Studies of Flerovium Homologs with Macrocyclic Extractants John D. Despotopulos 1,2, Kelly N. Kmak 3, Narek Gharibyan 1, Roger A. Henderson 1, William Kerlin 2, Kenton J. Moody 1, Ralf Sudowe 2, Dawn A. Shaughnessy 1 1 Lawrence Livermore National Laboratory,Chemical Sciences Division, Livermore, California 94551, USA 2 University of Nevada Las Vegas, Las Vegas, Nevada 89154, USA 2 University of California Berkeley, Berkeley, California 94720, USA TASCA14, Darmstadt, Germany, 10/21/2014 LLNL-PRES-662093 Lawrence Livermore National Laboratory
Chemical properties of the heaviest elements are determined through systematic studies of chemical groups 1 1 H Li Na K Rb Cs 2 3 4 Be Mg Ca Sr Ba Sc Y La Fr Ra Ac Ti Zr Hf V Nb Ta 87 88 89-103 104 105 Some chemical experiments have been performed on Groups 4-8, 12 Depending on the chemical system, inversions in group trends have been observed in the transactinides from relativistic effects Rf Db Cr Mo W Mn Tc Re Fe Ru 55 56 57-71 72 73 74 75 76 77 Os Co Ni Cu Zn Ga Ge As Rh Pd Ag Cd In 109 Mt 112 Cn B C N O F 11 12 13 14 15 16 17 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 5 6 7 8 9 Al Si P S Cl 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Sn Sb Ir Pt Au Hg Tl Pb Bi Se Br 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 57 La 89 Ac 58 Te I 78 79 80 81 82 83 84 85 113 114 115 Po At Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 90 106 Sg 59 60 61 62 91 92 93 94 Th Pa U 107 Bh 108 Hs 63 110 Ds Rg 111 Np Pu Am Cm - - Fl? - - 64 65 66 67 68 69 116 Lv 117 - - 70 71 95 96 97 98 99 100 101 102 103 Bk Cf Es Fm Md No Lr 18 2 He 10 Ne 18 Ar 36 Kr 54 Xe 86 Rn 118 - -? Predictions of Fl chemistry indicate it could be a metal or inert gas Two gas-phase experiments (GSI and PSI/FLNR) show contradictory results Aqueous phase chemistry of Fl would provide insight into where it truly fits in the Periodic Table 2
Automated radiochemistry is being developed for heavy elements and other applications Accelerator target chamber Accelerator - Chemistry Interface Automated chemistry system 3
Isotope Production and Integration of Automated Systems Goal: Integrate chemical automation methods with isotope production, separation and transport at Texas A&M University Cyclotron Cyclotron (Texas A&M University) Target MARS Physical Pre-Separator Recoil Transfer Chamber (RTC) Super Heavy Element Liquid Automation (SHELA) Gas-Liquid Interface for Transferring Transactinides to Automated Radiochemistry (GLITTAR) Gas-liquid interface and automated radiochemistry developed for use at CAMS Leverage existing capability and adapt to atom-at-a-time chemistry Meets requirements for rapid chemistry 4
Carrier-Free Isotope Production at LLNL Center for Accelerator Mass Spectrometry (CAMS) nat Ta Au nat In 25 mm 25 mm 13 MeV H + 13/+ 1/- Hg197 23.8 h 2.672 d IT 165.0 ε ωe - γ77.3. γ134.0 ε γ279.1d. E 0.600 11/- Au197 3/+ 7.8 s 100 IT 130.2 e -, γ279.1, σ γ (0 + 98.7), 155E1 196.966569 5
212 Pb Generator 232 U solution with all daughters in secular equilibrium. Added to AG 50w x 8 cation exchange column in 1 M HCl. Retains all radionuclides above 212 Pb in decay chain. AG 50w x 8 generator Elution Solution 212 Pb 2.0 M HCl 212 Bi 0.5 M HCl 6
Crown complexes unusually stable Binding of cationsby electrostatic ion-dipole interaction between cationsand the negatively charged ring (oxygen, sulfur, etc.) donor atoms. Macrocyclicligands are known to extract Pbbased on cavity size, ionic radius, and complexation Suitable starting place Element Oxidation State Coordination Number Ionic Radius (Å) Sn II VI 0.93 IV VI 0.690 Pb II VI 1.19 Sb III IV / VI 0.76 V VI 0.60 Bi III VI 1.03 7
2.6-3.2 Å 2.6-3.2 Å 1.2-1.5 Å Eichrom s Pb Resin extractant: di-t-butylcyclohexano-18-crown-6 0.75M di-t-butylcyclohexano- 18-crown-6 Isodecanol solvent Available as free resin Available as 2mL pre-packed cartridges Hexathia-18-crown-6 Tetrathia-12-crown-4 Sulfur analog of 18-crown-6 and 12-crown-4. Thia-crown ethers should extract softer metals, such as Pb/Hg. Little known extraction studies. Synthesized in-house (HT18C6) 8
Batch Study Results All results are presented as k, the number free column volumes to reach peak maximum for a given elution. k can be determined from D w and a resin multiplication factor: Resin Correction Factor (F) Pb 0.55 d v ( ) extr s k' = Dw 0.4 v m Ao -A D w = A s ml g s d v extr s F = 0.4 v m 9
Batch Study 10-20 mg resin 1 ml 0.001- Conc. HCl Mix to wet resin 20 µl 212 Pb, 197 Hg, or 113 Sn spike, 2 M HCl Equilibrate for 3 hours Count by HPGe during equilibration Remove Resin Count by HPGe 10
Figure. The batch uptake (k ) of 212 Pb 2+, 113 Sn 4+ and 197 Hg 2+ as a function of hydrochloric acid media on Pb resin (50-100 µm) with a 3 hour equilibration time. 11
Kinetics Study 10-20 mg resin 1 ml 4 (Sn), 1 (Pb), or 0.4 (Hg) M HCl Mix to wet resin 100 µl 212 Pb, 197 Hg, or 113 Sn spike Equilibrate for 30s-24hr hours Remove Resin (~10s) Count by HPGe 12
(A) Figure. (A) Kinetics of 212 Pb in1 M HCl media and (B) 113 Sn in 4 M HCl media (C) 197 Hg in 0.4 M HCl media on Pb resin (50-100 µm) with a varying equilibration times. 13
(B) Figure. (A) Kinetics of 212 Pb in1 M HCl media and (B) 113 Sn in 4 M HCl media (C) 197 Hg in 0.4 M HCl media on Pb resin (50-100 µm) with a varying equilibration times. 14
(C) Figure. (A) Kinetics of 212 Pb in1 M HCl media and (B) 113 Sn in 4 M HCl media (C) 197 Hg in 0.4 M HCl media on Pb resin (50-100 µm) with a varying equilibration times. 15
Column Study Table. Column elution fractions. Fraction [HCl] Numberof Fractions (1 ml each) 1 Load 0.4 +10 µl H 2 O 2 Elute Sn Load + 0.4 8 1 ml 0.4 M HCl with 10 cps 212 Pb/ 113 Sn / 197 Hg Front end count Back end count 2 ml pre-packed column, 2 ml/min flow (2 mmhg) Elute Pb 8 9 Elute Hg Conc. 11 Note: 113 Sn fractions counted 24hrs later to allow for secular equilibrium of 113 In 16
Figure. Separation of Sn(IV), Pb(II) and Hg(II) with 2 ml pre-packed Pb resin (50-100 µm) on vacuum box with 2 ml/min flow rate. 17
Thiacrown Liquid-Liquid Studies 500 µl crown in DCM 480 µl 0.001 to Conc. HCL Mix to equilibrate phases 20 µl 212 Pb, 113 Sn, 197 Hg spike, 2 M HCl Equilibrate for 3 hours Remove 300 µl Aqueous and Organic Phase Count by HPGe 18
197 Hg Extraction by Hexathia-18-Crown-6 Figure. 197 Hg extraction by ~0.003 M hexathia-18-crown-6 in dichloromethane. 19
197 Hg, 212 Pb, and 113 Sn Extraction by Tetrathia-12-Crown-4 and Hexathia-18-Crown-6 Figure. 197 Hg, 212 Pb, and 113 Sn extraction by ~0.0001 M hexathia-18-crown-6 (Left) and ~0.0001 M tetrathia-12-crown-4 (Right) in dichloromethane. 20
Pb, Sn, and Hg can be fully separated with the Eichrom Pb resin. Pb and Sn can be separated on the second time scale. Hg has very slow sorption and desorption kinetics and therefore cannot be effectively separated from Pb/Sn without long wait times between elution. Not effective for a transactinide chemical system, if Hglike character is desired. 21
Hg kinetics on both TT12C4 and HT18C6 is much faster than the analogous crown ether. Extraction is presumably Hg coordinating with the sulfur ring atoms (not in the cavity). Pb/Sn show no extraction most-likely due to the fact that the un-substituted thiacrown ethers have charge density oriented perpendicular to the ring verses into the center of the cavity like normal crown ethers. Adding a substituent like potentially di-benzohexathia-18- crown-6, etc. can force the charge density to mimic that of a normal crown ether (toward the cavity) and thus should show far increased extraction of Pb as well as Hg. 22
Continue to investigate the thiacrown ethers. Synthesize thiacrowns with substituents that will force the charge density to mimic that of the traditional crown ether, to see if (as expected) it will extract Pb when this condition is met. Investigate the kinetics more completely, initial studies indicate the thiacrowns vastly increase the extraction kinetics for Hg and one would expect the same should occur for other soft-metals like Pb once the proper thiacrown for the extraction is found. Due to the low solubility of thiacrown ethers in most organic solvents, work on incorporating them into a resin of some form. 23
LLNL Heavy Element and UNLV Radiochemistry Group. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This work was funded by the Laboratory Directed Research and Development Program at LLNL under project tracking code 11-ERD-011. 24