This review covers publications ranging from 2005 to 2017 concerning the organic reactions of aromatic ligands η-coordinated to tungsten or molybdenum and the use of these reactions in the synthesis of novel organic substances. An emphasis is placed on C-C bond-forming reactions using conventional building blocks of organic synthesis such as acetals, enolates, Michael acceptors, acylating reagents, and activated aromatics. Substrates activated by the metal include arenes, pyridines, pyrroles, pyrimidines, furans, and thiophenes. General reactivity patterns are elucidated, as well as stereochemical preferences. These trends are compared to those of osmium and rhenium forebears as well as to the reactivity patterns of other methods of stoichiometric transition-metal-based dearomatization (i.e., η-arene complexes).

Homoleptic thorium isocyanide complexes have been prepared via the reactions of laser-ablated thorium atoms and (CN) in a cryogenic matrix, and the structures of the products were characterized by infrared spectroscopy and theoretical calculations. Thorium atoms reacted with (CN) under UV irradiation to form the oxidative addition product Th(NC), which was calculated to have closed-shell singlet ground state with a bent geometry. Further reaction of Th(NC) and (CN) resulted in the formation of Th(NC), a molecule with a tetrahedral geometry. Minor products such as ThNC and Th(NC) were produced upon association reactions of CN with Th and Th(NC). Homoleptic thorium cyanide isomers Th(CN) (x = 1-4) are predicted to be less stable than the corresponding isocyanides. The C-N stretches of thorium cyanides were calculated to be between 2170 and 2230 cm at the B3LYP level, more than 120 cm higher than the N-C stretches of isocyanides and with much weaker intensities. No experimental absorptions appeared where Th(CN) should be observed.

Reactions of laser-ablated U atoms with (CN)2 produce UNC, U(NC)2, and U(NC)4 as the major products, identified from their Ar matrix infrared spectra and precursors partially and fully substituted with (13)C and (15)N. Mixed isotopic multiplets substantiate product stoichiometries. Band positions and quantum chemical calculations verify the isocyanide bonding.