60 40 20
0 -20 -40 -60 -80 -100 -120
Chang, Kung, and Kung, Chem. Comm. submittted.
Metal-Oxygen Backbone of Designed Sequence and Structure
O
Si
M
Molecular templating:
Cat. 4 made from 2; control cat. 5 made from 1
K. Polborn and K. Severin, Chem. Commun. (2019) 2481-2482.
Molecular hinges to control accessibility of active sites
5.2% 8.7 3.8 10.2
29
7.9% 7.3 6.2 29.4 19.7 3.9
30.9
J.M. Thomas, et al. Nature 398 (2019) 227; Angew. Chem. Int. Ed. 39 (2000) 2310.
001203c
Atom-by-Atom Synthesis of Metal-Oxygen Chain
A. Corma, U. Diaz, M.E. Domine, V. Fornés, Angew. Chem. Int. Ed. 39 (2000) 1499.
(h00)
Eliminated pore diffusion control, Little shape selectivity.
Molecular Imprinting
Importance in controlling relative location of sites
• Two Co(III) ions in CoAlPO-18 at the desired distance apart in Co/P = 0.1 samples.
• CoAlPO-36 of larger pore structure and shape, produces much more 3-ol and 3-one.
O
Active site
O O
Al
O
Al
O Al O
HO OH
n
Al HO OH
-H2O
(HO)3Al (HO)3Al
O OH Al
O OH
HH OO
O
Al
O Al O
O
High temp -H2O
O
O Al O
O
Al
O Al O
Strategy: use amine (Lewis base) to preserve Lewis acidity. Can make
Reactant C6H14
1.5 MPa air, 373 K, 24 h, Selectivity %
Conv. 1-ol 1-ald 1-acid 1,6-acid 1,6-ol/al 2-ol/one
7.2% 4.5 3.3 53.5
36.1
9.3% 4 2.4 33 31.6 1.9
24.5
Preparation of uniform sized metal particles using functional resins
Corain, Centomo, Ferrari Meyer-Zaika, Schmid, Gold2019, October 2019.
P-SO32- + Mn+(aq) → P-SO32-Mn+ P-SO32-Mn+ + NaBH4 → P-SO32-/Mo
30
Conversion of epoxide (% )
25
20
15
10
5
0
0
500
1000
1500
Time (min)
Xue, Kung, Kozlov, Popp, and Kung, Catal. Today, 2019.
Generation of active site by building on a well-defined structure
A. Katz and M.E. Davis, Nature 403 (2000) 286.
• Introduce functional groups at specific locations in the cavity.
• Molecules diffuse through silica wall into and out of cavity.
Control of surface coordinative unsaturation sites of aluminum oxide (Al2O3) by synthesis
• Active sites are surface exposed Al ions (Lewis acid sites).
Metal clusters derived from metal carbonyl complexes
BC Gates J. Molec. Catal. A Chem 163 (2000) 55 Os5C on MgO
Ir4 in zeolite
Size-selective cluster beam deposition of Aun clusters on MgO
R
P
R
P
Active
At rest
Figure 1 Molecular model of endoclucanase 12A and schematic model of the DMAAm-enzyme molecular switch. The red residues represent the catalytic glutamic acid side chains at the active site of EG 12A, the green residue is the Asn 55 position, the purple residue is the Ser 25 position, and the N-terminus is represented as the blue circle.
Tsuyoshi Shimoboji, Edmund Larenas, Tim Fowler, Allan S. Hoffman,* and Patrick S. Stayton* Bioconjugate Chem., 14 (3), 517 -525, 2019
Figure 4 Characterization of ONPC enzyme activities for free DMAAmEG 12A conjugates in solution at as function of polymer size and conjugation site. The enzyme activities were measured for 100 nM conjugates using ONPC (8mM) as a substrate and normalized to the activity of N55C or S25C EG12A controls as 100% at each temperature. EG 12A-M10, 10 kDa DMAAm-EG12A conjugate; EG 12A-M6, 6 kDa DMAAm-EG 12A conjugate; EG 12A-M3, 3 kDa DMAAm-EG 12A conjugate; and EG 12A + M10, physical mixture of enzyme plus 10 kDa DMAAm.
Raja and Thomas, J. Molec. Catal. 181 (2019) 3
CoAlPO-18 (Co/P=0.04) CoAlPO-18 (Co/P=0.1) CoAlPO-36 (Co/P=0.04) CoAlPO-34 (Co/P=0.1)
Hexane (
) Oxidation
Heiz, Sanchez, Abbet, Schneider, Chem. Phys. 262 (2000) 189.
MS signal of C16O18O in TPD after exposure to 18O2 and then CO
Deposition of metal clusters using lithography Array of Pt on silica
R
RO O OR
Al Al
RO
OR
O
NRH2
monomer
RO OR
2
Al
RO
NRH2
R
monomer
Final solid an active catalyst
HR2
HR2
NN
O
Al
O Al O
O
H2O
Amine protection is retained
Kozlov, Kung, Xue, and Kung, Angew. Chem. Int. Ed. 42(2019) 2415
Metal Crystallite Catalytic Active Phase
• Surface arrangement of atoms
• Composition • Nature of support • Location of crystallite on
support (defect sites) ✓ Structure sensitivity ✓ Electronic effect ✓ Ligand effect