Thông báo: Seminar của GS. John Yip, ĐHQG Singapore (NUS)

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:

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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.
  1. Lin, R.; Yip, J. H. K.; Zhang, K.; Wong, K.-Y.; Ho, K. P. J. Am. Chem. Soc. 2004, 126, 15852.
  2. Wang, Y.; Ang, P. L.; Wong, C.-Y.; Yip, J. H. K. Chem. Eur. J. 2018, 24,18623-18628.
  3. Zhang, K.; Prabhavathy, J.; Yip, J. H. K.; Koh, L. L.; Tan, G. K.; Vittal, J. J. J. Am. Chem. Soc. 2003, 125, 8452.