 ag se2c2 cn 2 se6 k 2 2 2 Cryptand 2 ni se2c2 cn 2 2 and ni dppp se2c2 cn 2
    Inorganic Chemistry, 2000
    Co-Authors: Craig C Mclauchlan, James A Ibers
    Abstract:

    Facile syntheses of [K([2.2.2]-Cryptand)]3Ag(Se2C2(CN)2)(Se6)] (1) and [K([2.2.2]-Cryptand)]2[Ni(Se2C2(CN)2)2] (2) are achieved through reaction of polyselenides with KNH2, [2.2.2]-Cryptand, and AgBF4 or Ni(dppp)Cl2 in acetonitrile. The syntheses of 2 and Ni(dppp)(Se2C2(CN)2) (3) may be achieved by reaction of 1 with NiCl2 or Ni(dppp)Cl2 in dmf. These compounds represent the first easily prepared metal−maleonitrilediselenolate derivatives.

  • syntheses and crystal structures of k 2 2 2 Cryptand 2 m o m o 2 si ch 3 2 2 gese 2 and k 2 2 2 Cryptand 2 sb 2 se 6
    Inorganic Chemistry, 1997
    Co-Authors: Donna M Smith, Changwoo Park, James A Ibers
    Abstract:

    [K(2.2.2-Cryptand)]2[(μ-O){μ-O2Si(CH3)2}2(GeSe)2] (1) forms from the adventitious reaction of silicone grease with the residue (dissolved in CH3CN) from the reduction of GeSe2 by K in NH3(l) in the presence of 2.2.2-Cryptand. Reduction of SbSe under similar conditions leads to the isolation of [K(2.2.2-Cryptand)]2[Sb2Se6] (2).

  • different products from the chemical and electrochemical reduction of hgse2 k 2 2 2 Cryptand 2 hgse2 and pph4 2 hg se4 2 en
    Inorganic Chemistry, 1997
    Co-Authors: C W Park, Donna M Smith, Michael A Pell, James A Ibers
    Abstract:

    [PPh4]2[Hg(Se4)2]·en has been prepared from the electrochemical reduction of “HgSe2”, an intimate mixture of HgSe and Se. [K(2.2.2-Cryptand)]2[HgSe2] has been isolated from the reduction of HgSe2 by K in NH3(l) in the presence of 2.2.2-Cryptand. 77Se NMR experiments indicate that the difference in product formation is the result of the different reduction methods used.

Feihe Huang - One of the best experts on this subject based on the ideXlab platform.

  • n pseudorotaxanes n 2 3 from self assembly of two Cryptands and a 1 2 bis 4 pyridinium ethane derivative
    European Journal of Organic Chemistry, 2012
    Co-Authors: Xuzhou Yan, Peifa Wei, Mingming Zhang, Xiaodong Chi, Feihe Huang
    Abstract:

    Efficient host–guest complexation and interesting self-assembled structures formed between two crown ether-based Cryptands and a 1,2-bis(4-pyridinium)ethane derivative 3 are reported. By self-assembly of cis-dibenzo-24-crown-8-based Cryptand 1 and guest 3, a [3]pseudorotaxane was formed in solution, which further formed a supramolecular poly[3]pseudorotaxane structure in the solid state driven by π-π stacking interactions. Meanwhile, a [2]pseudorotaxane, obtained from self-assembly of a bis(m-phenylene)-32-crown-10-based Cryptand 2 and guest 3, can form a supramolecular poly[2]pseudorotaxane structure in the solid state. This difference in the binding model reflects the diversity of host–guest chemistry of crown ether-based Cryptands. Furthermore, these host–guest recognition processes and self-assembled structures were fully characterized by 1H NMR, UV/Vis spectroscopy, electrospray ionization mass spectrometry, and single-crystal X-ray analysis. Interestingly, formation of the [3]pseudorotaxane between Cryptand 1 and guest 3 can be reversibly controlled by adding and removing potassium cations in acetone. This reversible complexation process provides a simple on/off mechanism that can be used in the construction of controllable molecular switches.

  • pseudorotaxanes from self assembly of two crown ether based Cryptands and a 1 2 bis pyridinium ethane derivative
    Chemical Communications, 2012
    Co-Authors: Xuzhou Yan, Feihe Huang, Peifa Wei, Binyuan Xia, Qizhong Zhou
    Abstract:

    Pseudorotaxanes from self-assembly of two crown ether-based Cryptand wheels and a 1,2-bis(pyridinium) ethane derivative axle were prepared.

  • ph responsive assembly and disassembly of a supramolecular Cryptand based pseudorotaxane driven by π π stacking interaction
    Chemical Communications, 2011
    Co-Authors: Xuzhou Yan, Peifa Wei, Mingming Zhang, Xiaodong Chi, Bo Zheng, Feihe Huang
    Abstract:

    Driven by π-π stacking interaction, a supramolecular Cryptand-based [2]pseudorotaxane was formed and its formation was demonstrated to be pH-responsive.

  • synthesis of a bis 1 2 3 phenylene Cryptand and its dual response binding to paraquat and diquat
    European Journal of Organic Chemistry, 2010
    Co-Authors: Mingming Zhang, Kelong Zhu, Bo Zheng, Binyuan Xia, Feihe Huang
    Abstract:

    A bis(1,2,3-phenylene) Cryptand has been synthesized and used to prepare 1:1 complexes with paraquat and diquat, with association constants of 2.2 X 10 3 m -1 and 3.7 × 10 3 M -1 , respectively, in CHCl 3 /CH 3 CN (1:1). In the solid state this Cryptand forms a taco complex with paraquat, which has never been found before in Cryptand/paraquat complexes. Furthermore, its binding to paraquat and diquat in solution can be switched off (and back on) by addition of acid or K + (and then base or 18-crown-6).

  • improved complexation of paraquat derivatives by the formation of crown ether based Cryptands
    Chemical Communications, 2010
    Co-Authors: Mingming Zhang, Kelong Zhu, Feihe Huang
    Abstract:

    Self-assembly allows the construction of advanced molecular or supramolecular systems from small building blocks. Host–guest recognition, for its self-selectivity, environmental responsiveness and convenient application to complex molecular devices, plays a significant role in self-assembled systems. During this process, the association constant between the host and guest is an important standard to identify the properties of the systems. In order to prepare mechanically interlocked structures and large supramolecular systems efficiently from small molecules based on a host–guest recognition motif, it is necessary to increase host–guest association constants. Crown ether-based Cryptands have been designed and prepared to improve the binding of paraquat derivatives. This feature article aims to describe the design and syntheses of crown ether-based Cryptand hosts for paraquat derivatives and the application of the Cryptand/paraquat recognition motif in the fabrication of threaded structures, molecular switches and supramolecular polymers.

Craig C Mclauchlan - One of the best experts on this subject based on the ideXlab platform.

  • synthesis and characterization of the silver maleonitrilediselenolates and silver maleonitriledithiolates k 2 2 2 Cryptand 4 ag4 se2c2 cn 2 4 na 2 2 2 Cryptand 4 ag4 s2c2 cn 2 4 0 33mecn nbu4 4 ag4 s2c2 cn 2 4 k 2 2 2 Cryptand 3 ag se2c2 cn 2 2 2mecn
    Inorganic Chemistry, 2001
    Co-Authors: Craig C Mclauchlan, James A Ibers
    Abstract:

    Reaction of AgBF(4), KNH(2), K(2)Se, Se, and [2.2.2]-Cryptand in acetonitrile yields [K([2.2.2]-Cryptand)](4)[Ag(4)(Se(2)C(2)(CN)(2))(4)] (1). In the unit cell of 1 there are four [K([2.2.2]-Cryptand)](+) units and a tetrahedral Ag(4) anionic core coordinated in mu(1)-Se, mu(2)-Se fashion by each of four mns ligands (mns = maleonitrilediselenolate, [Se(2)C(2)(CN)(2)](2)(-)). Reaction of AgNO(3), Na(2)(mnt) (mnt = maleonitriledithiolate, [S(2)C(2)(CN)(2)](2)(-)), and [2.2.2]-Cryptand in acetonitrile yields [Na([2.2.2]-Cryptand)](4)[Ag(4)(mnt)(4)].0.33MeCN (2). The Ag(4) anion of 2 is analogous to that in 1. Reaction of AgNO(3), Na(2)(mnt), and [NBu(4)]Br in acetonitrile yields [NBu(4)](4)[Ag(4)(mnt)(4)] (3). The anion of 3 also comprises an Ag(4) core coordinated by four mnt ligands, but the Ag(4) core is diamond-shaped rather than tetrahedral. Reaction of [K([2.2.2]-Cryptand)](3)[Ag(mns)(Se(6))] with KNH(2) and [2.2.2]-Cryptand in acetonitrile yields [K([2.2.2]-Cryptand)](3)[Ag(mns)(2)].2MeCN (4). The anion of 4 comprises an Ag center coordinated by two mns ligands in a tetrahedral arrangement. Reaction of AgNO(3), 2 equiv of Na(2)(mnt), and [2.2.2]-Cryptand in acetonitrile yields [Na([2.2.2]-Cryptand)](3)[Ag(mnt)(2)] (5). The anion of 5 is analogous to that of 4. Electronic absorption and infrared spectra of each complex show behavior characteristic of metal-maleonitriledichalcogenates. Crystal data (153 K): 1, P2/n, Z = 2, a = 18.362(2) A, b = 16.500(1) A, c = 19.673(2) A, beta = 94.67(1) degrees, V = 5941(1) A(3); 2, P4, Z = 4, a= 27.039(4) A, c = 15.358(3) A, V = 11229(3) A(3); 3, P2(1)/c, Z = 6, a = 15.689(3) A, b = 51.924(11) A, c = 17.393(4) A, beta = 93.51(1) degrees, V = 14142(5) A(3); 4, P2(1)/c, Z = 4, a = 13.997(1) A, b = 21.866(2) A, c = 28.281(2) A, beta = 97.72(1) degrees, V = 8578(1) A(3); 5, P2/n, Z = 2, a = 11.547(2) A, b = 11.766(2) A, c = 27.774(6) A, beta = 91.85(3) degrees, V = 3772(1) A(3).

  • facile syntheses and structures of new metal maleonitrilediselenolates k 2 2 2 Cryptand 3 ag se2c2 cn 2 se6 k 2 2 2 Cryptand 2 ni se2c2 cn 2 2 and ni dppp se2c2 cn 2
    Inorganic Chemistry, 2000
    Co-Authors: Craig C Mclauchlan, James A Ibers
    Abstract:

    Facile syntheses of [K([2.2.2]-Cryptand)]3Ag(Se2C2(CN)2)(Se6)] (1) and [K([2.2.2]-Cryptand)]2[Ni(Se2C2(CN)2)2] (2) are achieved through reaction of polyselenides with KNH2, [2.2.2]-Cryptand, and AgBF4 or Ni(dppp)Cl2 in acetonitrile. The syntheses of 2 and Ni(dppp)(Se2C2(CN)2) (3) may be achieved by reaction of 1 with NiCl2 or Ni(dppp)Cl2 in dmf. These compounds represent the first easily prepared metal−maleonitrilediselenolate derivatives.

Xuzhou Yan - One of the best experts on this subject based on the ideXlab platform.

William J Evans - One of the best experts on this subject based on the ideXlab platform.

  • stabilization of u iii to oxidation and hydrolysis by encapsulation using 2 2 2 Cryptand
    Inorganic Chemistry, 2020
    Co-Authors: Daniel N Huh, Joseph W Ziller, Jeffrey M Barlow, Sierra R Ciccone, Jenny Y Yang, William J Evans
    Abstract:

    The electrochemical properties of U(III)-in-crypt (crypt = 2.2.2-Cryptand) were examined in dimethylformamide (DMF) and acetonitrile (MeCN) to determine the oxidative stability offered by crypt as ...

  • 2 2 2 Cryptand as a bidentate ligand in rare earth metal chemistry
    Inorganic chemistry frontiers, 2020
    Co-Authors: Amanda B Chung, Joseph W Ziller, Daniel N Huh, William J Evans
    Abstract:

    The 2.2.2-Cryptand ligand (crypt) that is heavily used in reductions of rare-earth metal complexes to encapsulate alkali metals has been found to function as a bidentate ligand to rare-earth metal ions in some cases. The X-ray crystal structures of the reduced dinitrogen metal complex, [{(R2N)2Ce(crypt-κ2-O,O′)}2(μ–η2:η2-N2)] (R = SiMe3), and the ytterbium metallocene, (C5Me5)2Yb(crypt-κ2-O,O′), are presented to demonstrate this binding mode. The implications of this available binding mode in rare-earth metal Cryptand chemistry are discussed.

  • insight into the electronic structure of formal lanthanide ii complexes using magnetic circular dichroism spectroscopy
    Organometallics, 2019
    Co-Authors: Valerie E Fleischauer, William J Evans, Gaurab Ganguly, David H Woen, Nikki J Wolford, Jochen Autschbach, Michael L Neidig
    Abstract:

    Magnetic circular dichroism (MCD) spectroscopy has been utilized to evaluate the electronic structure of the tris(cyclopentadienyl) rare-earth complexes [K(2.2.2-Cryptand)][LnCp′3] (Ln = Y, La, Pr,...

  • Using Diamagnetic Yttrium and Lanthanum Complexes to Explore Ligand Reduction and C–H Bond Activation in a Tris(aryloxide)mesitylene Ligand System
    2018
    Co-Authors: Chad T. Palumbo, Joseph W Ziller, Filipp Furche, Dominik P. Halter, Vamsee K. Voora, Guo P. Chen, Milan Gembicky, Arnold L. Rheingold, Karsten Meyer, William J Evans
    Abstract:

    [Y­(N­(SiMe3)2)3] reacts with (Ad,MeArOH)3mes to form the Y3+ complex [((Ad,MeArO)3mes)­Y], 1-Y. This complex reacts with potassium metal in the presence of 2.2.2-Cryptand to give a cocrystallized mixture of [K­(2.2.2-Cryptand)]­[((Ad,MeArO)3mes)­Y], 2-Y, and [K­(2.2.2-Cryptand)]­[((Ad,MeArO)3mes)­YH], 3-Y. The electron paramagnetic resonance spectrum of this crystalline mixture exhibits an isotropic signal at 77 K (giso = 2.000, Wiso = 1.8 mT), suggesting that 2-Y is best described as a Y3+ complex of the tris­(aryloxide)­mesitylene radical ((Ad,MeArO)3mes)4–. Evidence of the hydride ligand in 3-Y was obtained by 89Y–1H heteronuclear multiple quantum coherence NMR spectroscopy, and a coupling constant of JYH = 93 Hz was observed. A single crystal of 3-Y was also obtained in pure form and structurally characterized for comparison with the crystal data on the mixed component 2-Ln/3-Ln crystals. The origin of the hydride in 3-Ln is unknown, but further studies of the reduction of 1-La, previously found to form 2-La, revealed a possible source. Ligand-based C–H bond activation and loss of hydrogen can occur under reducing conditions to form a tetraanionic ligand derived from ((Ad,MeArO)3mes)3–, as observed in [K­(2.2.2-Cryptand)]­[((Ad,MeArO)3(C6Me3(CH2)2CH)­La], 4-La

  • Reactivity of Complexes of 4fn5d1 and 4fn+1 Ln2+ Ions with Cyclooctatetraene
    2017
    Co-Authors: Chad T. Palumbo, Joseph W Ziller, Megan E. Fieser, William J Evans
    Abstract:

    The Ln2+ complexes [K­(2.2.2-Cryptand)]­[Cp′3Ln] (Ln = La, Ce, Pr, Nd, Sm, Eu, Dy, Tm, Yb; Cp′ = C5H4SiMe3) were reacted with 1,3,5,7-cyclooctatetraene, C8H8, to determine if the reactivity of the complexes of 4fn+1 ions differed from that of 4fn5d1 ions. Crystallographically characterizable (C8H8)2– complexes were obtained only for the larger metals in the lanthanide series, and two types of products were obtained: [K­(2.2.2-Cryptand)]­[Cp′2Ln­(C8H8)] (Ln = La, Ce) and [K­(2.2.2-Cryptand)]­[Ln­(C8H8)2] (Ln = Ce, Pr, Nd, Sm). The expected co-products of the two-electron reduction of C8H8 by 2 equiv of [K­(2.2.2-Cryptand)]­[Cp′3Ln], namely, the tetrakis­(cyclopentadienyl) complexes, [K­(2.2.2-Cryptand)]­[Cp′4Ln], were crystallographically characterized for six metals (Ln = Ce, Pr, Nd, Sm, Dy, Tm)

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