title: Hierarchical assembly of discrete copper(II) metallo-structures from pre-assembled dinuclear (bis-β-diketonato)metallocycles and flexible difunctional co-ligands.
abstract: The sequential interaction of preformed [Cu2(L1)2(THF)2] (where H2L1 is 1,1-(1,3-phenylene)-bis(4,4-dimethylpentane-1,3-dione incorporating a 1,3-phenylene linker between its two β-diketone domains) and [Cu2(L4)2]·2H2O (where H2L4 is 1,1-(4,4′-oxybiphenylene)-bis(4,4-dimethylpentane-1,3-dione) incorporating a flexible oxybiphenylene linkage between the two β-diketone groups) with the potentially difunctional aliphatic non-planar co-ligands, N-methylpiperazine (mpip), N,N′-dimethylpiperazine (dmpip) and 1,4-thiomorpholine (thiomorph) is reported. A series of extended molecular assemblies exhibiting a range of di- and tetranuclear assemblies were obtained and their X-ray structures determined. Dinuclear [Cu2(L1)2(mpip)2]·2mpip incorporates two 5-coordinate, square pyramidal metal centres as does tetranuclear [{Cu2(L1)2}2(dmpip)2]·2dmpip. In contrast, dinuclear [Cu2(L1)2(dmpip)4]·dmpip and [{Cu2(L1)2}2(thiomorph)4]·3thiomorph each contain two 5-coordinate and two 6-coordinate centres. Each of [Cu2(L4)2(THF)2]·2THF and Cu2(L4)2(mpip)2]·H2O incorporate only 5-coordinate metal centres, with the latter complex forming a one-dimensional hydrogen bonded ribbon-like structure directed along the crystallographic a-axis. In keeping with the documented tendency for the smallest, least strained assembly to form in supramolecular self-assembly processes, the incorporation of the flexible “oxy” linkage between the 4,4′-linked phenylene rings of H2L3 results in generation of a dinuclear [Cu2L2] species rather than a trinuclear (triangular) [Cu3L3] species of the type formed by the more rigid bis-β-diketonato ligand analogue in which the biphenylene rings separating the β-diketone domains are directly coupled in their 4,4′ positions.
authors: School of Chemistry, F11, The University of Sydney, NSW 2006, Australia. l.lindoy@chem.usyd.edu.au.
authors: Jack K
authors: JK
authors: Clegg
authors: Feng
authors: F
authors: Li
authors: Katrina A
authors: KA
authors: Jolliffe
authors: Leonard F
authors: LF
authors: Lindoy
authors: George V
authors: GV
authors: Meehan
authors: Simon
authors: S
authors: Parsons
authors: Peter A
authors: PA
authors: Tasker
authors: Fraser J
authors: FJ
authors: White