Heterocumulene

Heterocumulenes are molecules consisting of a linear chain of carbon atoms with one or more of another atom attached to the end. The carbon atoms are all joined by double bonds C=C=C=C. Similar molecules termed cumulenic, have a chain of alternating triple and single bonds. C≡C-C≡C-.... Heterocumulenes are commonly found in space or flames. Most of the longer ones are very unstable and reactive, and thus have a transient existence, or can only survive when dilute or in an inert matrix. Molecular clouds in space are very dilute and allow heterocumulenes to exist long enough to be detected. Some simple heterocumulenes are common chemicals or ions. These include carbon dioxide, carbon disulfide, carbon diselenide, cyanate, thiocyanate. Some definitions of heterocumulenes include compounds that contain concatenated double bonds with more than one element, but may have other parts to them. This class includes ketene, sulfur diimide, and dicyclohexylcarbodiimide. Some heterocumulenes can act as ligands with various metals.

Reactions

Some energised herterocumulenes can cyclise by bending into a circle and bonding the two ends of the chain. Molecules that can do this are CCCB, CCCAl, CCCSi, CCCN, or CCCP.[1]

Other four atom heterocumulenes include CCBO, tricarbon monoxide (CCCO) and CCCS Four atom heterocumulenes when cyclised can have two forms. In the kite (or rhombic) form, a triangle of carbon has two of its atoms bonded to the heteroatom. In the fan form the hetero atom links to three carbon atoms arranged in a fan shape. CCCSi has linear, rhombic or fan isomers. The rhombic form is known in space near the carbon star IRC+10216.

CCCCO cyclises to a three-member ring.[1] CCCCN undergoes an isonitrile conversion.[1]

Molecules

Other known five atom heterocumulenes include CCBCC, CCCCB, CCOCC, CCCCSi, CNCCO, HCCCO, HCCCS, NCCCN CCCCSi is known as a linear molecule in space.

CCCCBO turns into a six-member ring. Other six atom heterocumulenes include OCCCCN and HCNCNH.

Seven atom heterocumulenes include NCCCCCN, HCCBCCH.

A known nine atom heterocumulene is HCCCCCCCH.

Thiocumulenes have a sulfur atom. They include dicarbon monosulfide CCS and tricarbon monosulfide CCCS both known from molecular clouds.[2] SCnS chains can be made by laser ablation with n up to 27.[3]

Table of molecules

This table lists heterocumulene molecules. Heterocumulenes are supposed to be straight, but some combinations of elements result in bent or cyclic molecules.

colspan=11 one kind of heteroatom
heteroatom 1 carbon 2 carbon 3 carbon 4 carbon 5 carbon 6 carbon 7 carbon 8 carbon 9 carbon
B CB CCB CCBCC, CCCCB
N CN CCN NCCN CCCN[4] NCCCN CCCCN NCCCCN NCCCCCN C5N[4]
O CO OCO CCO[5] CCCO OCCCO C4O[5] C6O[5] C8O[5]
Si CCSi bent CCCSi ring CCCCSi[4] C6Si[4]
P CP CCP
S CS SCS CCS CCCS SCCCS C4S[6] SCCCCS[6] C5S[6] SC5S[6][7] C6S[8] SC7S[8] SC9S[8]
Cl CCCl CCCCl is bent
Se CSe2 SeCCCSe[9]

Two different hetero atoms

atom 1 H B N O F Al Si P S Cl As Se Br
B
N HCNHCCCN HCnN n=5,7,9,11 HCNCC[4] HCCNC[4] -OCN -NCO -SNC -NCS
O
F
Al
Si
P
S HC2-8S (HCS bent)[10] NCS (NCCS bent) NC3-7S[10]
Cl
As
Se -SeCN
Br

References

  1. 1 2 3 Wang, Tianfang; Bowie, John H. (November 2011). "Studies of cyclization reactions of linear cumulenes and heterocumulenes using the neutralization-reionization procedure and/or ab initio calculations". Mass Spectrometry Reviews. 30 (6): 1225–1241. doi:10.1002/mas.20328.
  2. ↑ Yamamoto, Satoshi; Saito, Shuji; Kawaguchi, Kentarou; Kaifu, Norio; Suzuki, Hiroko (June 1987). "Laboratory detection of a new carbon-chain molecule C3S and its astronomical identification". The Astrophysical Journal. 317: L119. doi:10.1086/184924.
  3. ↑ Burnin, Andrei; BelBruno, Joseph J. (November 2003). "SCnS Linear Chain Production by Direct Laser Ablation". The Journal of Physical Chemistry A. 107 (45): 9547–9553. doi:10.1021/jp0304071.
  4. 1 2 3 4 5 6 Botschwina, Peter (2003). "Spectroscopic properties of interstellar molecules: Theory and experiment". Physical Chemistry Chemical Physics. 5 (16): 3337. doi:10.1039/b303753n.
  5. 1 2 3 4 Ohshima, Yasuhiro; Endo, Yasuki; Ogata, Teruhiko (22 January 1995). "Fourier‐transform microwave spectroscopy of triplet carbon monoxides, C2O, C4O, C6O, and C8O". The Journal of Chemical Physics. 102 (4): 1493–1500. doi:10.1063/1.468881.
  6. 1 2 3 4 Szczepanski, Jan; Hodyss, Robert; Fuller, Jason; Vala, Martin (April 1999). "Infrared Absorption Spectroscopy of Small Carbon−Sulfur Clusters Isolated in Solid Ar". The Journal of Physical Chemistry A. 103 (16): 2975–2981. doi:10.1021/jp984700q.
  7. ↑ Thorwirth, S.; Salomon, T.; Fanghänel, S.; Kozubal, J.R.; Dudek, J.B. (September 2017). "High-resolution infrared fingerprints of carbon-sulfur clusters: The ν1 band of C5S". Chemical Physics Letters. 684: 262–266. doi:10.1016/j.cplett.2017.06.032.
  8. 1 2 3 Wang, Haiyan; Szczepanski, Jan; Cooke, Andrew; Brucat, Philip; Vala, Martin (2005). "Vibrational absorption spectra of CnS (n = 2, 6) and CnS2 (n = 7, 9, 11, 13, 15) linear carbon-sulfur clusters". International Journal of Quantum Chemistry. 102 (5): 806–819. doi:10.1002/qua.20383.
  9. ↑ Pu, Liang; Zhao, Xiao; Zhang, Zhong; King, R. Bruce (May 2017). "Heavier Carbon Subchalcogenides as C3 Sources for Tungsten-Capped Cumulenes: A Theoretical Study". Inorganic Chemistry. 56 (10): 5567–5576. doi:10.1021/acs.inorgchem.6b02958.
  10. 1 2 McCarthy, M. C.; Cooksy, A. L.; Mohamed, S.; Gordon, V. D.; Thaddeus, P. (February 2003). "Rotational Spectra of the Nitrogen‐Sulfur Carbon Chains NCnS, n = 1–7". The Astrophysical Journal Supplement Series. 144 (2): 287–297. doi:10.1086/344727.
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