Synthesis of bismuth and antimony complexes of the “larger” calix[n]arenes (n = 6–8); from mononuclear to tetranuclear complexes

Abstract

A series of calix[n]arene (n=6-8) bismuth and antimony complexes were synthesized and fully characterized by NMR, X-ray, IR, UV-Vis and elemental analysis. The monobismuth calix[6]arene complex [Bi{tBuC6(H)3}]2 1 was prepared by the reaction of para-tert-butylcalix[6]arene (tBuC6(H)6) with one equivalent of Bi[N(SiMe3)2]3. Complex 1 featured a Bi2(micro-O)2 central core similar to other bismuth calixarene complexes prepared by our group. Reaction of calix[6]arene (HC6(H)6) with two equivalents of Bi(OtBu)3 yielded different outcomes depending on the reaction solvent. If THF was used, complex [Bi{HC6(H)3}] 2 was obtained in 72% yield; however, when toluene was used, complexes 2 and [Bi2{HC6}] 3 were isolated in 23 and 57% yields, respectively. Mononuclear complexes 1 and 2 displayed dimeric structures in the solid state with cone-like conformations for the calixarene ligands. The 1H NMR spectrum of complex 2 displays patterns for an asymmetric structure with two signals in a 2:1 ratio for the unreacted OH groups. Treatment of calix[6]arenes RC6(H)6 (R=H, tBu) with two equivalents of SbR3 (R=OtBu, NMe2) produced dinuclear complexes [Sb2{HC6}] 4, and [Sb2{tBuC6}] 5, respectively. The 1H NMR spectra for the dinuclear complexes 3, 4, and 5 showed the characteristic calixarene pattern for a 1,2,3-alternate conformer. In the process of recrystallization of complex 4 an unexpected trimetallic complex with composition [Sb3O2{HC6(H)}] 4a was obtained in low yield. Treatment of para-tert-butylcalix[7]arene (tBuC7(H)7) with two equivalents of Bi(OtBu)3 produced the bimetallic complex [Bi2O{tBuC7(H)3}]2 6. Complex 6 contains an overall Bi4O2(OAr)8 core system with a structural resemblance to other bimetallic bismuth calixarene complexes reported by our group. The larger para-benzylcalix[8]arene (BnC8(H)8) and calix[8]arene (HC8(H)8) reacted with excess Bi(OtBu)3 to produce the tetranuclear complexes [Bi4O2{HC8}] 7 and [Bi4O2{BnC8}] 8, respectively. The solid state structure of complex 8 featured a dimeric unit with the calixarene ligands in pinched-cone conformation and displaying an overall Bi8O4(OAr)16.H2O core. No metal pi-arene interactions were observed.

Heterobimetallic Bismuth(III)/Molybdenum(VI) and Antimony(III)/Molybdenum(VI) Calix[5]arene Complexes. Progress toward Modeling the SOHIO Catalyst

“…16,[26][27][28] All the Bi-OAr and Bi-Bi bond distances, and O-Bi-O and Bi-O-Bi angles, fall in the normal ranges for Bi III calixarene complexes. 16,[26][27][28] There are two types of Mo VI centers within the core structure of 1. The Mo(1) and Mo (2) Each calixarene ring in complex 1 contains an OH proton that could not be located on the crystal structure density map.…”

Anionic Bismuth Oxido Clusters with Pendant Silver Cations: Synthesis and Structures of {[Bi4(µ3‐O)2(TFA)9Ag(tol)2]2} and {Bi4(µ3‐O)2(TFA)10(AgPPh3)2}n

“…Compound 1 consists of discrete, nonpolymeric molecules and is one of only a handful of Bi 8 clusters. It is also the first discrete molecule to feature the edge‐on combination of two Bi 4 (µ 3 ‐O) 2 units , . A distinction is made between hinge and wingtip core bismuth atoms for structural clarification, as seen in Figure .…”

“…It is also the first discrete molecule to feature the edge-on combination of two Bi 4 (μ 3 -O) 2 units. [27,[37][38][39] A distinction is made between hinge and wingtip core bismuth atoms for structural clarification, as seen in Figure 2. Compound 2 may also be viewed as built from Bi 4 (μ 3 -O) 2 units, but in this case the array is polymeric with Bi 4 (μ 3 -O) 2 (TFA) 10 {Ag(PPh 3 )} 2 subunits ( Figure 3).…”

Bismuth(iii) complexes derived from α-amino acids: the impact of hydrolysis and oxido-cluster formation on their activity against Helicobacter pylori

“…In addition to having been effective in the formation of bismuth(III) amino-arenesulfonates, it has also been used successfully for the synthesis of a variety of bismuth(III) compounds such as silanolates, 37-40 aminetris( phenoxides), 41 calixarenes, [42][43][44] allyloxides, 45 and sulfabenzimides. Unlike BiPh 3 , however, it is air and moisture sensitive and is not so easily handled.…”