Chiral nanoporous metal-organic coordination network (MOCN) materials have emerged as an active area of research in the field of coordination polymerization. Such materials have great potential as tunable heterogeneous asymmetric catalysts. A key feature of MOCN materials is that considerable structural predictive ability exists over traditional solid-state inorganic compounds in their design. Current work on the synthesis and characterization of a unique class of covalent early transition metal aryloxide network compounds will be presented. In addition, the diverse network architectures obtained based on different 4,4'-bisphenoxide bridging ligands will be discussed. The reaction of Ti(OR)4 (R = isopropyl, S-(+)-2-butyl) with a dihydroxy functionalized organic spacer (4,4'-biphenol, bis(4-hydroxyphenyl)sulfide) in various solvents (benzene, tetrahydrofuran, and pyridine) at 130˚ C affords microcrystalline materials which have been characterized by single crystal X-ray diffraction. These include a homochiral three-dimensional coordination polymer, {[Ti(OC6H4C6H4O)1.5(O-(S)-(+)-2-Bu)(HO-(S)-(+)-2-Bu)]2}n, a one-dimensional chain, [Ti(OC6H4SC6H4O)2(py)2]n, a two-dimensional sheet {[Ti(OC6H4SC6H4O)2(THF)]2}n and a three-dimensional network {[Ti(OC6H4SC6H4O)2]2}n. In order to probe how the structural features of the dihydroxy spacer ligand precursors may affect MOCN structure, the X-ray structures of Bisphenol-A (4,4'-isopropylidenediphenol) and three of its derivatives have been determined. The results show that the Caryl-E-Caryl angle (where E = S, 104.21(4)º; C(CH3)2, 108.9(7)º; CH2, 114.85(7)º; O, 118.8(1)º) may be integral in controlling network dimensionality and topology in metal-aryloxide networks obtained from derivatives of Bisphenol-A.
Back to Organic 2
Back to The 34th Northeast Regional Meeting (October 5-7 2006)