The reaction of R'NHLi (R = (t)Bu, (t)Oct) with Ph(2)P(NSiMe(3))(2)Te(Cl)NPPh(2)NSiMe(3) in toluene at -78 degrees C, followed by warming to 23 degrees C, produces the tellurium diimide dimers RNTe(m-NR')(2)TeNR (2a, R' = (t)Bu, R = NPPh(2)NSiMe(3); 2b, R' = (t)Oct, R = NPPh(2)NSiMe(3)) and Ph(2)P(NHSiMe(3))(NSiMe(3)). X-ray analyses revealed that 2a and 2b have centrosymmetric structures containing a planar four-membered Te(2)N(2) ring and short exocyclic tellurium-nitrogen bond lengths (d(Te-N) = 1.900(5) and 1.897(4) or 1.905(4) A for 2a and 2b, respectively). The exocyclic imido substituents adopt a trans arrangement with respect to the Te(2)N(2) ring. By contrast, the reaction of 2,4,6-(t)Bu(3)C(6)H(2)NHLi with Ph(2)P(NSiMe(3))(2)Te(Cl)NPPh(2)NSiMe(3) in toluene under similar conditions produces the telluradiazole ((t)Bu(2)C(6)H(2)N(2)Te)(2) (3), which exists as a weakly associated dimer in the solid state with intramolecular Te-N distances of 2.628(4) A. The tellurium diimide dimer (t)BuNTe(m-N(t)Bu)(2)TeN(t)Bu (2c'), prepared by the reaction of TeCl(4) with (t)BuNHLi in a 1:4 molar ratio, consists of a folded Te(2)N(2) ring with exocyclic N(t)Bu groups in a cis orientation. The (1)H, (31)P, and (125)Te NMR spectra of 2a and 2b indicate that the trans isomers slowly transform into the corresponding cis isomers in solution. Crystals of 2b are triclinic, space group Po (No. 2), with a = 13.304(3) A, b = 16.927(3) A, c = 13.292(5) A, alpha = 98.94(2), beta = 109.27(2), gamma = 69.04(2) degrees, V = 2636(1) A(3), and Z = 4. The final R and R(w) values were 0.034 and 0.033, respectively. Crystals of 2c' are orthorhombic, space group Pnma (No. 62), with a = 9.535(3) A, b = 14.264(3) A, c = 16.963(4) A, V = 2307.1(9) A(3), and Z = 4. The final R and R(w) values were 0.040 and 0.040, respectively. Crystals of 3 are monoclinic, space group P2(1)/n (No. 14), with a = 9.117(3) A, b = 11.481(4) A, c = 16.550(4) A, beta = 97.76(2) degrees, V = 1716.5(8) A(3), and Z = 4. The final R and R(w) values were 0.031 and 0.034, respectively.

Preparation, Crystal Structures, and Isomerization of the Tellurium Diimide Dimers RNTe(m-NR')(2)TeNR (R = R' = (t)Bu; R = PPh(2)NSiMe(3), R' = (t)Bu, (t)Oct): X-ray Structure of the Telluradiazole Dimer [(t)Bu(2)C(6)H(2)N(2)Te](2).

Coordination chemistry of unsaturated cyclic and acyclic PNS and PNSe ligands

The previously unknown radical anions of unsaturated E2N4S2 ring systems (E = RC, R2NC, R2P) can be generated voltammetrically by the one-electron reduction of the neutral species and, despite half-lives on the order of a few seconds, have been unambiguously characterized by electron paramagnetic resonance (EPR) spectroelectrochemistry using a highly sensitive in situ electrolysis cell. Cyclic voltammetric studies using a glassy-carbon working electrode in CH3CN and CH2Cl2 with [nBu4N][PF6] as the supporting electrolyte gave reversible formal potentials for the [E2N4S2]0/- process in the range of −1.25 to −1.77 V and irreversible peak potentials for oxidation in the range of 0.66 to 1.60 V (vs the Fc+/0 couple; Fc = ferrocene). Reduction of the neutral compound undergoes an electrochemically reversible one-electron transfer, followed by the decay of the anion to an unknown species via a first-order (chemical) reaction pathway. The values of the first-order rate constant, kf, for the decay of all the radic...

Identification of the radical anions of C2N4S2 and P2N4S2 rings by in situ EPR spectroelectrochemistry and DFT calculations.

The reaction of Ph2P(NSiMe3)2Te(Cl)NR (R = PPh2NSiMe3) with ButNHLi in toluene at –78 °C produces the tellurium diimide dimer (ButNTeNR)2, which is shown by X-ray crystallography to consists of a planar four-membered Te2N2 ring with short exocyclic tellurium–nitrogen bonds.

Preparation and structure of (ButNTeNPPh2NSiMe3)2, a tellurium diimide dimer

NSERC ; U.S.A. by NSF [CHE-0716718]; Institute for Functional Nanomaterials [0701525]; U.S. Environmental Protection Agency [RD-83385601]; NSFC [20973137, 20721002, 20423002]; 973 program [2007CB815307]

Synthesis, properties, and bishomoaromaticity of the first tetrahalogenated derivative of a 1, 5-diphosphadithiatetrazocine: a combined experimental and computational investigation.

Trenton Parks

Papers

Specific syntheses of the unsaturated phosphorus−nitrogen−sulfur rings R2PN3S2, 1,5-(R2P)2N4S2 and R2PN5S3 (R=Ph, Me)

Specific Syntheses of the Unsaturated Phosphorus-Nitrogen-Sulfur Rings R2PN3S2, 1,5-(R2P)2N4S2, and R2PN5S3 (R: Ph, Me).