The digallane molecule, Ga2H6:: experimental update giving an improved structure and estimate of the enthalpy change for the reaction Ga2H6(g) → 2GaH3(g)

A.J. Downs; T.M. Greene; E. Johnsen; C.R. Pulham; H.E. Robertson; D.A. Wann

doi:10.1039/c000694g

The digallane molecule, Ga2H6: experimental update giving an improved structure and estimate of the enthalpy change for the reaction Ga2H6(g) → 2GaH3(g)

A.J. Downs, T.M. Greene, E. Johnsen, C.R. Pulham, H.E. Robertson, D.A. Wann

Chemistry

Research output: Contribution to journal › Article › peer-review

Abstract

Improved methods of analysis and new quantum chemical calculations have been applied to the results of earlier gas-phase electron diffraction (GED) studies of digallane to give what is judged to be the most realistic structure available to date. The principal distances (ra3,1 in pm) and interbond angles (∠a3,1 in deg) are as follows (t = terminal, b = bridging): r(Ga⋯Ga) 254.9(2), r(Ga-Ht) 155.0(6), r(Ga-H b) 172.3(6), ∠Ga-Hb-Ga 95.4(5), and ∠H t-Ga-Ht 128.6(9). Scrutiny of the IR spectra of solid Ar matrices doped with the vapour above solid samples of gallane at temperatures in the range 190-220 K reveals the presence of not only Ga2H 6 as the major component, but also a significant fraction of the monomer GaH3. Analysis of the relative proportions of the two molecules evaporating from the solid at different temperatures has led to a first experimental estimate of 59 ± 16 kJ mol-1 for the enthalpy change associated with the reaction Ga2H6(g) → 2GaH3(g). Together with a value of 52 kJ mol-1 delivered by fresh calculations at the MP2 level, this implies that the stability of the dimer with respect to dissociation has been overrated by earlier theoretical treatments. © 2010 The Royal Society of Chemistry.

Original language	English
Pages (from-to)	5637-5642
Journal	Dalton Transactions
Volume	39
Issue number	24
DOIs	https://doi.org/10.1039/c000694g
Publication status	Published - 2010

Bibliographical note

Cited By (since 1996):3

Export Date: 1 October 2013

Source: Scopus

doi: 10.1039/c000694g

Language of Original Document: English

Correspondence Address: Downs, A. J.; Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom; email: [email protected]

References: Wiberg, E., Johannsen, T., (1941) Naturwissenschaften, 29, p. 320; Wiberg, E., Johannsen, T., (1942) Angew. Chem., 55, pp. 38-40; Wiberg, E., Johannsen, T., Stecher, O., (1943) Z. Anorg. Allg. Chem., 251, pp. 114-124; Wiberg, E., Schmidt, M., (1952) Z. Naturforsch., 7, p. 577; Downs, A.J., Goode, M.J., Pulham, C.R., (1989) J. Am. Chem. Soc., 111, pp. 1936-1937; Pulham, C.R., Downs, A.J., Goode, M.J., Rankin, D.W.H., Robertson, H.E., (1991) J. Am. Chem. Soc., 113, pp. 5149-5162; Souter, P.F., Andrews, L., Downs, A.J., Greene, T.M., Ma, B., Schaefer Iii, H.F., (1994) J. Phys. Chem., 98, pp. 12824-12827; Dyke, J.M., Haggerston, D., Warschkow, O., Andrews, L., Downs, A.J., Souter, P.F., (1996) J. Phys. Chem., 100, pp. 2998-3004; Downs, A.J., Pulham, C.R., (1994) Adv. Inorg. Chem., 41, pp. 171-232; Downs, A.J., Pulham, C.R., (1994) Chem. Soc. Rev., 23, pp. 175-184; Downs, A.J., (1999) Coord. Chem. Rev., 189, pp. 59-100; Aldridge, S., Downs, A.J., (2001) Chem. Rev., 101, pp. 3305-3365; Wang, X., Andrews, L., (2003) J. Phys. Chem. A, 107, pp. 11371-11379; Andrews, L., Wang, X., (2003) Science, 299, pp. 2049-2052; Wang, X., Andrews, L., Tam, S., Derose, M.E., Fajardo, M.E., (2003) J. Am. Chem. Soc., 125, pp. 9218-9228; Andrews, L., Wang, X., (2004) J. Phys. Chem. A, 108, pp. 4202-4210; Andrews, L., Wang, X., (2004) Angew. Chem., Int. Ed., 43, pp. 1706-1709; Wang, X., Andrews, L., (2004) J. Phys. Chem. A, 108, pp. 4440-4448; Wang, X., Andrews, L., (2004) J. Phys. Chem. A, 108, pp. 3396-3402; Hunt, P., Schwerdtfeger, P., (1996) Inorg. Chem., 35, pp. 2085-2088; Liang, C., Davy, R.D., Schaefer Iii, H.F., (1989) Chem. Phys. Lett., 159, pp. 393-398; Lammertsma, K., Leszczýnski, J., (1990) J. Phys. Chem., 94, pp. 2806-2809; Duke, B.J., (1990) Theochem, 208, pp. 197-204; Bock, C.W., Trachtman, M., Murphy, C., Muschert, B., Mains, G.J., (1991) J. Phys. Chem., 95, pp. 2339-2344; Barone, V., Adamo, C., Fliszár, S., Russo, N., (1994) Chem. Phys. Lett., 222, pp. 597-602; Barone, V., Orlandini, L., Adamo, C., (1994) J. Phys. Chem., 98, pp. 13185-13188; Shen, M., Schaefer Iii, H.F., (1992) J. Chem. Phys., 96, pp. 2868-2876; C. R. Pulham, A. J. Downs, E. Johnsen, S. Parsons and P. F. Souter, unpublished workTurley, J.W., Rinn, H.W., (1969) Inorg. Chem., 8, pp. 18-22; Downs, A.J., Greene, T.M., Johnsen, E., Brain, P.T., Morrison, C.A., Parsons, S., Pulham, C.R., Rice, D.A., (2001) Inorg. Chem., 40, pp. 3484-3497; Bastiansen, O., Trætteberg, M., (1960) Acta Crystallogr., 13, pp. 1108-1108; Breed, H., Bastiansen, O., Almenningen, A., (1960) Acta Crystallogr., 13, pp. 1108-1108; Morino, Y., (1960) Acta Crystallogr., 13, pp. 1107-1107; Sipachev, V.A., (1985) Theochem, 121, pp. 143-151; Sipachev, V.A., (1999) Advances in Molecular Structure Research, pp. 323-371. , ed. I. Hargittai and M. Hargittai, JAI Press, Greenwich; Blake, A.J., Brain, P.T., McNab, H., Miller, J., Morrison, C.A., Parsons, S., Rankin, D.W.H., Smart, B.A., (1996) J. Phys. Chem., 100, pp. 12280-12287; Brain, P.T., Morrison, C.A., Parsons, S., Rankin, D.W.H., (1996) J. Chem. Soc., Dalton Trans., pp. 4589-4596; Mitzel, N.W., Rankin, D.W.H., (2003) Dalton Trans., pp. 3650-3662; McCaffrey, P.D., Mawhorter, R.J., Turner, A.R., Brain, P.T., Rankin, D.W.H., (2007) J. Phys. Chem. A, 111, pp. 6103-6114; Pullumbi, P., Bouteiller, Y., Manceron, L., Mijoule, C., (1994) Chem. Phys., 185, pp. 25-37. , See, for example; Himmel, H.-J., Downs, A.J., Greene, T.M., Andrews, L., (2000) Organometallics, 19, pp. 1060-1070. , http://www.nsccs.ac.uk, National Service for Computational Chemistry Software (NSCCS). URL; Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Scalmani, G., Fox, D.J., (2009) Gaussian 09, Revision A.02, , Gaussian, Inc., Wallingford CT; Møller, C., Plesset, M.S., (1934) Phys. Rev., 46, pp. 618-622; Hehre, W.J., Ditchfield, R., Pople, J.A., (1972) J. Chem. Phys., 56, pp. 2257-2261; Hariharan, P.C., Pople, J.A., (1973) Theor. Chim. Acta, 28, pp. 213-222; Gordon, M.S., (1980) Chem. Phys. Lett., 76, pp. 163-168; Dunning Jr., T.H., (1989) J. Chem. Phys., 90, pp. 1007-1023; Boys, S.F., Bernardi, F., (1970) Mol. Phys., 19, pp. 553-566; Barone, V., (2004) J. Chem. Phys., 120, pp. 3059-3065; Barone, V., (2005) J. Chem. Phys., 122, pp. 014108/1-014108/10; Huntley, C.M., Laurenson, G.S., Rankin, D.W.H., (1980) J. Chem. Soc., Dalton Trans., pp. 954-957; Fleischer, H., Wann, D.A., Hinchley, S.L., Borisenko, K.B., Lewis, J.R., Mawhorter, R.J., Robertson, H.E., Rankin, D.W.H., (2005) Dalton Trans., pp. 3221-3228; Hinchley, S.L., Robertson, H.E., Borisenko, K.B., Turner, A.R., Johnston, B.F., Rankin, D.W.H., Ahmadian, M., Cowley, A.H., (2004) Dalton Trans., pp. 2469-2476; Ross, A.W., Fink, M., Hilderbrandt, R., (1992) International Tables for Crystallography, pp. 245-338. , ed. A. J. C. Wilson, Kluwer Academic Publishers, Dordrecht, The Netherlands, vol. C; Pulham, C.R., (1991), D.Phil. thesis, University of Oxford, and unpublished resultsKolb, J.R., Marks, T.J., (1977) Chem. Rev., 77, pp. 263-293; H.-J. Himmel, unpublished resultsUR - http://www.scopus.com/inward/record.url?eid=2-s2.0-77953319518&partnerID=40&md5=29de8b7488063fc36f45817f76e75ea1

Keywords

Enthalpy change
Gallanes
Gas-phase electron diffraction
Improved methods
IR spectrum
MP2 levels
Quantum chemical calculations
Solid samples
Theoretical treatments
Enthalpy
Quantum chemistry
Gallium

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10.1039/c000694g

http://pubs.rsc.org/en/Content/ArticleLanding/2010/DT/c000694g#!divAbstract

Cite this

@article{875cecb90a484b9f94c5af10a6cdbd6f,

title = "The digallane molecule, Ga2H6:: experimental update giving an improved structure and estimate of the enthalpy change for the reaction Ga2H6(g) → 2GaH3(g)",

abstract = "Improved methods of analysis and new quantum chemical calculations have been applied to the results of earlier gas-phase electron diffraction (GED) studies of digallane to give what is judged to be the most realistic structure available to date. The principal distances (ra3,1 in pm) and interbond angles (∠a3,1 in deg) are as follows (t = terminal, b = bridging): r(Ga⋯Ga) 254.9(2), r(Ga-Ht) 155.0(6), r(Ga-H b) 172.3(6), ∠Ga-Hb-Ga 95.4(5), and ∠H t-Ga-Ht 128.6(9). Scrutiny of the IR spectra of solid Ar matrices doped with the vapour above solid samples of gallane at temperatures in the range 190-220 K reveals the presence of not only Ga2H 6 as the major component, but also a significant fraction of the monomer GaH3. Analysis of the relative proportions of the two molecules evaporating from the solid at different temperatures has led to a first experimental estimate of 59 ± 16 kJ mol-1 for the enthalpy change associated with the reaction Ga2H6(g) → 2GaH3(g). Together with a value of 52 kJ mol-1 delivered by fresh calculations at the MP2 level, this implies that the stability of the dimer with respect to dissociation has been overrated by earlier theoretical treatments. {\textcopyright} 2010 The Royal Society of Chemistry.",

keywords = "Enthalpy change, Gallanes, Gas-phase electron diffraction, Improved methods, IR spectrum, MP2 levels, Quantum chemical calculations, Solid samples, Theoretical treatments, Enthalpy, Quantum chemistry, Gallium",

author = "A.J. Downs and T.M. Greene and E. Johnsen and C.R. Pulham and H.E. Robertson and D.A. Wann",

note = "Cited By (since 1996):3 Export Date: 1 October 2013 Source: Scopus doi: 10.1039/c000694g Language of Original Document: English Correspondence Address: Downs, A. J.; Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom; email: [email protected] References: Wiberg, E., Johannsen, T., (1941) Naturwissenschaften, 29, p. 320; Wiberg, E., Johannsen, T., (1942) Angew. Chem., 55, pp. 38-40; Wiberg, E., Johannsen, T., Stecher, O., (1943) Z. Anorg. Allg. Chem., 251, pp. 114-124; Wiberg, E., Schmidt, M., (1952) Z. Naturforsch., 7, p. 577; Downs, A.J., Goode, M.J., Pulham, C.R., (1989) J. Am. Chem. Soc., 111, pp. 1936-1937; Pulham, C.R., Downs, A.J., Goode, M.J., Rankin, D.W.H., Robertson, H.E., (1991) J. Am. Chem. Soc., 113, pp. 5149-5162; Souter, P.F., Andrews, L., Downs, A.J., Greene, T.M., Ma, B., Schaefer Iii, H.F., (1994) J. Phys. Chem., 98, pp. 12824-12827; Dyke, J.M., Haggerston, D., Warschkow, O., Andrews, L., Downs, A.J., Souter, P.F., (1996) J. Phys. Chem., 100, pp. 2998-3004; Downs, A.J., Pulham, C.R., (1994) Adv. Inorg. Chem., 41, pp. 171-232; Downs, A.J., Pulham, C.R., (1994) Chem. Soc. Rev., 23, pp. 175-184; Downs, A.J., (1999) Coord. Chem. Rev., 189, pp. 59-100; Aldridge, S., Downs, A.J., (2001) Chem. Rev., 101, pp. 3305-3365; Wang, X., Andrews, L., (2003) J. Phys. Chem. A, 107, pp. 11371-11379; Andrews, L., Wang, X., (2003) Science, 299, pp. 2049-2052; Wang, X., Andrews, L., Tam, S., Derose, M.E., Fajardo, M.E., (2003) J. Am. Chem. Soc., 125, pp. 9218-9228; Andrews, L., Wang, X., (2004) J. Phys. Chem. A, 108, pp. 4202-4210; Andrews, L., Wang, X., (2004) Angew. Chem., Int. Ed., 43, pp. 1706-1709; Wang, X., Andrews, L., (2004) J. Phys. Chem. A, 108, pp. 4440-4448; Wang, X., Andrews, L., (2004) J. Phys. Chem. A, 108, pp. 3396-3402; Hunt, P., Schwerdtfeger, P., (1996) Inorg. Chem., 35, pp. 2085-2088; Liang, C., Davy, R.D., Schaefer Iii, H.F., (1989) Chem. Phys. Lett., 159, pp. 393-398; Lammertsma, K., Leszcz{\'y}nski, J., (1990) J. Phys. Chem., 94, pp. 2806-2809; Duke, B.J., (1990) Theochem, 208, pp. 197-204; Bock, C.W., Trachtman, M., Murphy, C., Muschert, B., Mains, G.J., (1991) J. Phys. Chem., 95, pp. 2339-2344; Barone, V., Adamo, C., Flisz{\'a}r, S., Russo, N., (1994) Chem. Phys. Lett., 222, pp. 597-602; Barone, V., Orlandini, L., Adamo, C., (1994) J. Phys. Chem., 98, pp. 13185-13188; Shen, M., Schaefer Iii, H.F., (1992) J. Chem. Phys., 96, pp. 2868-2876; C. R. Pulham, A. J. Downs, E. Johnsen, S. Parsons and P. F. Souter, unpublished workTurley, J.W., Rinn, H.W., (1969) Inorg. Chem., 8, pp. 18-22; Downs, A.J., Greene, T.M., Johnsen, E., Brain, P.T., Morrison, C.A., Parsons, S., Pulham, C.R., Rice, D.A., (2001) Inorg. Chem., 40, pp. 3484-3497; Bastiansen, O., Tr{\ae}tteberg, M., (1960) Acta Crystallogr., 13, pp. 1108-1108; Breed, H., Bastiansen, O., Almenningen, A., (1960) Acta Crystallogr., 13, pp. 1108-1108; Morino, Y., (1960) Acta Crystallogr., 13, pp. 1107-1107; Sipachev, V.A., (1985) Theochem, 121, pp. 143-151; Sipachev, V.A., (1999) Advances in Molecular Structure Research, pp. 323-371. , ed. I. Hargittai and M. Hargittai, JAI Press, Greenwich; Blake, A.J., Brain, P.T., McNab, H., Miller, J., Morrison, C.A., Parsons, S., Rankin, D.W.H., Smart, B.A., (1996) J. Phys. Chem., 100, pp. 12280-12287; Brain, P.T., Morrison, C.A., Parsons, S., Rankin, D.W.H., (1996) J. Chem. Soc., Dalton Trans., pp. 4589-4596; Mitzel, N.W., Rankin, D.W.H., (2003) Dalton Trans., pp. 3650-3662; McCaffrey, P.D., Mawhorter, R.J., Turner, A.R., Brain, P.T., Rankin, D.W.H., (2007) J. Phys. Chem. A, 111, pp. 6103-6114; Pullumbi, P., Bouteiller, Y., Manceron, L., Mijoule, C., (1994) Chem. Phys., 185, pp. 25-37. , See, for example; Himmel, H.-J., Downs, A.J., Greene, T.M., Andrews, L., (2000) Organometallics, 19, pp. 1060-1070. , http://www.nsccs.ac.uk, National Service for Computational Chemistry Software (NSCCS). URL; Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Scalmani, G., Fox, D.J., (2009) Gaussian 09, Revision A.02, , Gaussian, Inc., Wallingford CT; M{\o}ller, C., Plesset, M.S., (1934) Phys. Rev., 46, pp. 618-622; Hehre, W.J., Ditchfield, R., Pople, J.A., (1972) J. Chem. Phys., 56, pp. 2257-2261; Hariharan, P.C., Pople, J.A., (1973) Theor. Chim. Acta, 28, pp. 213-222; Gordon, M.S., (1980) Chem. Phys. Lett., 76, pp. 163-168; Dunning Jr., T.H., (1989) J. Chem. Phys., 90, pp. 1007-1023; Boys, S.F., Bernardi, F., (1970) Mol. Phys., 19, pp. 553-566; Barone, V., (2004) J. Chem. Phys., 120, pp. 3059-3065; Barone, V., (2005) J. Chem. Phys., 122, pp. 014108/1-014108/10; Huntley, C.M., Laurenson, G.S., Rankin, D.W.H., (1980) J. Chem. Soc., Dalton Trans., pp. 954-957; Fleischer, H., Wann, D.A., Hinchley, S.L., Borisenko, K.B., Lewis, J.R., Mawhorter, R.J., Robertson, H.E., Rankin, D.W.H., (2005) Dalton Trans., pp. 3221-3228; Hinchley, S.L., Robertson, H.E., Borisenko, K.B., Turner, A.R., Johnston, B.F., Rankin, D.W.H., Ahmadian, M., Cowley, A.H., (2004) Dalton Trans., pp. 2469-2476; Ross, A.W., Fink, M., Hilderbrandt, R., (1992) International Tables for Crystallography, pp. 245-338. , ed. A. J. C. Wilson, Kluwer Academic Publishers, Dordrecht, The Netherlands, vol. C; Pulham, C.R., (1991), D.Phil. thesis, University of Oxford, and unpublished resultsKolb, J.R., Marks, T.J., (1977) Chem. Rev., 77, pp. 263-293; H.-J. Himmel, unpublished resultsUR - http://www.scopus.com/inward/record.url?eid=2-s2.0-77953319518&partnerID=40&md5=29de8b7488063fc36f45817f76e75ea1",

year = "2010",

doi = "10.1039/c000694g",

language = "English",

volume = "39",

pages = "5637--5642",

journal = "Dalton Transactions",

issn = "1477-9226",

publisher = "The Royal Society of Chemistry",

number = "24",

}

TY - JOUR

T1 - The digallane molecule, Ga2H6:

T2 - experimental update giving an improved structure and estimate of the enthalpy change for the reaction Ga2H6(g) → 2GaH3(g)

AU - Downs, A.J.

AU - Greene, T.M.

AU - Johnsen, E.

AU - Pulham, C.R.

AU - Robertson, H.E.

AU - Wann, D.A.

N1 - Cited By (since 1996):3 Export Date: 1 October 2013 Source: Scopus doi: 10.1039/c000694g Language of Original Document: English Correspondence Address: Downs, A. J.; Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom; email: [email protected] References: Wiberg, E., Johannsen, T., (1941) Naturwissenschaften, 29, p. 320; Wiberg, E., Johannsen, T., (1942) Angew. Chem., 55, pp. 38-40; Wiberg, E., Johannsen, T., Stecher, O., (1943) Z. Anorg. Allg. Chem., 251, pp. 114-124; Wiberg, E., Schmidt, M., (1952) Z. Naturforsch., 7, p. 577; Downs, A.J., Goode, M.J., Pulham, C.R., (1989) J. Am. Chem. Soc., 111, pp. 1936-1937; Pulham, C.R., Downs, A.J., Goode, M.J., Rankin, D.W.H., Robertson, H.E., (1991) J. Am. Chem. Soc., 113, pp. 5149-5162; Souter, P.F., Andrews, L., Downs, A.J., Greene, T.M., Ma, B., Schaefer Iii, H.F., (1994) J. Phys. Chem., 98, pp. 12824-12827; Dyke, J.M., Haggerston, D., Warschkow, O., Andrews, L., Downs, A.J., Souter, P.F., (1996) J. Phys. Chem., 100, pp. 2998-3004; Downs, A.J., Pulham, C.R., (1994) Adv. Inorg. Chem., 41, pp. 171-232; Downs, A.J., Pulham, C.R., (1994) Chem. Soc. Rev., 23, pp. 175-184; Downs, A.J., (1999) Coord. Chem. Rev., 189, pp. 59-100; Aldridge, S., Downs, A.J., (2001) Chem. Rev., 101, pp. 3305-3365; Wang, X., Andrews, L., (2003) J. Phys. Chem. A, 107, pp. 11371-11379; Andrews, L., Wang, X., (2003) Science, 299, pp. 2049-2052; Wang, X., Andrews, L., Tam, S., Derose, M.E., Fajardo, M.E., (2003) J. Am. Chem. Soc., 125, pp. 9218-9228; Andrews, L., Wang, X., (2004) J. Phys. Chem. A, 108, pp. 4202-4210; Andrews, L., Wang, X., (2004) Angew. Chem., Int. Ed., 43, pp. 1706-1709; Wang, X., Andrews, L., (2004) J. Phys. Chem. A, 108, pp. 4440-4448; Wang, X., Andrews, L., (2004) J. Phys. Chem. A, 108, pp. 3396-3402; Hunt, P., Schwerdtfeger, P., (1996) Inorg. Chem., 35, pp. 2085-2088; Liang, C., Davy, R.D., Schaefer Iii, H.F., (1989) Chem. Phys. Lett., 159, pp. 393-398; Lammertsma, K., Leszczýnski, J., (1990) J. Phys. Chem., 94, pp. 2806-2809; Duke, B.J., (1990) Theochem, 208, pp. 197-204; Bock, C.W., Trachtman, M., Murphy, C., Muschert, B., Mains, G.J., (1991) J. Phys. Chem., 95, pp. 2339-2344; Barone, V., Adamo, C., Fliszár, S., Russo, N., (1994) Chem. Phys. Lett., 222, pp. 597-602; Barone, V., Orlandini, L., Adamo, C., (1994) J. Phys. Chem., 98, pp. 13185-13188; Shen, M., Schaefer Iii, H.F., (1992) J. Chem. Phys., 96, pp. 2868-2876; C. R. Pulham, A. J. Downs, E. Johnsen, S. Parsons and P. F. Souter, unpublished workTurley, J.W., Rinn, H.W., (1969) Inorg. Chem., 8, pp. 18-22; Downs, A.J., Greene, T.M., Johnsen, E., Brain, P.T., Morrison, C.A., Parsons, S., Pulham, C.R., Rice, D.A., (2001) Inorg. Chem., 40, pp. 3484-3497; Bastiansen, O., Trætteberg, M., (1960) Acta Crystallogr., 13, pp. 1108-1108; Breed, H., Bastiansen, O., Almenningen, A., (1960) Acta Crystallogr., 13, pp. 1108-1108; Morino, Y., (1960) Acta Crystallogr., 13, pp. 1107-1107; Sipachev, V.A., (1985) Theochem, 121, pp. 143-151; Sipachev, V.A., (1999) Advances in Molecular Structure Research, pp. 323-371. , ed. I. Hargittai and M. Hargittai, JAI Press, Greenwich; Blake, A.J., Brain, P.T., McNab, H., Miller, J., Morrison, C.A., Parsons, S., Rankin, D.W.H., Smart, B.A., (1996) J. Phys. Chem., 100, pp. 12280-12287; Brain, P.T., Morrison, C.A., Parsons, S., Rankin, D.W.H., (1996) J. Chem. Soc., Dalton Trans., pp. 4589-4596; Mitzel, N.W., Rankin, D.W.H., (2003) Dalton Trans., pp. 3650-3662; McCaffrey, P.D., Mawhorter, R.J., Turner, A.R., Brain, P.T., Rankin, D.W.H., (2007) J. Phys. Chem. A, 111, pp. 6103-6114; Pullumbi, P., Bouteiller, Y., Manceron, L., Mijoule, C., (1994) Chem. Phys., 185, pp. 25-37. , See, for example; Himmel, H.-J., Downs, A.J., Greene, T.M., Andrews, L., (2000) Organometallics, 19, pp. 1060-1070. , http://www.nsccs.ac.uk, National Service for Computational Chemistry Software (NSCCS). URL; Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Scalmani, G., Fox, D.J., (2009) Gaussian 09, Revision A.02, , Gaussian, Inc., Wallingford CT; Møller, C., Plesset, M.S., (1934) Phys. Rev., 46, pp. 618-622; Hehre, W.J., Ditchfield, R., Pople, J.A., (1972) J. Chem. Phys., 56, pp. 2257-2261; Hariharan, P.C., Pople, J.A., (1973) Theor. Chim. Acta, 28, pp. 213-222; Gordon, M.S., (1980) Chem. Phys. Lett., 76, pp. 163-168; Dunning Jr., T.H., (1989) J. Chem. Phys., 90, pp. 1007-1023; Boys, S.F., Bernardi, F., (1970) Mol. Phys., 19, pp. 553-566; Barone, V., (2004) J. Chem. Phys., 120, pp. 3059-3065; Barone, V., (2005) J. Chem. Phys., 122, pp. 014108/1-014108/10; Huntley, C.M., Laurenson, G.S., Rankin, D.W.H., (1980) J. 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PY - 2010

Y1 - 2010

N2 - Improved methods of analysis and new quantum chemical calculations have been applied to the results of earlier gas-phase electron diffraction (GED) studies of digallane to give what is judged to be the most realistic structure available to date. The principal distances (ra3,1 in pm) and interbond angles (∠a3,1 in deg) are as follows (t = terminal, b = bridging): r(Ga⋯Ga) 254.9(2), r(Ga-Ht) 155.0(6), r(Ga-H b) 172.3(6), ∠Ga-Hb-Ga 95.4(5), and ∠H t-Ga-Ht 128.6(9). Scrutiny of the IR spectra of solid Ar matrices doped with the vapour above solid samples of gallane at temperatures in the range 190-220 K reveals the presence of not only Ga2H 6 as the major component, but also a significant fraction of the monomer GaH3. Analysis of the relative proportions of the two molecules evaporating from the solid at different temperatures has led to a first experimental estimate of 59 ± 16 kJ mol-1 for the enthalpy change associated with the reaction Ga2H6(g) → 2GaH3(g). Together with a value of 52 kJ mol-1 delivered by fresh calculations at the MP2 level, this implies that the stability of the dimer with respect to dissociation has been overrated by earlier theoretical treatments. © 2010 The Royal Society of Chemistry.

AB - Improved methods of analysis and new quantum chemical calculations have been applied to the results of earlier gas-phase electron diffraction (GED) studies of digallane to give what is judged to be the most realistic structure available to date. The principal distances (ra3,1 in pm) and interbond angles (∠a3,1 in deg) are as follows (t = terminal, b = bridging): r(Ga⋯Ga) 254.9(2), r(Ga-Ht) 155.0(6), r(Ga-H b) 172.3(6), ∠Ga-Hb-Ga 95.4(5), and ∠H t-Ga-Ht 128.6(9). Scrutiny of the IR spectra of solid Ar matrices doped with the vapour above solid samples of gallane at temperatures in the range 190-220 K reveals the presence of not only Ga2H 6 as the major component, but also a significant fraction of the monomer GaH3. Analysis of the relative proportions of the two molecules evaporating from the solid at different temperatures has led to a first experimental estimate of 59 ± 16 kJ mol-1 for the enthalpy change associated with the reaction Ga2H6(g) → 2GaH3(g). Together with a value of 52 kJ mol-1 delivered by fresh calculations at the MP2 level, this implies that the stability of the dimer with respect to dissociation has been overrated by earlier theoretical treatments. © 2010 The Royal Society of Chemistry.

KW - Enthalpy change

KW - Gallanes

KW - Gas-phase electron diffraction

KW - Improved methods

KW - IR spectrum

KW - MP2 levels

KW - Quantum chemical calculations

KW - Solid samples

KW - Theoretical treatments

KW - Enthalpy

KW - Quantum chemistry

KW - Gallium

U2 - 10.1039/c000694g

DO - 10.1039/c000694g

M3 - Article

SN - 1477-9226

VL - 39

SP - 5637

EP - 5642

JO - Dalton Transactions

JF - Dalton Transactions

IS - 24

ER -