¹¹⁹Sn NMR Spectroscopy of Some Iron-Tin Compounds – First Measurements of One-Bond Coupling Constants ¹J(¹¹⁹Sn⁵⁷Fe), Geminal Coupling Constants ²J(¹¹⁹SnFe¹¹⁹Sn) and the Dependence of ¹¹⁹Sn Chemical Shifts on the Nature of the Sn–Fe Bond

Abstract

Carbonyliron-Tin Complexes, 119Sn N M R , Coupling ConstantsCarbonyliron tin complexes CpFe(CO )2-S n M e 3 (1), a5-(CO)4Fe(SnM e3)2 (2), cis-(CO)4Fe(SnM e2Cl)2 (3), [R2SnFe(CO)4]2 (4a, R = Me; 4b, R = Bu), {Me2Sn[Fe(CO)4]2}2Sn (5), Me2Sn[Fe(CO)4]2Sn[Fe(CO)4]2 (6) and Sn[Fe(CO)4]4 (7) were studied by ll9Sn N M R . It proved possible for the first time to observe coupling constants './(119Sn57Fe) in the range of 36 to 64 Hz. The large magnitude of geminal coupling constants 12/ ( 119SnFell9Sn)| (1400 to 1800 Hz) in the cyclic com pounds 4 to 6 indicates the presence of tin-tin interactions as an efficient coupling pathway. Extreme deshielding o f 119Sn nuclei in the complexes 6 (<5u9Sn + 953) and 7 (<5119Sn + 1532) is associated with three-centre FeSnFe bonds in these compounds.Carbonyliron complexes containing F e -S n bonds are readily available by various synthetic methods [1], The reaction of Fe(CO)5 with organotin compounds appears to be particularly conven ient, since the product distribution depends criti cally on the reaction conditions. In the case of methyltin compounds, major products (4, 5, 7) which could be crystallized were finally character ized by X-ray analysis [2], Although these results appear to be conclusive, there is some doubt about the correct assessment of all major species present in the reaction solution. We have now repeated some of the reactions between organotin com pounds and Fe(CO)5 and have applied 119Sn NM R in order to get more information on the composi tion of the reaction solutions. Furthermore, we wanted to determine one-bond coupling constants '7(119Sn57Fe) and to compare the magnitude of geminal coupling constants 2/ ( 119Sn119Sn) across Fe in non-cyclic and cyclic compounds. For these purposes we have studied compounds 1 to 7. Results and DiscussionWith the exception of compounds 3 and 6, all complexes were prepared following known proce-* Reprint requests to Prof. Dr. Bernd Wrackmeyer.Verlag der Zeitschrift für Naturforschung, D-W -7400 Tübingen 0 9 3 2 -0 7 7 6 /9 2 /1 2 0 0 -1 7 4 9 /$ 01.00/0 Cp Fe(CO)2-SnMe3

Synthesis, Characterization, and Electronic Structures of a Series of Two-Dimensional Trimetallic Cluster Complexes, Ru3(CO)9(μ-SnPh2)3[Pt(PBut3)]x, x = 0−3

“…When they are bonded to two metal atoms they are much more shielded, ca. 85−125 ppm, but in 13 the metal atoms are also mutually bonded.

1 An ORTEP diagram of the molecular structure of Ru 3 (CO) 9 (μ-SnPh 2 ) 3 , 13 , showing 40% probability thermal ellipsoids.

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Indirect nuclear 57Fe13C and 57Fe1H spin–spin coupling in ferrocenes and cyclopentadienyliron complexes: measurements and DFT calculations

“…1 If X is a highly abundant nucleus and/or the magnitude of J 57 Fe,X is fairly large (e.g. X D 1 H, 1,2 31 P, 1 -3 119 Sn 4 or 207 Pb 5 ), values for J 57 Fe,X can be measured from the X NMR spectra. This is also possible for rare spin- 1 2 nuclei such as 13 C, 1,3a,6 -9 15 N 10 or 29 Si, 11 if the conditions for the measurement of the X NMR spectra are optimized.…”