Synthesis and Reactions of a Hybrid Tristibine Ligand

• Published in: Organometallics Vol. 32; no. 9; pp. 2760 - 2767
• Main Authors: Benjamin, Sophie L, Levason, William, Reid, Gillian
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 13.05.2013; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Inorganic & Nuclear; Chemistry, Organic; Physical Sciences; Science & Technology; ANIONS; COPPER(I); COORDINATION-NUMBER; SPECTROSCOPY; STIBINE; COMPLEXES; CHEMISTRY; METAL; IRON; CATION
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om400205d

The tripodal tristibine N(CH2-2-C6H4SbMe2)3 (L) has been prepared in high yield and characterized by 1H and 13C{1H} NMR spectroscopy and elemental analysis. A range of reactions with transition-metal acceptors were carried out to probe the coordinative properties of L. The 3/1 M/L complex [{FeCp(CO)2}3(L)-κSb:κSb′:κSb″][BF4]3 involves tridentate bridging coordination of L to three CpFe(CO)2 fragments. In [Mn(CO)3(L)][CF3SO3] the ligand adopts a tridentate chelating mode via a Sb3 donor set; treatment of this complex with Me3NO in MeCN solution gave crystals of [Mn(CO)2(L)(MeCN)][CF3SO3], which lost MeCN in vacuo, probably resulting in coordination of CF3SO3 – coordination of the [CF3SO3]− anion. [M(L)][BF4] (M = Ag, Cu) were also prepared. The reaction of L with CuBr leads to isolation of [Cu4Br4(L)2] in the solid state, which contains a Cu2Br4 core with a short central Cu···Cu distance, capped with Cu(L) units at each end. The transition-metal complexes of L were characterized by elemental analysis, ESI+ mass spectrometry, IR spectroscopy, and 1H, 13C{1H}, and (where appropriate) 55Mn or 63Cu NMR spectroscopy. Solid-state X-ray structures were determined for [Mn(CO)3(L)][CF3SO3], [Mn(CO)2(L)(MeCN)][CF3SO3], [Cu4Br4(L)2], and [Cu3Br2(L)2][BF4]. In each of these structures the chelating ligand adopts a twisted, propeller-like conformation. NMR spectroscopic analysis suggests that the ligand also adopts this rigid conformation in solution.