Phosphine-Substituted Diborane(4)yl Complexes of Tungsten

Abstract

The reaction of the 1,2-dihalodiborane(4) B 2 (NMe 2 ) 2 Cl 2 with the lithium tungsten salts Li[(η 5 -C 5 H 5 )(R 3 P)(OC) 2 W] [R = Me (3a), Ph (3b)] yields via alkali salt elimination the phosphinesubstituted diborane(4)yl tungsten complexes [(η 5 -C 5 H 5 )(R 3 P)(OC) 2 W-{B(NMe 2 )-B(NMe 2 )Cl}] [R = Me (4a), Ph (4b)]. Both compounds have been fully characterized in solution by NMR and IR spectroscopy and 4a additionally by X-ray diffraction analysis.

Synthesis of Half‐Sandwich Tungsten Chlorogermyl and Chlorostannyl Complexes

“…In an extension of our work on the reactivity of boryl‐, borylene‐,8 or diborane(4)yl9 moieties linked to half‐sandwich metal fragments (e.g. compound [(η 5 ‐C 5 Me 5 )(OC) 2 Fe–(BX 2 ←py)] (X = Cl, Br; py = pyridine),8f [(η 5 ‐C 5 H 5 )(R 3 P)(OC) 2 W–{B(NMe 2 )–B(NMe 2 )Cl}] (R = Me, Ph)9a in Figure 2) which included the addition of Lewis bases to BCl 2 ligands8f,8i analogous to Cl 3 Sn complexes, we became interested in some aspects of the chemistry of corresponding halogermyl and stannyl complexes.…”

Molybdenum-Boron Bonds in the Crystal – Structural Characterization of K[(η5-C5H5)Mo(CO)3] and[(η5-C5H5) (OC)3Mo-{B(NMe2)-B(NMe2)Br}]

“…While the bonding patterns such as boryl [4], diboran(4)yl [9,15] as well as base-stabilized boryl complexes [16], have been unequivocally established in solution by IR and multinuclear NMR spectroscopy, very few crystallographic data have been published on molybdenum boryl complexes of the general formula 0932-0776 / 10 / 0900-1073 $ 06.00 c 2010 Verlag der Zeitschrift für Naturforschung, Tübingen · http://znaturforsch.com [L x M-BR 2 ]. In fact, the rather complex diboran(4)yl compound [(η 5 -C 5 H 5 )(OC) 3 Mo-B(NMe 2 )-B(NMe 2 )-OC≡Mo(CO) 2 (η 5 -C 5 H 5 )] [17] appears to represent the only structurally characterized Mo-BR 2 species with three-coordinate boron.…”

“…The absence of structural data on molybdenum boryl bonds is somewhat surprising, considering the excessive knowledge on boryl complexes in general [19,20] and the well-established class of diboran(4)yl complexes in particular, which without exception were derived from the aforementioned alkali metal salts M [(η 5 -C 5 H 5 )M(CO) n ] [9,15].…”