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Journal of the American Chemical Society
which gives the energy change that is associated with the bond
ical investigations. This material is available free of charge via the
1
2
3
4
5
6
7
8
9
formation, is a useful indicator for the type of bond. Those fragꢀ
ments, which gives the smallest ꢁEorb 1values provide the best
3
description of the bonding interactions. Tables S1 and S2 of
Supporting information gives the numerical results of the EDAꢀ
NOCV calculations where closedꢀshell fragments or openꢀshell
AUTHOR INFORMATION
Corresponding Author
(triplet) fragments are used as interacting species. The results for
compound 2 (Tables S1 and S2) suggest that the use of closedꢀ
shell fragments for analyzing the PꢀcAAC bonds gives slightly
smaller ꢁEorb values than the triplet fragments. This holds for both
cAAC ligands, which have different conformations with regard to
the Cl SiP fragment. But the difference between the two values is
* Herbert W. Roesky (hroesky@gwdg.de)
* Birger Dittrich (birger.dittrich@uniꢀduesseldorf.de)
* Gernot Frenking (frenking@chemie.uniꢀmarburg.de)
2
2
Notes
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1
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1
2
2
2
2
2
2
2
2
2
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6
0
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9
0
1
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7
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9
0
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9
0
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6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
not very large.
The authors declare no competing financial interests.
Table 1: Calculated NBO partial charges q and Wiberg bond
orders P(AꢀB) of 2 and 3
ACKNOWLEDGMENT
H. W. R. is thankful to the DFG for financial support (RO 224/68ꢀ
1
). GF acknowledges financial support by the Deutsche Forꢀ
2
3
2
3
schungsgemeinschaft. Tao Yang is grateful to the Alexander von
Humboldt Foundation for a postdoctoral fellowship. Dedicated to
Professor Vadapalli Chandrasekhar on the occasion of his 60th
birthday.
q
P(AꢀB)
Si
P1
0.95
ꢀ0.09
ꢀ0.06
0.80
0.73
ꢀ0.08
ꢀ0.02
0.63
SiꢀP1
SiꢀP2
SiꢀC1
P1ꢀC1
P2ꢀC2
0.98
0.98
0.98
0.98
1.38
1.53
1.55
P2
REFERENCES
SiP
2
1.48
1.50
(1) (a) Liu, L.; Ruiz, D. A.; Munz, D.; Bertrand, G. Chem 2016, 1,
147ꢀ153; (b) Hansmann, M. M.; Bertrand, G. J. Am. Chem.
Soc., 2016, 138, 15885–15888. (c) Peters, M.; Doddi, A.; Bannenberg, T.;
Freytag, M.; Jones, P. G.; Tamm, M. Inorg. Chem. 2017, 56, 10785–
Cl
2
SiP
2
ꢀ0.02
0.03
(
cAAC)P1
cAAC)P2
ꢀ0.04
ꢀ0.06
ꢀ0.54
1
0793.
(2) Ecker, A.; Schmidt, U. Chem. Ber. 1973, 106, 1453 1453–1458 and
literature cited therein.
(
<0.01
(
cAAC)c1
(
(4) (a) Roy, S. Dittrich, B.; Mondal, T.; Koley, D.; Stückl, A. C.;
Wright, D. S. J. Organomet. Chem. 2006, 691, 1435ꢀ1808; (c) Merrill, W.
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Schleyer, P. v. R.; Robinson, G. H. Science 2008, 321, 1069−1071; (b)
Franz, D. ; Szilvási, T.; Irran, E.; Inoue, S. Nature Commun. 2015, 6,
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Tan, G. ; Enthaler, S. ; Inoue. S. ; Epping, J. D. ; Driess, M. J. Am. Chem.
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Hammond, K. ; Mies, J. ; Radacki, K. ; Vargas, A. Science 2012, 336,
1420–1422; (f) Bonyhady, S. J. ; Collis, D. ; Frenking, G. ; Holzmann,
N. ; Jones, C.; Stasch, A. Nat. Chem. 2010, 2, 865–869; (g) Soleilhavoup,
M.; Bertrand, G. Acc. Chem. Res., 2015, 48, 256ꢀ266. (h) Kundu,
S.; Samuel, P. P.; Sinhababu, S.; Luebben, A. V.; Dittrich, B.; Andrada,
D.; Kaim, W.; Roesky, H. W. J. Am. Chem. Soc. 2017, 32, 11028ꢀ11031.
The EDAꢀNOCV results for 3, which are shown in Tables S3 ꢀ S5
Supporting Information) are very interesting. The ꢁEorb values
(
for the PꢀcAAC bonds using closedꢀshell fragments are slightly
smaller than using triplet fragments for one cAAC ligand whereas
for the other cAAC ligand the use of triplet fragments is more
favorable. This means that the PꢀcAAC bonds should be described
with resonance forms that have dative bonds and electronꢀsharing
bonds. A similar situation has been found by us in a recent moleꢀ
[12a]
cule where a Si H molecule is bonded to two cAAC ligands.
2
2
The situation for the SiꢀcAAC bond is different. Here we found
that the use of triplet fragments gives a much lower value for
ꢁEorb than using singlet fragments. The SiꢀC bond in 3 should
therefore be depicted with a classical double bond Si=cAAC,
which means that the silicon bonded carbene carbon atom of the
cAAC ligand is formally a C(IV). The oxidation state of Si in 2
and 3 is +4.
(6) Arduengo III, A. J. ; Calabrese, J. C. ; Cowley, A. H. ; Dias, H. V.
R. ; Goerlich, J. R. ; Marshall, W. J. ; Riegel, B. Inorg. Chem. 1997, 36,
In conclusion, two terminal phosphinidene complexes of silicon
2
151 – 2158.
which are attached to
a
silicon(IV)dichloride moiety
Cl )Si{P(cAAC)} (2) as well as silylene species
cAAC)Si{P(cAAC)} have been synthesized. To our surprise the
(
(
a
dal, K. C.; Kundu, S.; Li, B.; Schermann, C. J.; Dutta, S.; Koley, D.;
HerbstꢀIrmer, R.; Stalke, D.; Roesky, H. W. Chem. Eur. J. 2017, 23,
12153ꢀ12157.
2
2
2
SiꢀP bond lengths in 2 and 3 are not significant different, although
the silicon atoms are four and three coordinated. Theoretical
calculations suggest that the PꢀcAAC bonds in 2 and 3 may be
described with a resonance between dative bonds and electronꢀ
sharing double bonds whereas the siliconꢀcarbon in 3 is best
described with a double bond Si=cAAC.
(
8) Arduengo III, A. J.; Carmalt, C. J.; Clyburne, J. A. C.; Cowley, A.
(
Chem. 2014, 126, 13786–13790; (b) Bispinghoff, M.; Tondreau, A. M.;
Grützmacher, H.; Faradjib, C. A.; Pringle, P. G.; Dalton
Trans. 2016, 45, 5999–6003; (c) Balmer, M.; Gottschling, H.; Hänisch, C.
V. Chem. Commun. 2018, 54, 2659ꢀ2661; (d) Lemp, O.; Balmer, M.;
Reiter, K.; Weigend, F.; Hänisch, C. v. Chem. Commun. 2017, 53, 7620ꢀ
ASSOCIATED CONTENT
Supporting Information
7
623; (e) Kundu, S.; Li, B.; Kretsch, J.; HerbstꢀIrmer, R.; Andrada, D. M.;
Frenking, G.; Stalke, D.; Roesky, H. W. Angew. Chem. Int. Ed. 2017, 56,
219 –4223; Angew. Chem. 2017, 129, 4283 –4287. (f) Kundu,S.;
The cif files of 2 and 3 [CCDC: 1846575 (2), 1847620 (3)] few
figures and the details of crystal structure refinements and theoretꢀ
4
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