GS. John Yip của ĐHQG Singapore (NUS) sang thăm và có buổi seminar với cán bộ và sinh viên Khoa Hóa học. Abstract được đưa phía dưới.
- Thời gian: 9h30, thứ Năm, 20/6/2019
- Địa điểm: Phòng Hội thảo, Khoa Hóa học, 19 Lê Thánh Tông
Thông tin về GS. John Yip có thể tham khảo tại: https://www.chemistry.nus.edu.sg/people/academic_staff/yipjohn.htm
Thông báo tới toàn thể sinh viên để các em được biết và tham dự đúng giờ, nghiêm túc.
Dưới đây là nội dung Abstract:
Supramolecular Chemistry of Gold Clips, Rectangles and Boxes
John H. K. Yip - Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543.
[email protected]
Our studies of the diphosphine, 9,10-bis(diphenylphosphino)anthrance (PAnP), led to expeditions into various areas of inorganic supramolecular chemistry. We demonstrated that the binuclear [Au2(𝜇-PAnP)]2+ complex (X = OTf or NO3- ) can be used as a molecular “clip” to assemble metallocyclophanes with large cavity. Combining [the digold(I) complex with 4,4’-bipyridine (bipy) gives a luminescent gold rectangle [Au4(PAnP)2 (bipy)2 ](OTf)4 . (7 x 12Å). The gold rectangle forms host-guest complexes with electron-rich polyaromatics i.e. pyrene and anthracenes. In addition, a series of molecular cages composed of two cofacical porphyrins can be assembled from the molecular clip and porphyrins MTPyP (TPyP = meso-tetrapyridylporphyrin, M = H<sub>2</sub> , Zn(II), Fe(III) etc). Unlike the gold rectangle, the gold cages are receptors for electron-accepting quinones. The cofacial bis(FeIII-porphyrin) cage {Au8(μ-PAnP)4[Fe(H2O)2(TPyP)]2(OTf)2}(OTf)8 is a molecular machine which undergoes reversible contraction upon addition of acid. 2 Reacting [Au2(𝜇-PAnP)(X)2] (X = Cl or Br) and ½ mol. equiv. of AgSbF6 . {[(𝜇-PAnP)(AuX)2]2Ag} + SbF6 halonium ions which exhibit distorted Au4X4 dodecahedron which encapsulates an Ag ion at its center. 3 The halonium ions are stabilized by collective actions of metallophilic Au-Ag, aromatic 𝜋-𝜋 and Ag-X interactions. In a recent study we discovered a very fast, concerted ligand scrambling in [Au2(𝜇-PAnP)(SPh)(X)] which presumably involves a four-center [Au2SX] transition state whose formation is promoted by Au-Au attraction and S(Au 2 ) coordination.
John H. K. Yip - Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543.
[email protected]
Our studies of the diphosphine, 9,10-bis(diphenylphosphino)anthrance (PAnP), led to expeditions into various areas of inorganic supramolecular chemistry. We demonstrated that the binuclear [Au2(𝜇-PAnP)]2+ complex (X = OTf or NO3- ) can be used as a molecular “clip” to assemble metallocyclophanes with large cavity. Combining [the digold(I) complex with 4,4’-bipyridine (bipy) gives a luminescent gold rectangle [Au4(PAnP)2 (bipy)2 ](OTf)4 . (7 x 12Å). The gold rectangle forms host-guest complexes with electron-rich polyaromatics i.e. pyrene and anthracenes. In addition, a series of molecular cages composed of two cofacical porphyrins can be assembled from the molecular clip and porphyrins MTPyP (TPyP = meso-tetrapyridylporphyrin, M = H<sub>2</sub> , Zn(II), Fe(III) etc). Unlike the gold rectangle, the gold cages are receptors for electron-accepting quinones. The cofacial bis(FeIII-porphyrin) cage {Au8(μ-PAnP)4[Fe(H2O)2(TPyP)]2(OTf)2}(OTf)8 is a molecular machine which undergoes reversible contraction upon addition of acid. 2 Reacting [Au2(𝜇-PAnP)(X)2] (X = Cl or Br) and ½ mol. equiv. of AgSbF6 . {[(𝜇-PAnP)(AuX)2]2Ag} + SbF6 halonium ions which exhibit distorted Au4X4 dodecahedron which encapsulates an Ag ion at its center. 3 The halonium ions are stabilized by collective actions of metallophilic Au-Ag, aromatic 𝜋-𝜋 and Ag-X interactions. In a recent study we discovered a very fast, concerted ligand scrambling in [Au2(𝜇-PAnP)(SPh)(X)] which presumably involves a four-center [Au2SX] transition state whose formation is promoted by Au-Au attraction and S(Au 2 ) coordination.
- Lin, R.; Yip, J. H. K.; Zhang, K.; Wong, K.-Y.; Ho, K. P. J. Am. Chem. Soc. 2004, 126, 15852.
- Wang, Y.; Ang, P. L.; Wong, C.-Y.; Yip, J. H. K. Chem. Eur. J. 2018, 24,18623-18628.
- Zhang, K.; Prabhavathy, J.; Yip, J. H. K.; Koh, L. L.; Tan, G. K.; Vittal, J. J. J. Am. Chem. Soc. 2003, 125, 8452.