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Microporous Metal-Organic Frameworks Formed in a Stepwise Manner from Luminescent

Building Blocks

Brett D. Chandler, David T. Cramb,* and George K. H. Shimizu*

J. Am. Chem. Soc. 2006, 128, 10403-10412

2Angew. Chem., Int. Ed. 1998, 37, 3085-3103

Lanthanide Ions Are Employed Photonic Applications

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1.Different Ln ions emit spans a wide spectrum from infrared radiation to blue light.

2. 4f orbitals are shielded by the 5s and 5p orbitals leading to desired sharp emission lines.

Several Properties of Lanthanides

4

Antenna Effect

This occurs from direct excitation of the ligand to a singlet state followed by an i

ntersystem crossing to a triplet state.

J. Chem. Soc., Dalton Trans. 1985, 2247.

5

zeolite Y (Na7(NH4)49Y; Si/AI = 2.5).

+

EuCl3

Ligand exchange

porous

J. Am. Chem. Soc. 1988, 110, 5709-5714.

Exchanging Ln Ions for Intrachannel Cations in Zeolites

6J. Am. Chem. Soc. 2001, 123, 5735-5742.

Hydrothermal conditions

Ln Silicates with the Ln Ion

AV-9： Aveiro microporous solid no. 9 AV-9 = Na4K2X2Si16O38 10H‧ 2O

7J. Mater. Chem. 2004, 14, 642-645 J. Am. Chem. Soc. 1999, 121, 1651-1657

Metal-Organic Frameworks (MOFs) of Ln-Containing Solids

Eu(NO3)3 6H‧ 2O + HO2C-C10H14-CO2H Tb3++1,4-benzenedicarboxylic acid (H2-BDC)

O

HO

O

OH

8J. Lumin. 2000, 86, 137-146.

Antenna Ligand

N N

O O

4 Eu3+Eu(bypO2)4

3+

(bpyO2)2,2'-bipyridine-N,N'-dioxide

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Cryst. Growth Des. 2005, 5, 807-812

+ Ba2+ MOF

Possible Bonding Modes for Sulfonate Ligand

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N NO O

S

O

OO

S

O

OO

4,4’-disulfo-2,2’-bipyridine N,N’-dioxide

L

Antenna ligand

+

sulfonate groups

Target Antenna Ligand

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Densed Structure

M : L = 1 : 3

To Design the MOFs

M : L = 1 : 4

increase M/L ratio

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A Stepwise Approach to the Formation of Metal-Organic Frameworks

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3 H2L + EuCl3 x 6 H2O EuL33- + 3 Cl- + 6H2O + 6 H+

Ba2ClEuL3 x 10 H2O + 6 HClEuL3+ 3 Cl- + 6 H+ + 2 BaCl2 x 2 H2O

General Synthesis of Compound 2

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12.49 × 9.84 Å2

The Local Environment of the Ln Ion

N NO O

S

O

OO

S

O

OO

M

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S

O

O

OR M

S

O

O

OR

M

M

M

Sulfonate Groups Bonding Mode of Ba1 Ion

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Ba1 Center Cross-Link of [EuL3(H2O)2]3-

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S

O

O

OR M

M

Sulfonate Groups Bonding Mode of Ba2 Ion

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Ba2 Center Cross-Link of [EuL3(H2O)2]3-

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O(i) ... Cl =3.133 ÅCl ...C(ii)=3.60(1)-3.85(1) Å, Cl ... H-C(ii)= 166.2(3)°-178.8(3)°(i) H2O on the Eu center(ii)C is -carbons of pyridine ring

The Cl- Ions Occupying the Complex’s Channels

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105 oC loss 13.29%

The TGA Analysis

320 oCNo weight loss

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heat

crystal amorphous

Dehydration of Compound 2 under Heat

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Reversible Water Vapor Sorption by Compound 2

136.2 min, 86.79%

138.8 min, 86.29%

196.3 min, 97.06%

200.1 min, 99.73%

391.7 min, 96.85%

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+ CO2 at 273K

- CO2 at 160 oC?

+ N2 at 77K- N2

?

CO2 and N2 Adsorption Experiments

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For CO2 :A Dubinin-Radushkevich (DR) analysis gave a surface area of 718 m2/g, an average pore width of 6.2 Å, and a micropore volume of 0.25 mL/g.

CO2 sorption experiment was repeated at -42 °C using a dry ice/acetonitrile bath and gave a DR surface area of 210 m2/g.

Carbon Dioxide Sorption Isotherm for Compound 2

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For N2 :DR surface 15 m2/gm

1.The presence of a narrow micropore2.The lower temperature employed for the N2 analysis (77 K) 3.The slightly larger diameter of N2 (3.64Å)versus CO2 (3.30 Å)4.The topology of the pore structure (one dimensional)

High Activation Barrier for N2 Sorption

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N NO O

S

O

OO

S

O

OO

M

Emission band with a maximum appearing at 473 nm. The excitation spectrum shows two main peaks, 325 nm and 395 nm

Antenna Ligand

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Energy Level Diagram for the Lanthanides

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S0

Phosphorescence Emission Spectrum for the Gd Compound 3

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5D0 → 7F1 is the second most intense transition; 5D0 → 7F2, is consists of an intense band with two weak shoulders. 5D0 →7F3 transition is consists of a less intense broad peak with a small shoulder5D0 → 7F4 transition is comprised of two well- defined peaks.

lifetime 243 s

The Phosphorescence Spectrum of the Eu Compound 2

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5D4 → 7F6 consists of an intense peak with a shoulder. 5D4 → 7F5 consists of a single intense peak with a second shoulder. 5D4 → 7F4 and 5D4 → 7F2 transitions consist of two peaks of equal intensity.5D4 → 7F3 transition consist a weak shoulder followed by a second intense peak5D4 → 7F1 and 5D4 → 7F0 transitions are single peakswith weak but measurable intensities.

lifetime:95 s

The Spectrum of the Tb Compound 4

31J. Am. Chem. Soc. 1979, 101, 334-340.

Radiationless Deexcitation Scheme for Tb( III )

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lifetime:5 slifetime:6 s

The Spectrum of the Sm and Dy Compounds 1&5

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Connolly surfaces were calculated for compound 2 in two scenarios, first with the noncoordinated water molecules occupying the channels removed and then with both free and coordinated water molecules removed.

noncoordinated water removed: 695 m2/gmfree and coordinated water molecules removed: 963m2/gm measured surface area : 718 m2/gm

To Relate the Observed Surface Area to the Single Crystal Structure

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the Ba sulfonate solids was observed typically that, upon loss of coordinated water from the Ba coordination sphere, the solid shifts structure to optimally arrange the remaining sulfonate O donor atoms about the metal ion.

it was not expected that Eu complex 2

5D0 → 7F2: only a single peak 5D0 → 7F4: a small but noticeable shift of the higher frequency peak by 3 nm to a longer wavelength.lifetime:319 s

Comparing Luminescent Property of Eu Compound 2 Hydrated and Dehydrated Forms

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Conclusions

1. A series of isostructural lanthanide-containing metal-organic frameworks which demonstrate permanent microporosity but also incorporate predictable photophysical properties.

2. A DR surface area of 718 m2/g for the dehydrated form of compound 2 was measured by CO2 sorption, the rigid building block enabling the formation of this porous material.

3. Luminescence spectroscopy was also employed as a diagnostic tool to gain additional insight to the nature of the amorphous microporous state.

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Summary of Crystallographic Data for Compounds 1, 2, 3, 4, and 5

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Term Symbol

1. The ground term (term of lowest energy) has the highest spin multiplicity.

2. If two or more terms share the maximum spin multiplicity, the ground term is the one having the highest value of L.

3. For subshell that are less than half-filled, the sate having the lowest J value has lowest energy.

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Eu3+:Xe4f6

3 2 1 0 -3-2-1

L:3 S:1/2×6=3 2S+1=7

因為未多於半滿 ,所以 J要較小→Ｌ -S=0

Ground state term symbol:7F0