Compounds of Copper(II) and Nickel(II) with 6,8,8,13,13,15-Hexamethyl-1,2,4,5,9,12- hexaazacyclopentadeca-5,15(1)-diene and Some 3-Substituted Homologues

Abstract

Copper(II) and nickel(II) compounds, [M(L)]2+, of the macrocyclic ligand 6,8,8,13,13,15-hexamethyl-1,2,4,5,9,12-hexaazacyclopentadeca-5,15(1)-diene are formed by reaction of compounds of 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dihydrazone with methanal. Analogous reactions with aldehydes RHCO, or ketones RR′CO, form compounds of 3-R or 3-RR′ substituted ligands, [M(r- L)]2+ or [M(rr′-L)]2+, respectively. The nickel(II) cations form singlet ground state salts, e.g. [Ni(L)]X2, X = [ClO4]- or ½[ZnCl4]2-, and also triplet ground state compounds, e.g. [Ni(L) (NCS)2] and [Ni(L)(X)] (ClO4) (X = NO2-, C2O42-, N3-, etc.). The structures of [Cu(L)] (ClO4)2, [Ni(L)] (ClO4)2, the 3-propyl compound formed from butanal, [Cu(pr-L)] (ClO4)2.H2O, and the compounds of 9,11,11,16,16,18-hexamethyl-7,8,12,15,19,20-hexaazaspiro[5.14]eicosa-8,18(1)-diene (chex-L), formed from cyclohexanone, namely [Cu(chex-L)] (ClO4)2.MeOH, [Ni(chex-L)] (ClO4)2, and [Ni(chex-L)] (ClO4)2.MeOH, were determined. All have the metal ions in tetrahedrally twisted square-planar coordination, by N1, N5, N9 and N12 , with N9N12-rac, for the (L) and (pr-L) compounds, or by the structurally equivalent N3, N7, N10 and N14, with N7N10-rac, for the (chex-L) compounds. The [Cu(L)]2+ and [Cu(pr-L)]2+cations have saddle-like macrocycle conformations, with approximate mirror symmetry, while the other compounds have ′twisted′ macrocycle conformations with approximate twofold symmetry {[Cu(L)] (ClO4)2, C15H32Cl2CuN6O8, orthorhombic,P 212121, a 8·562(7), b 13·096(8), c 20·257(6) Å, Z 4, R 0·041 for 1540 reflections; [Ni(L)] (ClO4)2, C15H32Cl2N6NiO8, orthorhombic, P21/n, a 13·500(3), b 9·207(2), c 19·478(5) Å, β 103·94(2)°, Z 4, R1 0·055 for 2650 reflections; [Cu(Pr-L)] (ClO4)2.H2O, C18H40Cl2CuN6O9, monoclinic, C 2, a 24·229(5), b 13·780(3), c 8·877(2) Å, β 108·79(3)°, Z 4, R1 0·067 for 1765 reflections; [Cu(chex-L)] (ClO4)2.MeOH, C21H44Cl2CuN6O9, monoclinic, C 2/c, a 17·086(5), b 24·539(2), c 14·496(1) Å, β 89·94(2), Z 8, R1 0·072 for 2521 reflections; [Ni(chex-L)] (ClO4)2, C20H40Cl2N6NiO8, monoclinic, P 21/c, a 14·820(2), b 18·599(4), c 10·282(1) Å, β 106·26(1)°, Z 4, R1 0·067 for 2552 reflections; [Ni(chex-L)] (ClO4)2.MeOH, C21H44Cl2CuN6O9, monoclinic, C 2/c, a 14·451(2), b 24·11(2), c 16·740(3) Å, β 90·14(1)°, Z 8, R1 0·064 for 2598 reflections}.

Reactivity of Nickel(II) and Copper(II) Complexes of a β-Aminohydrazone Ligand with Pyridine-2-aldehyde: Macrocyclization vs Unprecedented Pyrazole Ring Synthesis via C–C Bond-Forming Reaction

“…The pyridine ring N7 forces one of the C(CH 3 ) 2 groups (on the N3 side) to assume a different conformation with respect to that on the N2 side, likely dictated by steric crowding. This arrangement is completely different from the macrocyclic systems of the ligand derived from hydrazone and carbonyl compounds …”

“…This arrangement is completely different from the macrocyclic systems of the ligand derived from hydrazone and carbonyl compounds. 17 The perchlorate anions in 1 are involved in weak hydrogen bonding interactions with the amine nitrogen N3 and with hydrazone nitrogens N5 and N6 via NÀH 3 3 3 O, resulting in the formation of a one-dimensional hydrogen-bonded polymeric network where the cationic units are held together by a perchlorate bridge (Figure S1, Supporting Information).…”

“…The nickel(II)-dihydrazone complex, [Ni(L 1 )]-(ClO 4 ) 2 , has been shown to react with aliphatic and aromatic aldehydes and ketones to form azamacrocycles. 17 In this study, reactivity of the dihydrazone with pyridine-2-aldehyde was studied in the presence of nickel(II) and copper(II) salts. The metal ions act as templates in the cyclization reaction, forming a new macrocycle ligand containing a pendant pyridine donor.…”

“…2,16À22 The copper(II)-and nickel(II)-hydrazone complexes have been shown to react with monofunctional aldehydes and ketones to form the corresponding complexes of azamacrocylic ligand. 17 However, there is no report on the reaction of heterocyclic carbonyls with metal complexes of 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dihydrazone (L 1 ) (Chart 1). In this work, we have explored the reactivity of copper(II) and nickel(II) complexes of dihydrazone derivatives of β-aminoketone with pyridine-2-aldehyde (PyCHO).…”

“…Aminoketones are important precursors for the synthesis of various functional derivatives exhibiting versatile reactivity with transition metal ions. The β-aminoketone, 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione reported by Love et al in 1968, , is one of the well-studied ligands in this category from which metal complexes of β-iminoamines, β-aminoketoximes, and β-aminohydrazones have been synthesized. − The copper(II), cobalt(II), and nickel(II) complexes of dihydrazone derivatives of the β-aminoketone ligand have been reported by Curtis et al The nickel(II)-dihydrazone complex shows versatile reactivity with 1,2-diketones. ,− The copper(II)- and nickel(II)-hydrazone complexes have been shown to react with monofunctional aldehydes and ketones to form the corresponding complexes of azamacrocylic ligand . However, there is no report on the reaction of heterocyclic carbonyls with metal complexes of 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dihydrazone (L 1 ) (Chart ).…”