Phenanthrolines

Groundwater samples were collected from 93 well clusters from the Oak Ridge Field Research Site between November 2012 and February 2013. Samples collected include groundwater from both contaminated and noncontaminated background wells, with each well representing a distinct geochemical transect.
All groundwater and filtered-groundwater samples were collected from the midscreen level and analyzed to determine geochemistry and to characterize the microbial community structure. Prior to collection of samples, groundwater was pumped until pH, conductivity, and oxidation-reduction (redox) values were stabilized. This was done to purge the well and the line of standing water. Approximately 2 to 20 liters of groundwater was purged from each well. For all wells, water was collected with either a peristaltic or a bladder pump using low flow in order to minimize drawdown in the well.
A total of 38 geochemical and 2 microbial parameters were measured for each well during the course of the study. Bulk water parameters, including temperature, pH, dissolved oxygen (DO), conductivity, and redox, were measured at the wellhead using an In-Situ Troll 9500 system (In-Situ Inc., CO, USA). To ensure accuracy, dissolved oxygen and pH probes were calibrated daily and the remaining probes were calibrated monthly. Sulfide and ferrous iron [Fe(II)] groundwater concentrations were determined using the U.S. EPA methylene blue method (Hach; EPA Method 8131) and the 1,10-phenanthroline method (Hach; EPA Method 8146), respectively, and analyzed with a field spectrophotometer (Hach DR 2800). All other biological and geochemical parameters were preserved, stored, and analyzed using EPA-approved and/or standard methods (41 ), unless otherwise indicated. A description of the sampling and analytical methods for each parameter is provided in the following sections. Lists of geochemical and microbial measurements and summary values are provided in Tables S2 to S6 in the supplemental material found at https://sites.google.com/a/lbl.gov/enigma-extranet/pubs-review/100-well-genome-survey.

3,8-Dibromo-1,10-phenanthroline (1.49 g, 4.4 mmol) and a stirring bar were placed in an autoclave (125 mL) with a PTFE inner vessel and Ni(dppp)Cl₂ (138 mg, 6 mol%) and THF (50 mL) were gradually added. A THF solution of (iPrO)₃SiCH₂MgCl (12.5 mmol) was added dropwise over 3 min under continuous stirring. The autoclave was sealed and stirred at room temperature for 1 h, and then heated to 140 °C. After 17 h, the mixture was cooled to room temperature and then quenched with water. The mixture was extracted with CHCl₃ and the organic layer was washed with brine and dried over Na₂SO₄. The solvents were removed by rotary evaporator. The crude product was dissolved in n-hexane and stirred for 15 min. The mixture was filtered through a Celite pad and the solvent was removed by rotary evaporator. The crude product was purified by silica gel column chromatography (n-hexane/AcOEt) to give the Phen-PMO precursor, 3,8-bis[(triisopropoxysilyl)methyl]-1,10-phenanthroline (1a), as a pale-yellow solid (1.11 g, 41%). ¹H NMR (600 MHz, CDCl₃): δ 9.00 (d, J = 2.1 Hz, 2H), 8.00 (d, J = 2.1 Hz, 2H), 7.65 (s, 2H), 4.21 (sept, J = 6.1 Hz, 6H), 2.36 (s, 4H), 1.15 ppm (d, J = 6.1 Hz, 36H). ¹³C{¹H} NMR (151 MHz, CDCl₃): δ 151.9, 143.9, 134.8, 133.4, 127.9, 126.2, 65.7, 25.7, 19.6 ppm. ²⁹Si{¹H} NMR (119 MHz, CDCl₃): δ −56.5 ppm. Anal. calcd for C₃₂H₅₂N₂O₆Si₂: C, 62.30; H, 8.50; N, 4.54. Found: C, 62.30; H, 8.90; N, 4.50.

All experiments were performed under nitrogen atmosphere using either the Schlenk technique or a glove box. All chemicals were purchased from Kanto Chemical Co., Inc., FUJIFILM Wako Chemicals, Sigma-Aldrich, or Tokyo Chemical Industry (TCI), and used as received without further purification. 3,8-Dibromo-1,10-phenanthroline was prepared according to a previously reported procedure.²² Silica gel column chromatography was performed on a Yamazen AI-580 Single Channel Automated Flash Chromatography System. ¹H, ¹³C{¹H} and ²⁹Si{¹H} NMR spectra were recorded on a Bruker AVANCE III HD NMR spectrometer (¹H NMR at 600 MHz; ¹³C{¹H} NMR at 151 MHz; ²⁹Si{¹H} NMR at 119 MHz). ¹³C CP/MAS NMR and ²⁹Si CP/MAS NMR measurements were performed using a 4 mm diameter ZrO₂ rotor at a sample spinning frequency of 8 kHz using a Bruker AVANCE II NMR spectrometer (¹³C CP/MAS NMR at 100.6 MHz; ²⁹Si CP/MAS NMR at 79.49 MHz). ICP-AES was performed on a Hitachi High-Tech PS3520VDDII in the Toray Research Center, Inc. Nitrogen adsorption/desorption isotherms were measured using a MicrotracBEL BELSORP MAX-II instrument. BET surface areas were calculated from the linear sections of the BET plots (P/P₀ = 0.1–0.2). Pore-size distributions were calculated from adsorption branch using the Barrett–Joyner–Halenda (BJH) method. XRD patterns were recorded on a Rigaku RINT-TTR diffractometer under Cu Kα radiation (50 kV, 300 mA). TEM images were obtained on a JEOL JEM-2100F operating at 200 kV.