Optical, Magnetic, and Electronic Properties of Peripherally Fused Macrocycles:  Molybdocene Porphyrazines

Abstract

Metal-free and copper porphyrazines, [H(2)pz] and [Cu pz], have been fused at the periphery with molybdocene dithiolene, [Cp(2)Mo]. The optical, magnetic, and electronic properties of the resulting neutral and cationic complexes are studied, using first-principles density functional theory implemented by the discrete variational method. Analysis of the charge and spin distribution shows that the porphyrazine core is strongly coupled with the peripheral complex. The calculated optical absorption is found to be in reasonable agreement with experimental spectra, lending support to our theoretical model. Under appropriate circumstances one observes interaction of unpaired spins localized in the vicinity of both metal sites. The calculated spin distribution shows that [Cp(2)Mo][Cu pz] and [Cp(2)Mo][H(2)pz](+) have a magnetic moment of 1 micro(B) while [Cp(2)Mo][Cu pz](+) and [Cp(2)Mo][H(2)pz] have no moment, in good agreement with the results of X-band EPR spectra. The Cu-Mo magnetic interaction is antiferromagnetic, being mediated by pyrrol nitrogens, meso nitrogens, carbons, and sulfurs.

New Investigations of Geometric, Electronic, and Spectroscopic Properties of Tetrapyrrolic Macrocycles by a TD−DFT Approach. Carbon, Nitrogen, and Chalcogen (O, S, Se) Peripheral Substitution Effects on Ni(II) Porphyrazinato Complexes

“…42,43 The results are reported in Table 4. For a better description of the system, we chose the metal fragment in the +2 oxidation state (Ni 2+ ) with the following electronic configuration of the valence orbitals: (d x 2 -y 2 ) 0 (d xy ) 2 -(d π ) 4 (d z 2 ) 2 ; while the macrocycle fragment is chosen in the ionic (-2) state (oXHpz 2-). As regards the D 4h complexes, the metal does not participate to the a 2g , a 1u , b 1u , and b 2u MOs; therefore, their contribution is based only on polarization effects due to the mixing between occupied and unoccupied orbitals of the macrocycle fragment.…”

“…Furthermore, the contemporary increasing in new techniques to synthesize porphyrazines 1 has provided a new chance to improve the knowledge of these compounds. Indeed, a high growing interest in studying these compounds has been developed because of their high flexibility; rich coordination chemistry; and excellent chemical, thermal, and photochemical stability. − These new molecules are characterized by a highly delocalized electronic structure in which the four pyrrole moieties are linked to each other by four aza bridges.…”

“…Indeed, a high growing interest in studying these compounds has been developed be-cause of their high flexibility; rich coordination chemistry; and excellent chemical, thermal, and photochemical stability. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] These new molecules are characterized by a highly delocalized electronic structure in which the four pyrrole moieties are linked to each other by four aza bridges.…”

Diastereoselective Assembling of 21-C-Alkylated Nickel(II) Complexes of Inverted Porphyrin on a Platinum(II) Template

“…Porphyrins and metalloporphyrins provide an attractive class of building blocks for the construction of large multicomponent 2D and 3D molecular arrays, which are being considered as possible biomimetic models, catalysts, and materials for the transport of charge, molecules, and ions. Both covalent , and coordination linkages − have been exploited in the design of a variety of discrete porphyrin or porphyrazin assemblies. The supramolecular approach based on intermolecular interactions of appropriately selected peripheral functionalities is particularly promising, though it requires well-planned substitution either at β-pyrrole or meso -positions of the porphyrin.…”

Synthesis and investigation of thermal properties of octakis (ethylsulfanyl) porphyrazine

“…Porphyrazines are molecules with high delocalised electronic structure in which the four aza bridges are present between four pyrrole moieties. The electronic spectrum of these molecules has been analysed from a theoretical point of view only in few works [2][3][4][5].…”