The present invention relates to a linear inorganic coordination polymer and a metal complex compound which are prepared in the form of a metal nanostructure having various stereo structures and thus can be used as a catalyst or the like having an excellent activity in preparing a polyalkylene carbonate resin and the like, and a metal nanostructure and a catalyst composition comprising the same. The linear inorganic coordination polymer comprises a repeating unit having a form in which a predetermined oxalic acid derivative is coordinately bonded to a transition metal, and the metal complex compound comprises a plurality of linear inorganic coordination polymer chains and has a structure in which the plurality of polymer chains are linked to each other via a predetermined neutral ligand.

A polycarbonate copolymer is formed through polycondensation of a monomer represented by a formula (3) as follows and a monomer represented by a formula (4) as follows. The content of a biphenyl compound having three phenolic hydroxyl groups in one molecule in the monomer represented by the formula (3) is 300 mass ppm or less. In the formula R¹ and R² each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. In the formula R³ and R⁴ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms or a halogen atom; and X represents any one of bonding groups represented by -O-, -S-, -SO-, -SO₂-, -CO- and 9,9- fluorenylidene group.

An electrophotographic photoreceptor contains a polycarbonate copolymer for an electrophotographic photoreceptor. The polycarbonate copolymer is obtained through polymerization conducted in a biphasic solvent under the presence of a phase transfer catalyst. The biphasic solvent comprises a solvent in which 5 mass% or more of a finally-obtained polycarbonate copolymer is soluble, which solvent is substantially non-miscible with water, and an aqueous solution in which alkaline metal hydroxide or alkaline earth metal hydroxide is dissolved. The polycarbonate copolymer contains 0.1 to 50 mol% of a monomer unit represented by the following formula (1); and a monomer unit represented by the following formula (2). The Yl of the polycarbonate copolymer is 3 or less.

In the formula R¹ and R² each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,

In the formula R³ and R⁴ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms or a halogen atom; and X represents any one of bonding groups represented by -O-, -S-, -SO-, -SO₂-, -CO-, 9,9- fluorenylidene group.

A polymeric peroxide comprising a divalent recurring unit having the formula: wherein the recurring unit of Formula I has a 10 hour half-life temperature of at least 80 °C and optionally a divalent recurring unit having the formula: wherein R¹, R², R³, R⁵, X, X¹, Y, Z, y and z are as defined in the Detailed Description of the Preferred Embodiments and the polymeric peroxide has a molecular weight of 1,000 to 200,000. The polymeric peroxides are derived from hydroxy-hydroperoxides or dihydroxy dialkyl peroxides. These polymeric peroxides can be used for preparing block copolymers and compatibilizing polymer blends and alloys.