Reaction of at ethered triamine ligand with Bi-(NMe 2 ) 3 gives aBitriamide,for which aBi I electronic structure is shown to be most appropriate.T he T-shaped geometry at bismuth provides the first structural model for edge inversion in bismuthines and the only example of aplanar geometry for pnictogen triamides.A nalogous phosphorus compounds exhibit ad istorted pyramidal geometry because of different BiÀNa nd PÀNb ond polarities.A lthough considerable Bi I character is indicated for the title Bi triamide,i te xhibits reactivity similar to Bi III electrophiles,a nd expresses either avacant or afilled porbital at Bi, as evidenced by coordination of either pyridine N-oxideo rW (CO) 5 .T he product of the former shows evidence of coordination-induced oxidation state change at bismuth. Scheme 1. Synthesis of low-oxidation-state p-block complexes by either external reductants or redox-active ligands.

Electron-rich (lone-pair bearing) non-metal elements offer a potentially diverse coordination chemistry as acceptors, and this chemistry is enhanced by the presence of a cationic charge which augments the Lewis acidity at the acceptor site. As such, the coordination chemistry of non-metals offers new synthetic and structural opportunities with guidance from established coordination chemistry of transition metals, and with the possibility of catenation of the nonmetal. For example, the maximally charged Sb 3+ trication can engage a crown ether [1] or two 2,2-bipyridine (bipy) ligands. [2] While phosphine ligands are also expected to support the Sb 3+ cation, we have discovered that the redox activity between antimony and phosphorus results in formation of an unusual cyclo-tetrastibinotetraphosphonium salt.Addition of three equivalents of trimethylsilyltrifluoromethanesulfonate (TMSOTf) to a suspension of SbF 3 in acetonitrile results in immediate gaseous evolution of Me 3 SiF. After the subsequent addition of PMe 3 and heating to reflux for 30 minutes, the 31 P, 1 H, and 13 C NMR spectra of the clear yellow reaction mixture show quantitative formation of [Me 3 PPMe 3 ][OTf] 2 ( 31 P NMR: d = 28.4 ppm; 1 H NMR: d = 2.39 ppm; 13 C NMR: d = 7.10 ppm), [3] and a new compound characterized as [(Me 3 P) 4 Sb 4 ][OTf] 4 (1[OTf] 4 ; 31 P NMR: d = À24.5 ppm). Identical NMR spectral features are observed for the mixtures of [bipy 2 Sb][OTf] 3 or Sb(OTf) 3 and PMe 3 in a 1:3 ratio at room temperature. It was not possible to separate 1[OTf] 4 from its crystalline mixture with [Me 3 PPMe 3 ][OTf] 2 . In comparison, mixtures of [bipy 2 SbF]-[OTf] 2 or FSb(OTf) 2 and PMe 3 in a 1:2 ratio at 25 8C give 1[OTf] 4 and [Me 3 PF][OTf] ( 31 P NMR: d = 148 ppm; 19 F NMR: d = À138 ppm). [11] Upon cooling this reaction mixture to À30 8C, fractional crystallization affords yellow crystals of 1[OTf] 4 ·3 CH 3 CN.

Catalytic hydrodefluorination (HDF) of unactivated fluoroalkanes or CF -substituted aryl species is performed using the P Lewis acids, [(bipy)PPh] (1 ) and [(terpy)PPh] (2 ) under mild conditions (25 or 50 °C). Mechanistic studies indicate that activation of C-F bond by the P center is key. Particularly noteworthy is that the catalyst 2[B(C F ) ] is air-stable and readily accessible from bench-stable, commercially available reagents in one-step and can be used without isolation.

Ar igid naphthalenediamine framework has been used to prepare antimony hydrides that feature LUMO shapes and energies similar to those found in secondary boranes.B y exploiting this feature,w ei ntroduce the first examples of uncatalyzed hydrostibination reactions of robust CC, C=C, C = O, and N = Nb onds as new elementary hydrometalation reactions analogous to hydroboration. These results endorse the notion of ad iagonal relationship between the lightest p-block element and the heaviest Group 15 elements and may lead to the conception of novel reaction chemistry.

Reactions of trimethylphosphine or diphosphines with SbCl(3) in the presence of AlCl(3) or Me(3)SiSO(3)CF(3) give ligand stabilized stibenium and stibinidenium cations. The geometry at each antimony center reveals a variety of environments for antimony that describes new bonding and highlights new directions in the chemistry of the pnictogen elements.