Synthesis
The commercially available Hg(CH3COO)2 (0.01mol, 3.19g), 2,4-dinitrophenol (DNP, 0.01mol, 1.84g) and guanidine hydrochloride (CH6N3Cl, 0.01mol, 0.96g), was dissolved in 30 mL CH3CN solution, by using a pot in the teflon in the reaction kettle, and then set at 180ºC in 8 hours. Then, temperature control to reduce the rate of 60ºC/h to room temperature, opening the reaction kettle get acicular red block crystal, the yield of 78.5% based on Hg(CH3COO)2. The red block crystals suitable for diffraction is obtained directly. The single crystals X-ray confirmed that the red block crystal was [HgCl(DNP)]•CH5N3•CH3CN. The elemental analysis supports this formulation. Anal. Calc. for C9H10ClHgN6O5: C, 20.84%; H, 1.93%; N, 16.21%; Cl, 6.85%; Hg, 38.70%; O, 15.44%. Found: C, 20.67%; H, 1.89%; N, 16.04%.
Structure determination
The diffraction data were collected on an SMART APEXII diffractometer with graphite monchromatic Mo-Kα (λ = 0.71073 Å, T = 293K) radiation. Empirical absorption correction was carried out by using the SADABS program. Their structures were solved by direct methods and refined by least squares on Fobs2 with SHELXTL software package. All non-H atoms were anisotropically refined. The hydrogen atoms were located by difference synthesis and refined isotropically. The molecular graphics were plotted using SHELXTL. Atomic scattering factors and anomalous dispersion corrections were taken from International Tables for X-ray Crystallography. A summary of the key crystallographic information was given in Supporting Information (SI) Table S1. The CCDC number is 2042589.
Antibacterial property test for guanidine derivative
Main instruments and equipment: High temperature and high pressure steam sterilizer (Hirayama VE-50). Multi-function marker (Switzerland TECAN SPARK 10M). Clean table (SW-CJ-2FD). Constant temperature vibration Swing device (IS-RDV1). Analytical Electronic balance (FA2004).
The main reagent: Tryptone (AR), Yeast powder (AR), Agar powder (AR), NaCl (AR).
Bacterial strain: E. coli, Staphylococcus aureus.
Sample to be tested: Sample 1 to 9, for the structure of compounds 1-9 see Supporting Information (SI) page 4-6.
Preparation of LB medium
LB liquid medium: Using a measuring cylinder, 100 mL distilled water was poured into a 250 mL reagent bottle, and 1 g tryptone, 0.5 g yeast powder and 1 g sodium chloride were weighed by analytical electronic balance, respectively. The above weighing reagent was added to mix well, and sterilized in a high-temperature and high-pressure steam sterilization pot at 121 ℃ for 15 minutes.
LB solid medium: Using a measuring cylinder, 100 mL distilled water was poured into a 250 mL reagent bottle, and then 1 g tryptone, 0.5 g yeast powder, 1 g sodium chloride and 1.5 g AGAR powder were weighed by analytical electronic balance. The above weighing reagent was added to mix well, and put in a high temperature and high pressure steam sterilization pot at 121℃ for 15min to be used after sterilization.
Preparation of bacterial suspension
Three 12 mL bacterial culture tubes were added into 3 mL LB liquid medium. 6 L Staphylococcus aureus and Escherichia coli freezers were added to two of them, and the other one was used as blank control. It was placed in a thermostatic oscillator (37 ℃, 200 RPM) and incubated overnight (15 h). OD 460 (1.25 for E. coli OD 460, corresponding concentration of 5.9×108 CFU/mL) was measured on a multifunctional microplate reader.Staphylococcus aureus OD 460 was 1.5 and the corresponding bacterial liquid concentration was 5.8×108 CFU/mL. Then LB medium was used to dilute the bacterial suspension to 5×106 CFU/mL for later use.
Treatment of samples to be tested
5 mg samples to be tested were respectively weighed and placed in a 15 mL centrifuge tube according to groups, and then sterilized at 121℃ for 20 min in a high temperature and high pressure steam sterilization pot.
Plate coating count test
The LB liquid medium was used to dilute the bacterial suspension to a concentration of 5×106 CFU/mL, and then 1 mL of the bacterial suspension was absorbed and added to a 15 mL centrifuge tube with the sterilized sample. The suspension was placed in a thermostatic oscillator at 37℃ and oscillated at 200 RPM for 18 h.
After the culture was completed, 100 L bacterial suspension was diluted with a ratio of 10 times (10-5, 10-6 and 10-7 were used in this test), and 100 L was uniformly coated on LB solid medium. Placed in a constant temperature incubator for 18 h at 37℃, the number of colonies was recorded and photos were taken.