A simple 1,10-phenanthroline-based fluorescent receptor in solution and 1,10-phenanthroline in solid state for urea recognition

Molecular and Electronic Structures of Homoleptic Six-Coordinate Cobalt(I) Complexes of 2,2′:6′,2″-Terpyridine, 2,2′-Bipyridine, and 1,10-Phenanthroline. An Experimental and Computational Study

“…In excellent agreement with the experimental structures, geometry optimizations for the monocations [Co­(tpy) 2 ] + , [Co­(bpy) 3 ] + , and [Co­(phen) 3 ] + yielded ligands that appear to be coordinated in their neutral forms, thereby rendering the central metal ion Co I (d 8 , S = 1). More specifically, the C py –C py and C–N chel bond distances within each complex are, within experimental error limits (3σ ∼ 0.01 Å), identical and agree well with those reported for the uncoordinated neutral ligands tpy 0 , bpy 0 , and phen 0 . Consistent with this statement, the occupied FMOs (Figures and S15 and S20) have predominant 3d orbital character.…”

“… − As a search of the Cambridge Crystallographic Database reveals, these dications have been structurally characterized many times in the past, and structures for the aforementioned purpose have been selected based on the following criteria: (1) no static disorder problems are present; (2) data collection was preferably performed at cryogenic temperatures (100–150 K); (3) the estimated standard deviations (σ) for the C–C and C–N bond lengths should not exceed 0.005 Å; (4) the R factor should be less than 5%. The experimentally observed average Ni–N, C py –C py , and C–N chel bond lengths in the selected nickel­(II) structures (Table S24) match exactly, within an error limit of ±0.01 Å, those of the cobalt­(I) complexes and those reported for the uncoordinated ligands. ,, Thus, the Co I monocations and corresponding Ni II dications are isostructural and isoelectronic.…”

“…The high-resolution crystal structure determinations for complexes 3 , 4 , 7 , and 9 presented herein containing the monocations [Co I (tpy 0 ) 2 ] + , [Co I ( t bpy 0 ) 3 ] + , and [Co I (phen 0 ) 3 ] + exhibit C py –C py and C–N chel bond lengths identical, within error limits (3σ) of only ±0.01 Å, with those reported for the uncoordinated molecules tpy 0 , , bpy 0 , and phen 0 . This indicates that the redox level of the coordinated ligands is neutral and, by extension, the Co ions possess a 1+ oxidation state.…”

“…Analysis of the structure of the monocation in 9 , depicted in Figure , results in conclusions analogous to those outlined above for the corresponding tpy and t bpy complexes. The three phen ligands in 8 are, within experimental error (3σ), identical with those of the dication in 9 and a typical neutral phen 0 . Additionally, the Co–N distances in 8 are characteristic of six-coordinate high-spin Co II , and those in 9 are marginally shorter and consistent with the presence of Co I .…”

Synthetic Hosts for Molecular Recognition of Ureas

“…The first three hosts used (Chart ) , were Thummel’s host 1 , based on the acidity of indolic N–H in lieu of amides N–H; and hosts 2 and 3 were previously reported by Goswami et al , Many other hosts for ureas recognition were described in chronological order by Goswami; , by Gozin; by Gale; by Boyer; by Ghosh and Sen; , Goswami; by Yatsimirsky; by Roesky; and by Ghosh . Some hosts were prepared by Ghosh specifically for biotin salt, while related pyridine-based oligoamides were prepared by Gunnlaugsson as DNA-targeting supramolecular binders …”