Cofacial assembly of partially oxidized metallamacrocycles as an approach to controlling lattice architecture in low-dimensional molecular solids. Chemical, structural, oxidation state, transport, magnetic, and optical properties of halogen-doped [M(phthalocyaninato)O]n macromolecules, where M = Si, Ge, and Sn

Abstract

This contribution reports an integrated chemical and physicochemical study of the effects of halogen (I2, Br2) doping on the cofacially joined metallomacrocyclic polymers [M(Pc)O],. Resonance Raman and transmission infrared spectroscopy indicates the formation of ( [ M ( P c ) O ]~~~+ (~/ , I , -)~)~, M = Si, Ge, and ([Si(P~)o]y/~+(~/,Br,-)~), materials for y I 1.1. In contrast, for M = Sn, evidence is presented for the destruction of the tin-oxygen bonds upon doping. For M = Si and Ge,the transmission infrared spectra also reveal the progressive growth of electronic absorption with incremental doping; the effect is somewhat stronger for Si than for Ge. Transmission optical spectra of these materials reveal the formation of phthalocyanine x radical cation species and chains of 13-counterions. EPR spectra are also in accord with the ligand-centered P radical character of the halogen oxidation. Studies of the doping process (M = Si, Ge) by X-ray diffractometry indicate that it is inhomogeneous and that a single, limiting phase of stoichiometry y = 1.1 is produced upon halogenation. Structural characterization of the ( [S~(PC)O]I,,,~),, ( [G~(PC)O]I~,,~),, and ([S~(PC)O]B~,,,~), phases by computer analysis of the diffraction data (supported by judiciously selected model compounds) indicates architectural motifs that are essentially isomorphous with Ni(Pc)I, Le., stacks of staggered M(Pc) units and parallel chains of I,-counterions. The data can be indexed in space group P4/mcc, Z = 2, with a = 13.936 (6) A, c = 6.488 (3) A, phthalocyanine staggering angle = 39.5' (Ni); a = 13.97 ( 5 ) A, c = 6.60 (4) A, staggering angle = 39 (3)' (M = Si); a = 13.96 ( 5 ) A, c = 6.96 (4) A, staggering angle = 40 (4)' (M = Ge). Evidence is presented that the I,-(or Br,-) counterions are disordered along c. Variable-temperature static magnetic susceptibility studies of the ([M(Pc)O]I,), polymers reveal a small, sample-dependent Curie component and a Pauli-like, weakly temperature-dependent contribution. The magnitude of the latter is linearly proportional to y and can be associated with the fully doped, y 1.1 phase. The magnitude of the Pauli-like component increases with increasing interplanar ring-ring spacing (Ni -Si -Ge) while bandwidths ( 4 t ) calculated on the basis of a simple tight-binding model decrease. High-resolution 13C NMR spectra ('H decoupled with cross-polarization and magic angle spinning) reveal a downfield shift of [Si(Pc)O], carbon resonances upon doping. Optical reflectivity studies of the M = Si and Ge materials reveal the development of a plasma-like edge in the infrared upon incremental doping with iodine (the effect is stronger for Si than for Ge). Comparison of the data for Ni(Pc)I, ([Si(Pc)O] and ([Ge(Pc)O]I,,,,), reveals the progressive shift of the edge to lower energy with increasing interplanar spacing (Ni -Si -Ge). This trend is paralleled by plasma frequencies (w,) derived from a Drude analysis and tight-binding bandwidths calculated therefrom. Four-probe electrical conductivity measurements for poly...

Iodine doping of substituted μ-carbido iron diphthalocyanines

“…Furthermore IR spectra are characterized by the presence of a broad absorption spreading in the region 4000-1000 cm -1 observed for partially oxidized phthalocyanine derivatives [17] and typical of systems that exhibit charge transfer phenomena. All the spectrum below 1600 cm -1 is clearly visible.…”

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Aerospace Power Scholarly Research Program. Delivery Order 0011: Modeling Lithium-Ion Conducting Channel

“…Other metal phthalocyanines are known to be polymorphic. [3][4][5][6][7][8][9][10][11][12][13] Particularly, a great deal of research has been done on the polymorphism of lithium phthalocyanine because of its potential use as an oximetry probe and its interesting electrical and magnetic behavior. 7,8 Depending on the preparation conditions, LiPc can crystallize in three different structures, namely, α-, β-, and χ-forms.…”