Complexes

1. A palladium(II) complex of formula (1):

wherein:

Pd ⊕ is a cationic palladium atom;

R 1 and R 2 are, independently, an organic group having 1-20 carbon atoms, or R 1 and R 2 are linked to form a ring structure with E;

R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are, independently, —H or an organic group having 1-20 carbon atoms; or

R 1 /R 3 or R 2 /R 3 forms a ring structure with the atoms to which they are attached and in this instance R 4 /R 5 , R 5 /R 6 , R 7 /R 8 , R 8 /R 9 , R 9 /R 10 or R 10 /R 11 , independently, form a ring structure with the carbon atoms to which they are attached or R 1 , R 2 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are as defined above;

R 12 is an organic group having 1-20 carbon atoms;

m is 0, 1, 2, 3, 4 or 5;

E is P or As; and

X ⊖ is a non-coordinated anionic ligand.

2. A palladium(II) complex according to claim 1 , wherein E is P.

3. A palladium(II) complex according to claim 1 , wherein R 1 and R 2 are, independently, substituted or unsubstituted straight-chain alkyl, substituted or unsubstituted branched-chain alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl wherein the heteroatoms of the substituted or unsubstituted heteroaryl are, independently, sulfur, nitrogen or oxygen.

4. A palladium(II) complex according to claim 1 , wherein R 3 , R 4 , R 5 and R 6 are, independently, —H, substituted or unsubstituted straight-chain alkyl, substituted or unsubstituted branched-chain alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted —N(alkyl) 2 (wherein the alkyl is the same or different and is, independently, a straight-chain or branched-chain alkyl), substituted or unsubstituted —N(cycloalkyl) 2 (wherein the cycloalkyl is the same or different), substituted or unsubstituted —N(aryl) 2 (wherein the aryl is the same or different), substituted or unsubstituted —N(heteroaryl) 2 (wherein the heteroaryl is the same or different) or substituted or unsubstituted heterocycloalkyl.

5. A palladium(II) complex according to claim 4 , wherein R 3 , R 4 , R 5 and R 6 are —H.

6. A palladium(II) complex according to claim 4 , wherein R 3 , R 4 , R 5 and R 6 are, independently, a straight-chain alkyl.

7. A palladium(II) complex according to claim 1 , wherein two of R 3 , R 4 , R 5 and R 6 are —H, and the other two of R 3 , R 4 , R 5 and R 6 are, independently, unsubstituted straight-chain alkyl, unsubstituted branched-chain alkyl, unsubstituted cycloalkyl, or unsubstituted alkoxy.

8. A palladium(II) complex according to claim 1 , wherein R 7 , R 8 , R 9 , R 10 and R 11 are, independently, —H, substituted or unsubstituted straight-chain alkyl, substituted or unsubstituted branched-chain alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted —N(alkyl) 2 (wherein the alkyl is the same or different and is, independently, a straight-chain or branched-chain alkyl), substituted or unsubstituted —N(cycloalkyl) 2 (wherein the cycloalkyl is the same or different), substituted or unsubstituted —N(aryl) 2 (wherein the aryl is the same or different), substituted or unsubstituted —N(heteroaryl) 2 (wherein the heteroaryl is the same or different) or substituted or unsubstituted heterocycloalkyl.

9. A palladium(II) complex according to claim 7 , wherein R 7 , R 8 , R 9 , R 10 and R 11 are —H.

10. A palladium(II) complex according to claim 7 , wherein three of R 7 , R 8 , R 9 , R 10 and R 11 are —H, and the other two of R 7 , R 8 , R 9 , R 10 and R 11 are, independently, unsubstituted straight-chain alkyl, unsubstituted branched-chain alkyl, unsubstituted cycloalkyl, unsubstituted alkoxy, unsubstituted —N(alkyl) 2 (wherein the alkyl is the same or different and, independently, straight-chain or branched-chain alkyl), or unsubstituted —N(aryl) 2 (wherein the aryl is the same or different).

11. A palladium(II) complex according to claim 7 , wherein two of R 7 , R 8 , R 9 , R 10 and R 11 are —H, and the other three of R 7 , R 8 , R 9 , R 10 and R 11 are, independently, unsubstituted straight-chain alkyl, unsubstituted branched-chain alkyl, unsubstituted cycloalkyl, unsubstituted alkoxy, unsubstituted —N(alkyl) 2 (wherein the alkyl is the same or different and, independently, straight-chain or branched-chain alkyl) or unsubstituted —N(aryl) 2 (wherein the aryl is the same or different).

12. A palladium(II) complex according to claim 1 , wherein the

moiety is a monodentate tertiary phosphine ligand that is:

13. A palladium(II) complex according to claim 1 , wherein each R 12 is, independently, substituted or unsubstituted straight-chain alkyl, substituted or unsubstituted branched-chain alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl wherein the heteroatoms of the heteroaryl are, independently, sulfur, nitrogen or oxygen.

14. A palladium(II) complex according to claim 1 , wherein X ⊕ is triflate, tetrafluoroborate, hexafluoroantimonate, hexafluorophosphate, [B[3,5-(CF 3 ) 2 C 6 H 3 ] 4 ] − or mesylate.

15. A palladium(II) complex according to claim 1 , wherein the complex of formula (1) is:

16. A palladium(II) complex of formula (3):

wherein:

R 1 and R 2 are, independently, an organic group having 1-20 carbon atoms, or R 1 and R 2 are linked to form a ring structure with E;

R 12 is an organic group having 1-20 carbon atoms;

R 20 , R 21 , R 22 , R 23 and R 24 are, independently, —H or an organic group having 1-20 carbon atoms; or

one or more pairs of R 1 /R 20 , R 2 /R 20 , R 20 /R 21 or R 22 /R 23 , independently, form a ring structure with the atoms to which they are attached;

m is 0, 1, 2, 3, 4 or 5; and

X ⊕ is a non-coordinated anionic ligand.

17. A palladium(II) complex according to claim 16 , wherein R 1 and R 2 are, independently, substituted or unsubstituted straight-chain alkyl, substituted or unsubstituted branched-chain alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl wherein the heteroatoms of the heteroaryl are independently, sulfur, nitrogen or oxygen.

18. A palladium(II) complex according to claim 16 , wherein each R 12 is, independently, substituted or unsubstituted straight-chain alkyl, substituted or unsubstituted branched-chain alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl wherein the heteroatoms of the heteroaryl are, independently, sulfur, nitrogen or oxygen.

19. A palladium(II) complex according to claim 16 , wherein X ⊕ is triflate, tetrafluoroborate, hexafluoroantimonate, hexafluorophosphate, [B[3,5-(CF 3 ) 2 C 6 H 3 ] 4 ] − or mesylate.

20. A palladium(II) complex according to claim 16 , wherein R 20 and R 21 are, independently, —H, substituted or unsubstituted straight-chain alkyl, substituted or unsubstituted branched-chain alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl, substituted or unsubstituted —N(alkyl) 2 (wherein the alkyl is the same or different and, independently, straight-chain or branched-chain alkyl), substituted or unsubstituted —N(cycloalkyl) 2 (wherein the cycloalkyl is the same or different), substituted or unsubstituted —N(aryl) 2 (wherein the aryl is the same or different), substituted or unsubstituted —N(heteroaryl) 2 (wherein the heteroaryl is the same or different) or substituted or unsubstituted heterocycloalkyl.

21. A palladium(II) complex according to claim 20 , wherein R 20 and R 21 are —H.

22. A palladium(II) complex according to claim 16 , wherein R 22 and R 24 are, independently, —H, substituted or unsubstituted straight-chain alkyl, substituted or unsubstituted branched-chain alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted thioalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted —N(alkyl) 2 (wherein the alkyl is the same or different and, independently, straight-chain or branched-chain alkyl), substituted or unsubstituted —N(cycloalkyl) 2 (wherein the cycloalkyl is the same or different), substituted or unsubstituted —N(aryl) 2 (wherein the aryl is the same or different), or substituted or unsubstituted —N(heteroaryl) 2 (wherein the heteroaryl is the same or different).

23. A palladium(II) complex according to claim 16 , wherein R 23 is —H, substituted or unsubstituted straight-chain alkyl, substituted or unsubstituted branched-chain alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, or substituted and unsubstituted heteroaryl.

24. A palladium(II) complex according to claim 16 , wherein R 22 , R 23 and R 24 are phenyl.

25. A palladium(II) complex according to claim 16 , wherein the complex of formula (3) is:

26. A process for preparing a complex of formula (1), the process comprising the steps of:

(a) reacting a complex of formula (4) with a monodentate biaryl ligand of formula (5) to form a complex of formula (6)

and;

(b) reacting the complex of formula (6) with a silver salt of formula (7) to form the complex of formula (1),

wherein:

R 1 and R 2 are, independently, an organic group having 1-20 carbon atoms, or R 1 and R 2 are linked to form a ring structure with E;

R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are, independently, —H or an organic group having 1-20 carbon atoms; or

one or more pairs selected from R 1 /R 3 , R 2 /R 3 , R 3 /R 4 , R 4 /R 5 , R 5 /R 6 , R 7 /R 8 , R 8 /R 9 , R 9 /R 10 or R 10 /R 11 , independently, form a ring structure with the atoms to which they are attached;

R 12 is an organic group having 1-20 carbon atoms;

m is 0, 1, 2, 3, 4 or 5;

E is P or As;

Y is a coordinating anionic ligand; and

X ⊕ is a non-coordinated anionic ligand.

27. A process for preparing a complex of formula (1) or a complex of formula (3), the process comprising the steps of:

(a) reacting a complex of formula (4) with a silver salt of formula (7),

and;

(b) reacting the product of step (a) with a monodentate biaryl ligand of formula (5) or a monodentate bi-heteroaryl tertiary phosphine ligand of formula (8) to form the complex of formula (1) or the complex of formula (3),

wherein:

R 1 and R 2 are, independently, an organic group having 1-20 carbon atoms, or R 1 and R 2 are linked to form a ring structure with E;

R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 and R 11 are, independently, —H or an organic group having 1-20 carbon atoms; or

one or more pairs selected from R 1 /R 2 , R 2 /R 3 , R 3 /R 4 , R 4 /R 5 , R 5 /R 6 , R 7 /R 8 , R 8 /R 9 , R 9 /R 10 or R 10 /R 11 , independently, form a ring structure with the atoms to which they are attached;

R 12 is an organic group having 1-20 carbon atoms;

R 20 , R 21 , R 22 , R 23 and R 24 are, independently, —H or an organic group having 1-20 carbon atoms; or

one or more pairs of R 1 /R 20 , R 2 /R 20 , R 20 /R 21 or R 22 /R 23 , independently, form a ring structure with the atoms to which they are attached;

m is 0, 1, 2, 3, 4 or 5;

E is P or As;

Y is a coordinating anionic ligand; and

X ⊕ is a non-coordinated anionic ligand.

28. A process for performing a carbon-carbon coupling reaction in the presence of a catalyst, the process comprising using a complex of formula (1) according to claim 1 or a complex of formula (3):

wherein:

R 1 and R 2 are, independently, an organic group having 1-20 carbon atoms, or R 1 and R 2 are linked to form a ring structure with E;

R 12 is an organic group having 1-20 carbon atoms;

R 20 , R 21 , R 22 , R 23 and R 24 are, independently, —H or an organic group having 1-20 carbon atoms; or

one or more pairs of R 1 /R 20 , R 2 /R 20 , R 20 /R 21 or R 22 /R 23 independently form a ring structure with the atoms to which they are attached;

m is 0, 1, 2, 3, 4 or 5; and

X ⊕ is a non-coordinated anionic ligand.

29. A process for performing a carbon-heteroatom coupling reaction in the presence of a catalyst, the process comprising using a complex of formula (1) according to claim 1 or a complex of formula (3):

wherein:

R 1 and R 2 are, independently, an organic group having 1-20 carbon atoms, or R 1 and R 2 are linked to form a ring structure with E;

R 12 is an organic group having 1-20 carbon atoms;

R 20 , R 21 , R 22 , R 23 and R 24 are, independently, —H or an organic group having 1-20 carbon atoms; or

one or more pairs of R 1 /R 20 , R 2 /R 20 , R 20 /R 21 or R 22 /R 23 , independently, form a ring structure with the atoms to which they are attached;

m is 0, 1, 2, 3, 4 or 5; and

X ⊕ is a non-coordinated anionic ligand.

30. A palladium (II) complex according to claim 6 , wherein R 3 , R 4 , R 5 and R 6 are −Me.