Question 1

MOFs are naturally occurring minerals that are mined from the earth for industrial use.

Accepted Answer

MOFs are entirely synthetic, engineered materials created in laboratories by chemically linking metal ions with organic molecules.

Question 2

The 'organic' part of a Metal-Organic Framework refers to living or biological tissue.

Accepted Answer

The term 'organic' in MOFs refers strictly to carbon-based chemical compounds acting as struts or linkers between the metal nodes, completely independent of biological matter.

Question 3

Consider the following statements regarding Metal-Organic Frameworks (MOFs), which were the subject of the 2025 Nobel Prize in Chemistry:
1. They are constructed using transition metal ions as cornerstones connected by inorganic linkers to form a porous lattice.
2. Their exceptionally high internal surface area enables the storage of hydrogen gas at lower pressures compared to empty tanks.
3. The concept of 'reticular chemistry' allows for the rational design of MOFs by varying the size and nature of their molecular building blocks.
How many of the above statements are correct?

Accepted Answer

(b) Only two — Statement 1 is incorrect because MOFs use 'organic' (carbon-based) linkers, not inorganic linkers, to connect the metal ions. Statement 2 is correct; the massive internal surface area acts like a molecular sponge, allowing high-density gas storage at much lower pressures via adsorption. Statement 3 is correct; reticular chemistry, pioneered by Omar Yaghi, is the systematic method of linking well-defined molecular building blocks into predetermined, custom crystalline structures.

Question 4

Match the 2025 Nobel Laureates in Chemistry (List I) with their specific pioneering contribution to the development of MOFs (List II):

List I (Laureate)
A. Richard Robson
B. Susumu Kitagawa
C. Omar M. Yaghi

List II (Contribution)
1. Demonstrated that coordination networks had dynamic porosity and could reversibly capture gases.
2. Created highly robust structures like MOF-5 and established the principles of reticular chemistry.
3. Synthesized the first early models of coordination networks using copper ions in 1989.

Select the correct code:

Accepted Answer

(a) A-3, B-1, C-2 — Richard Robson (A) synthesized the earliest models of these structures in 1989 using copper ions, though they were fragile and collapsed without solvents (3). Susumu Kitagawa (B) proved in the late 1990s that these frameworks were dynamic materials that could reversibly absorb and release gases without collapsing (1). Omar Yaghi (C) achieved a major breakthrough in 1999 by creating MOF-5, a highly stable framework, and formalized the field of reticular chemistry to design custom MOFs predictably (2).

Question 5

Assertion (A): Metal-Organic Frameworks (MOFs) can successfully extract liquid water from desert air even when the relative humidity is extremely low (below 20 percent).
Reason (R): The high density of purely metallic bonds within the MOF structure creates strong electrical currents that rapidly condense atmospheric moisture.
Select the correct answer from the codes given below:

Accepted Answer

(c) A is true but R is false. — Assertion (A) is true; one of the most celebrated real-world applications of MOFs, spearheaded by Omar Yaghi's laboratory, is their ability to harvest drinking water from arid desert air. Reason (R) is false; MOFs do not rely on strong electrical currents or purely metallic bonds to condense water. Instead, their highly porous structure and specifically tailored internal chemistry selectively adsorb water molecules at the nanoscale through intermolecular forces, which can subsequently be released using gentle heat, such as natural sunlight.

2025 Nobel Prize in Chemistry for Metal-Organic Frameworks

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