Effects of Remote Ligand Substituents on the Structures, Spectroscopic, and Magnetic Properties of Two-Coordinate Transition-Metal Thiolate Complexes.

The first-row transition-metal(II) dithiolates M(SAr) [Ar = CH-2,6-(CH-2,6-iPr); M = Cr (1), Mn (3), Fe (4), Co (5), Ni (6), and Zn (7)] and Cr(SAr) [2; Ar = CH-2,6-(CH-2,4,6-Me)] and the ligand-transfer reagent (NaSAr) (8) are described. In contrast to their M(SAr) (M = Cr, Mn, Fe, Co, Ni, and Zn; Ar = CH-2,6-(CH-2,4,6-iPr)) congeners, which differ from 1 and 3-6 in having p-isopropyl groups on the flanking aryl rings of the terphenyl substituents, compounds 1 and 4-6 display highly bent coordination geometries with S-M-S angles of 109.802(2)° (1), 120.

Studies on the Activation and Hydrosilylation Catalysis of RhCl(BuS).

RhCl(BuS) is an industrial precatalyst utilized in the curing of some solventless silicone-release coatings formulations. The catalyst requires no additional inhibitor, in contrast to typical Pt formulations, and so questions arose about how fast the catalyst could trigger curing if it were used in a more activated form. Studies on the activation of RhCl(BuS) revealed multiple intermediates, of which [RhCl(BuS)] and [RhHCl(SiMe(OSiMe)) (BuS)] were isolated.

Lewis base assisted B-H bond redistribution in borazine and polyborazylene.

Lewis bases react with borazine and polyborazylene, yielding borane adducts. In the case of NH3 (l), ammonia-borane (AB) is formed and quantified using NMR spectroscopy against an internal standard. Calculations indicate that the formation of B(NH2)3 may provide the driving force of this redistribution.

Dispersion forces and counterintuitive steric effects in main group molecules: heavier group 14 (Si-Pb) dichalcogenolate carbene analogues with sub-90° interligand bond angles.

The synthesis and spectroscopic and structural characterization of an extensive series of acyclic, monomeric tetrylene dichalcogenolates of formula M(ChAr)2 (M = Si, Ge, Sn, Pb; Ch = O, S, or Se; Ar = bulky m-terphenyl ligand, including two new acyclic silylenes) are described. They were found to possess several unusual features-the most notable of which is their strong tendency to display acute interligand, Ch-M-Ch, bond angles that are often well below 90°. Furthermore, and contrary to normal steric expectations, the interligand angles were found to become narrower as the size of the ligand was increased.

Stable plumbylene dichalcogenolate monomers with large differences in their interligand angles and the synthesis and characterization of a monothiolato Pb(II) bromide and lithium trithiolato plumbate.

The complexes, Pb(ChAr(Pri4))2 (Ch = O (1), S (2); Ar(Pri4) = C6H3-2,6-(C6H3-2,6-Pr(i)2)2) were synthesized by alcoholysis and salt metathesis routes and represent the first fully characterized monomeric, two-coordinate, lead dichalcogenolates in the solid state. Structural studies showed that the S-Pb-S angle (77.21(4)°) is about 22° narrower than the corresponding O-Pb-O angle.

Isolation of a stable, acyclic, two-coordinate silylene.

The synthesis and characterization of a stable, acyclic two-coordinate silylene, Si(SAr(Me(6)))(2) [Ar(Me(6)) = C(6)H(3)-2,6(C(6)H(2)-2,4,6-Me(3))(2)], by reduction of Br(2)Si(SAr(Me(6)))(2) with a magnesium(I) reductant is described. It features a V-shaped silicon coordination with a S-Si-S angle of 90.52(2)° and an average Si-S distance of 2.