# US 4,394,858 A · Photochemical conversion and storage of light energy by endoergic isomerizations

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- Number: US 4,394,858 A
- Document ID: US4394858A
- Status: Granted
- Kind: A
- Application number: 06/221,589
- Filed: 1980-12-31
- Granted: 1983-07-26
- Earliest claimed: 1980-12-31
- Assignees: The Standard Oil Company
- Inventors: Paul J. Giordano; Richard C. Smierciak
- Web page: https://patentgrep.com/patent/US4394858A

## CPC

- C09K 5/16: Materials undergoing chemical reactions when used
- Y10S 204/90: Effecting a change in isomerization by wave energy
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A process is provided for the capture and storage of radiant energy in highly strained carbon containing ring structures of isomerizable compounds. The process includes exposing a photocatalyst containing a compound of a metal selected from Re, Ir, Rh, Ru, Os, Pt, Pd and mixtures thereof, to radiant energy in the presence of an isomerizable compound capable of forming strained intramolecular ring structures.

## Claims

### Claim 1

A process for the capture and storage of radiant energy comprising exposing an oxidatively stable photocatalyst to said radiant energy in the presence of a reversibly isomerizable carbon containing compound, wherein said photocatalyst comprises a carbonyl compound of a metal selected from Re, Ir, Rh, Ru, Os, Pt and Pd and wherein said isomerizable compound is capable of forming an intramolecular strained carbon containing ring structure.

### Claim 2 (depends on 1)

A process as in claim 1, wherein said photocatalyst is contacted with said isomerizable compound in the presence of a solvent.

### Claim 3 (depends on 1)

A process as in claim 1, wherein said isomerizable compound has an activation energy of at least 62 kilocalories per mole.

### Claim 4 (depends on 1)

A process as in claim 1, wherein said photocatalyst contains an organic ligand capable of accepting a redistribution of electron density from said metal upon absorbance of radiant energy.

### Claim 5 (depends on 1)

A process as in claim 1, wherein said photocatalyst includes a salt of said metal.

### Claim 6 (depends on 1)

A process as in claim 1, wherein said photocatalyst has the formula
X.sub.2 Me(CO).sub.3 L.sub.b
wherein
Me is selected from Re, Ir, Rh, Ru, Os, Pt, Pd and mixtures thereof,
X is selected from Cl, Br, I and mixtures thereof,
L is selected from substituted and unsubstituted olefins, substituted and unsubstituted aromatics, and substituted and unsubstituted aromatic heterocyclic compounds having at least one of oxygen or nitrogen in the heterocyclic ring, and mixtures thereof; and
wherein
a=1 to 2 and
b=0.5 to 10.

### Claim 7 (depends on 1)

A process as in claim 1, wherein said radiant energy is solar radiation.

### Claim 8 (depends on 1)

A process as in claim 1, wherein said isomerizable compound comprises bicyclo (2.2.1) hepta-2,5-diene.

### Claim 9 (depends on 1)

A process as in claim 1, wherein said isomerizable compound is selected from carboxylic acid and ester substituted norbornadienes.

### Claim 10 (depends on 1)

A process as in claim 1, wherein said photocatalyst comprises ClRe(CO).sub.3 (4-phenylpyridine).sub.2.