Electronic Structure of Heavier Main Group 14

Multiple Bonded Compounds

2  

Heavier Gp 13 and 14 Multiple Bonded Species Have ‘Strained’ Geometries and Quasi Open-Shell Configurations.

3

Variation in the Most Probable Radii of the s and p Valence Orbitals of Group 14 Elements

J. P. Desclaux, At. Dat. Nucl. Data Tables 1973, 12, 31.���W. Kutzelnigg, Angew. Chem. Int. Ed. Engl. 1984, 23, 272.

3

Stable Singlet Diradicaloid, Non-Kekulé Main Group Molecules

1Chivers, Guide to Chalcogen-Nitrogen Chemistry, World Scientific, NJ, 2005; 2Masamune et al. Angew Chem Int Ed 1986, 25, 173; 3Sita et al. J Am Chem Soc 1992, 114, 7024; 4Niecke et al. Angew Chem Int Ed 1995, 34, 555; 5Bertrand et al. Science 2002, 295, 1880; 6Power et al. J Am Chem Soc 2004, 126, 6510, Lappert et al. Angew Chem Int Ed 2004, 43 4500.

5

The “Strained” Geometry in Main Group Molecules May Resemble Surface Atom Arrangements

• Bonding representation of the E(100)-2X1 reconstructed surface (a) circles = E(Si or Ge) atoms as illustrated by ordered arrays of E=E double bonds (b).

• J. M. Buriak, Chem. Rev., 2002, 102, 1271 5

6  

Multiple Bonding in the E2 Surface Units

React directly with H2 and alkenes�

7  

Synthesis of Ge, Si, Sn, Pb Alkyne Analogues: Synthesis

Ø  2000, Synthesis of the first stable heavier group 14 element analogues of an alkyne.

Ø  2002, Synthesis of stable Ge, Sn alkyne analogues.

Ø  2002, Wiberg synthesized the first Si quasi stable alkyne species, and characterized it spectroscopically in solution. Wiberg, N; Niedermayer, W.; Fischer, G.; Noth, H.; Suter, M., Eur. J. Inorg. Chem. 2002, 1066.

Ø  2004, The first stable structurally characterized silicon-silicon triple bond was prepared by Sekiguchi.

Sekiguchi, A.; Kinjo, R.; Ichinohe, M. Science 2004, 305, 1755

Phillips, A. D.; Wright, R. J.; Olmstead, M. M.; Power, P. P.; J. Am. Chem. Soc., 2002, 124, 5930 Stender, M.; Phillips, A. D.; Wright, R. J. Power, P. P. Angew. Chem,. Int. Ed, 2002, 41, 1785

Pu, l.; Twamley, B.; Power, P. P.; J. Am. Chem. Soc., 2000, 122, 3524

Alkynes and their Heavier Group 14 Element Analogues�

a  Sekiguchi,  Kinjo,  Ichinohe.  Science.  2004,  305,  1755.          b  Stender,  Phillips,  Power.  Angew.  Chem.  Int.  Ed.  2002,  41,  1785.    c  Phillips,  Wright,  Olmstead,  Power.  J.  Am.  Chem.  Soc.  2002,  124,  5930.          d  Pu,  Twamley,  Power.  J.  Am.  Chem.  Soc.  2000,  122,  3534.    

2  

3  

NMR Spectroscopy �δ  29Si  

91.5  

89.9  

δ11  =      364c  

δ22  =      221  δ33  =    -­‐350  

δ  =  18.7  

a.  Wiberg,  N.;  Niedermayer,  W.;  Fischer,  G.;  Nöth,  H.;  Suter,  M.  Eur.  J.  Inorg.  Chem.  2002,  1066.            b.  Sekiguchi,  A.;  Kinjo,  R.;  Ichinohe,  M.  Science.  2004,  305,  1755.            c.  Kravchenko,  V.;  Kinjo,  R.;  Sekiguchi,  A.;  Ichinohe,  M.;  West,  R.;  Balazs,  S.;  Schmidt,  A.;  Karni,  M.;  Apeloig,  Y.  J.  Am.  Chem.  Soc.  2006,  128,  14472.          d.  Sasamori,  T.;  Hironaka,  K.;  Sugiyama,  Y.;  Takagi,  N.;  Nagase,  S.;  Hosoi,  Y.;  Furukawa,  Y.;  Tokitoh,  N.  J.  Am.  Chem.  Soc.  2008,  130,  13856.         17  

Solid State 119Sn NMR Spectra of AriPr4SnSnAriPr4 and AriPr6SnSnAriPr6

AriPr4SnSnAriPr4 AriPr6SnSnAriPr6

δ11 = +1,125.2 ppm δ22 = +740.4 ppm δ33 = -860.3 ppm

δiso = +335.1 ppm η = 0.32

δ11 = +726.1 ppm δ22 = +193.3 ppm

δ33 = -1028.0 ppm δiso = -36.2 ppm

η = 0.54 G.H.Spikes, J. R. Guiliani, M.P Augustine, I. Nowik, R.H. Herber, P.P. Power, Inorg. Chem. 2006, 45, 9132.

Mössbauer Spectra of ArPri6SnSnArPri6 and ArPri4SnSnArPri4 Indicate the Presence of Sn(II)�

I.  S.   Q.  S.  2.960(3)   3.730(3)  

2.658(2)   2.995(2)  

I.S.  Sn(IV)    -­‐0.5  →  

1.80  I.S.  Sn(II)    1.80  ➝  4.50  

.  2  

G.H.Spikes, J. R. Guiliani, M.P Augustine, I. Nowik, R.H. Herber, P.P. Power, Inorg. Chem. 2006, 45, 9132.

Calculations Show Large Structural Changes Require Little Energy for M = Sn or Pb

Jung, Brynda, Power, Head-Gordon, J. Am. Chem. Soc., 2006, 128, 7185.

Δ Sn-Sn = ca. 0.4Å Δ Sn-Sn-C = ca. 25º

Single and Multiple Bonded Distannyne Structural Data

Distannyne Sn-Sn (Å) Sn-Sn-C (º) CSnSnC (º)

Ar'SnSnAr' a 2.6675(4) 125.24(7) 180 Cl-4-Ar'SnSnAr'-4-Cl b 2.672(2) 121.8(4) 180 But-4-Ar'SnSnAr'-4-But b 2.6461(3) 124.0(1) 180 MeO-4-Ar'SnSnAr'-4-OMe b 2.648(1) 124.2(2) 180 3,5-Pri

2-Ar'SnSnAr'-3,5-Pri2

b 2.666(1) 127.96(2) 180 3,5-Pri

2Ar*SnSnAr*-3,5-Pri2b 2.736(1) 127.62(2) 160-166

Me3Si-4-Ar'SnSnAr'-4-SiMe3 c 3.066(1) 99.3(1) 180

MeGe-4-Ar'SnSnAr'-4-GeMe3b 3.076(1) 97.9(1) 180

a A. D. Phillips, R. J. Wright, M. M. Olmstead, P. P. Power, J. Am. Chem. Soc., 2002, 124, 5930. b Y. Peng, R. C. Fischer, W.A. Merrill, J. Fischer, L. Pu, B.D. Ellis, R.H Herber, J. C. Fettinger, P. P. Power, Chem. Sci., 2010, 1,461.c R. C. Fischer, L. Pu, J. C. Fettinger, M. A. Brynda, P. P. Power, J. Am. Chem. Soc., 2006, 128, 11366.