Phenanthro[9, 10-B]furans for electronic applications
The present invention relates to an electronic device, especially an electroluminescent devices, comprising a compound of the formula especially as host for phosphorescent compounds. The hosts may function with phosphorescent materials to provide improved efficiency, stability, manufacturability, or spectral characteristics of electroluminescent devices.
1. A compound of formula (I):
wherein R 1 and R 2 are a group of formula
R 7 , R 8 and R 9 are independently of each other H, C 1 -C 18 alkyl, C 1 -C 18 alkoxy, or C 1 -C 18 alkyl which is interrupted by O;
wherein -L 3 -X 1 and -L 4 -X 2 are independently of each other a group of formula -NA 1 A 1′ , or a group
A 1 and A 1′ are independently of each other
A 1 and A 1′ together with a nitrogen atom to which they are bonded form a heteroaromatic ring, or form a structure
m′ is 0, 1, or 2; m1 can be same or different at each occurrence and is 0, 1, 2, 3, or 4;
R 116 , R 117 and R 117′ are independently of each other H, halogen, —CN, C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, C 2 -C 20 heteroaryl, C 2 -C 20 heteroaryl which is substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, C 7 -C 25 aralkyl, —C(═O)—R 77 , —C(═O)OR 78 , or —C(═O)NR 75 R 76 ,
R 75 , R 76 and R 78 are independently of each other H; C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 77 is C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
BU is
R 119 and R 120 are independently of each other C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, C 2 -C 20 heteroaryl, C 2 -C 20 heteroaryl which is substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, or C 7 -C 25 aralkyl, or
R 119 and R 120 together form a group of formula ═CR 121 R 122 , wherein
R 121 and R 122 are independently of each other H, C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, or C 2 -C 20 heteroaryl, or C 2 -C 20 heteroaryl which is substituted by G, or
R 119 and R 120 together form a five or six membered ring selected from the group consisting of cyclohexyl and cyclopentyl, which optionally can be substituted by C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, C 2 -C 20 heteroaryl, C 2 -C 20 heteroaryl which is substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, C 7 -C 25 aralkyl, or —C(═O)—R 28 ,
R 28 is H; C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
D is —CO—, —COO—, —S—, —SO—, —SO 2 —, —O—, —NR 65 —, —SiR 70 R 71 —, —POR 72 —, —CR 63 ═CR 64 —, or —C≡C—, and
E is —OR 69 , —SR 69 , —NR 65 R 66 , —COR 68 , —COOR 67 , —CONR 65 R 66 , —CN, or halogen,
G is E, or C 1 -C 18 alkyl,
R 63 and R 64 are independently of each other C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—;
R 65 and R 66 are independently of each other C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—;
R 67 is C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 68 is H; C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 69 is C 6 -C 18 aryl; C 6 -C 18 aryl, which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 70 and R 71 are independently of each other C 1 -C 18 alkyl, C 6 -C 18 aryl, or C 6 -C 18 aryl, which is substituted by C 1 -C 18 alkyl, and
R 72 is C 1 -C 18 alkyl, C 6 -C 18 aryl, or C 6 -C 18 aryl, which is substituted by C 1 -C 18 alkyl;
R 41 can be the same or different at each occurrence and is C1, F, CN, NR 45 R 45′ , a C 1 -C 25 alkyl group, a C 4 -C 18 cycloalkyl group, a C 1 -C 25 alkoxy group, wherein one or more hydrogen atoms can be replaced by F, a C 6 -C 24 aryl group, or a C 6 -C 24 aryloxy group, wherein one or more carbon atoms can be replaced by O, S, or N, and/or which can be substituted by one or more non-aromatic groups R 41 ;
R 45 and R 45′ are independently of each other a C 1 -C 25 alkyl group, a C 4 -C 18 cycloalkyl group, wherein one or more hydrogen atoms can be replaced by F, a C 6 - C 24 aryl group, or a C 6 -C 24 aryloxy group, wherein one or more carbon atoms can be replaced by O, S, or N, and/or which can be substituted by one or more non-aromatic groups R 41 ;
-L 3 -X 1 and -L 4 -X 2 are independently of each other a group of formula
wherein R 116′ is same as R 116 ;
or
-L 3 -X 1 and -L 4 -X 2 are independently of each other a group of formula
R 124 , R 125 and R 126 are independently of each other H, C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 1 -C 18 fluoroalkyl, C 6 -C 24 aryl, which can optionally be substituted by G, C 2 -C 20 heteroaryl, which can optionally be substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, or C 7 -C 25 aralkyl.
2. The compound according to claim 1 , which is a compound of formula
wherein R 1 and R 2 are a group of formula
R 7 , R 8 and R 9 are independently of each other H, C 1 -C 18 alkyl, C 1 -C 18 alkoxy, or C 1 -C 18 alkyl which is interrupted by O;
wherein -L 3 -X 1 and -L 4 -X 2 are independently of each other a group of formula -NA 1 A 1′ , or a group
A 1 and A 1′ are independently of each other
A 1 and A 1′ together with a nitrogen atom to which they are bonded form a heteroaromatic ring, or form a structure
m′ is 0, 1, or 2; m1 can be same or different at each occurrence and is 0, 1, 2, 3, or 4;
R 116 , R 117 and R 117′ are independently of each other H, halogen, —CN, C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, C 2 -C 20 heteroaryl, C 2 -C 20 heteroaryl which is substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, C 7 -C 25 aralkyl, —C(═O)—R 77 , —C(═O)OR 78 , or —C(═O)NR 75 R 76 ,
R 75 , R 76 and R 78 are independently of each other H; C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 77 is C 6 - C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
BU is
R 119 and R 120 are independently of each other C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, C 2 -C 20 heteroaryl, C 2 -C 20 heteroaryl which is substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, or C 7 -C 25 aralkyl, or
R 119 and R 120 together form a group of formula ═CR 121 R 122 , wherein
R 121 and R 122 are independently of each other H, C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, or C 2 -C 20 heteroaryl, or C 2 -C 20 heteroaryl which is substituted by G, or
R 119 and R 120 together form a five or six membered ring selected from the group consisting of cyclohexyl and cyclopentyl, which optionally can be substituted by C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, C 2 -C 20 heteroaryl, C 2 -C 20 heteroaryl which is substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, C 7 -C 25 aralkyl, or —C(═O)—R 28 ,
R 28 is H; C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
D is —CO—, —COO—, —S—, —SO—, —SO 2 —, —O—, —NR 65 —, —SiR 70 R 71 —, —POR 72 —, —CR 63 ═CR 64 —, or —C≡C—, and
E is —OR 69 , 13 SR 69 , —NR 65 R 66 , —COR 68 , —COOR 67 , —CONR 65 R 66 , —CN, or halogen,
G is E, or C 1 -C 18 alkyl,
R 63 and R 64 are independently of each other C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—;
R 65 and R 66 are independently of each other C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—;
R 67 is C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 68 is H; C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 69 is C 6 -C 18 aryl; C 6 -C 18 aryl, which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 70 and R 71 are independently of each other C 1 -C 18 alkyl, C 6 -C 18 aryl, or C 6 -C 18 aryl, which is substituted by C 1 -C 18 alkyl, and
R 72 is C 1 -C 18 alkyl, C 6 -C 18 aryl, or C 6 -C 18 aryl, which is substituted by C 1 -C 18 alkyl;
R 41 can be the same or different at each occurrence and is C1, F, CN, NR 45 R 45 ′ , a C 1 -C 25 alkyl group, a C 4 -C 18 cycloalkyl group, a C 1 -C 25 alkoxy group, wherein one or more hydrogen atoms can be replaced by F, a C 6 -C 24 aryl group, or a C 6 -C 24 aryloxy group, wherein one or more carbon atoms can be replaced by O, S, or N, and/or which can be substituted by one or more non-aromatic groups R 41 ;
R 45 and R 45′ are independently of each other a C 1 -C 25 alkyl group, a C 4 -C 18 cycloalkyl group, wherein one or more hydrogen atoms can be replaced by F, a C 6 -C 24 aryl group, or a C 6 -C 24 aryloxy group, wherein one or more carbon atoms can be replaced by O, S, or N, and/or which can be substituted by one or more non-aromatic groups R 41 ;
-L 3 -X 1 and -L 4 -X 2 are independently of each other a group of formula
wherein R 116′ is same as R 116 ;
or
-L 3 -X 1 and -L 4 -X 2 are independently of each other a group of formula
R 124 , R 125 and R 126 are independently of each other H, C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 1 -C 18 fluoroalkyl, C 6 -C 24 aryl, which can optionally be substituted by G, C 2 -C 20 heteroaryl, which can optionally be substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, or C 7 -C 25 aralkyl.
3. The compound according to claim 1 ,
wherein -L 3 -X 1 and -L 4 -X 2 are independently of each other a group of formula -NA 1 A 1′ , or a group
wherein
A 1 and A 1′ are independently of each other
or A 1 and A 1′ together with a nitrogen atom to which they are bonded form a group of formula
R 116 and R 117 are independently of each other C 1 -C 18 alkyl, which is optionally interrupted by —O—, or C 1 -C 18 alkoxy;
Bu is
wherein R 41 can be same or different at each occurrence and is C 1 -C 18 alkyl, which is optionally interrupted by —O—, or C 1 -C 18 alkoxy; m1 is 0, 1, or 2.
4. The compound according to claim 1 ,
wherein -L 3 -X 1 and -L 4 -X 2 are independently of each other a group of formula
5. The compound according to claim 1 ,
wherein -L 3 -X 1 and -L 4 -X 2 are independently of each other a group of formula
6. The compound according to claim 1 , which is selected from the group consisting of
Cpd.
R 1 = R 2
A 1
A 1′
A-1
A-2
A-3
A-4
A-5
A-8
2)
2)
Cpd.
R 1 = R 2
A 1
A 1′
B-1
B-2
B-3
B-4
B-5
B-8
2)
2)
Cpd.
R 1 = R 2
X 1
X 2
C-1
AR-1
AR-1
C-2
AR-2
AR-2
C-3
AR-3
AR-3
Cpd.
R 1 = R 2
X 1
X 2
D-1
AR-1
AR-1
D-2
AR-2
AR-2
D-3
AR-3
AR-3
Cpd.
R 1 = R 2
X 1
X 2
E-1
HE-1
HE-1
E-2
HE-2
HE-2
E-3
HE-3
HE-3
E-4
HE-4
HE-4
E-5
HE-5
HE-5
E-6
HE-6
HE-6
E-8
HE-8
HE-8
E-9
HE-9
HE-9
E-19
HE-10
HE-10
Cpd.
R 1 = R 2
X 1
X 2
F-1
HE-1
HE-1
F-2
HE-2
HE-2
F-3
HE-3
HE-3
F-4
HE-4
HE-4
F-5
HE-5
HE-5
F-6
HE-6
HE-6
F-8
HE-8
HE-8
F-9
HE-9
HE-9
F-19
HE-10
HE-10
7. A process for preparing the compound according to claim 1 , comprising:
reacting a compound of formula
with a compound of formula HNA 1 A 1′ ,
in the a presence of a base and a catalyst in a solvent,
wherein X 1 and X 2 are independently of each other -NA 1 A 1′ ,
m′ is 0, 1, or 2;
wherein X 11 and X 12 stand for halogen,
wherein
A 1 and A 1′ are independently of each other
A 1 and A 1′ together with the nitrogen atom to which they are bonded form a heteroaromatic ring, or form a structure
m1 can be same or different at each occurrence and is 0, 1, 2, 3, or 4;
R 116 , R 117 and R 117′ are independently of each other H, halogen, —CN, C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, C 2 -C 20 heteroaryl, C 2 -C 20 heteroaryl which is substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, C 7 -C 25 aralkyl, —C(═O)—R 77 , —C(═O)OR 78 , or —C(═O)NR 75 R 76 ,
R 75 , R 76 and R 78 are independently of each other H; C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 77 is C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
wherein L 3 and L 4 are independently of each other a single bond, or a bridging unit BU,
BU is
R 119 and R 120 are independently of each other C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, C 2 -C 20 heteroaryl, C 2 -C 20 heteroaryl which is substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, or C 7 -C 25 aralkyl, or
R 119 and R 120 together form a group of formula ═CR 121 R 122 , wherein
R 121 and R 122 are independently of each other H, C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, or C 2 -C 20 heteroaryl, or C 2 -C 20 heteroaryl which is substituted by G, or
R 119 and R 120 together form a five or six membered ring selected from the group consisting of cyclohexyl and cyclopentyl, which optionally can be substituted by C 1 -C 18 alkyl, C 1 -C 18 alkyl which is substituted by E and/or interrupted by D, C 6 -C 24 aryl, C 6 -C 24 aryl which is substituted by G, C 2 -C 20 heteroaryl, C 2 -C 20 heteroaryl which is substituted by G, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 18 alkoxy, C 1 -C 18 alkoxy which is substituted by E and/or interrupted by D, C 7 -C 25 aralkyl, or —C(═O)—R 28 ,
R 28 is H; C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
D is —CO—, —COO—, —S—, —SO—, —SO 2 —, —O—, —NR 65 —, —SiR 70 R 71 —, —POR 72 —, —CR 63 ═CR 64 —, or —C≡C—, and
E is —OR 69 , —SR 69 , —NR 65 R 66 , —COR 68 , —COOR 67 , —CONR 65 R 66 , —CN, or halogen,
G is E, or C 1 -C 18 alkyl,
R 63 and R 64 are independently of each other C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—;
R 65 and R 66 are independently of each other C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—;
R 67 is C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 68 is H; C 6 -C 18 aryl; C 6 -C 18 aryl which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 69 is C 6 -C 18 aryl; C 6 -C 18 aryl, which is substituted by C 1 -C 18 alkyl, or C 1 -C 18 alkoxy; C 1 -C 18 alkyl; or C 1 -C 18 alkyl which is interrupted by —O—,
R 70 and R 71 are independently of each other C 1 -C 18 alkyl, C 6 -C 18 aryl, or C 6 -C 18 aryl, which is substituted by C 1 -C 18 alkyl, and
R 72 is C 1 -C 18 alkyl, C 6 -C 18 aryl, or C 6 -C 18 aryl, which is substituted by C 1 -C 18 alkyl;
wherein R 1 and R 2 are a group of formula
R 7 , R 8 and R 9 are independently of each other H, C 1 -C 18 alkyl, C 1 -C 18 alkoxy, or C 1 -C 18 alkyl which is interrupted by O;
R 205 , R 206 , R 207 , and R 208 are independently of each other H, C 1 -C 18 alkyl, C 1 -C 18 alkyl which is interrupted by O, C 1 -C 18 alkoxy, or C 1 -C 18 alkoxy which is interrupted by O, or C 1 -C 18 fluoroalkyl;
wherein R 41 can be the same or different at each occurrence and is C1, F, CN, NR 45 R 45′ , a C 1 -C 25 alkyl group, a C 4 -C 18 cycloalkyl group, a C 1 -C 25 alkoxy group, wherein one or more hydrogen atoms can be replaced by F, a C 6 -C 24 aryl group, or a C 6 -C 24 aryloxy group, wherein one or more carbon atoms can be replaced by O, S, or N, and/or which can be substituted by one or more non-aromatic groups R 41 ;
R 45 and R 45′ are independently of each other a C 1 -C 25 alkyl group, a C 4 -C 18 cycloalkyl group, wherein one or more hydrogen atoms can be replaced by F, a C 6 -C 24 aryl group, or a C 6 -C 24 aryloxy group, wherein one or more carbon atoms can be replaced by O, S, or N, and/or which can be substituted by one or more non-aromatic groups R 41 .