title: Unprecedented high-nuclear transition-metal-cluster-substituted heteropolyoxoniobates: synthesis by {V8 } ring insertion into the POM matrix and antitumor activities.
abstract: Reactions of hexaniobate with vanadate in the presence of Ni(2+) , Zn(2+) , or Cu(2+) have furnished three high-nuclear vanadium cluster-substituted heteropolyoxoniobates (HPNs): {Ni(en)3 }5 H{V(V) Nb8 V(IV) 8 O44 }⋅9 H2 O (1), (H2 en)Na2 [{Zn(en)2 (Hen)}{Zn(en)2 (H2 O)}2 {PNb8 V(IV) 8 O44 }]⋅11 H2 O (2), and Na{Cu(en)2 }3 {[Cu(en)2 ]2 [PNb8 V(IV) 8 O44 ]}⋅11 H2 O (3) (en=1,2-diaminoethane). Their structures have been determined and characterized by single-crystal X-ray diffraction analysis, thermogravimetric analysis (TGA), and elemental analysis. Structural analysis has revealed that compounds 1-3 contain similar {V8 }-substituted [X(V) Nb8 V(IV) 8 O44 ](11-) (X=P, V) clusters, obtained by inserting a {V8 } ring into tetravacant HPN [XNb8 O36 ](27-) . To the best of our knowledge, compounds 1-3 represent the first high-nuclear vanadium cluster-substituted HPNs, and compound 1 is the largest vanadoniobate cluster yet obtained in HPN chemistry. Nickel and zinc cations have been introduced into HPNs for the first time, which might promise a more diverse set of structures in this family. Antitumor studies have indicated that compounds 1 and 2 exhibit high activity against human gastric cancer SGC-7901 cells, SC-1680 cells, and MG-63 cells.
authors.affiliation: Key Laboratory of Polyoxometalate Science of Ministry of Education, Department of Chemistry, Northeast Normal University, Renmin Street No. 5268, Changchun, Jilin, 130024 (P.R. China).
authors.forename: Jian-Qiang
authors.initials: JQ
authors.lastname: Shen
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wu
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhi-Ming
authors.initials: ZM
authors.lastname: Zhang
authors.forename: Yang-Guang
authors.initials: YG
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Lu
authors.forename: En-Bo
authors.initials: EB
authors.lastname: Wang
mesh_terms: D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry; D045744:Cell Line, Tumor; D018360:Crystallography, X-Ray; D006801:Humans; D015394:Molecular Structure; D013274:Stomach Neoplasms / Q000737:chemistry* / Q000188:drug therapy*; D028561:Transition Elements / Q000737:chemistry*; D014639:Vanadium / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D028561:Transition Elements; D014639:Vanadium
keywords: antitumor agents; cluster compounds; niobium; phosphoniobate; vanadoniobate