Daniel P. Zaleski and Nick R. Walker School of Chemistry, Bedson Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK. David P. Tew and Anthony C. Legon School of Chemistry, University of Bristol, Bristol BS8 1TS, UK. Formation of M-C ≡ C-Cl (M = Ag or Cu) and Characterization by Rotational Spectroscopy The 70 th International Symposium on Molecular Spectroscopy, June 25 th, 2015.

Chemical Themes Interstellar Chemistry and the Chemistry of Harsh Environments The Basic Chemistry of Life Emerges from the Cold and the Dust Orion Horsehead Nebula  Organic chemistry is prevalent in the hot core regions of star and planet formation  Molecule formation requires a combination of gas- phase, surface, and ice chemistry  Unusual energy sources drive these chemical trans- formations (cosmic rays, EUV radiation, outflows) Despite inhospitable conditions, the full range of organic chemistry functional groups are produced in the places where planets form The carbon-rich chemistry of the interstellar medium has direct connections to many technologically important areas of chemistry Combustion chemical intermediates in flames Electrical Discharge lightning planetary atmospheres Nanotechnology fullerenes carbon nanotubes ESO

Discharge and Ablation  Well known that DC electric discharges can produce small (un)stable molecules and hitherto unknown species  Laser ablation of solids is another convenient method of producing plasmas  Nd:YAG operating at 532 nm (pulse duration ~ 900 μs) is about 25 mJ/pulse: enough to ablate common metals If this plume immediately interacts with a gas of neutral molecules in its vicinity, fragmentation of the molecules can occur and the fragments can then undergo reactions. Phys. Chem. Chem. Phys., 2014, 16,

Chirped Pulse FTMW Spectroscopy Broadband spectrometers with instantaneous frequency coverage from 2-8 GHz, GHz, GHz, and 25 – 40 GHz have been constructed. Current Technology: AWG24 Gs/s (12 GHz) Digital Oscilloscope 100 Gs/s (33 GHz) Phys. Chem. Chem. Phys., 2014, 16,

3M FIDs (100 hr) for normal species 1000x 1% CCl 4 6 bar Ar

Weaker signals due to Cu/Cl hyperfine 3M FIDs (100 hr) for the normal species 1% CCl 4 6 bar Ar

X-AgCl Trends J. Chem. Phys., 2011, 135, Species χ aa (MHz) r(Ag-Cl) (Å) AgCl Ar Kr Xe H 2 O NH H 2 S C 2 H OC C 2 H C 6 H χ aa = (26) MHz r s (Ag-Cl) = (12) Å Z. Naturforsch., 1978, 33a, Theory: χ aa = -31 MHz r(Ag-Cl) = Å

Structure Determination (A,B,C) = (I A,I B,I C ) I = Σ m i ∙r i 2 (A ˊ,B ˊ,C ˊ ) = (I A ˊ,I B ˊ,I C ˊ ) |r a |,|r b |,|r c | Isotopic substitution produces small (and predictable) shifts in the rotational constants that are site-specific. Free from other assumptions about the molecular structure Am. J. Phys., 1953, 21, 17. MP2/aug-cc-pVTZ-PP

Isotopologues M = AgM = Cu SpeciesCalc.Exp.Calc.Exp. n M 12 C 12 C 35 Cl742.6 (n=107) (16)974.0 (n=63) (73) n M 12 C 12 C 35 Cl738.3 (n=109) (19)961.7 (n=65) (78) n M 12 C 12 C 37 Cl717.4 (n=107) (21)944.4 (n=63) (38) n M 12 C 12 C 37 Cl713.2 (n=109) (28)932.3 (n=65)- n M 13 C 13 C 35 Cl738.6 (n=107) (30)971.2 (n=63) (29) n M 13 C 13 C 35 Cl734.3 (n=109) (10)958.9 (n=65)- Ag, Cu, C: CCSD(T)/aug-cc-pV5Z Cl: CCSD(T)/aug-cc-pV(5+d) J. Chem. Phys., 2010, 133,

Properties M = AgM = Cu Calc.r0r0 r0r0 r(M-C) (Å ) (14) (16) r(C≡C) (Å ) [1.2219]1.2233[1.2233] r(C-Cl) (Å ) (6) (6) r(M∙∙∙Cl) (Å) (2) (6) Ag, Cu, C: CCSD(T)/aug-cc-pV5Z Cl: CCSD(T)/aug-cc-pV(5+d) difference between r 0 and r e for the triple bond in acetylene is Å J. Chem. Phys., 2011, 134,

Population Analysis J. Chem. Phys., 2003, 119, J. Mol. Spectrosc., 2005, 232, Plasma Chem. Plasma Proc., 2005, It is difficult to discuss the precise mechanism by which these slightly exotic substances are formed, but it is well known that CCl, CCCl and CCl 2 are among the products when a thermal plasma is sustained in CCl 4 /Ar mixtures. AgCCCl: CCl 2 : CCCl 1 : 1 : 0.1 The geometry of the 2 Σ ground state of the CCCl radical has r(C ‒ C) = Å, r(C ‒ Cl) = Å and ∠ CCCl = 156.9°. The first and third of these lie midway between the corresponding values in ethyne and ethane, while r(C ‒ Cl) = Å is very similar to the corresponding distance determined here for both Ag ‒ C≡C ‒ Cl and Cu ‒ C≡C ‒ Cl.

Conclusions  Demonstrated the usefulness of unbiased broadband survey spectra  Identified a “pathway” for synthesizing MCCCl - M = Ag or Cu  Would be interesting to further investigate the MCCCl binding properties -look at gas phase clusters coordinating to either side -M or Cl  Look to synthesize longer chains

Acknowledgments Engineering and Physical Sciences Research Council AWE (Aldermaston )