A novel sandwich shaped {(Co2Co12Mo24V)-Co-III-Mo-II} cluster with a Co-4(II) triangle encapsulated in two capped (CoCo4Mo12O40)-Co-III-Mo-II-O-V fragments

摘要

A novel discrete {Co14Mo24} nanoscale cluster, {(Co2Co10Cl2)-Co-III-Cl-II(dpbt)(3)(H2O)(2)[(CoMo12O31)-Mo-II-O-V(CH3O)(9)](2)}center dot 24CH(3)OH (1) (here, dpbt = 5,5 '-di(pyridin-2-yl)-3,3 '-bi(1,2,4-triazole)), with a triangular Co-4 core encapsulated in two novel capped Co-substituted Keggin-type Co5Mo12O40 anions, has been isolated from alkaline methanol solution. The high-resolution electrospray ionization mass spectrum (HRESI-MS) of microcrystalline 1 in MeOH/CH2Cl2 (v:v = 2:1) was recorded. Two prominent overlapping peaks in the range of m/z = 2740-2840 and 1820-1880 for the discrete fragments of [(Co2Co12Mo24O62Cl2)-Co-III-Mo-II-O-V(dpbt)(3)(H2O)(2)(CH3O)(x)(OH)(18-x)-2H](2-) (x = 9-18, F1) and [(Co2Co12Mo24O62Cl2)-Co-III-Mo-II-O-V(dpbt)(3)(H2O)(2)(CH3O)(x)(OH)(19-x)-2H](3-) (x = 6-13, F2), respectively, are obtained, confirming the {Co14Mo24} composition in 1. In addition, weak anti-ferromagnetic interactions in 1 are observed.