The present invention relates to per-substituted pentalene compounds, including permethylpentalene and precursors thereof. In particular, the invention provides substituted pentalene compounds and methods of preparing substituted pentalene compounds; complexes of metals with substituted pentalene compounds and methods for their production; and the use of complexes of metals with substituted pentalene compounds in catalysis.
1. A compound which is a substituted pentalene of formula (I):
wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently a substituent group having up to 40 carbon atoms, provided that the substituent groups R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are not all phenyl.
2. A compound according to claim 1 in which each of the substituent groups R 1 , R 2 , R 3 , R 4 , R 5 and R 6 is the same.
3. A compound according to claim 1 in which R 2 and R 5 are the same; and/or R 1 and R 4 are the same; and/or R 3 and R 6 are the same.
4. A compound according to claim 1 in which not all of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are chloride groups.
5. A compound according to claim 1 in which R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are such that there are no heteroatoms attached directly to the pentalenic ring.
6. A compound according to claim 1 in which R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently a substituent group having up to 20 carbon atoms.
7. A compound according to claim 6 in which R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently a substituent group having either no carbon atoms or from 1 to 12 carbon atoms.
8. A compound according to claim 1 in which two or more of R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are alkyl, aryl, aralkyl or vinyl groups.
9. A compound according to claim 1 in which R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently selected from alkyl, aryl, aralkyl and vinyl groups.
10. A compound according to claim 1 in which R 1 , R 3 , R 4 , and R 6 are each independently selected from unbranched or branched C1-12 alkyl groups.
11. A compound according to claim 10 in which R 1 , R 3 , R 4 , and R 6 are each independently selected from unbranched or branched C1-4 alkyl groups.
12. A compound according to claim 1 in which R 2 and R 5 are each independently selected from unbranched or branched C1-12 alkyl groups and C6-C12 aryl groups.
13. A compound according to claim 12 in which R 2 and R 5 are each independently selected from unbranched or branched C1-4 alkyl groups.
14. A compound which is a substituted pentalene selected from the group consisting of formulae (Ia), (Ib), (Ic), and (Id):
wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently a substituent group having up to 40 carbon atoms.
15. A metal complex, which is a complex formed from one or more metal atoms or ions and one or more ligands, wherein one or more of the ligands comprises a compound as defined in any one of claims 1 to 14 .
16. A complex according to claim 15 wherein the metal complex is a complex of a single metal atom or ion with one or more ligands.
17. A complex according to claim 15 wherein the metal complex is a complex of two or more metal atoms or ions with one or more ligands.
18. A complex according to claim 15 wherein the metal is a transition metal, lanthanide or actinide atom or ion.
19. A complex according to claim 18 wherein the metal is a Group 3, 4, 5, 6, 7, 8, 9 or 10 transition metal, or a lanthanide metal atom or ion.
20. A method of catalysing a reaction, the method comprising: providing a complex as defined in any one of claims 15 to 19 ; and using said complex as a catalyst in the reaction.
21. The method according to claim 20 , wherein the reaction is an organic transformation.
22. The method according to claim 21 , wherein the organic transformation is selected from hydrogenation, hydroformylation, hydrosilylation, hydroamination, C—H activation, C—C bond formation, cyclotrimerisation, oxidation, epoxidation, dihydroxylation, and cycloaddition.
23. The method according to claim 20 , wherein the reaction is a polymerisation.
24. The method according to claim 23 , wherein the polymerisation is selected from olefinic polymerisation and polymerisation of polar monomers.
25. The method according to claim 23 , wherein the polymerisation is selected from oligomerisation, co-polymerisation and homo-polymerisation.