6533b7d4fe1ef96bd126274e

RESEARCH PRODUCT

Synthesis and spectroscopic studies (Mo¨ssbauer, IR and NMR) of [R2SnCl2bipym] (R = butyl or phenyl) and the crystal and molecular structure of [Ph2SnCl2bipym]

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Abstract The complexes [R 2 SnCl 2 bipym] (R = phenyl or butyl, bipym = 2,2′,6,6′-bipyrimidine) were synthesized and studied in solution by 1 H- and 13 C-NMR spectroscopy and in the solid state by IR and Mo¨ssbauer spectroscopy. The latter was also performed in frozen ethanolic solution. The structure of the phenyl complex was determined by single crystal diffraction methods. The value obtained for the angle C-SN-C in the phenyl compound is 169.3(2)° (X-ray) and 151° (Mo¨ssbauer), but the assignment of an octahedral configuration by Mo¨ssbauer spectroscopy is consistent with the structure determined by diffraction. The butyl complex is also octahedral and the two techniques show better agreement. The value of the C-SN- C angle is 171° (Mo¨ssbauer in the solid state), 163° (Mo¨ssbauer in frozen solution) and 175.1(6)° (X-ray). The NMR coupling constant, 1 J ( 119 Sn- 13 C), was also used to estimate the C-SN-C angle. The 13 C-NMR spectrum for the butyl complex is markedly concentration-dependent. At the highest concentration, this angle is 138° (Lockhart) and 145° (Holecˇek); for less concentrated samples the angle tends to decrease. This suggests that the coordination number of tin in solution is less than six.