Surface chiroselective assembly of enantiopure crystalline porous films containing bichiral building blocks

• Published in: Chemical science (Cambridge) Vol. 12; no. 37; pp. 12346 - 12352
• Main Authors: Chen, Hao, Gu, Zhi-Gang, Zhang, Jian
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 29-09-2021; The Royal Society of Chemistry
• Subjects: Assembly; Butanol; Cages; Chemistry; Chirality; Circular polarization; Coordination compounds; Crystal structure; Crystallinity; Enantiomers; Photoluminescence; Porous materials; Substrates
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d1sc03089b

The development of chiral crystalline porous materials (CPMs) containing multiple chiral building blocks plays an important role in chiral chemistry and applications but is a challenging task. Herein, we report the first example of bichiral building block based enantiopure CPM films containing metal-organic cages (MOCs) and metal complexes. The functionalized substrate was immersed subsequently into homochiral metal complex (
R
)- or (
S
)-Mn(DCH)
3
(DCH = 1,2-diaminocyclohexane) and racemic Ti
4
L
6
cage (L = embonate) solutions by a layer-by-layer growth method. During the assembly process, the substrate surface coordinated with (
R
)- or (
S
)-Mn(DCH)
3
can, respectively, layer-by-layer chiroselectively connect Δ- or Λ-Ti
4
L
6
cages to form homochiral (
R
, Δ)- or (
S
, Λ)-CPM films with a preferred [111] growth orientation, tunable thickness and homogeneous surface. The resulting enantiopure CPM films show strong chirality, photoluminescence, and circularly polarized luminescence (CPL) properties as well as good enantioselective adsorption toward enantiomers of 2-butanol and methyl-lactate. The present
in situ
surface chiroselective strategy opens a new route to assemble homochiral CPM films containing multiple chiral building blocks for chiral applications.
Bichiral building block based enantiopure CPM films containing metal-organic cages (MOCs) and metal complexes are chiroselectively assembled on the substrate surface by a layer-by-layer method.