Trigonal Bipyramidal M2Ch32- (M = Sn, Pb; Ch = S, Se, Te) and TlMTe33- Anions: Multinuclear Magnetic Resonance, Raman Spect

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• 作者：Horst Borrmann ; Janette Campbell ; David A. Dixon ; Hé ; lè ; ne P. A. Mercier ; Ayaaz M. Pirani ; and Gary J. Schrobilgen
• 刊名：Inorganic Chemistry
• 出版年：1998
• 出版时间：December 28, 1998
• 年：1998
• 卷：37
• 期：26
• 页码：6656 - 6674
• 全文大小：368K
• 年卷期：v.37,no.26(December 28, 1998)
• ISSN：1520-510X

文摘

The series of group 14 metal trigonal bipyramidal anions has been extended to the mixed group 13/group 14metal TlMTe₃^3- anions (M = Sn, Pb), obtained by the reaction of Tl₂M₂Te₃ and K₂Te in en or in en/ethylaminemixtures and a stoichiometric excess of 2,2,2-crypt with respect to K⁺. The thallium anions were characterizedin solution by ¹¹⁹Sn, ²⁰⁵Tl, ²⁰⁷Pb, and ¹²⁵Te NMR spectroscopy. The small magnitudes of the relativistically correctedreduced coupling constants, ¹(K_M-Ch)_RC and ¹(K_Tl-Ch)_RC, observed for the previously reported M₂Ch₃^2- (Ch =Se, Te) and the TlMTe₃^3- anions are consistent with predominantly p-bonded cages, and this observation issupported by local and nonlocal density functional theory (DFT) calculations. Theory indicates M-M and Tl-Minteractions of high s character corresponding to Mayer bond orders of 0.13-0.32. The (K_M-M)_RC and (K_Tl-M)_RCcouplings are unusually large compared to those of the butterfly-shaped Tl₂Ch₂^2- anions and likely arise fromhigher M-M and Tl-M bond orders, a larger number of coupling pathways, and smaller M-Ch-M and M-Ch-Tl bond angles. The TlPbTe₃^3- anion has also been structurally characterized by X-ray crystallography in (2,2,2-crypt-K⁺)₃TlPbTe₃^3-·2en [monoclinic system, space group P2₁/c, Z = 4, a = 15.256(5) Å, b = 26.087(9) Å, c= 20.984(8) Å, and mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> = 93.03(3)mages/entities/deg.gif">] along with Pb₂Ch₃^2- (Ch = S, Se) in (2,2,2-crypt-K⁺)₂Pb₂Ch₃^2-·0.5en [Pb₂S₃^2-: triclinic system, space group Pmages/entities/onemacr.gif">, Z = 2, a = 10.189(2) Å, b = 11.329(2) Å, c = 23.194(4) Å, mages/gifchars/alpha.gif" BORDER=0> = 95.439(14)mages/entities/deg.gif">,mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> = 92.562(14)mages/entities/deg.gif">, and mages/gifchars/gamma.gif" BORDER=0 > = 90.549(14)mages/entities/deg.gif">; Pb₂Se₃^2-: triclinic system, space group Pmages/entities/onemacr.gif">, Z = 2, a = 10.187(2) Å, b= 11.403(2) Å, c = 23.360(6) Å, mages/gifchars/alpha.gif" BORDER=0> = 95.26(2)mages/entities/deg.gif">, mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> = 92.17(2)mages/entities/deg.gif">, and mages/gifchars/gamma.gif" BORDER=0 > = 90.89(2)mages/entities/deg.gif">]. Density functional theorycalculations show that the experimental structures for the M₂Ch₃^2- and TlPbTe₃^3- anions are true minima andreproduce the experimental bond distances and angles. The vibrational frequencies determined by DFT calculationsare in good agreement with those determined by Raman spectroscopy and have been used in their assignment.