Synthesis and Reactivity of Nickel(II) Complexes of the Pyridine-Based Phosphorus-Containing Macrocycle 6-Phenyl-15-aza-6-phospha-3,9- dithiabicyclo[9,3,1]pentadeca-1(15),11,13-triene

Abstract

The reactivity of the phosphomacrocycle 6-phenyl-15-aza-6-phospha-3,9-dithiabicyclo[9,3,1]pentadeca-1(15), 11,13-triene (L) toward different Ni(II) salts has been studied. The reaction of L with 1 molar equiv of Ni(II) perchlorate in acetonitrile solution gives the complex [Ni(L)(CH(3)CN)(2)](ClO(4))(2) (1), which crystallizes in the monoclinic space group P2(1)/c (No. 14) with a = 12.704(2) Å, b = 13.538(2) Å, c = 17.377(2) Å, beta = 107.554(8) degrees, and Z = 4. The Ni(II) atom in 1 shows an octahedral environment defined by the four donor atoms of L and two acetonitrile molecules in a cis disposition. The reaction of L with Ni(II) perchlorate in 2:1 molar ratio yields the green complex [Ni(Lox)(2)](ClO(4))(2) (2) in which the phosphine groups of the ligand L are in their phosphine-oxide form (Lox). The same complex is also obtained by adding more ligand L to an acetonitrile solution of 1. Complex 2 crystallizes in the triclinic space group P&onemacr; (No. 2) with a = 10.564(1) Å, b = 11.975(2) Å, c = 9.124(2) Å, alpha = 109.79(1) degrees, beta = 95.67(2) degrees, gamma = 109.19(1) degrees, and Z = 1. The octahedral coordinated Ni(II) atom in 2 lies on a crystallographic center of symmetry, and it is surrounded by two pyridine nitrogen atoms, two thioether sulfur atoms, and two phosphine-oxide oxygen atoms provided by two facially coordinated Lox ligands. The reaction of L with Ni(II) chloride and Ni(II) thiocyanate yields the complexes [NiCl(2)(L)] (3) and [Ni(NCS)(2)(L)] (4), respectively, which are also obtained by adding Me(4)NCl or KSCN to an acetonitrile solution of 1. Complex 4 crystallizes in the monoclinic space group P2(1)/n (No. 14), with a = 11.139(2) Å, b = 13.270(2) Å, c = 14.885(1) Å, beta = 92.34(1) degrees, and Z = 4, and its structure is similar to that of complex 1, simply replacing the two acetonitrile molecules by two SCN(-) anions. The reactions of the complex 1 with different chelating (en, bipy, o-phen) and nonchelating (py) N-donor ligands have also been carried out. In all cases the two acetonitrile molecules of 1 are easly replaced by the N-donor ligands, but the macrocycle L molecule remains coordinated to the Ni(II) atom. The crystal structure of the complex [Ni(L)(py)(2)](ClO(4))(2) (5) is also elucidated. Crystal data: monoclinic space group P2(1)/c (No. 14) a = 13.063(2) Å, b = 16.615(3) Å, c = 14.973(3) Å, beta = 91.76(2) degrees, Z = 4.

Syntheses, Structures, and Coordination Chemistry of Phosphole-Containing Hybrid Calixphyrins: Promising Macrocyclic P,N2,X-Mixed Donor Ligands for Designing Reactive Transition-Metal Complexes

“…The development of phosphorus-containing macrocyclic mixed-donor ligands has emerged as an important subject in coordination chemistry, because they provide characteristic chelating sites that are difficult to construct with their acyclic analogues. − Such hybrid macrocyclic donors are highly promising for designing reactive and multifunctional transition-metal catalysts, as (1) the metal center can be supported and stabilized by multidentate platforms, (2) various coordination properties, such as coordination number, cavity size, and σ-donating and π-accepting abilities, are available by changing the components of the heteroatom donors, and (3) conformational mobility of the ligands is controllable by suitable choice of the bridging atoms/groups. Despite these promising aspects, however, transition-metal catalysts featuring phosphorus-containing hybrid macrocycles as supporting ligands have not been explored much, owing to limited information on the relationship between their fundamental reactivities and their structural and electronic properties.…”

A non-radioactive method for measuring Cu uptake in HepG2 cells

“…The approach is limited, however, since the isotope is not commercially available. Phen Green FL has been used for detecting divalent metals such as Fe 2+ , Hg 2+ , Cd 2+ , Pb 2+ and Ni 2+ at submicromolar concentrations [23][24][25] but can also be used for Cu 2+ . For example, Chavez-Crooker et al [26] have used the dye to differentiate between intracellular Cu levels for four types of lobster hepatopancreatic epithelial cells.…”