Supporting Information: Zhang HomoCoupling-NatCommuns12

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Supplementary Information

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Supplementary! Figure! S1! |! DFT! calculated! TEB! covalent! dimer! and! Ag! bis;acetylide!complex,! compared! with! STM! data! on! Ag(111).! (a)'(b)! DFT'calculated! simulation! of! STM!images!(U!=!'0.6!V)!of!(a)!a!covalent!dimer!and!(b)!a!Ag!bis'acetylide!complex!on!a!Ag(111)!slab,! superimposed!with! the!corresponding!ball'and'stick!model.! (c)'(d)!A!STM! image! (U! =!0.1! V,! I! =! 0.1! nA)! of! an! ordered! dimer! array! and! the! dense'packed! monomer! phase!superimposed!with!the!ball'and'stick!models!of!the!DFT!calculated!(c)!covalent!dimer!and!(d)!Ag!bis'acetylide!complex,!respectively.!The!unit!cell!of!the!superstructure!and!its!orientation!with!respect!to!the!Ag(111)!high!symmetry!axes!are!indicated!in!(c),!α!=!88°,!β!=!25°.!

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Supplementary! Figure! S2! |! Tip!manipulation!of! a! TEB!molecule! and! a! TEB!dimer!on! the!Ag(111)! surface.! ! ! (a)'(b)! STM! images! before! and! after! a! lateral! manipulation,! moving! a!single!TEB!molecule!out!of!the!dense'packed!phase!island.!(Constant!current!manipulation:!U!=!0.1!V,!I!=!15!nA).!!(c)'(d)!STM!images!before!and!after!a!lateral!manipulation,!moving!a!single!TEB!dimer.!(Constant!current!manipulation:!U!=!0.1!V,!I!=!20!nA).!The!green!lines!in!(a)!and!(b)!give!the!starting!(A)!and!ending!(B)!positions!of!the!manipulation.!

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Supplementary! Figure! S3! |!Apparent!height!of! isolated!TEB!monomer!and!dimer!on! the!Ag(111)!surface.!Constant'current!STM!image!(U!=!'1!V,!I!=!0.1!nA).!The!maximum!apparent!height!of!the!TEB!monomers!and!dimers!indicated!by!black!arrows!is!shown.!The!averaged!apparent!height!of!the!dimers!is!approximately!0.1!Å!higher!than!that!of!the!monomers.!The!apparent!height!difference!is!also!clearly!visible!with!the!colour!scale!employed.!

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Supplementary! Figure! S4! |!Top! and! side! views! of! favourable! adsorption! geometries! for!TEB!on!Ag(111).!The!binding!energies!for!the!different!configurations!from!(a)!to!(d)!are!1.19,!1.25,! 1.26,! and! 1.40!eV,! respectively.! Higher! energies! signify! stronger! adsorption.! The!average!adsorption!heights!are!3.12!Å,!3.11!Å,!3.07!Å,!and!2.93!Å,!respectively.!Black!lines!in!the!top!views!indicate!the!surface!unit!cells!used!in!the!calculations.!

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Supplementary! Figure!S5!|!STM!topographic! images!of! Ext;TEB!after!annealing! to!400!K.!Apart! from! the! intended! butadiyne! covalent! bridges! irregular! features! are! visible! where!three!molecular! terminations! join! together.! In! some! cases! (red! circles)! these! connections!appear! brighter! than! in! other! cases! (red! dashed! circles).! The! origin! of! these! structural!features! remains! unclear.! Probably! one! of! these! cases! is! related! to! covalent! connections!differing! from! the! intended! butadiyne! bridges,! while! the! other! could! be! explained! by!terminal! groups! exhibiting! unusually! short! distances! due! to! being! forced! by! the! covalent!backbone!of!surrounding!molecules.!!!

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Supplementary!Figure!S6!|!Charge!difference!plot!of!the!Ag!bis;acetylide!complex.!Electron!charge! density! difference! in! the! organometallic! dimer! calculated! as! the! electron! density!difference!between! the! full! system!and! three! reference! systems! consisting!of! each!of! the!two! molecules! and! the! silver! surface! (with! Ag! adatom).! The! red! contours! are! electron!accumulation! and! the! blue! contours! electron! depletion! and! the! value! of! the! contours! is!0.02e.! The!Ag!adatom!donates!electrons! to! the! former!ethyne!groups,!which!at! the! same!time!back'donates!into!the!organometallic!dimer.!

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Br

Br Brnn

n

1, 3, 5, n = 02, 4, 6, n = 1

nn

n

3, 4 5, 6

nn

n

1, 2SiSi

Si

i ii

!Supplementary!Figure!S7!|!Synthesis.$Reagents,and,conditions:$(i)!TMSA,!Pd(PPh3)2Cl2'CuI,!Et2NH/THF;!(ii)!K2CO3,!MeOH/THF;!!