STRACTURAL INVESTIGATION OF GRIGNARD REAGENTS BY MEANS OF SPRAY IONIZATION MASS SPECTROMETRY AND RAPID X-RAY CRYSTALLOGRAPHY

The cold ESI，operating ionization under low temperature was recently developed in our laboratory and proved to beeffective to preserve thermally unstable compounds unchanged.某些有意义的spectra wereobtained form MeMgCl, MeMgBr, EtMgCl, EtMgBr, PhMgCl t-BuMgClAllyMgCl and i-PrMgCl in tetrahydrofuran (THF) solution using the cold ESI. the characteristic ionpeaks consistent with these three spectra of m/z 529，601 and 673 indicate the ion species of [NMg d - 22 d - 2cl d - 23 d - D2(THF) d - 2n d - D2] d - D1+ d - D1 formedbased on the atomic nitrogen attached break down products[RMg - D22 - D2Cl - D23 - D2(THF) - D2n - D2- h] - D1+ - D1 ion peaks directly responding to the correspondingGrignard species are definitely observed in EtMgCl and PhMgCl. The isotopic ion peak patterns as分析检测sequential THF cleavage from the parent ion suggest these ionstructures. Following equilibrium is then derived. 3rmgx (THF) - D2n - D2【double arrow】- D22 - D2Mg +RMg - D22 - D2X - D23 - D2(THF) -More D2n D2 (eq.1)On the other hand，X-ray crystallographic analyses were undertaken. We determined the crystal结构2[Mg D22 D2Cl D23 D2(THF) D26 D2] [Ph D24 D2Mg D22 D2Cl D22 D2] obtained from PhMgCl，and [Mg D22 D2Cl D23 D2(THF) D26 D2] [t-BuMgCl D22 D2(THF)] from t-BuMgCl. The structure ofdimagnesium cationic species included in the both crystals obtained from PhMgCl and t-BuMgCl wassolved. This cationic species [Mg - D22 - D2Cl - D23 - D2(THF) - D26 - D2] - D1+ - D1 which is detected inthe Grignard reagent for the first time has rarely observed. the first crysta lstructure of RMgXwithout solvent molecule was observed. In case of the crystal obtained from t-BuMgCl，monomeric structure (t-BuMgCl D22 D2THF) was observed together with the cationic species. Theseconstitutions were thought to be included in the Schlenk equilibrium.8PhMgCl(THF) - D2n - D2【double】arrow】2phi D22 D2Mg + 2[(Mg D22 D2Cl D23 D2)(THF) i D26 D2] i D1+ i D1+[phi D24 D2Mg D2Cl D2Cl D22 D22 D2] phi D12- phi D1 (eq. 2)5t- bumgcl (THF) phi D2n D2【double arrow】2t- bu - D22 - D2Mg + [(Mg - D22 - D2Cl - D23 - D2)(THF) - D26 - D2] - D1+ - D1+[t-BuMgCl - D22 - D2(THF)] - D1- D1 (eq. 3)Other crystal structures of Grignard species have also beeninvestigated in the same manner for comparison. in case of MeMgCl，the crystal structure of Me - D22 - D2Mg - D24 - D2Cl - D26 - D2(THF) - D26 - D2包含在Schlenkequilibrium was found.6MeMgCl(THF) - D2n - D2【double arrow】2me - D22 - D2Mg +Me - D22 - D2Mg - D24 - D2Cl - D26 - D2(THF) - D26 - D2(eq. 4) Less

The cold ESI, operating ionization under low temperature was recently developed in our laboratory and proved to be effective to preserve thermally unstable compounds unchanged. Some significant spectra were obtained form MeMgCl, MeMgBr, EtMgCl, EtMgBr, PhMgCl t-BuMgCl, AllyMgCl and i-PrMgCl in tetrahydrofuran (THF) solution using the cold ESI. The characteristic ion peaks consistent with these three spectra of m/z 529, 601 and 673 indicate the ion species of [NMgィイD22ィエD2ClィイD23ィエD2(THF)ィイD2nィエD2]ィイD1+ィエD1 formed based on the atomic nitrogen attached break down products. The [RMgィイD22ィエD2ClィイD23ィエD2(THF)ィイD2nィエD2-H]ィイD1+ィエD1 ion peaks directly related to the corresponding Grignard species are definitely observed in EtMgCl and PhMgCl. The isotopic ion peak patterns as well as MS/MS analysis detecting sequential THF cleavage from the parent ion suggest these ion structures. Following equilibrium is then derived.3RMgX(THF)ィイD2nィエD2【double arrow】RィイD22ィエD2Mg + RMgィイD22ィエD2XィイD23ィエD2(THF)ィイ … More D2nィエD2 (eq.1)On the other hand, X-ray crystallographic analyses were undertaken. We determined the crystal structures of 2[MgィイD22ィエD2ClィイD23ィエD2(THF)ィイD26ィエD2]・[PhィイD24ィエD2MgィイD22ィエD2ClィイD22ィエD2] obtained from PhMgCl, and [MgィイD22ィエD2ClィイD23ィエD2(THF)ィイD26ィエD2]・[t-BuMgClィイD22ィエD2(THF)] from t-BuMgCl. The structure of dimagnesium cationic species included in the both crystals obtained from PhMgCl and t-BuMgCl was solved. This cationic species [MgィイD22ィエD2ClィイD23ィエD2(THF)ィイD26ィエD2]ィイD1+ィエD1 which is detected in the Grignard reagent for the first time has rarely observed. The first crysta lstructure of RMgX without solvent molecule was observed. In case of the crystal obtained from t-BuMgCl, monomeric structure (t-BuMgClィイD22ィエD2THF) was observed together with the cationic species. These constitutions were thought to be included in the Schlenk equilibrium.8PhMgCl(THF)ィイD2nィエD2 【double arrow】2PhィイD22ィエD2Mg + 2[(MgィイD22ィエD2ClィイD23ィエD2)(THF)ィイD26ィエD2]ィイD1+ィエD1 + [PhィイD24ィエD2MgィイD22ィエD2ClィイD22ィエD2]ィイD12-ィエD1 (eq. 2)5t-BuMgCl(THF)ィイD2nィエD2 【double arrow】 2t-BuィイD22ィエD2Mg + [(MgィイD22ィエD2ClィイD23ィエD2)(THF)ィイD26ィエD2]ィイD1+ィエD1 + [t-BuMgClィイD22ィエD2(THF)]ィイD1-ィエD1 (eq. 3)Other crystal structures of Grignard species have also been investigated in the same manner for comparison. In case of MeMgCl, the crystal structure of MeィイD22ィエD2MgィイD24ィエD2ClィイD26ィエD2(THF)ィイD26ィエD2 included in Schlenk equilibrium was found.6MeMgCl(THF)ィイD2nィエD2 【double arrow】 2MeィイD22ィエD2Mg + MeィイD22ィエD2MgィイD24ィエD2ClィイD26ィエD2(THF)ィイD26ィエD2 (eq. 4) Less