Synthesis, structure and reactivity of disila- and distanna ansa half-sandwich complexes of molybdenum and tungsten.

We present the synthesis and characterization of disila- and distanna ansa half-sandwich complexes of Group 6 transition metals. These compounds exhibit high ring strain within the ansa bridge, which is the key factor for the insertion of elemental chalcogens.

Synthesis and structure of a ferrocenylboron dication.

Treatment of the borane Br 2BFc (Fc = ferrocenyl) with the Lewis base 4-methylpyridine and Na[BAr (f) 4] [Ar (f) = 3,5-(CF 3) 2C 6H 3] afforded the boron dication [FcB(NC 5H 4-4-Me) 3][BAr (f) 4] 2. This compound is a rare example of a structurally characterized boron dication.

T-shaped platinum boryl complexes: synthesis and structure.

A series of cationic T-shaped 14-electron boryl complexes of the type trans-[(Cy3P)2Pt(B(X)X')]+ (X=Br; X'=ortho-tolyl, tBu, NMe2, piperidyl, Br; XX'=(NMe2)2, catecholato) were synthesized by halide abstraction from trans-[(Cy3P)2Pt(Br)(B(X)X')] (Cy=cyclohexyl) with Na[BArf 4] (Arf=3,5-(CF3)2C6H3), K[B(C6F5)4], or Na[BPh4]. X-ray diffraction studies were performed on all compounds, revealing a subtle correlation between the trans-influence of the boryl moiety and the Pt-H and Pt-C separations. However, no notable agostic C-H interaction with the platinum center was detected.

Synthesis of eta1-borazine complexes of palladium and platinum.

The eta(1)-borazine complexes trans-[(Cy(3)P)(2)M(Br)(Br(2)B(3)N(3)H(3))] (Cy = cyclohexyl) were prepared by oxidative addition of a B-Br bond of (BrBNH)(3) to [M(PCy(3))(2)] (M = Pd, Pt). Furthermore the platinum compound was converted into the T-shaped cationic complex trans-[(Cy(3)P)(2)Pt(Br(2)B(3)N(3)H(3))][BAr(f)(4)] [Ar(f) = 3,5-(CF(3))(2)C(6)H(3)] by addition of Na[BAr(f)(4)].

Synthesis and reactivity studies of iminoboryl complexes.

A range of new iminoborylcomplexes of the type [L(n)M-B[triple bond]N-R], which are isoelectronic with sigma-alkynyl complexes [L(n)M-C[triple bond]C-R], was obtained by systematically varying the metal M, the coligands L, and the nitrogen bound substituent R. Selected examples include, for example, trans-[(Cy3P)2(Br)Pt(B[triple bond]N iBu)], which is characterized by a sterically less demanding N-R group or the unprecedented rhodium species cis,mer-[(Br)2(Me3P)3Rh(B[triple bond]NSiMe3)]. All compounds were fully characterized in solution by multinuclear NMR spectroscopy and, where appropriate, in the solid state by X-ray crystallography.

Syntheses of mono- and dinuclear diiodoboryl complexes of platinum.

Treatment of [Pt(PCy(3))(2)] (Cy = cyclohexyl) with BI(3) afforded trans-[(Cy(3)P)(2)Pt(I)(BI(2))] by the oxidative addition of a B-I bond. The title compound represents the first diiodoboryl complex and was fully characterized by NMR spectroscopy and X-ray diffraction analysis. The latter revealed a very short Pt-B distance, thus indicating a pronounced pi contribution to this bond.

Experimental studies on the trans-influence of boryl ligands in square-planar platinum(II) complexes.

A series of platinum(II) boryl complexes of general formula trans-[(Cy(3)P)2Pt(Br)(BX2)], including the rare dibromoboryl species trans-[(Cy(3)P)2Pt(Br)(BBr2)], were synthesized by oxidative addition of the B-Br bond of a number of bromoboranes to [Pt(PCy3)2]. X-ray diffraction studies were performed on several such compounds. Comparison of the Pt--Br bond lengths allowed an empirical assessment of the trans-influence of different boryl ligands.

Aminoborylene complexes of group 6 elements and iron: a synthetic, structural, and quantum chemical study.

Transition-metal-borylene complexes of the type [(OC)(5)M=BR] {M=Cr, Mo, W; R=N(SiMe(3))(2), 1a-3a, Si(SiMe(3))(3), 4a} and [(OC)(4)Fe=B=N(SiMe(3))(2)] (8) were prepared by salt elimination reactions. Synthesis of the latter complex was accompanied by the formation of substantial amounts of an unusual dinuclear iron complex [Fe(2){mu-C(2)O(2)(BN(SiMe(3))(2))}(2)(CO)(6)] (9). The aminoborylene complexes of Group 6 metals were converted to trans-[(Cy(3)P)(CO)(4)M=B=N(SiMe(3))(2)] (5a-7a) by irradiation in the presence of PCy(3).

Heterodinuclear bridged borylene complexes.

Heterodinuclear bridged borylene complexes are synthesized via oxidative addition of the B-Br bond of bromoboryl complex precursors to an electron-rich palladium species. The synthetic protocol grants access to the first compound featuring the reactive bromoborylene ligand.