A novel silathiogermylene [Bu(I)2(ATI)GeSSiMe3] (2) containing a reactive Ge(II)-SSiMe3 moiety showed an unusual reaction when treated with elemental selenium and sulfur to afford the germaacid anhydrides [{Bu(I)2(ATI)Ge(Se)}2Se] (3) and [{Bu(I)2(ATI)Ge(S)}2S] (4) in excellent yields, respectively. This single-step conversion of compound 2 to compounds 3 and 4 involves condensation along with insertion and oxidative addition reactions and such reactivity of a germylene with elemental chalcogens is observed for the first time.
The biological applications of germylenes remain an unconceivable domain owing to their unstable nature. We report the isolation of air, water, and culture-medium stable germylene DPMGeOH (3) and its potential biological application (DPM = dipyrromethene ligand). Compound 3 exhibits antiproliferative effects comparable to that of cisplatin in human cancer cells. The cytotoxicity of compound 3 on normal epithelial cells is minimal and is similar to that of the currently used anti-cancer drugs. These findings provide a framework for a plethora of biological studies using germylenes and have important implications for low-valent main group chemistry. File list (2) download file view on ChemRxiv Supporting Information.pdf (3.68 MiB) download file view on ChemRxiv Manuscript.pdf (698.84 KiB)
Aminotroponiminate (ATI) ligand stabilized
silathiogermylene [(Bu
i
2ATI)GeSSiMe3] (11) and siloxygermylenes [(Bu
i
2ATI)GeOSiR3] (R = Me 2, Ph 3) react differently with the same reagents,
i.e., N-methylmorpholine-N-oxide
(nmmo), diironnonacarbonyl,
and elemental sulfur/selenium. Whereas silathiogermylene 11 afforded the first O-silylthionogermaester [(Bu
i
2ATI)Ge(S)OSiMe3] (1) in its reaction with nmmo involving 1,3-silyl
migration, siloxygermylenes 2 and 3 reacted
with the same to give 1,3-dioxadigermetanes [{(Bu
i
2ATI)Ge(O)OSiR3}2] (R = Me 14 and Ph 4, respectively) as
dimerized products. Similarly, in the reaction with diironnonacarbonyl,
compound 3 behaved in the anticipated way and led to
its complex with irontetracarbonyl [(Bu
i
2ATI)Ge(Fe(CO)4)OSiPh3] (5), but compound 11 did not offer the
desired complex. Further, unlike compound 11, compounds 2 and 3 afford the anticipated O-silylthiono- and selenogermaesters [(Bu
i
2ATI)Ge(E)OSiR3] (E = S; R = Me 1, Ph 7; E = Se; R = Me 6, Ph 8) when treated with elemental sulfur and selenium. As there
is no report on the reactivity of germaesters, the reactions of O-silylthiono- and selenogermaesters 1 and 6–8 are also carried out with methanol
and nmmo.
A germylene monochloride complex ((DPM)GeCl, 1) that is water stable was isolated for the first time. Interestingly, it reacts with cesium fluoride under ambient conditions (non-inert atmosphere and water-containing solvent) to afford water stable germylene monofluoride complex ((DPM)GeF, 2). Due to the usage of DPM (dipyrrinate) ligand, germylene monohalides 1 and 2 show fluorescence in the visible region at 555 and 538 nm, respectively. Compounds 1 and 2 are the first fluorescent germylene complexes and were characterized by multinuclear NMR spectroscopy. The structure of compound 1 was also proved by single crystal X-ray diffraction studies.
A rapid and sensitive liquid chromatography tandem mass spectrometry method has been developed and validated for the determination of the active metabolite (R-138727) of prasugrel in human plasma. Because R-138727 contains a thiol group, it requires stabilization by derivatizing with N-ethyl maleimide. Commercially available trandolapril was used as the internal standard (IS). The derivatives of R-138727 and IS were extracted from human plasma using a liquid-liquid extraction technique. Chromatography was performed on a Hypurity C18, 5 µ (50 mm × 4.6 mm, i.d.) column, with the mobile phase consisting of acetonitrile and 10 mM ammonium formate (pH 3.0, 50:50 V/V), followed by detection using mass spectrometry. No significant endogenous peaks corresponding to R-138727 or IS were detected in the blank human plasma samples and no significant matrix effect was observed for R-138727 and IS in the human plasma samples. The mean recovery for R-138727 ranged from 90.1 to 104.1%, with the lower limit of quantification set at 1 ng/ml. Linearity was established for concentrations in the range of 1.0-500.12 ng/ml, with a coefficient of determination (r(2) ) of 0.9958. The derivatized R-138727 was stable in human plasma for 3 months at -20 °C. This method increased the sensitivity and selectivity, resulting in high-throughput analysis of R-138727 using trandolapril as the IS in pharmacokinetic and bioequivalence studies, with a chromatographic run time of 3.7 min.
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