Structural and spectral studies of diorganotin(IV) complexes containing bis-tridentate N,N-bis(4-oxo-4-phenylbutan-2-ylidene)oxalohydrazide ligand

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• 作者：Dilip Kumar Dey ; Sankar Prasad Dey ; Nirmal Kumar Karan ; Antonin Ly膷ka ; Georgina M. Rosair
• 关键词：Diorganotin(IV) complex ; Bis-tridentate Schiff base ; 119Sn NMR ; H ; C-COSY ; gs-HMQC ; gs-HMBC
• 刊名：Journal of Organometallic Chemistry
• 出版年：1 January, 2014
• 年：2014
• 卷：749
• 期：Complete
• 页码：320-326
• 全文大小：536 K

文摘

Three new symmetrical binuclear diorganotin(IV) complexes with the symmetrical bis-tridentate Schiff base, N,N-bis(4-oxo-4-phenylbutan-2-ylidene)oxalohydrazide, (R₂Sn)₂[Ph-C(O)CH-C(Me)N-NC(O)-C(O)N-NC(Me)-CHC(O)鈭扨h] (R聽=聽Ph: Ia; R聽=聽Me: Ib; R聽=聽n-Bu: Ic) have been synthesized by reaction with corresponding diorganotin(IV) dichloride at room temperature in methanol in presence of triethylamine. The complexes have been characterized by elemental analyses, IR, ¹H, ¹³C, ¹⁵N and ¹¹⁹Sn NMR spectroscopy. Two dimensional H,H-COSY, NOESY, H,C-COSY, gs(gradient selected)-HMQC and gs-HMBC techniques were applied in order to assign proton and carbon chemical shifts unambiguously. The 未(¹¹⁹Sn) values for the complexes Ia-Ic are聽鈭?20.1,聽鈭?81.9 and聽鈭?50.7聽ppm respectively, indicating pentacoordinated tin centres. The C-Sn-C angles calculated from ¹J(¹¹⁹Sn, ¹³C) for Ia, 1b and Ic are found to be 135.6掳, 133.85掳 and 135.0掳 respectively. From the ²J(¹¹⁹Sn, ¹H) value, the Me-Sn-Me angle for Ib is found to be 130.46掳. From NMR spectra a distorted trigonal-bipyramidal geometry at each tin centre is proposed. The structures of the complexes have been confirmed by single crystal X-ray diffraction analysis of one representative compound Ia. The ligand, N,N-bis(4-oxo-4-phenylbutan-2-ylidene)oxalohydrazide (H₄L) coordinates to the metal centre in enolate form via the phenolic O, imino N and enolic O atoms. The X-ray structure indicates that the coordination geometry of tin atoms are intermediate between trigonal bipyramid and a square pyramid. The oxygen atoms are in axial positions while the imino nitrogen atom of the ligand and two phenyl groups occupy the equatorial sites.