Slavi Sevov

Chemistry of Main-Group Metals and Semimetals in Negative Oxidation States: The heavier members of Groups 14 and 15, both metals and semimetals, are known for their chemistry in various positive oxidation states. What we are interested in is how they behave when forced to accept electrons and become negatively charged, i.e. when in negative oxidation states. It turns out that such atoms tend to cluster together and form: nine-atom deltahedral clusters E94- for Si, Ge, Sn, and Pb; seven-atom species E73- for P, As, and Sb; etc. We have studied extensively the reactivity of Ge94- towards various reagents and have found, to our and many other people's surprise, that they can be readily functionalized with various groups and form [R-Ge9-R]2- and [Ge9-R]3- for R = alkyl, alkenyl, main-group and transition-metal organometallic fragments, etc. Furthermore, they can oligo- and poly-merize to form dimers trimers, tetramers, and infinite chains, for example [Ge9-Ge9]6-, [Ge9=Ge9=Ge9]6-, and [-(Ge92-)-], and they can be centered by transition-metal atoms. The bismuth fragments, on the other hand, can react with various organometallic compounds and form mixed main-group/transition-metal clusters such as [Bi3Mo2(CO)6]3-, [Bi3Ni4(CO)6]3-, [Bi4Ni4(CO)6]2-, [Bi3Ni6(CO)9]3-, and the Ni-centered [Ni@{Bi6Ni6(CO)8}]4-.Hydrothermal Exploratory Synthesis of Hybrid Organic-Inorganic Materials with Framework Structures: We are interested in compounds with open-framework structures as well as compounds that contain large multiatomic molecular anions built of transition-metal, borate, and phosphate or phosphonate groups. We have synthesized the first such open-framework borophosphate, CoB2P3O12(OH)•en where ethylenediamine (en) is the organic template, and the first borophosphate templated by a transition-metal complex, [Co(en)3][B2P3O11(OH)2]. Also, we have synthesized the first large borophosphate polyoxometalate, [MoV5MoVIO30(BPO4)2(PO4)3(HPO4)3]8- and its phenyl-functionalized version [MoV5MoVIO30(BPO4)2(Ph-PO4)6]5-. Other systems of interest include extended frameworks made of transition-metal centers connected by organic linkers with two or more functional groups such as di-phosphonates, carboxylate-phosphonates, boronate-phosphonates, carboxylate-boronates, etc.