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The first example of a diphosphaborolediide, the benzo‐fused [C6H4P2BPh]2− (12−), is prepared from ortho‐bis(phosphino)benzene (C6H4{PH2}) and dichlorophenylborane, via a sequential lithiation approach. The dilithio‐salt can be obtained as an oligomeric THF solvate or discrete TMEDA adduct, both of which are fully characterized, including by X‐ray diffraction. Alongside NICS calculations, data strongly suggest some aromaticity within 12−, which is further supported by preliminary coordination studies that demonstrate η5‐coordination to a zerovalent molybdenum center, as observed crystallographically for the oligomeric [{Mo(CO)3(η5‐1)}{μ‐η1‐Mo(CO)3(TMEDA)}2] ⋅ [μ‐Li(THF)][μ‐Li(TMEDA)]. [ABSTRACT FROM AUTHOR]

ABSTRACT Detailed computational studies have been carried out to explain the unexpected differing reactions that occur between dimethylamine and the difluorophosphines, CX3PF2 (X = F, Cl). The reaction affords the thermodynamically controlled product chloroform in the case of X = Cl, whereas when X = F the analogous reaction pathway leading to fluoroform is hindered by a substantial reaction barrier in the gas phase, where the reaction should take place due to the volatility of the reactant. While the gas-phase reaction energy gap is somewhat reduced when X = Cl, due to the stability of the migrating CCl3− moiety, the still substantial barrier does not account for the chloroform formation. Polarizable continuum model (PCM) calculations indicate a reduction of the barrier, facilitating the liquid-phase reaction. The alternative gas-phase reaction path, resulting in the aminolysis of a P-F bond is reversible and is shifted toward the product by capturing HF as the dimethylamino salt of the [CF3PF4H]− anion. [ABSTRACT FROM AUTHOR]

The facile two-electron reduction of the phosphaalkyne tBuC≡P by the UIII cyclopentadienyl-pentalene mixed-sandwich complex [U(η5-C5Me5){η8-C8H4(Si iPr3)2}] is reported. A single-crystal X-ray structural analysis of the diuranium(IV) product [(U{η5-C5Me5}{η8-C8H4(Si iPr3)2})2(μ- tBuCP)] shows that it contains a slightly unsymmetrical, bridging μ-η2:η1-ligated phosphaalkene dianion. [ABSTRACT FROM AUTHOR]

DFT and hybrid HF-DFT studies of structure and bonding of CpMP6MCp triple-decker sandwich complexes, ranging from 18–28 valence electrons (VE) with M = Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, show that the middle P6 ring complexes adopt symmetric planar (28 valence electron count [VEC]), asymmetric planar (26 VEC), and puckered (24 VEC) geometries. According to the mno Rule, 50 skeletal electrons are needed for these triple-decker cluster frameworks. For 28 VEC, this corresponds to 10 electrons more than the 50 electrons of the mno Rule if all VE of the metal are included. These additional electrons control the distortion of a P6 middle ring and other finer structural details. Completely filled 2a* and 2b* orbitals in 28 VE complexes lead to a planar symmetrical P6 middle ring, while the occupancy in either 2a* or 2b* alone explains the in-plane distortions (asymmetric) in 26 VE complexes. In comparison with 28 VE complexes, the puckering of P6 middle ring in 24 VE complexes is due to the greater stabilization of 5a and the extra stabilization of the +4 oxidation state of Ti. The quintet state of 22 VE complexes is planar as 2a* and 2b* are half filled. Similar geometrical and bonding patterns of CpScP6ScCp and C2P3H2ScC3P3H3ScC2P3H2 support the carbon–phosphorus analogy further. The 18 VE systems, CpScC3B3H6ScCp+ and CpScP3B3H3ScCp+, have the 50 skeletal electrons as stipulated by the mno Rule. Corresponding anions have 52 skeletal electrons (20 VE); the middle rings here are distorted in the plane. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2007 [ABSTRACT FROM AUTHOR]