Research group of Professor Lang Jianping of Suzhou University: coordination driven directional synthesis strategy for solid-phase [2 + 2] photoreaction to generate pure cyclobutane isomers

The construction of three-dimensional organic molecules with target structure has become a new research field, and has been applied to drug discovery, material engineering and other fields As a catalyst free synthesis method, [2 + 2] photochemical reaction has been widely used in the synthesis of Cyclobutanes However, the stereochemical control of [2 + 2] photochemical reactions is still facing severe challenges In recent years, template control has been used to avoid the disorder of C = C, and stereochemical control of single ring products in [2 + 2] photochemical reactions has been widely used However, the current synthesis methods can not synthesize bicyclobutane or polycyclobutane compounds, because it is difficult to control the arrangement of multiple C = C in a single reaction, resulting in the formation of complex isomer mixture in the photocyclic addition reaction Recently, on the basis of previous work, Lang Jianping Group of Suzhou University proposed for the first time a kind of directional synthesis strategy based on coordination interaction to realize the precise stereochemical control of diene dimer in the photocyclic addition reaction, and successfully synthesized all the photocyclic addition products in the system for the first time, without isomer by-products and without separation The related research results were published in J am Chem SOC (DOI: 10.1021 / JACS 9b12358) under the title of "coordination driven stereospecific control strategy for purecyclosomers in solid state diene Photocyclization" Professor Lang Jianping's brief introduction to the research group: the research group has been engaged in the design, synthesis and application of complex catalysts for a long time; the design and synthesis of complex (cluster) photoelectric materials; the design and application of MOFs with nano space; the simulation of the synthesis and reactivity of metal protein and metal center in enzyme Brief introduction to Professor Lang Jianping, Professor of materials and Chemical Engineering Department of Suzhou University In 1984, he graduated from Suzhou University with a bachelor's degree In 1993, he received a doctor's degree from the Institute of coordination chemistry of Nanjing University From 1995 to 2001, he received a JSPS postdoctoral degree from the Department of chemistry of Nagoya University in Japan and a postdoctoral degree from the Department of chemistry and chemical biology of Harvard University in the United States 2001.3 researcher and doctoral supervisor of Suzhou University He has successively served as the vice president and President of the College of chemical engineering, the executive director, director and Secretary of the Party committee of the Department of materials and chemical engineering, the executive vice president and President of the graduate school, the vice chairman of the academic degree evaluation committee and Secretary General of the Secretariat (January 2018 to present) Currently, he is the leader of inorganic chemistry discipline of Suzhou University, foreign fellow of European Academy of Sciences (2018), FRSC (2014 present), member of Inorganic Chemistry Discipline Committee of Chinese Chemical Society (2009.12 present), vice chairman of crystal chemistry Professional Committee of Chinese Chemical Society (2018.10)- So far), member of molecular sieve Committee of China Chemical Society (September 2018 to present), member of the 10th-12th Council of Jiangsu Chemical Society (April 2009 to present) Since 2001, he has presided over 10 NSFC projects and more than 20 provincial and ministerial fund projects He has published more than 430 official papers in core Chemical Journals at home and abroad, such as chem SOC Rev., J am Chem SOC., angel Chem Int ed., coord Chem Rev., and published SCI retrieval papers cited by him for more than 6500 times 22 invention patents have been authorized by China, and won the outstanding achievement award of scientific research (NATURAL SCIENCE) (2011) of the Ministry of education, the science and technology progress award of Jiangsu Province (2010), the second prize of science and technology progress award of China Petroleum and Chemical Industry Association (2009) Winner of National Science Fund for Distinguished Young Scholars (2005), national candidate for one million talents project in the new century (2007), national excellent teacher of the Ministry of Education (2004), special allowance of the State Council (2005), young and middle-aged experts with outstanding contributions in Jiangsu Province (2006), training object of scientific and technological innovation team of "blue and green project" in Jiangsu Province (2008) In 2011), the distinguished professor of the Yangtze River scholars award program of the Ministry of Education (2011), the National May 1st Labor Medal (2011), the second level young and middle-aged science and technology leaders of the fourth "333 high level talent training project" of Jiangsu Province (2011), and the third "333 project" outstanding contribution award of Jiangsu Province (2011) Currently, he is the editorial board member of Dalton Transactions international consultant (2010 present), Springer nature press scientific reports international consultant (2015 present), etc Leading scientific achievements: as a catalyst free synthesis method, [2 + 2] photochemical reaction has been widely used in the synthesis of Cyclobutanes However, the stereochemical control of [2 + 2] photochemical reactions is still facing severe challenges In recent years, the research team of Professor Lang Jianping of Suzhou University has avoided the disordered arrangement of C = C through the method of template control, and has carried out a series of studies on the synthesis and properties of monocyclic products in the [2 + 2] photocyclic addition reaction (angel Chem Int ed 2019, 58, 9453; angel Chem Int ed 2018, 57, 12696; chem Commun 2019, 55, 3532; chem Commun 2017, 53, 5515; Chem Commun 2016 , 52 , 7990 ）。 However, it is difficult to control the arrangement of C = C in a single reaction, so a complex mixture of stereoisomers will be formed in the diene photocyclic addition reaction In order to solve this problem and synthesize pure bicyclobutanes, Professor Lang Jianping's research group found that the arrangement of monomers in coordination polymers can be controlled by metal coordination, and proposed a coordination driven directional synthesis strategy Fig 1 The structure of 1,3-bpeb and its stereoisomeric products (source: J am Chem SOC.) firstly, the monomer 1,3-bis ((E) - 2 - (pyridin-4-yl) vinyl) benzene (1,3-bpeb) was designed and synthesized by the author The products of the photocyclic addition have five configurations (Fig 1) The one dimensional coordination polymer material with photosensitive properties [CD (1,3-hbeb) (L 1)] (CP1, HL 1 = pyromellitic acid) was successfully designed and obtained by solvothermal method Single crystal X-ray diffraction results show that the 1,3-bpeb monomers in CP1 are arranged in the form of off set due to metal coordination CP1 undergoes a [2 + 2] cycloaddition reaction after UV irradiation, resulting in isomer 1 The pure organic compound isomer 1 can be obtained by destroying the coordination bond with nitric acid and removing the organic carboxylic acid and metal The structure of isomer 1 was confirmed by NMR and single crystal X-ray diffraction (Fig 2) Fig 2 The single crystal structure of the isomer 1 was formed after the photoreaction of the complex CP1 with 1,3-bpeb monomer arranged in off set (source: J am Chem SOC.) the author continued to design and synthesize a series of one-dimensional chain coordination polymer materials with photosensitive properties [CD2 (1,3-bpeb) 2 (L2) 4] (CP2, HL 2 = 2,4-dichlorobenzoic acid), [CD8 (1,3-bpeb) 8 (L3) 14 (HCOO) 2] (HL 3) 2 (H2O) 3 (CP3, HL 3 = m-methylbenzoic acid), [CD2 (1,3-bpeb) 2 (L 4) 4] (CP4, HL 4 = 3,5-dimethoxybenzoic acid) Among the three complexes, there are different kinds of organic carboxylic acids and different structural interactions (hydrogen bond, π - π stacking, etc.) The weak interactions in coordination polymers are used to control the dynamic movement of molecules at the molecular level, so that they show different arrangements The results of single crystal X-ray diffraction show that the monomers of the three complexes are arranged in the form of face to face, the difference is that the two olefin double bonds in the monomers are arranged in the form of type І, type II and type III respectively Through further research, the author found that in the process of halo addition, light provides the energy to initiate the reaction, and the wavelength of the light source has a significant impact on the product When the wavelength is more than 420 nm, CP2 is added by a single ring, only isomer 2 is produced, and there is no other dimer product In order to avoid molecular rotation, CP2 undergoes the photocyclic addition reaction at low temperature (- 50 ℃), only isomer 3 α is generated (Fig 3) Fig 3 1,3-bpeb monomers arranged in the form of type ІІІІІІІІІІІІІІІІІІІІ (source: J am Chem SOC.) CP3 undergoes UV irradiation at low temperature (- 196 ℃), and the cycloaddition reaction produces isomer 3 β; CP4 undergoes UV irradiation at room temperature to generate isomer 3 γ The structure of isomer 3 β and isomer 3 γ was confirmed by NMR and single crystal X-ray diffraction analysis of the extracted organic compounds (Fig 4) So far, through this strategy, the author has synthesized all the products of the system Fig 4 The 1,3-bpeb monomers in the complexes CP3 and CP4 are arranged in the form of type II and type III respectively, and the single crystal structure of isomer 3 β and isomer 3 γ are generated under ultraviolet light (source: J am Chem SOC.) Summary: by adjusting the arrangement of 1,3-bpeb monomers in the complexes, the author developed the first system based on metal coordination interaction to control the generation of products of different stereoscopic configuration This study not only provides a new strategy for the synthesis of pure cyclic compounds, but also expands the application of photocyclic addition reaction This research result was recently published in J am Chem SOC (DOI: 10.1021 / JACS 9b12358) Wang Mengfan and Mi Yan, associate professors of master's degree, are the co first authors of the paper, Hu Feilong, associate professors, Niu Zheng and Lang Jianping are the corresponding authors This work was supported by NSFC key projects (21531006, 21701035 and 21773163), Jiangsu University Key Discipline Development Project and Suzhou science and technology infrastructure project (szs201905) Nowadays, people and scientific research have been paid more and more attention in the economic life China has ushered in the "node of science and technology explosion" Behind the progress of science and technology is the work of countless scientists In the field of chemistry, in the context of the pursuit of innovation driven, international cooperation has been strengthened, the influence of Returned Scholars in the field of R & D has become increasingly prominent, and many excellent research groups have emerged in China For this reason, CBG information adopts the 1 + X reporting mechanism CBG information website, chembeangoapp, chembeango official micro blog, CBG information wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the representative research groups in China, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.