Metal-metal multiply bonded complexes of technetium. 5. Tris and tetrakis(formamidinato) complexes of ditechnetium

Journal Article · Wed Dec 04 00:00:00 EST 1996 · Inorganic Chemistry

DOI:https://doi.org/10.1021/ic960535m· OSTI ID:450691

Cotton, F A ^[1]; Sattelberger, A P ^[2]; Haefner, S C ^[1]

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1. Texas A&M Univ., College Station, TX (United States)
2. Los Alamos National Lab., NM (United States)

Compounds of the type Tc{sub 2}Cl{sub 4}(PR{sub 3}){sub 4} (PR{sub 3} = PEt{sub 3}, PMe{sub 2}Ph, PMePh{sub 2}) react with the molten formamidines HDPhF (HDPhF = diphenylformamidine) and HDTolF (HDTolF = di-p-tolylformamidine) to produce mixtures of tris-and tetrakis-bridged formamidinate complexes of ditechnetium. The displacement of chloride and phosphine by [DPhF]{sup -} was accompanied by the oxidation of the dimetal core to produce the mixed-valent complexes Tc{sub 2}(DPhF){sub 3-} Cl{sub 2}(1) and Tc{sub 2}(DPhF){sub 4}Cl (2) in modest yield. The solid-state structures of the di-p-tolyl analog of 1, Tc{sub 2}(DTolF){sub 3-} Cl{sub 2} (1a), and Tc{sub 2}(DPhF){sub 4}Cl{center_dot}C{sub 7}H{sub 8}(2{center_dot}C{sub 7}H{sub 8}) have been determined by single crystal X-ray diffraction studies are described in detail. The structure of 1a consists of three formamidinate ligands spanning the two technetium atoms. The two chloride ligands, which complete the coordination sphere, are bound equatorially at distances of 2.357(1) and 2.346(2) {angstrom} from the metals. Though possessing no crystallographic symmetry, 1a approximates C{sub 2{nu}} symmetry. The metal-metal bond length of 2.0937(6) {angstrom} ranks among the shortest reported for technetium and is indicative of a Tc-Tc multiple bond. Compound 2 crystallizes with the Tc atoms colinear with a crystallographic 4-fold axis. The four bridging formamidinate ligands are arranged in a lantern geometry about the dimetal unit. The chloride is bonded in an axial position at a distance of 2.450(4) {angstrom}. The Tc-Tc bond length of 2.119(2) {angstrom} is also consistent with the presence of a high order Tc-Tc bond.

• OSTI ID: 450691
• Journal Information: Inorganic Chemistry, Vol. 35, Issue 25; Other Information: PBD: 4 Dec 1996
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
TECHNETIUM COMPLEXES
CRYSTAL STRUCTURE
MOLECULAR STRUCTURE
OXIDATION
CHEMICAL REACTION YIELD
FORMAMIDE
X-RAY DIFFRACTION
MOLECULAR ORBITAL METHOD
ELECTRONIC STRUCTURE
MATHEMATICAL MODELS