An　inclusion　compound　of　Mo(VI,V,IV)　complexes　and　poly(vinyl　alcohol)　(PVA)　that　contains　some　carbonyl　groups　was　prepared　by　a　photoelectron　transfer　reaction　between　PVA　and　12-molybdophosphoric　acid　(PMo12).　A　dark-blue　film　was　obtained　when　the　aqueous　solution　of　PMo12　and　PVA　was　irradiated　with　UV　light.　The　film　exhibited　the　characteristic　electron　spin　resonance　(ESR)　signal　of　Mo(V).　The　existence　of　Mo(VI,V,IV)　complexes　was　supported　by　XPS　analysis　of　the　film.　Furthermore,　the　infrared　(IR)　and　ultra　violet-visible　(UV-Vis)　spectra　of　the　film　showed　weak　absorption　bands　at　1710　cm-1　and　300-314　nm　that　are　consistent　with　carbonyl　groups,　which　presumably　are　a　result　of　partial　oxidation　of　secondary　hydroxyl　groups　on　PVA.　Differential　scanning　calorimetry　(DSC)　of　the　dark-blue　film　exhibited　a　peak　at　220.37deg;C　that　is　different　from　PMo12　and　PVA.　Except　for　the　IR　absorption　at　1710　cm-1,　the　wavelengths　and　shapes　of　the　other　IR　bands　were　similar　to　those　of　PVA.　The　UV-Vis　spectrum　of　the　film　showed　a　new　absorption　band　at　742-770　nm.　In　addition,　the　XRD　spectrum　of　the　film,　the　diffraction　angles,　and　the　crystalline　sites　were　different　from　that　in　PMo12　or　PVA.　However,　the　peak　shape　was　similar　to　that　of　PVA.　In　summary,　the　DSC,　IR,　UV-Vis,　and　XRD　data　support　a　Mo(VI,V,IV)　complex　that　is　included　into　the　spiral　tube　structure　of　PVA,　which　contains　some　carbonyl　groups.　©　2002　Plenum　Publishing　Corporation.