Double-decker bis(tetradiazepinoporphyrazinato) rare earth complexes: crucial role of intramolecular hydrogen bonding

Abstract

A series of homoleptic bis{tetrakis(5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazinato}lanthanide sandwich complexes [(tBuPh)DzPz]2Ln (Ln = Lu, Er, Dy, Eu, Nd, Ce, La) were prepared and their physicochemical properties were studied to gain insight into the nature of specific interactions in diazepinoporphyrazines. The effect of annulated diazepine moieties and the Ln ionic radius on the properties of the complexes was investigated in comparison with double-decker phthalocyanines. A combination of experimental and theoretical studies revealed the presence of two types of hydrogen bonding interactions in the metal-free porphyrazine and the corresponding sandwich complexes, namely, interligand C-H(ax)N(meso) hydrogen bonding and O-HN(Dz) ligand-water interaction. The interligand hydrogen bonding imparts high stability of the ligand dimer and the double-decker compounds in a reduced state. This work is the first comprehensive investigation into the fundamental understanding of the unusual properties of diazepine-containing macroheterocycles.

Impressive near-infrared brightness and singlet oxygen generation from strategic lanthanide–porphyrin double-decker complexes in aqueous solution

“…Tarakanova et al performed the first comprehensive study on double-decker lanthanide complexes and investigated their interaction with water. Unfortunately, only one incorporated water molecule was considered and only intramolecular hydrogen bonding was examined, without the description of an aqueous solution 19 . Recently, water-soluble gadolinium–porphyrin complexes were reported by Zang et al 20 .…”

A Sterically Driven Approach to the Efficient Synthesis of Low-Symmetry 1,4-Diazepinoporphyrazines

“…Recently, it has been demonstrated that the physicochemical properties of diazepinoporphyrazine macrocycles can be easily controlled by the specific choice of peripheral diazepine substituents with a special accent on their steric effect. [2][3][4]27] However, classical procedure of the condensation between diaminomaleonitrile (DAMN) and sterically hindered 2-substituted-1,3-diketone [26] (in our case, 3-n-propyl-2,4-pentanedione 1b) proved to be ineffective, resulting in low yield of 1,4-diazepine-2,3-dicarbonitrile 2b. Therefore, we have attempted to increase the yield of 2b [ †] by applying the method [28][29][30] commonly used for synthesis of imines from sterically hindered ketones.…”

“…The Efficient Synthesis of Low-Symmetry 1,4-Diazepinoporphyrazines tion of the corresponding diazepinoporphyrazine [2,4,5] since the formation of the intermolecular hydrogen bonds with participation of axial protons at the C6 position will be sterically blocked. It turned out that 6-propyl substituted dinitrile 3b exists as a 1:1 mixture of two isomers with equatorial and axial positions of the propyl group.…”

Tiara-like Complexes acting as Iodine Encapsulating Agents: The Role of M···I Interactions in [M(μ-SCH2CO2Me)2]8⊂I2 (M = Ni, Pd, Pt) Inclusion Compounds

“…Relativistic density functional theory calculations were carried out by using the ADF code, via the scalar ZORA Hamiltonian. An all electron triple-ξ Slater basis set including a polarization function (STO-TZP) was employed within the generalized gradient approximation (GGA) of Becke and Perdew (BP86). , The good performance of the BP86 functional has been demonstrated in the study of equilibrium bond lengths of transition-metal diatomic molecules, intermolecular hydrogen bonds in a series of sandwich double-decker tetradiazepinoporphyrazine-based lanthanide complexes, and in the rationalization of noncovalent interactions of cadmium­(II) coordination compounds . Geometry optimizations were conducted via the analytical energy gradient method implemented by Verluis and Ziegler .…”