Hybrid Dibismuthines and Distibines: Preparation and Properties of Antimony and Bismuth Oxygen, Sulfur, and Nitrogen Donor Ligands

Abstract

The hybrid dibismuthines O{(CH2)2BiPh2}2, MeN(CH2-2-C6H4BiR2)2, and S(CH2-2-C6H4BiR2)2 (R = Me, Ph), have been prepared and characterized by microanalysis, 1H and 13C{1H} NMR spectroscopy, and FAB mass spectrometry. The X-ray structures of O{(CH2)2BiPh2}2 and S(CH2-2-C6H4BiPh2)2 show close to symmetrical hypervalent interactions between the O or S atoms and both bismuth centers. The antimony analogue S(CH2-2-C6H4SbMe2)2 is quaternized by MeI to [S(CH2-2-C6H4SbMe3)2]I2, which also shows a hypervalent S···Sb interaction, but in this case to only a single antimony center. Complexes of these and related ligands with the CpFe(CO)2 + group, of the type [{CpFe(CO)2}2L][BF4]2 (L = O{(CH2)2BiPh2}2, MeN(CH2-2-C6H4BiR2)2, S(CH2-2-C6H4BiR2)2, O{(CH2)2SbR2}2, S(CH2-2-C6H4SbMe2)2, MeN(CH2-2-C6H4SbMe2)2, Ph2Sb(CH2)3SbPh2), have been prepared and characterized by microanalysis (antimony complexes only), 1H and 13C{1H} NMR and IR spectroscopy, and ES+ mass spectrometry. The X-ray crystal structure of [{CpFe(CO)2}2{O{(CH2)2SbMe2}2}][BF4]2 shows a hypervalent Sb···O contact to one of the antimony centers, whereas no hypervalent contacts are seen in the structure of [{CpFe(CO)2}2{MeN(CH2-2-C6H4SbMe2)2}][BF4]2. IR (carbonyl region) and NMR spectroscopy indicate that, uniquely, [{CpFe(CO)2}2{MeN(CH2-2-C6H4BiPh2)2}][BF4]2 shows hypervalent N···Bi interactions in both the solid and solution, but for the other dibismuthine complexes, there is evidence for inequivalence of the iron centers (and hence hypervalency) only in the solid state. Spectroscopic data indicate that hypervalent interactions are absent in [{CpFe(CO)2}2{MeN(CH2-2-C6H4SbMe2)2}][BF4]2 and [{CpFe(CO)2}2{S(CH2-2-C6H4SbMe2)2}][BF4]2, but present in solid [{CpFe(CO)2}2{O{(CH2)2SbR2}2}][BF4]2. The preparation and X-ray structure of [CpFe(CO)2{BiPh2(o-C6H4OMe)}][BF4] is also reported, but attempts to isolate [CpFe(CO)2(BiPhMe2)]][BF4] resulted in rapid scrambling of the substituents at bismuth to give [CpFe(CO)2(BiPh3−n Me n )][BF4] (n = 0−3).

Neutral organoantimony(III) and organobismuth(III) ligands as acceptors in transition metal complexes – Role of substituents and co-ligands

“…suggesting that the interaction is retained in solution (Table 2). 21 Without structural information it is difficult to probe these interactions fully, although on the basis of the spectroscopic data available, it seems probable that they are equally, if not more, prevalent in these dibismuthine complexes as compared with complexes of the analogous distibines. …”

“…19,20,21 These were originally of interest as ligands which could present a mixed donor set to a transition metal fragment, allowing examination of stibine coordination within a more robust, chelating ligand framework. As part of this work, complexes with low-valent metal carbonyls were pursued as appropriate acceptors for the soft stibine donors.…”

Lewis base complexes of methyldihalobismuthines BiMeX2 (X = Cl or Br)

“…Methylhalobismuthines can be prepared by comproportionation of BiMe 3 and BiX 3 (X ¼ Cl, Br or I), by cleavage of Ph groups from BiPh 3-n Me n (n ¼ 1 or 2) with HX (X ¼ Cl or Br), or by reaction of BiX 3 with a stoichiometric amount of MeLi at low temperatures [10,12,15,16]. We have found the last of these to be most effective in this work (Section 3).…”

“…In our recent work we have reported several bismuth-containing polydentate ligands and their complexes with [CpFe(CO) 2 ] þ and Group 6 and 7 metal carbonyls [12,13]. During this study we prepared several methylhalobismuthines, BiMeX 2 and BiMe 2 X (X ¼ Cl or Br) as synthons for the introduction of Bi-containing donor groups into the ligands.…”

Synthesis, Structure and Applications of Hypervalent Organoantimony Compounds Having Intramolecular E→Sb (E = N, O, S) Coordinations

“…The structure, reactivity, and property of this kind of compounds have been widely investigated both experimentally and theoretically [29][30][31][32][33]. The outcome enables us to know more about the nature of hypervalent organoantimony compounds, especially those with intramolecular N, O, S Sb coordinations [34][35][36][37][38][39]. In the monograph edited by Akiba in 1999 on hypervalent compounds, the static and dynamic structures of hypervalent Sb (III) halides were only briefly presented (by Yamada and Okuda) [33].…”