Synthesis, Structural Characterization, and Host–Guest Studies of Aminoquinonato-Bridged Re(I) Supramolecular Rectangles

Aminoquinonato bridged Re­(I)-based metallarectangles have been constructed via an orthogonal bonding approach. Self-assembly of Re2(CO)10 and aminoquinone ligands in the presence of ditopic linear pyridyl ligands has resulted in the formation of metallarectangles of the general formula [{(CO)3Re­(μ-η4-L)­Re­(CO)3}2­(μ-N-L′-N)2] (1–4), wherein 1, L = 2,5-bis­(n-butylamino)-1,4-benzoquinonato (bbbq) and N-L′-N = 4,4′-bipyridine (bpy); 2, L = 2,5-bis­(phenethylamino)-1,4-benzoquinonato (bpbq) and N-L′-N = 4,4′-bipyridine; 3, L = 2,5-bis­(n-butylamino)-1,4-benzoquinonato (bbbq) and N-L′-N = trans-1,2-bis­(4-pyridyl)­ethylene (bpe) and 4, L = 2,5-bis­(phenethylamino)-1,4-benzoquinonato (bpbq) and N-L′-N = trans-1,2-bis­(4-pyridyl)­ethylene (bpe). Metallarectangles 1–4 have been characterized by elemental analysis, IR, NMR, and UV–vis absorption spectroscopic techniques. The molecular structures of 1 and 4 were determined by single-crystal X-ray diffraction methods. The molecular recognition capability of 1 and 3 with pyrene and triphenylene has been investigated using UV–vis absorption and emission spectroscopic techniques. The formation of host–guest complex has been further corroborated by the single-crystal X-ray structural evidence of carceplex system (3⊃pyrene)·(DMF).