cs@c n k@c n rb@c n group i group i metallofullerenes donate 1 electron to cage m + @c 2n −...
TRANSCRIPT
50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90
48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90
Cs@Cn
48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90
K@Cn
Rb@Cn
Group I Group I MetallofullerenesDonate 1 electron to cage M+@C2n
− Distribution similar to empty cages C60 and C70 dominant
n = 60
n = 70
42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Ca@Cn
Ba@Cn
44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84
Sr@Cn
Group II metals• Donate 2 electron to cage M2+@C2n
2−
• M@C50 exhibits dominance as well as M@C60 M@C70 no longer dominant
n = 50 60
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Sc@Cn
Y@Cn
Group III metals• Donate 3 electron to cage• M3+@C2n
3−
• Now, M@C44 dominates • M@C50 is also abundant.• M@C60 no longer dominates
n = 44
n = 50
n = 60
Clear correlation to charge transfer and growth
• More charge transferred, the distribution of fullerenes shifts to very small metallofullerenes
• Thus, when more charge is transferred they “grow slower”. As the number of transferred electrons are increased, the growth distribution is shifts to smaller fullerenes.
• This can explain why the larger metallofullerenes appear to only form as a small fraction of, for example, empty cage C60. Under conditions where empty cage C60 dominates of C2n distribution, the M@C2n distributions exhibits mostly small fullerenes…….which will likely “react away” in the solid state, in solution, or air.
• Charge transfer appears to be extremely important in determining metallofullerenes formation. It is likely the most important growth factor
C84
+ carbon vapor
C84
1,1751,1701,165
m/z1,6001,5001,4001,3001,2001,1001,000900
1165 1170 1175
Gd@C82 Gd@C82 calculated
Gd@C84
Metallofullerenes “grow slower” than empty cages in carbon vapor?
+ carbon vapor
C84
m/z20001900180017001600150014001300120011001000900800700600
Compare Gd@C80 to C84
from our Nature Communications paper
50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90
Cs@C2n
48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90
Rb@C2n
42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Ca@C2n
44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Ba@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70
Sc@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Y@C2n
Cs@C60
Cs@C70
Ca@C50
48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90
K@C2n
K@C60
K@C70
Rb@C70
Rb@C60
Ba@C50
Ca@C60
Sc@C44Ca@C70
Ba@C70
Ba@C60
44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84
Sr@C2n
Sr@C60
Sr@C50
Sr@C70
Sc@C50
Sc@C60
Y@C50Y@C44
Y@C50
Group I metals• Donate 1 electron to cage• M+@C2n
−
• Distribution similar to empty cages (ie, C60 and C70 dominate)
Group II metals• Donate 2 electron to cage• M2+@C2n
2−
• M@C50 exhibit much greater abundance, although M@C60 just a bit more dominate. M@C70 forms in lower abundance
Group III metals• Donate 3 electron to cage• M3+@C2n
3−
• Now, M@C44 dominates over other endo cages. M@C50 is also highly abundant.
• M@C60 no longer dominates
Comparison of Group I, II, III metallofullerene growth distributions
m/z20001900180017001600150014001300120011001000900800700600
Metallofullerenes “grow slower” than empty cages in carbon vapor?
La2@C80
+ carbon vapor
m/z
1,8001,7001,6001,5001,4001,3001,2001,1001,000
La2@C82
La2@C80
C84
+ carbon vapor
C84
Compare growth of La2@C80 to C84
from our Nature Communications paper
C84
+ carbon vapor
C84
1,1751,1701,165
m/z1,6001,5001,4001,3001,2001,1001,000900
1165 1170 1175
Gd@C82 Gd@C82 calculated
Gd@C84
Metallofullerenes “grow slower” than empty cages in carbon vapor?
+ carbon vapor
C84
m/z20001900180017001600150014001300120011001000900800700600
Compare Gd@C80 to C84
from our Nature Communications paper
Does more charge transfer from metal to cage render metallofullerenes less reactive?
• That could explain striking difference in growth of metallofullerenes vs empty cages
• Thus, as one moves from Group I to Group III metals, M@C2n should become less reactive due to more transfer to cage. Thus, Group III would exhibit a greater distribution of smaller fullerenres than Group II, and Group I
• A good test of this is to look at the Lanthanides• It is known there are two groups of lanthanides, those that
transfer 3 electrons to cage M3+@C2n
3-
La, Ce, Pr, Nd, Pm, Gd, Tb, Dy, Ho, Er, Lu
• And those that only transfer 2 electrons to cage M2+@C2n
2-
Sm, Eu, Tm, Yb
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
La@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Ce@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Pr@C2n
42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Sm@C2n
42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Eu@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Tb@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Dy@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Ho@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Er@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Nd@C2n
44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82
Yb@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Lu@C2n
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Gd@C2n
Comparison of Lanthanides
La@C44
La@C50
La@C60
Tb@C44 Tb@C50
Tb@C60
Sm@C44
Sm@C50
Sm@C70
Sm@C60
M3+@M@C2n3− Lanthanides
M2+@M@C2n2− Lanthanides
• Striking difference for Sm, Eu, Tm, Yb
These are M2+@M@C2n2−
M@C60 > M@C50 >M@C70
M@C44 is weak
Matches Group II metal M@C2n distributions (for example, Sr@C2n below), which can, of course, only donate 2 electrons
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
La@C2n
42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Sm@C2n
Comparison of Lanthanides
La@C44La@C50
La@C60
Sm@C44
Sm@C50
Sm@C70
Sm@C60
M3+@M@C2n3− Lanthanides
M2+@M@C2n2− Lanthanides
• La, Ce, Nd, Gd, Tb, Dy, Ho, Er, Lu all exhibit the same distributions
M@C44 > M@C50 >M@C60
M@C60 relatively weak for these M3+@M@C2n
3− Lanthanides
Matches the growth distributions of the Group III metals….for example, Y@C2n below
44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84
Sr@C2n
Sr@C60
Sr@C50
Sr@C70
36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80
Y@C2nY@C50Y@C44
Y@C50
Clear correlation to charge transfer and growth
• More charge transferred, the distribution of fullerenes shifts to very small metallofullerenes
• Thus, when more charge is transferred they “grow slower”. As the number of transferred electrons are increased, the growth distribution is shifts to smaller fullerenes.
• This can explain why the larger metallofullerenes appear to only form as a small fraction of, for example, empty cage C60. Under conditions where empty cage C60 dominates of C2n distribution, the M@C2n distributions exhibits mostly small fullerenes…….which will likely “react away” in the solid state, in solution, or air.
• Charge transfer appears to be extremely important in determining metallofullerenes formation. It is likely the most important growth factor