TY - JOUR
T1 - The crystal structure and variable temperature 119mSn Mössbauer study of trimethyltin glycinate, a one-dimensional, amino-bridged polymer
AU - Ho, B. Y.K.
AU - Molloy, K. C.
AU - Zucker, J. J.
AU - Reidinger, F.
AU - Zubieta, J. A.
N1 - Funding Information:
Our work is supported by the Office of Naval Research and the National Science Foundation under Grant CHE-7326584. We thank M & T Chemicals, Inc. for the donation of organotin starting materials, Mr. G.A. Bksi for help withthecomputations,ProfessorR.E.Fkechforhelpwithrecordingthe Raman spectra, and Professors H. Chessin of the State University of New York at Albany and D. van der Helm of the University of Oklahoma for helpful discussions.
PY - 1980/3/18
Y1 - 1980/3/18
N2 - The crystal structure of trimethyltin glycinate has been determined by Patterson and Fourier techniques to a final "R"-factor of 0.066 for 1103 unique reflections. The crystals are tetragonal with space group P41with a = b = 7.839(9) and c = 14.659(11) Å, Z = 4, and are composed of stacks of linearly polymeric trimethyltin glycinate molecules bridled axially at tin through the amino nitrogen atoms of the amino acid. There is hydrogen bonding between carbonyl oxygen and amino group NH moieties along the chains and between the chains to produce a perpendicular weave of one-dimensional polymer threads. The axial NSnO connections make an angle approaching linearity, but the tin atom is distinctly displaced toward the oxygen to give non-planar SnC3 units which are eclipsed in the {A figure is presented} chain. This bridging rather than chelated amino acid configuration is only found in glycinatosilver(I) hemihydrate. Tin-119m Mössbauer resonance area data have been collected in the temperature range 77 ≤ T ≤ 185 K, and a logarithmic plot of the normalized area vs. temperature is linear in this range and the slope of -1.15 x 10-2 K-1 yields values of the logarithmic tempemture coefficient of the recoil-free fraction (which at 296 is less than a tenth of its value at 77 K). These data have been used to evaluate the isotropic mean-square amplitudes of vibration <χiso(T)2> of the tin atom, normalized to the value at 296 K available from the crystallographic study, in the same temperature range. Isotropic-mean-square values of the vibrational amplitude increase from 1.78 x 10-2 at 77 to 2.63 x 10-2 at 185 and 3.5 x 10-2 at 296 K. From the doublet line asymmetry data assuming that the electric field gradient tensor, Vzz, is positive in sign and lies along the polymer axis (oblate field about the cylindrical axis), it is concluded that the tin atom vibrates with greater amplitude normal to the propagating axis (<χ2⊥> = 1.93 x 10-2 at 77 and 3.11 x 10-2 Å2 at 185 K) than along it (<χ2∥> = 1.48 x 10-2 at 77 and 1.67 x 10-2 Å2 at 185 K). The temperature coefficient of the motion normal to the axis is also greater over the range examined. The differrence in the mean-square amplitudes perpendicular and parallel to the axis 2.96 x 10-2 from the Mössbauer treatment and 4.24 x 10-2 Å2 from the X-ray anisotropic thermal ellipsoids at 296 K.
AB - The crystal structure of trimethyltin glycinate has been determined by Patterson and Fourier techniques to a final "R"-factor of 0.066 for 1103 unique reflections. The crystals are tetragonal with space group P41with a = b = 7.839(9) and c = 14.659(11) Å, Z = 4, and are composed of stacks of linearly polymeric trimethyltin glycinate molecules bridled axially at tin through the amino nitrogen atoms of the amino acid. There is hydrogen bonding between carbonyl oxygen and amino group NH moieties along the chains and between the chains to produce a perpendicular weave of one-dimensional polymer threads. The axial NSnO connections make an angle approaching linearity, but the tin atom is distinctly displaced toward the oxygen to give non-planar SnC3 units which are eclipsed in the {A figure is presented} chain. This bridging rather than chelated amino acid configuration is only found in glycinatosilver(I) hemihydrate. Tin-119m Mössbauer resonance area data have been collected in the temperature range 77 ≤ T ≤ 185 K, and a logarithmic plot of the normalized area vs. temperature is linear in this range and the slope of -1.15 x 10-2 K-1 yields values of the logarithmic tempemture coefficient of the recoil-free fraction (which at 296 is less than a tenth of its value at 77 K). These data have been used to evaluate the isotropic mean-square amplitudes of vibration <χiso(T)2> of the tin atom, normalized to the value at 296 K available from the crystallographic study, in the same temperature range. Isotropic-mean-square values of the vibrational amplitude increase from 1.78 x 10-2 at 77 to 2.63 x 10-2 at 185 and 3.5 x 10-2 at 296 K. From the doublet line asymmetry data assuming that the electric field gradient tensor, Vzz, is positive in sign and lies along the polymer axis (oblate field about the cylindrical axis), it is concluded that the tin atom vibrates with greater amplitude normal to the propagating axis (<χ2⊥> = 1.93 x 10-2 at 77 and 3.11 x 10-2 Å2 at 185 K) than along it (<χ2∥> = 1.48 x 10-2 at 77 and 1.67 x 10-2 Å2 at 185 K). The temperature coefficient of the motion normal to the axis is also greater over the range examined. The differrence in the mean-square amplitudes perpendicular and parallel to the axis 2.96 x 10-2 from the Mössbauer treatment and 4.24 x 10-2 Å2 from the X-ray anisotropic thermal ellipsoids at 296 K.
UR - http://www.scopus.com/inward/record.url?scp=0001083750&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0001083750&partnerID=8YFLogxK
U2 - 10.1016/S0022-328X(00)81790-8
DO - 10.1016/S0022-328X(00)81790-8
M3 - Article
AN - SCOPUS:0001083750
SN - 0022-328X
VL - 187
SP - 213
EP - 226
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
IS - 2
ER -