Organosilver chemistry

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Organosilver chemistry in chemistry is the study of organometallic compounds containing a carbon to silver chemical bond and the study of silver as catalyst in organic reactions.123 In the group 11 elements silver is the element below copper. The chemistries have much in common but organosilver catalysis is much less common (mostly academic study) than organocopper chemistry due both to the relatively high price of silver and to the poor thermal stability of organosilver compounds. The oxidation state for silver in organosilver compounds in exclusively +1 with the notable exception of Ag(III) in the trifluoromethyl silver anion Ag(CF3)4- because of the electron-withdrawing effect of the trifluoromethyl groups. Poor thermal stability is reflected in decomposition temperatures of AgMe (-50 °C) versus CuMe (-15 °C) and PhAg (74 °C) vs PhCu (100 °C)

The first attempts in organosilver were recorded by Buckton in 18594 and by J. A. Wanklyn & L. Carius in 1861.5 The first synthesis of an organosilver compound (methyl silver) was described by Semerano and Riccoboni6 in 1941.

Compounds

Phenylsilver can be obtained by reaction of silver nitrate with an trialkylphenyllead compound:

AgNO3 + R3PhPb → PhAg

Alternatively, diphenylzinc may be used:7

Ph2Zn + AgNO3 → PhAg + PhZnNO3

The silver mesitylene adduct is a tetramer. it can be formed from silver chloride and the Grignard reagent:8

AgCl + MesMgBr → Ag4(Mes)4 + MgClBr

Silver forms stable complexes with ylides such as triphenylphosphonium methylide:

AgCl + Ph3P=CH2 → AgCl(Ph3P=CH2)

The C-Ag bond is stabilized by perfluoroalkyl ligands:9

AgF + CF2=CF(CF3) → AgCF(CF3)2

Alkenylsilver compounds are also more stable than their alkylsilver counterparts. Vinylsilver can be obtained by reaction of silver nitrate with tetravinyllead:10

AgNO3 + (CH2=CH)4Pb → (CH2=CH)Ag + (CH2=CH)3PbNO3

Silver-NHC complexes are easily prepared, and are commonly used to prepare other NHC complexes by displacing labile ligands. For example, the reaction of the bis(NHC)silver(I) complex with bis(acetonitrile)palladium dichloride or chlorido(dimethyl sulfide)gold(I):11

Silver-NHC as carbene transmetallation agent.png

Catalysis

In catalysis silver is active as silver oxide in the Wolff rearrangement. Silver nitrate is used to separate out alkenes as the η2-alkene complex. Silver is also present in other carbon-carbon bond skeletal rearrangements such as the quadricyclane to norbornadiene rearrangement, the cubane to cuneane rearrangement and the rearrangement of the cyclobutadiene dimer to cyclooctatetraene.

See also

  • Chemical bonds of carbon with other elements in the periodic table:
CH He
CLi CBe CB CC CN CO CF Ne
CNa CMg CAl CSi CP CS CCl CAr
CK CCa CSc CTi CV CCr CMn CFe CCo CNi CCu CZn CGa CGe CAs CSe CBr CKr
CRb CSr CY CZr CNb CMo CTc CRu CRh CPd CAg CCd CIn CSn CSb CTe CI CXe
CCs CBa CHf CTa CW CRe COs CIr CPt CAu CHg CTl CPb CBi CPo CAt Rn
Fr CRa Rf Db Sg Bh Hs Mt Ds Rg Cn Uut Fl Uup Lv Uus Uuo
CLa CCe CPr CNd CPm CSm CEu CGd CTb CDy CHo CEr CTm CYb CLu
Ac CTh CPa CU CNp CPu CAm CCm CBk CCf CEs Fm Md No Lr
Chemical bonds to carbon
Core organic chemistry Many uses in chemistry
Academic research, but no widespread use Bond unknown

References

  1. ^ W.A. Herrmann, ed. (1999). Synthetic Methods of Organometallic and Inorganic Chemistry. 5, Copper, Silver, Gold, Zinc, Cadmium, and Mercury. Stuttgart: Thieme. ISBN 3-13-103061-5. 
  2. ^ Christoph Elschenbroich (2006). Organometallics (3 ed.). Weinheim: Wiley-VCH. ISBN 3-527-29390-6. 
  3. ^ The Chemistry of Organic Derivatives of Gold and Silver. Edited by Saul Patai and Zvi Rappoport Copyright 1999 John Wiley & Sons, Ltd. ISBN 0-471-98164-8
  4. ^ Buckton, G. B. (1859). "Untersuchungen über organische Metallverbindungen". Annalen der Chemie und Pharmacie 109 (2): 218–227. doi:10.1002/jlac.18591090216. 
  5. ^ Wanklyn, J. A.; Carius, L. (1861). "10. Ueber eine neue Wasserstoffverbindung des Eisens". Annalen der Chemie und Pharmacie 120 (1): 69. doi:10.1002/jlac.18611200107. 
  6. ^ Semerano, G.; Riccoboni, L. (1941). "Beitrag zur Kenntnis der metallorganischen Verbindungen, I. Mitteil.: Silbermethyl, Silber-äthyl und Silber-n-propyl". Berichte der deutschen chemischen Gesellschaft (A and B Series) 74 (7): 1089. doi:10.1002/cber.19410740703. 
  7. ^ Boersma, J; Des Tombe, F.J.A.; Weijers, F.; Van Der Kerk, G.J.M. (1977). "A new, easy synthesis of phenylsilver". J. Organomet. Chem. 124 (2): 229. doi:10.1016/S0022-328X(00)90970-7. 
  8. ^ Meyer, Edouard Marc.; Gambarotta, Sandro.; Floriani, Carlo.; Chiesi-Villa, Angiola.; Guastini, Carlo. (1989). "Polynuclear aryl derivatives of Group 11 metals. Synthesis, solid state-solution structural relationship, and reactivity with phosphines". Organometallics 8 (4): 1067–1079. doi:10.1021/om00106a031. 
  9. ^ Miller, W. T.; Burnard, R. J. (1968). "Perfluoroalkylsilver compounds". J. Am. Chem. Soc. 90 (26): 7367–7368. doi:10.1021/ja01028a047. 
  10. ^ Holliday, A; Pendlebury, R.E. (1967). "Vinyllead compounds I. Cleavage of vinyl groups from tetravinyllead". J. Organomet. Chem. 7 (2): 281–284. doi:10.1016/S0022-328X(00)91078-7. 
  11. ^ Wang, Harrison M. J.; Lin, Ivan J. B. (1998). "Facile Synthesis of Silver(I)−Carbene Complexes. Useful Carbene Transfer Agents". Organometallics 17 (5): 972. doi:10.1021/om9709704.