**5. Acknowledgment**

614 Advances in Crystallization Processes

59.6 (background)

16.1


Fig. 10. 27Al NMR spectrum in acetonitrile-*d*3 of [(*n*-C4H9)4N]4[α-PW11{Al(OH2)}O39].


400 300 200 100 0 -100 -200 -300

ppm


ppm

Fig. 11. 183W NMR spectrum in acetonitrile-*d*3 of [(*n*-C4H9)4N]4[α-PW11{Al(OH2)}O39].

The synthesis of a monomeric, *mono*-aluminum-substituted -Keggin polyoxometalate is described in this study. We successfully obtained single crystals of acetonitrile-soluble tetra*n*-butylammonium salt [(*n*-C4H9)4N]4[α-PW11{Al(OH2)}O39] by reacting aluminum nitrate with a *di*-lacunary γ-Keggin phosphotungstate. The characterization of [(*n*-C4H9)4N]4[α-PW11{Al(OH2)}O39] was accomplished by X-ray crystallography, elemental analysis,


**4. Conclusion** 

This work was supported by a Grant-in-Aid for Scientific Research on Innovative Areas (No. 21200055) of the Ministry of Education, Culture, Sports, Science and Technology, Japan. Y. Kataoka acknowledges the JSPS Research Fellowship for Young Scientist. Y. Kitagawa also has been supported by Grant-in-Aid for Scientific Research on Innovative Areas ("Coordination Programming" area 2170, No. 22108515) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT). This research was partially carried out using equipment at the Center for Instrumental Analysis, Shizuoka University.
