Nida Shahid, Vishal Budhija and Amrendra K. Singh*,
{"title":"在酸和盐水溶液中利用卤化物辅助亲电 C-H 活化法合成 Ru(III)-Anormal NHC 配合物","authors":"Nida Shahid, Vishal Budhija and Amrendra K. Singh*, ","doi":"10.1021/acs.organomet.4c0027310.1021/acs.organomet.4c00273","DOIUrl":null,"url":null,"abstract":"<p >Synthesis of Ru(III)-aNHC complexes <b>1a’</b> and <b>1b’</b> has been achieved in the aqueous acid medium at ambient temperature. The abnormal binding mode of NHC through this method was undoubtedly confirmed by the synthesis of Ru(III)-aNHC complex <b>2a’</b> from the C(2)-methylated ligand precursor. The conversion of abnormal to normal NHC complexes (<b>1a</b> and <b>1b</b>) was observed in the reaction medium. A pyridine-rollover mechanism for the conversion of abnormal to normal NHC has been proposed and validated by suitable substitution at the ligand backbone. Complexes <b>3a</b> (Ru-nNHC) and <b>3a’</b> (Ru-aNHC) were prepared with the bidentate ligand precursor having a Me-substituted pyridine to prohibit the “pyridine-rollover” pathway. The conversion of abnormal NHC complex <b>3a’</b> to the normal NHC complex <b>3a</b> was found to be suppressed in aqueous solutions at room temperature as the λ<sub>max</sub> for <b>3a’</b> remained the same even after 15 days, suggesting the role of C(3)-H of pyridine in the process. An investigation of this synthetic protocol in various aqueous acid/salt solutions indicates that Cl<sup>–</sup> ions are required to form the complexes, indicating a halide-assisted C–H activation pathway. All complexes have been characterized using various spectroscopic techniques. The molecular structures of complexes <b>1a’</b>, <b>1b</b>, <b>2a’</b>, and <b>3a</b> have been determined using the single-crystal X-ray diffraction technique.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Halide-Assisted Electrophilic C–H Activation in Aqueous Acid and Salt Solutions for the Synthesis of Ru(III)-Abnormal NHC Complexes\",\"authors\":\"Nida Shahid, Vishal Budhija and Amrendra K. Singh*, \",\"doi\":\"10.1021/acs.organomet.4c0027310.1021/acs.organomet.4c00273\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >Synthesis of Ru(III)-aNHC complexes <b>1a’</b> and <b>1b’</b> has been achieved in the aqueous acid medium at ambient temperature. The abnormal binding mode of NHC through this method was undoubtedly confirmed by the synthesis of Ru(III)-aNHC complex <b>2a’</b> from the C(2)-methylated ligand precursor. The conversion of abnormal to normal NHC complexes (<b>1a</b> and <b>1b</b>) was observed in the reaction medium. A pyridine-rollover mechanism for the conversion of abnormal to normal NHC has been proposed and validated by suitable substitution at the ligand backbone. Complexes <b>3a</b> (Ru-nNHC) and <b>3a’</b> (Ru-aNHC) were prepared with the bidentate ligand precursor having a Me-substituted pyridine to prohibit the “pyridine-rollover” pathway. The conversion of abnormal NHC complex <b>3a’</b> to the normal NHC complex <b>3a</b> was found to be suppressed in aqueous solutions at room temperature as the λ<sub>max</sub> for <b>3a’</b> remained the same even after 15 days, suggesting the role of C(3)-H of pyridine in the process. An investigation of this synthetic protocol in various aqueous acid/salt solutions indicates that Cl<sup>–</sup> ions are required to form the complexes, indicating a halide-assisted C–H activation pathway. All complexes have been characterized using various spectroscopic techniques. The molecular structures of complexes <b>1a’</b>, <b>1b</b>, <b>2a’</b>, and <b>3a</b> have been determined using the single-crystal X-ray diffraction technique.</p>\",\"PeriodicalId\":56,\"journal\":{\"name\":\"Organometallics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.5000,\"publicationDate\":\"2024-10-03\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Organometallics\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://pubs.acs.org/doi/10.1021/acs.organomet.4c00273\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"CHEMISTRY, INORGANIC & NUCLEAR\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organometallics","FirstCategoryId":"92","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acs.organomet.4c00273","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
Halide-Assisted Electrophilic C–H Activation in Aqueous Acid and Salt Solutions for the Synthesis of Ru(III)-Abnormal NHC Complexes
Synthesis of Ru(III)-aNHC complexes 1a’ and 1b’ has been achieved in the aqueous acid medium at ambient temperature. The abnormal binding mode of NHC through this method was undoubtedly confirmed by the synthesis of Ru(III)-aNHC complex 2a’ from the C(2)-methylated ligand precursor. The conversion of abnormal to normal NHC complexes (1a and 1b) was observed in the reaction medium. A pyridine-rollover mechanism for the conversion of abnormal to normal NHC has been proposed and validated by suitable substitution at the ligand backbone. Complexes 3a (Ru-nNHC) and 3a’ (Ru-aNHC) were prepared with the bidentate ligand precursor having a Me-substituted pyridine to prohibit the “pyridine-rollover” pathway. The conversion of abnormal NHC complex 3a’ to the normal NHC complex 3a was found to be suppressed in aqueous solutions at room temperature as the λmax for 3a’ remained the same even after 15 days, suggesting the role of C(3)-H of pyridine in the process. An investigation of this synthetic protocol in various aqueous acid/salt solutions indicates that Cl– ions are required to form the complexes, indicating a halide-assisted C–H activation pathway. All complexes have been characterized using various spectroscopic techniques. The molecular structures of complexes 1a’, 1b, 2a’, and 3a have been determined using the single-crystal X-ray diffraction technique.
期刊介绍:
Organometallics is the flagship journal of organometallic chemistry and records progress in one of the most active fields of science, bridging organic and inorganic chemistry. The journal publishes Articles, Communications, Reviews, and Tutorials (instructional overviews) that depict research on the synthesis, structure, bonding, chemical reactivity, and reaction mechanisms for a variety of applications, including catalyst design and catalytic processes; main-group, transition-metal, and lanthanide and actinide metal chemistry; synthetic aspects of polymer science and materials science; and bioorganometallic chemistry.