The Magnetic Properties of Manganese(II) Phthalocyanine

Abstract

The magnetic transition from the ferro- to the para-magnetic state of manganese(II) phthalocyanine (C32H16N8Mn) has been observed by measurements of the magnetic susceptibility, the magnetization and the proton magnetic resonance in the low-temperature range. The positive Weiss constants were obtained from the static susceptibility measurements and the proton magnetic measurements. Moreover, the magnetic-field dependences of the experimental results were found in the low-temperature range. All of those findings confirm the ferromagnetic behavior of this substance in the lower-temperature region. From the measurements of the frequency shift in the resonant circuit of the proton magnetic resonance apparatus, the transition temperature was determined to be 8.6 K. A possible mechanism of long-range ordering was also discussed on the basis of the crystal structure of this substance.

Packing Motifs and Magneto‐Structural Correlations in Crystal Structures of Metallo‐Tetrakis(1,2,5‐thiadiazole)porphyrazine Series, MTTDPz (M=H2, Fe, Co, Ni, Cu, Zn)

“…The parameters for the g phase are C = 0.42 AE 0.04 emu K mol À1 (g = 2.1) and q = 0.7 AE 0.2 K. This Weiss constant suggests a weak ferromagnetic intermolecular interaction through the axial nitrogen atom, as in b-MnPc. [3] It is concluded that the magnetic interactions in a'-and g-CuTTDPz are very weak due to long distances between the paramagnetic metal ions.…”

“…[1] Thin films of MPc are utilized as gas sensors; oxidizing gases such as NO x , HCl, CO introduce mobile holes in MPc leading to a significant enhancement in conductivity. [1,2] MnPc [3] and FePc [4] possess ferromagnetically ordered states at low temperatures and [N(C 4 H 9 ) 4 ] [Ln(Pc) 2 ] exhibits the behavior of a single-molecule magnet. [5] There are two well-known crystal forms for MPc, a, and b.…”

Preparation and magnetic properties of manganese(II) phthalocyanine thin films

“…14 Only the ␤ polymorph of manganese͑II͒ phthalocyanine ͑␤-MnPc͒ is known as a ferromagnet among undoped MPc's. Magnetic susceptibility of ␤-MnPc obeys the Curie-Weiss law with a positive Curie-Weiss constant 14 with the transition temperature T c determined to be 8.6 K. 15 The ferromagnetic behavior is explained qualitatively by the 90°superexchange interaction between nearest-neighboring Mn atoms via N atoms in phthalocyanine rings, resulting in the ordering of Mn 2ϩ having an Sϭ3/2 state. 16 While the nature of interchain interaction is not clear, it is probably induced by the overlap between the -electrons of the molecules in adjacent columns.…”

Mixed configuration ground state in iron(II) phthalocyanine

“…Another field of potential interest of MPc's is their use as magnetic materials [4,5], with applications as magnetic storage devices, quantum computing, and molecular spintronics [6,7]. Understanding the microscopic interactions that govern their magnetic properties is of key importance in the design of functional materials.…”