This document summarizes a research article about the synthesis of four-membered heterocycles containing phosphorus, antimony, or bismuth. Specifically, it discusses the synthesis of dipictadiazanes and dipnictadiazenium cations, including [ClE(μ-NTer)]2 (where E = Sb, Bi), [XE(μ-NTer)2E]+, and [E2(μ-NR)2]2+. It describes methods to generate these compounds, such as HCl elimination or using a distannadiazane, as well as challenges in isolating the bismuth derivatives. The synthesis of [IBi(μ-NTer)]2

1. Group Meeting
Literature Review: Main Group,
Four Membered Heterocycles
July 18, 2012
Stewart Lucas

2. Cyclic Distiba- and
Dibismadiazenium Cations1
Mathias Lehmann, Axel Schulz, and Alexander Villinger
Angew. Chem. Int. Ed., 2012, Advance Article
Universität Rostock, Institut für Chemie, Albert-Einstein-Strasse 3a,
and Leibniz-Institut für Katalyse e.V. an der Universität Rostock Albert-
Einstein-Strasse 29a, 18059 Rostock (Germany)

3. Four-membered Pnictogen-Nitrogen
Heterocycles
• 1,3-dihalogen-cyclo-1,3-dipicta(III)-2,4-diazenes.
• E = P: Used in preparative phosphorus-nitrogen chemistry
(macrocycles, polymers, main-group complexes, and
generation of cyclic binary PN cations)2-6.
• Diazanes with bulky R groups provide kinetic
stabilization7-13.
• Lewis acids used to generate cyclo-1,3-dipnicta(III)-2,4-
diazenium cations14-16.
• Ion pairs with large interatomic distances.

4. Four-membered Pnictogen-Nitrogen
Heterocycles
• 1,3-dihalogen-cyclo-1,3-dipicta(III)-2,4-diazenium
cations.
• Antimony and bismuth analogs are unknown.
• Few examples of
17-21
N-E+-N compounds are known.
• The [Me2Si(µ-NR)2E]+ contains strong intermolecular
Draw out [ClE(µ-NTer)]2,
interactions.
[XE(µ-NTer)2E]+and [E2(µ-
• This paper presents the synthesis of NR)2]2+.
[ClE(µ-NTer)]2 which is subsequently used to
generate [XE(µ-NTer)2E] + and [E (µ-NR) ]2+
2 2 .

5. Synthesis of Dipictadiazanes and
Dipnictadiazenium Cations
• [ClE(µ-NTer)]2 from HCl elimination of RNH2 and
ECl3 or RHN-ECl2. Draw out HCl emim
• When E = Sb or Bi side reactions occur which lead to
scheme
reduced yield of [ClE(µ-NTer)]2. Yield?
• Alternate route to [ClE(µ-NTer)]2 involves a
distannadiazane.
• Formed via metallation of a primary amine and a Sn(II)
diamide.
• [ClSn(µ-NTer)]2 has been reported by Power.

6. Synthesis of Dipictadiazanes and
Dipnictadiazenium Cations
• Reaction of pnictogen(III) chlorides with the
distannadiazane yields dipnictadiazanes.
• Yield for Sb species: 79%, Bi species: 68%.
Reaction scheme
• Addition of GaCl3 to [ClSb(µ-NTer)]2 results in the
formation of [ClSb(µ-NTer)2Sb][GaCl4].
Reaction scheme

7. Synthesis of Dipictadiazanes and
Dipnictadiazenium Cations
• Addition of GaCl3 to [ClBi(µ-NTer)]2 yields a dark-
brown solution (1H, 13C NMR suggest formation
of [ClBi(µ-NTer)2Bi]+).
Reaction scheme
• Attempts to isolate [ClBi(µ-NTer)2Bi][GaCl4] result
in decomposition.
• SbCl5 and Ag[SbF6] yielded same results.
• A more weekly coordinating anion was expected to help.
Ag[B(C6F5)4] still resulted in decomposition.

8. Synthesis of Dipictadiazanes and
Dipnictadiazenium Cations
• The iodine species, [IBi(µ-NTer)]2, was expected
to be more easily isolated.
• [ClE(µ-NTer)]2 converted to [E(µ-NTer)]2[OTf]2 (Sb: 65%,
Bi: 88%) by reaction with AgOTf
• [Bi(µ-NTer)]2[OTf]2 is then transformed to [IBi(µ-NTer)]2
(68%) by reaction with Me3SiI.
Reaction scheme
• Reaction of [IBi(µ-NTer)]2 with Ag[B(C6F5)4] led to
[IBi(µ-NTer)2Bi][B(C6F5)4]●3CH2Cl2 (46%).
Reaction scheme

9. Synthesis of Dipictadiazanes and
Dipnictadiazenium Cations
• fffssadsre

10. • f-number

11. Tellurium–Nitrogen -
Heterocyclic Chemistry
Mathias Lehmann, Axel Schulz, and Alexander Villinger
Angew. Chem. Int. Ed., 2012, Advance Article
Universität Rostock, Institut für Chemie, Albert-Einstein-Strasse 3a,
and Leibniz-Institut für Katalyse e.V. an der Universität Rostock Albert-
Einstein-Strasse 29a, 18059 Rostock (Germany)

12. References
1. Lehmann, Schulmanz, et. al., Angew. Chem. Int. Ed., 2012, Advance Article.
2. Keat, et. al., Top. Curr. Chem., 1982, 102, 89.
3. Balakrishna, Sreenivasa Reddy, et. al., Coord. Chem. Rev. 1994, 129, 1.
4. Stahl, Coord. Chem. Rev., 2000, 210, 203.
5. Beswick, Wright, Coord. Chem. Rev. 1998, 176, 373.
6. Doyle, Riera, et. al., Eur. J. Inorg. Chem. 2003, 3279.
7. Reiß, Schulz, et. al., Dalton Trans. 2010, 39, 9962.
8. Burford, Cameron et. al., Inorg. Chem. 2005, 44, 8058.
9. Kuhn, Scherer, Z. Naturforsch. B 1979, 34, 888.
10. Haagenson, Stahl, Inorg. Chem. 2001, 40, 4491.
11. Eisler, Chivers, Inorg. Chem. 2006, 45, 10734.
12. Lehmann, Schulz, et. al., Eur. J. Inorg. Chem. 2010, 5501.
13. Michalik, Schulz, et. al., Angew. Chem. Int. Ed. 2010, 49, 7575.
14. Michalik, Schulz, et. al., Angew. Chem. Int. Ed. 2008, 47, 6465.
15. Schulz, Villinger, Inorg. Chem. 2009, 48, 7359.
16. Cowley, Kemp, Chem. Rev. 1985, 85, 367.
17. Veith, Bertsch, Z. Anorg. Allg. Chem. 1988, 557, 7.
18. Veith, Bertsch, et. al., Z. Anorg. Allg. Chem. 1988, 559, 73.
19. Veith, Angew. Chem. Int. Ed. Engl. 1987, 26, 1.
20. Gudat, Gans-Eichler, et. al., Chem. Commun. 2004, 2434.
21. Spinney, Korobkov, et. al., Chem. Commun. 2007, 1647.