Weak Interactions between Trivalent Pnictogen Centers: Computational Analysis of Bonding in Dimers X(3)E center dot center dot center dot EX(3) (E = Pnictogen, X = Halogen)

The nature of weak interactions in dimers X(3)E center dot center dot center dot EX(3) (E = N-Bi, X = F-I) was investigated by wave function and density functional theory (DFT)-based methods. Out of the 20 systems studied, 10 are found to be bound at the CP-MP2 and LMP2 levels of theory. Detailed partition of the interaction energy into different components revealed that dispersion is the primary force holding the dimers together but there also exists an important ionic component whose contribution increases with increasing halogen size. As expected, standard density functionals fail to describe bonding in the studied systems. However, the performance of DFT methods can be easily improved via empirical dispersion correction though full agreement with high level ab initio results was not obtained. Total binding energies calculated at the SCS-MP2 and LCCSD(T) levels of theory yield an energy scale of 10-15 W mol(-1) which is comparable to a weak hydrogen bond and demonstrates that E center dot center dot center dot E interactions, and P center dot center dot center dot P interactions in particular, can be considered relevant for determining supramolecular structure in the solid state. In addition to high-level energy estimates, results from detailed bonding analysis showed that group 13 dimetallenes are structural analogues of the studied dimers, and as such contain a slipped,pi-interaction which is antibonding in nature

Copper(I) complexes of bis(2-(diphenylphosphino)phenyl) ether: Synthesis, reactivity, and theoretical calculations

The tricoordinated cationic Cu-I complex [Cu(kappa(2)-P,P'-DPEphos)(kappa(1)-P-DPEphos)][BF4] (1) (DPEphos = bis(2-(diphenylphosphino)phenyl) ether) containing a dangling phosphorus center was synthesized from the reaction of [Cu(CH3CN)(4)][BF4] with DPEphos in a 1:2 molar ratio in dichloromethane. When complex 1 is treated with MnO2, elemental sulfur, or selenium, the uncoordinated phosphorus atom undergoes oxidation to form a PE bond resulting in the formation of complexes of the type [Cu(kappa(2)-P,P'-DPEphos)(kappa(2)-P,E-DPEphos-E)][BF4] (2, E = O; 3, E = S; 4, E = Se) containing a Cu-E bond. The zigzag polymeric Cu-I complex [Cu(kappa(2)-P,P'-DPEphos)(mu-4,4'-bpy)](n)[BF4](n) (5) was prepared by the reaction of [Cu(CH3CN)(4)][BF4] with DPEphos and 4,4'-bipyridine in an equimolar ratio. The stereochemical influences of DPEphos on its coordination behavior are examined by density functional theory calculations

New tetraphosphane ligands {(x2p)(2)nc6h4n(px2)(2)} (x = cl, f, ome, oc6h4ome-o): synthesis, derivatization, group 10 and 11 metal complexes and catalytic investigations. Dft calculations on intermolecular p center dot center dot center dot p interactions in halo-phosphines

The reaction of p-phenylenediamine with excess PCl3 in the presence of pyridine affords p-C6H4[N(PCl2)(2)](2) (1) in good yield. Fluorination of 1 with SbF3 produces p-C6H4[N(PF2)(2)](2) (2). The aminotetra(phosphonites) p-C6H4[N{P(OC6H4OMe-o)(2)}(2)](2) (3) and p-C6H4[N{P(OMe)(2)}(2)](2) (4) have been prepared by reacting 1 with appropriate amount of 2-(methoxy)phenol or methanol, respectively, in the presence of triethylamine. The reactions of 3 and 4 with H2O2, elemental sulfur, or selenium afforded the tetrachalcogenides, p-C6H4[N{P(O)(OC6H4OMe-o)(2)}(2)](2) (5), p-C6H4[N{P(S)(OMe)(2)}(2)](2) (6), and p-C6H4[N{P(Se)(OMe)(2)}(2)](2) (7) in good yield. Reactions of 3 with [M(COD)Cl-2] (M = Pd or Pt) (COD = cycloocta-1,5-diene) resulted in the formation of the chelate complexes, [M2Cl4-p-C6H4{N{P(OC6H4OMe-o)(2)}(2)}(2)] (8, M = Pd and 9, M = Pt). The reactions of 3 with 4 equiv of CuX (X = Br and I) produce the tetranuclear complexes, [Cu-4(mu(2)-X)(4)(NCCH3)(4)-p-C6H4{N(P(OC6H4OMe-o)(2))(2)}(2)] (10, X = Br; 11, X = I). The molecular structures of 1-3, 6, 7, and 9-11 are confirmed by single-crystal X-ray diffraction studies. The weak intermolecular P center dot center dot center dot P interactions observed in 1 leads to the formation of a 2D sheetlike structure, which is also examined by DFT calculations. The catalytic activity of the Pd(II) 8 has been investigated in Suzuki-Miyaura cross-coupling reactions

Bi-, tetra-, and hexanuclear au-i and binuclear ag-i complexes and ag-i coordination polymers containing phenylaminobis(phosphonite), phn{p(oc6h4ome-o)(2)}(2), and pyridyl ligands

The reactions of phenylaminobis(phosphonite), PhN{P(OC6H40Me-P)(2))}(2) (1) (PNP), with [AuCl(SMe2)] in appropriate ratios, afford the bi- and mononuclear complexes, [(AuCl)(2)(U-PNP)] (2) and [(AuCl)(PNP)](2) (3) in good yield. Treatment of 2 with 2 equiv of AgX (X = OTf or ClO4) followed by the addition of 1 or 2,2'-bipyridine affords [Au-2(mu-PNP)(2)](OTf)(2) (4) and [Au-2(C10H8N2)(2)(mu-PNP)](ClO4)(2) (5), respectively. Similarly, the macrocycles [Au-4(C4H4N2)(2)(mu-PNP)(2)](ClO4)(4) (6), [Au-4(C10H8N2)(2)(mu-PNP)(2)](ClO4)(4) (7), and [Au-6(C3H3N3)(2)(mu-PNP)(3)](ClO4)(6) (8) are obtained by treating 2 with pyrazine, 4,4'-bipyridine, or 1,3,5-triazine in the presence of AgClO4. The reaction of 1 with AgOTf in a 1:2 molar ratio produces [Ag-2(mu-OTf)(2)(mu-PNP)) (9). The displacement of triflate ions in 9 by 1 leads to a disubstituted derivative, [Ag-2(mu-PNP)(3)](OTf)(2) (10). The equimolar reaction of 1 with AgClO4 in THF affords [Ag-2(C4H80)(2)(mu-PNP)(2)](ClO4)(2) (11). Treatment of 1 with AgClO4 followed by the addition of 2,2'-bipyridine affords a discrete binuclear complex, [Ag-2(C10H8N2)(2)(mu-PNP)](ClO4)(2) (12), whereas similar reactions with 4,4'-bipyridine or pyrazine produce one-dimensional zigzag Ag' coordination polymers, [Ag-2(C10H8N2)(mu-ClO4)(ClO4)(mu-PNP)](n) (13) and [Ag-2(C4H4N2)(mu-ClO4)(ClO4)(mu-PNP)](n) (14) in good yield. The nature of metal-metal interactions in compounds 2, 4, 5, and 12 was analyzed theoretically by performing HF and CC calculations. The structures of the complexes 2, 4, 5, 7, 9, 12, and 14 are confirmed by single crystal X-ray diffraction studies

Molecular Complexes Featuring Unsupported Dispersion-Enhanced Aluminum-Copper and Gallium-Copper Bonds

The reaction of the copper(I) β-diketiminate copper complex {(Cu(BDI^{Mes}))_{2}(μ-C_{6}H_{6})} (BDI^{Mes} = N,N'-bis(2,4,6-trimethylphenyl)pentane-2,4-diiminate) with the low-valent group 13 metal β-diketiminates M(BDI^{Dip}) (M = Al or Ga; BDI^{Dip} = N,N'-bis(2,6-diisopropylphenyl)pentane-2,4-diiminate) in toluene afforded the complexes {(BDI^{Mes})CuAl(BDI^{Dip})} and {(BDI^{Mes})CuGa(BDI^{Dip})}. These feature unsupported copper-aluminum or copper-gallium bonds with short metal-metal distances, Cu-Al = 2.3010(6) Å and Cu-Ga = 2.2916(5) Å. Density functional theory (DFT) calculations showed that approximately half of the calculated association enthalpies can be attributed to London dispersion forces

Synthesis, structure and reaction chemistry of a nucleophilic aluminyl anion

The reactivity of aluminium compounds is dominated by their electron deficiency and consequent electrophilicity; these compounds are archetypal Lewis acids (electron-pair acceptors). The main industrial roles of aluminium, and classical methods of synthesizing aluminium–element bonds (for example, hydroalumination and metathesis), draw on the electron deficiency of species of the type AlR3 and AlCl31,2. Whereas aluminates, [AlR4]−, are well known, the idea of reversing polarity and using an aluminium reagent as the nucleophilic partner in bond-forming substitution reactions is unprecedented, owing to the fact that low-valent aluminium anions analogous to nitrogen-, carbon- and boron-centred reagents of the types [NX2]−, [CX3]− and [BX2]− are unknown3,4,5. Aluminium compounds in the +1 oxidation state are known, but are thermodynamically unstable with respect to disproportionation. Compounds of this type are typically oligomeric6,7,8, although monomeric systems that possess a metal-centred lone pair, such as Al(Nacnac)Dipp (where (Nacnac)Dipp = (NDippCR)2CH and R = tBu, Me; Dipp = 2,6-iPr2C6H3), have also been reported9,10. Coordination of these species, and also of (η5-C5Me5)Al, to a range of Lewis acids has been observed11,12,13, but their primary mode of reactivity involves facile oxidative addition to generate Al(III) species6,7,8,14,15,16. Here we report the synthesis, structure and reaction chemistry of an anionic aluminium(I) nucleophile, the dimethylxanthene-stabilized potassium aluminyl [K{Al(NON)}]2 (NON = 4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene). This species displays unprecedented reactivity in the formation of aluminium–element covalent bonds and in the C–H oxidative addition of benzene, suggesting that it could find further use in both metal–carbon and metal–metal bond-forming reactions.peerReviewe