title: Synthesis and Properties of the Heterospin (S1 = S2 = (1)/2) Radical-Ion Salt Bis(mesitylene)molybdenum(I) [1,2,5]Thiadiazolo[3,4-c][1,2,5]thiadiazolidyl.
abstract: Low-temperature interaction of [1,2,5]thiadiazolo[3,4-c][1,2,5]thiadiazole (1) with MoMes2 (Mes = mesitylene/1,3,5-trimethylbenzene) in tetrahydrofuran gave the heterospin (S1 = S2 = (1)/2) radical-ion salt [MoMes2](+)[1](-) (2) whose structure was confirmed by single-crystal X-ray diffraction (XRD). The structure revealed alternating layers of the cations and anions with the Mes ligands perpendicular, and the anions tilted by 45°, to the layer plane. At 300 K the effective magnetic moment of 2 is equal to 2.40 μB (theoretically expected 2.45 μB) and monotonically decreases with lowering of the temperature. In the temperature range 2-300 K, the molar magnetic susceptibility of 2 is well-described by the Curie-Weiss law with parameters C and θ equal to 0.78 cm(3) K mol(-1) and -31.2 K, respectively. Overall, the magnetic behavior of 2 is similar to that of [CrTol2](+)[1](-) and [CrCp*2](+)[1](-), i.e., changing the cation [MAr2](+) 3d atom M = Cr (Z = 24) with weak spin-orbit coupling (SOC) to a 4d atom M = Mo (Z = 42) with stronger SOC does not affect macroscopic magnetic properties of the salts. For the XRD structure of salt 2, parameters of the Heisenberg spin-Hamiltonian were calculated using the broken-symmetry DFT and CASSCF approaches, and the complex 3D magnetic structure with both the ferromagnetic (FM) and antiferromagnetic (AF) exchange interactions was revealed with the latter as dominating. Salt 2 is thermally unstable and slowly loses the Mes ligands upon storage at ambient temperature. Under the same reaction conditions, interaction of 1 with MoTol2 (Tol = toluene) proceeded with partial loss of the Tol ligands to afford diamagnetic product.
authors.forename: Nikolay A
authors.initials: NA
authors.lastname: Pushkarevsky
authors.forename: Nikolay A
authors.initials: NA
authors.lastname: Semenov
authors.forename: Alexey A
authors.initials: AA
authors.lastname: Dmitriev
authors.forename: Natalia V
authors.initials: NV
authors.lastname: Kuratieva
authors.forename: Artem S
authors.initials: AS
authors.lastname: Bogomyakov
authors.forename: Irina G
authors.initials: IG
authors.lastname: Irtegova
authors.forename: Nadezhda V
authors.initials: NV
authors.lastname: Vasilieva
authors.affiliation: ∇EaStCHEM School of Chemistry and Centre of Magnetic Resonance, University of St. Andrews, St. Andrews, Fife KY16 9ST, United Kingdom.
authors.forename: Bela E
authors.initials: BE
authors.lastname: Bode
authors.forename: Nina P
authors.initials: NP
authors.lastname: Gritsan
authors.affiliation: ○Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia.
authors.forename: Lidia S
authors.initials: LS
authors.lastname: Konstantinova
authors.affiliation: ∇EaStCHEM School of Chemistry and Centre of Magnetic Resonance, University of St. Andrews, St. Andrews, Fife KY16 9ST, United Kingdom.
authors.forename: J Derek
authors.initials: JD
authors.lastname: Woollins
authors.affiliation: ○Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia.
authors.forename: Oleg A
authors.initials: OA
authors.lastname: Rakitin
authors.forename: Sergey N
authors.initials: SN
authors.lastname: Konchenko
authors.forename: Victor I
authors.initials: VI
authors.lastname: Ovcharenko
authors.affiliation: ◆Department of Chemistry, Tomsk State University, 634050 Tomsk, Russia.
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Zibarev