One-pot conversion of tetraiminodiphenols to diiminodiaminodiphenols via methyl transfer at aluminium

One-pot Synthesis of a Truncated Cone-shaped Porphyrin Macrocycle and Its Self-assembly into Permanent Porous Material

Here, we report the synthesis of a truncated cone-shaped triangular porphyrinic macrocycle, P₃ L₃ , via a single step imine condensation of a cis-diaminophenylporphyrin and a bent dialdehyde-based linker as building units. X-ray diffraction analysis reveals that the truncated cone-shaped P₃ L₃ molecules are stacked on top of each other by π⋯π and CH⋯π interactions, to form 1.7 nm wide hollow columns in the solid state. The formation of the triangular macrocycle is corroborated by quantum chemical calculations. The permanent porosity of the P₃ L₃ crystals is demonstrated by several gas sorption experiments and powder X-ray diffraction analysis.

Coordination chemistry of [2 + 2] Schiff-base macrocycles derived from the dianilines [(2-NH2C6H4)2X] (X = CH2CH2, O): structural studies and ROP capability towards cyclic esters

Reaction of the [2 + 2] Schiff-base macrocycles {[2-(OH)-5-(R)-C6H2-1,3-(CH)2][CH2CH2(2-C6H4N)2]}2 (R = Me, L1H2; tBu, L2H2) with FeBr2 afforded the complexes [FeBr(L1H2)]2[(FeBr3)2O]·2MeCN (1·2MeCN), [FeBr(L2H2)][X] (X = 0.5(FeBr3)2O, 2·0.5MeCN, X = Br, 3·5.5MeCN), respectively. Reaction of L2H2 with [KFe(OtBu)3(THF)] (formed in situ from FeBr2 and KOtBu), following work-up, led to the isolation of the complex [Fe(L2)(L2H)]·3MeCN (4·3MeCN), whilst with [CuBr2] afforded [CuBr(L2H2)][CuBr2]·2MeCN (5·2MeCN). Attempts to form mixed Co/Ti species by reaction of [CoBrL2][CoBr3(NCMe)] with TiCl4 resulted in [L2H4][CoBr4]·2MeCN (6·2MeCN). Use of the related oxy-bridged Schiff-base macrocycles {[2-(OH)-5-(R)-C6H2-1,3-(CH)2][O(2-C6H4N)2]}2 (R = Me, L3H2; tBu, L4H2) with CoBr2 led to the isolation of the complexes [(CoBr)2(L3)]·2C3H6O (7·2C3H6O), [Co(NCMe)2(L4H2)][CoBr4]·5MeCN (8·5MeCN), [Co(NCMe)6][CoBr3(MeCN)]2·2MeCN (9·2MeCN). For comparative structural/polymerisation studies, the complexes {CoBr(NCMe)L5}2·2MeCN (10·2MeCN) and [Co(NCMe)2L5]2[CoBr3(NCMe)]2 (11), [FeBr(NCMe)L5]2·2MeCN (12·2MeCN) where L5H = 2,6-(CHO)2-4-tBu-C6H2OH, as well as the chelate-free salt [Fe(NCMe)6][FeBr3OFeBr3] (13) have been isolated and structurally characterized. The ability of these complexes to act as catalysts for the ring opening polymerisation (ROP) of ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL) was investigated, as well as co-polymerisation of ε-CL with rac-lactide (r-LA) and vice versa.

Synthesis and structures of mono- and di-nuclear aluminium and zinc complexes bearing α-diimine and related ligands, and their use in the ring opening polymerization of cyclic esters

Multi-metallic complexes (of Al, Zn) derived from imine-based ligands effectively operate as catalysts for the ring opening polymerization (ROP) of ε-caprolactone (ε-CL), δ-valerolactone (δ-VL) and co-polymerization thereof.

Turning on ROP activity in a bimetallic Co/Zn complex supported by a [2+2] Schiff-base macrocycle

Homo-dinuclear Co and Zn complexes derived from the macrocycle LH2, {[2-(OH)-5-(R)-C6H2-1,3-(CH)2][CH2CH2(2-C6H4N)2]}2 (R = Me, tBu), revealed near inactivity for the ring opening polymerization (ROP) of the cyclic esters δ-valerolactone (δ-VL) and ε-caprolactone (ε-CL). By contrast, the hetero-bimetallic complexes [LCo(NCMe)(μ-Br)ZnBr]·nMeCN (n = 3 or 3.25) were found to be efficient catalysts for the ROP of ε-CL and δ-VL.

Manganese coordination chemistry of bis(imino)phenoxide derived [2 + 2] Schiff-base macrocyclic ligands

Products resulting from the reaction of MnCl₂ with [2 + 2] Schiff-base macrocycles have been structurally characterized, and were found to be poorly active for the ROP of ε-caprolactone.

Structural studies of Schiff-base [2 + 2] macrocycles derived from 2,2′-oxydianiline and the ROP capability of their organoaluminium complexes

Structures of [2 + 2] Schiff base macrocycles and aluminium complexes thereof, together with ROP studies using the latter are reported.