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We developed a cost-effective spiro-type 4,4 ',4 '',4 '''\-(2H,2 ' H,4H,4 ' H-3,3 '-spiro-bi[thieno[3,4-b][1,4] dioxepine]-6,6 ',8,8 '-tetrayl) tetrakis(N,N-bis(4-methoxyphenyl)aniline) hole transporting material (PST1) for perovskite solar cells (PSCs) that works efficiently even without a cobalt dopant. The PST1 is obtained by employing facile synthetic routes and tends to crystallize in the solid state. An X-ray diffraction study of PST1 revealed a unique quasi-spiro molecular configuration and found multiple CH/pi and pi-pi intermolecular contacts. For the first time, the crystal structure of 2,2 ',7,7 '-tetrakis(N,N '-di-p-methoxyphenylamine)-9,9 '-spirobifluorene (spiro-OMeTAD) is also studied for comparison. The device based on PST1 exhibited a PCE of 13.44%, and a comparable 12.74% PCE was achieved for its undoped form, which paves the way for developing new low cost hole transporting materials and final industrialization of perovskite solar cells.

Anodic voltammetry and electrolysis of the metallocenes ferrocene, ruthenocene, and nickelocene have been studied in dichloromethane containing two different fluorine-containing anions in the supporting electrolyte. The perfluoroalkoxyaluminate anion [Al(OC(CF3)3)4]− has very low nucleophilicity, as shown by its inertness towards the strong electrophile [RuCp2]+ and by computation of its electrostatic potential in comparison to other frequently used electrolyte anions. The low ion-pairing ability of this anion was shown by the large spread in E1/2 potentials (ΔE1/2 = 769 mV) for the two one-electron oxidations of bis(fulvalene)dinickel. The hexafluoroarsenate anion [AsF6]−, on the other hand, reacts rapidly with the ruthenocenium ion and is much more strongly ion-pairing towards oxidized bis(fulvalene)dinickel (ΔE1/2 = 492 mV). In terms of applications of these two anions to the anodic oxidation of organometallic sandwich complexes, the behavior of [Al(OC(CF3)3)4]− is similar to that of other weakly-coordinating anions such as [B(C6F5)4]−, whereas that of [AsF6]− is similar to the more traditional electrolyte anions such as [PF6]− and [BF4]−. Additionally, the synthesis and crystal structure of [Cp2Fe][Al(OC(CF3)3)4] are reported.

Exposure of the tetrameric, heterocubane-like perfluorinated lithium alkoxide [Li{OC(CF3)3}]4 to humid air gaverise to the hydrolysis products [{(CF3)3CO}Li(H2O)2-μ-(H2O)-Li(H2O)2{OC(CF3)3}], [{(CF3)3CO}Li(H2O)2-μ-(H2O)-Li-(H2O)3]+[OC(CF3)3]– and [Li(H2O)4]+[OC(CF3)3]– because of stepwise addition of water molecules in a gas-solid reaction without solvent. All compounds were studied by X-ray crystallography and their solid-state structures are strongly influenced by hydrogen bonding and fluorophilic interactions.

The room-temperature stable CI3+ salts [CI3+[pftb](-)1 and [CI3]+[al-f-al](-) 2([pftb](-) = [Al(OC(CF3)3)4](-); [al-f-al](-) = [((CF3)3CO)3Al-F-Al(OC(CF3)3)3](-)) were prepared in quantitative yields from purified CI4 and the corresponding silver aluminates with total exclusion of light (NMR, IR, UV-VIS, X-ray diffraction). The isolated CI(3)(+) cation is trigonal planar with a sum of(I-C-I) = 360.0 degrees (1) and 359.9 degrees (2). Attempts to prepare CHI2+ and CH2I+ salts from CHI3 or CH2I2/Ag[pftb] mixtures remained unsuccessful; the reaction with CH2I2 leads to the formation of the adduct [Ag(CH2I2)3]+[pftb](-)3, while for HCI3, dismutation with formation of 1 as well as 3 was observed. All particles were also calculated at the MP2/TZVPP level to predict the vibrational and electronic spectra as well as to calculate the Gibbs free energies of all reactions (DeltaG degrees , gas phase and CH2Cl2 solution). Quantum chemical calculations were also used to investigate the stability of the [pftb](-) anion against the electrophilic attack of the CX3+ and CHnX3-n+ cations (X = F-I, n = 1-3). The strength of the Lewis acidity of these cations and of the isoelectronic boron halides BX()and BHnX3-n have been established on the basis of their fluoride ion affinities (FIAs). The FIAs of the carbon and the boron containing compounds show opposite trends, with fluorinated halomethyl cations being stronger acids than their heavier congeners but iodinated holoboranes being stronger acids than their lighter homologues.

To compensate for lacking experimental standard enthalpies of formation ΔfH° of haloboranes/−boranates as well as the isoelectronic halocarbenium ions and halomethanes, high-level quantum chemical calculations up to the ccsd(t)/(SDB-)aug-cc-pVQZ level have been performed to establish these values. Very reliable experimental data (e.g., ΔfH° of HCl, F, and CH4) or at the G3 level established values (e.g., ΔfH° of CF3+ = 410 kJ mol-1) were used as anchor points to obtain accurate absolute ΔfH° and mean bond enthalpy (mBE) values. To further minimize systematic errors of the protocol, all derived quantities were assessed in isodesmic reactions at the G3 and ccsd(t) level using the (SDB-)aug-cc-PVTZ basis set. The obtained ΔfH° values are in very good agreement to (scarcely available) accurate experimental and computational data. Almost all B-containing compounds have been assessed for the first time. We derived “best” ΔfH° values and used them to determine the mean E−X bond enthalpies in H4-nEXn-/0 and H3-nE...

This contributions shows with a series of ab initio MP2 and DFT (BP86 and B3-LYP) computations with large basis sets up to cc-pVQZ quality that the literature value of the std. enthalpy of depolymn. of 1/4Sb4F20(g) to give SbF5(g) (+18.5 kJ mol-1) [J. Fawcett, J. H. Holloway, R. D. Peacock, D. R. Russell, J. Fluorine Chem. 20 (1982) 9] is by about 50 kJ mol-1 in error and that the correct value of DrH Degdeploy. (1/4Sb4F20(g)) is +68 +- 10 kJ mol-1. We assign DrH Degdeploydepoly., DrH Deg, DrG Deg and DrG Deg values for SbnF5n with n = 2-4 and compare the results to available exptl. gas phase data. Esp. the MP2/TZVPP values obtained in an indirect procedure that rely on isodesmic reactions or the highly accurate compd. methods G2 and CBS-Q are in excellent agreement with the exptl. data, and reproduce also the fine exptl. details at temps. of 423 and 498 K. With these data and the addnl. calcn. of [SbnF5n+1]- (n = 1-4), we then assessed the fluoride ion affinities (FIAs) of SbnF5n(g), nSbF5(g), nSbF5(l) and the std. enthalpies of formation of SbnF5n(g) and [SbnF5n+1]-(g): FIA(SbnF5n(g)) = 514 (n = 1), 559 (n = 2), 572 (n = 3) and 580 (n = 4) kJ mol-1; FIA(nSbF5(g)) = 667 (n = 2), 767 (n = 3) and 855 (n = 4) kJ mol-1; FIA(nSbF5(l)) = 434 (n = 1), 506 (n = 2), 528 (n = 3) and 534 (n = 4) kJ mol-1. Error bars are approx. +-10 kJ mol-1. Also the related Gibbs energies were derived. DfH Deg([SbnF5n+1]-(g)) = -2064 +- 18 (n = 1), -3516 +- 25 (n = 2), -4919 +- 31 (n = 3) and -6305 +- 36 (n = 4) kJ mol-1. [on SciFinder (R)]

The unexpected but facile preparation of the silver salt of the least coordinating [(RO)3Al-F-Al(OR)3]- anion (R=C(CF3)3) by reaction of Ag[Al(OR)4] with one equivalent of PCl3 is described. The mechanism of the formation of Ag[(RO)3Al-F-Al(OR)3] is explained based on the available experimental data as well as on quantum chemical calculations with the inclusion of entropy and COSMO solvation enthalpies. The crystal structures of (RO)3Al--OC4H8, Cs+[(RO)2(Me)Al-F-Al(Me)(OR)2]-, Ag(CH2Cl2)3+[(RO)3Al-F-Al(OR)3]- and Ag(eta2-P4)2+[(RO)3Al-F-Al(OR)3]- are described. From the collected data it will be shown that the [(RO)3Al-F-Al(OR)3]- anion is the least coordinating anion currently known. With respect to the fluoride ion affinity of two parent Lewis acids Al(OR)3 of 685 kJ mol(-1), the ligand affinity (441 kJ mol(-1)), the proton and copper decomposition reactions (-983 and -297 kJ mol(-1)) as well as HOMO level and HOMO-LUMO gap and in comparison with [Sb4F21]-, [Sb(OTeF5)6]-, [Al(OR)4]- as well as [B(R(F))4]- (R(F)=CF3 or C6F5) the [(RO)3Al-F-Al(OR)3]- anion is among the best weakly coordinating anions (WCAs) according to each value. In contrast to most of the other cited anions, the [(RO)3Al-F-Al(OR)3] anion is available by a simple preparation in conventional inorganic laboratories. The least coordinating character of this anion was employed to clarify the question of the ground state geometry of the Ag(eta2-P4)2+ cation (D(2h), D(2) or D(2d)?). In agreement with computational data and NMR spectra it could be shown that the rotation along the Ag-(P-P-centroid) vector has no barrier and that the structure adopted in the solid state depends on packing effects which lead to an almost D(2h) symmetric Ag(eta2-P4)2+ cation (0 to 10.6 degrees torsion) for the more symmetrical [Al(OR)4]- anion, but to a D2 symmetric Ag(eta2-P4)2+ cation with a 44 degrees twist angle of the two AgP2 planes for the less symmetrical [(RO)3Al-F-Al(OR)3]- anion. This implies that silver back bonding, suggested by quantum chemical population analyses to be of importance, is only weak.

Good quality ab initio calculations (MP2) show that the water adducts of BX(3) and CX(3)(+) have totally different structures (X = F-I). While all H(2)O-BX(3) complexes have classical C(s) symmetric structures with strong B-O bonds and additional H-bonding, the heavier CX(3)(+) cations (X = Cl-I) form weakly bonded "non-classical" water adducts that maximize C-X pi-bonding rather than C-O sigma-bonding. The delocalization of the positive charge as the driving force for pi-bond formation is absent in BX(3), and therefore, pi-bonding is only weak and not structure determining in H(2)O-BX(3). Since the PES of all H(2)O --EX(3)(0/+1) particles (E = B, C) is very flat, flexible basis sets (like TZVPP) are required to rigorously characterize the adducts. In earlier calculations (J. Am. Chem. Soc. 1997, 119, 6648), classical structures were reported for all H(2)O --EX(3)(0/+1) (E = B, C) complexes, likely resulting from the insufficient quality of the basis sets employed. By introducing a positive charge to three coordinate boron-halogen cations Do --BX(2)(+) (Do = NH(3), OH(2), X-H), also the B-X bonds shrink due to the stronger pi-bonding induced by the positive charge delocalization and if compared to the respective neutral compounds like H(2)N-BX(2) or BX(3). The "non-classical" water adducts also suggest that the mechanism of organic reactions involving carbenium ion intermediates with alpha-bromine or -iodine substituents and a nucleophile may proceed through halogen- rather than carbon coordination.

Is there anything resembling a truly noncoordinating anion? Would it not be great to be able to prepare any crazy, beautiful, or simply useful cationic species that one has in mind, or has detected by mass spectroscopy? In condensed phases the target cation has to be partnered with a suitable counteranion. This is the moment when difficulties arise and many wonderful ideas end in the sink owing to coordination or decomposition of the anion. However, maybe these counteranion problems can be overcome by one of the new weakly coordinating anions (WCAs). Herein is an overview on the available candidates in the quest for the least coordinating anion and a summary of new applications, available starting materials, and general strategies to introduce a WCA into a system. Some of the unusual properties of WCA salts such as high solubility in low dielectric media, pseudo gas-phase conditions in condensed phases, and the stabilization of weakly bound and low-charged complexes are rationalized on thermodynamic grounds. Limits of the WCAs, that is, anion coordination and decomposition, are shown and a quantum chemical analysis of all types of WCAs is presented which allows the choice of a particular WCA to be based on quantitative data from a wide range of different anions.

Prepn. of the title compd. (I) from starting materials CI4 and Ag[Al{OC(CF3)3}4](II) was performed with the complete exclusion of light and with carefully purified diiodine-free CI4, since CI4 decomps. within minutes in soln. in light with formation of I2 and other carbon iodides, and II reacts immediately with I2 to give yet unidentified decompn. products. With these precautions I was prepd. in quant. yield. According to calcns. at the MP2/TZVPP level and estn. of the sublimation and lattice enthalpies in a suitable cycle, we est. that the reaction is exothermic by -33 kJmol-1 in the gas phase and by -127 kJmol-1 in the solid state. In CH2Cl2 soln., I is dark blood red and in situ NMR reactions show only resonance signals for the CI3+ ion (d(13C)= 97 ppm; in SO2ClF: d(13C) = 95 ppm; calcd. value: d(13C) = 106 ppm) and the anion (d(13C) = 121.5 ppm (q); d(27A1)= 38.0 ppm). A CH2Cl2 soln. of I is stable for about 8 to 12 h at ambient temp. and much longer if stored at -30 or -78 DegC. Single crystals that appeared yellow as thin plates but black when thicker were grown at -78 DegC from cooled concd. CH2Cl2 solns. of I. The crystal structure detn. of a dark orthorhombic block of I showed that it contained isolated trigonal-planar CI3+ ions with a sum of I-C-I bond angles of 360.0 Deg (range: 118.8-122.1 Deg0) and Al{OC(CF3)3}4 ions. [on SciFinder (R)]

Insertion of the intermediately formed carbene-analogous PX24 ion (X = Br, I) into one of the P-P bonds of the P4 tetrahedron led to the P5X2+ ion - the 1st example of the previously unknown class of phosphorus-rich binary P-X cations. The crystal structure of [P5Br2]+[Al{OC(CF3)3}]- was detd. and mol. structure calcns. were performed on both the bromide and iodide analogs. [on SciFinder (R)]

We present a solar cell architecture that simultaneously accentuates the benefits of lead chalcogenide colloidal quantum dots while addressing their shortcomings. The resulting 3-dimensional heterojunction exhibits over 5% power conversion efficiency.

We have designed and synthesized highly efficient organic sensitizers with a planar thienothiophene-vinylene-thienothiophene linker. Under standard global AM 1.5 solar conditions, the JK-113-sensitized cell gave a short circuit photocurrent density (J(sc)) of 17.61 mA cm(-2), an open-circuit voltage (V(oc)) of 0.71 V, and a fill factor (FF) of 72%, corresponding to an overall conversion efficiency (eta) of 9.1%. The incident monochromatic photo-to-current conversion efficiency (IPCE) of JK-113 exceeds 80% over the spectral region from 400 to 640 nm, reaching its maximum of 93% at 475 nm. The band tails off toward 770 nm, contributing to the broad spectral light harvesting. Solar-cell devices based on the sensitizer JK-113 in conjunction with a volatile electrolyte and a solvent-free ionic liquid electrolyte gave high conversion efficiencies of 9.1% and 7.9%, respectively. The JK-113-based solar cell fabricated using a solvent-free ionic liquid electrolyte showed excellent stability under light soaking at 60 degrees C for 1000 h.

In this study, we investigated the tetraalkylammonium salts of the weakly coordinating fluorinated alkoxyaluminates [pftb](-) ([Al(O(C(CF(3))(3))(4)](-)), [hfip](-) ([Al(OC(H)(CF(3))(2))(4)](-)) and [hftb](-) ([Al(OC(CH(3))(CF(3))(2))(4)](-)) in order to obtain information on their undisturbed spectral and structural properties, as well as to study their electrochemical behavior (i.e., conductivities in non-polar solvents and electrochemical windows). Several of the compounds qualify as ionic liquids with melting points as low as 42 degrees C for [NBu(4)](+)[hfip](-). Simple and almost quantitative metathesis reactions yielding these materials in high purity were developed. These [NR(4)](+) salts serve as model compounds for undisturbed anions and their vibrational spectra--together with simulated spectra based on quantum chemical DFT calculations--were used for the clear assignment of the anion bands. Besides, the ion volumes of the anions (V(ion)([pftb](-)) = 0.736 nm(3), V(ion)([hftb](-)) = 0.658 nm(3), V(ion)([hfip](-)) = 0.577 nm(3)) and their decomposition pathways in the mass spectrometric measurements have been established. The salts are highly soluble in non-polar solvents (up to 1.09 mol L(-1) are possible for [NBu(4)](+)[hftb](-) in CH(2)Cl(2) and 0.41 mol L(-1) for [NBu(4)](+)[hfip](-) in CHCl(3)) and show higher molar conductivities if compared to [NBu(4)](+)[PF(6)](-). The electrochemical windows of CH(2)Cl(2), CH(3)CN and 1,2-F(2)C(6)H(4) using the [NBu(4)](+) aluminate electrolytes are up to +0.5 V/-0.7 V larger than those using the standard [NBu(4)](+)[PF(6)](-).

What is the preferred coordination site of CI3+? Recent computational work suggested the iodine atoms of the Lewis acid CI3+ to be more electrophilic than the classically expected carbon atom, e.g. the complex with water is of type I2C-I...OH2+ and not the classically expected I3C-OH2+. If this structure is correct, one may also anticipate reactions of CI3+ as an I+ donor. Thus, we were interested in investigating the chemistry of CI3+ in the room-temperature stable salt [CI3]+[pftb](-) ([pftb](-) = [Al(OC(CF3)3)4]-) with weak nucleophiles that i) mimic water (OEt2) or ii) are electronically deactivated weak nucleophiles (PX3, X = Cl-I; AsI3). One question was: is it possible to obtain iodine-coordinated Lewis acid-base adducts of the CI3+ cation? With Et2O as a base, the cation behaves as a strong Lewis acid and cleaves the ether to give I3C-OEt, C2H4 and [H(Et2O)2]+. By contrast PX3 and AsI3 coordinate to the CI3+ cations and the adducts have classical, carbon-bound ethane-like structures, as proven by X-ray single-crystal diffraction, IR, UV-Vis and NMR spectroscopy. From variable temperature 13C NMR studies, it followed for the I3C-AsI3+ salt that the equilibrium between CI3+ and AsI3 is reversible and temperature dependent in solution. The I3C-PI3+ salt decomposes at room temperature giving PI4+ and C2I4, likely through an iodine coordinated I2C-I[dot dot dot]PI3+ intermediate. Thus CI3+ may also act as an I+ donor. All reactions are in agreement with ab initio quantum chemical calculations at the MP2/TZVPP level and assignments of experimental spectra were aided by quantum chemistry.

A review on the available candidates in the quest for the least coordinating anion and a summary of new applications, available starting materials, and general strategies to introduce a WCA into a system. Some of the unusual properties of WCA salts such as high soly. in low dielec. media, pseudo gas-phase conditions in condensed phases, and the stabilization of weakly bound and low-charged complexes are rationalized on thermodn. grounds. Limits of the WCAs, i.e., anion coordination and decompn., are shown and a quantum chem. anal. of all types of WCAs is presented which allows the choice of a particular WCA to be based on quant. data from a wide range of different anions. [on SciFinder (R)]

PX(4) (+)[Al(OR)(4)](-) (X=I: 1 a, X=Br: 1 b) was prepared from X(2), PX(3), and Ag[Al(OR)(4)] [R=C(CF(3))(3)] in CH(2)Cl(2) at -30 degrees C in 69-86 % yield. P(2)X(5) (+) salts were prepared from 2 PX(3) and Ag[Al(OR)(4)] in CH(2)Cl(2) at -30 degrees C yielding almost quantitatively P(2)X(5) (+)[Al(OR)(4)](-) (X=I: 3 a, X=Br: 3 b). The phosphorus-rich P(5)X(2) (+) salts arose from the reaction of cold (-78 degrees C) mixtures of PX(3), P(4), and Ag[Al(OR)(4)] giving P(5)X(2) (+)[Al(OR)(4)](-) (X=I: 4 a, X=Br: 4 b) with a C(2v)-symmetric P(5) cage. Silver salt metathesis presumably generated unstable PX(2) (+) cations from PX(3) and Ag[Al(OR)(4)] (X=Br, I) that acted as electrophilic carbene analogues and inserted into the Xbond;X (Pbond;X/Pbond;P) bond of X(2) (PX(3)/P(4)) leading to the highly electrophilic and CH(2)Cl(2)-soluble PX(4) (+) (P(2)X(5) (+)/P(5)X(2) (+)) salts. Reactions that aimed to synthesize P(2)I(3) (+) from P(2)I(4) and Ag[Al(OR)(4)] instead led to anion decomposition and the formation of P(2)I(5)(CS(2))(+)[(RO)(3)Al-F-Al(OR)(3)](-) (5). All salts were characterized by variable-temperature solution NMR studies (3 b also by (31)P MAS NMR), Raman and/or IR spectroscopy as well as X-ray crystallography (with the exception of 4 a). The thermochemical volumes of the Pbond;X cations are 121 (PBr(4) (+)), 161 (PI(4) (+)), 194 (P(2)Br(5) (+)), 271 (P(2)I(5) (+)), and 180 A(3) (P(5)Br(2) (+)). The observed reactions were fully accounted for by thermochemical calculations based on (RI-)MP2/TZVPP ab initio results and COSMO solvation enthalpy calculations (CH(2)Cl(2) solution). The enthalpies of formation of the gaseous Pbond;X cations were derived as +764 (PI(4) (+)), +617 (PBr(4) (+)), +749 (P(2)I(5) (+)), +579 (P(2)Br(5) (+)), +762 (P(5)I(2) (+)), and +705 kJ mol(-1) (P(5)Br(2) (+)). The insertion of the intermediately prepared carbene analogue PX(2) (+) cations into the respective bonds were calculated, at the (RI-)MP2/TZVPP level, to be exergonic at 298 K in CH(2)Cl(2) by Delta(r)G(CH(2)Cl(2))=-133.5 (PI(4) (+)), -183.9 (PBr(4) (+)), -106.5 (P(2)I(5) (+)), -81.5 (P(2)Br(5) (+)), -113.2 (P(5)I(2) (+)), and -114.5 kJ mol(-1) (P(5)Br(2) (+)).

The metathesis reaction of Ag[(RO)3Al—F—Al(OR)3] and n-Bu4NBr in CH2Cl2 yields nearly quanti­tatively n-Bu4N+.[(RO)3Al—F—Al(OR)3]− [with R = C(CF3)3)] or (C16H36N)[Al2(C4F9O)6F]. In the asymmetric unit, two entire cations and four half-anions (one is disordered over two positions) are found. The intra­molecular distances are comparable to those found in other n-Bu4N+ or [(RO)3Al—F—Al(OR)3]− salts. Only weak inter­actions outside the sum of the van der Waals radii [r(F + H) = 2.6 A] are found between the cations and anions. The title compound is considerably soluble in CH2Cl2, which makes this salt a possible candidate as supporting electrolyte for electrochemical applications in nonpolar solvents. In addition, the [(RO)3Al—F—Al(OR)3]− anion is very stable against oxidation. Two CF3 groups of one anion are disordered over two positions; the site occupancy ratios are 0.64:0.36 and 0.78:0.22.

Insertion of the intermediately formed carbene-analogous PX24 ion (X = Br, I) into one of the P-P bonds of the P4 tetrahedron led to the P5X2+ ion - the 1st example of the previously unknown class of phosphorus-rich binary P-X cations. The crystal structure of [P5Br2]+[Al{OC(CF3)3}]- was detd. and mol. structure calcns. were performed on both the bromide and iodide analogs. [on SciFinder (R)]

Total halide abstraction from LnCl3 by Ag[Al(OC(CF3)3)4]/CH3CN has been confirmed for a series of lanthanide metal ions by the structural characterization of [Ln(CH3CN)n][Al(OC(CF3)3)4]3 (n = 9, Ln3+ = Nd, Eu, Gd, Dy; n = 8, Ln3+ = Tm) complexes. Evidence for the very low coordinating ability of the [Al(OC(CF3)3)4]− anion towards Ln3+ ions is provided in the solid state (X-ray, IR and Raman spectroscopy) and in anhydrous acetonitrile solution (conductivity, EPR and NMR measurements). In the solid state homoleptic nine-coordinated acetonitrile species are characteristic for lanthanides for the beginning (Nd) and the middle (Eu, Gd, Dy) of the Ln series, with a mono-capped square antiprismatic arrangement of the N donor atoms around the metal centres; while for those from the end of the series (Tm) eight-coordinated species are representative with a square antiprismatic arrangement. In anhydrous acetonitrile solution, conductivity measurements revealed 3:1 electrolyte types for all compounds. EPR and 19F NMR line broadening measurements attest lanthanide complexes free of any coordinating [Al(OC(CF3)3)4]− anion.

This article describes BP86/SV(P) (DFT) calculations on a representative set of weakly coordinating anions (WCAs) of type [M(L)n]-, their parent neutral Lewis acids M(L)(n-1) and their ate complexes with fluoride, that is, [FM(L)(n)](n-1) (M=B, L=F, OTeF5, C6H5, C6F5, C6H3(CF3)2, CF3; M=P, As, Sb, L=F, OTeF5; M=Al, L=OC(CF3)3). Compounds with fluoride bridges, that is, Sb(n)F(5n) and [Sb(n)F(5n+1)]- (n=2, 3, 4), Al2(L)5F and [(L)3Al-F-Al(L)3]- (L=OC(CF3)3), (F4C6[1,2-B(L)2]2, [F4C6[1,2-B(L)2]2F]-, [F4C6[1,2-B(L)2]2OMe]- (L=C6F5) were also calculated. Based on these BP86/SV(P) and auxiliary MP2/TZVPP, G2, and CBS-Q calculations the relative stabilities and coordinating abilities of these WCAs were established with regard to the fluoride ion affinities (FIA) of the parent Lewis acids, the ligand affinity (LA) of the WCAs, the decomposition of a given WCA in the presence of a hard (H+, proton decomposition PD) and a soft electrophile (Cu+, copper decomposition CuD), the position of the HOMO, the HOMO-LUMO gap, and population analyses of the anions providing partial charges for all atoms. To obtain data that is more reliable, the assessed quantities were calculated through isodesmic reactions. If parts of the calculations could not be done isodesmically, higher levels such as MP2/TZVPP, G2, and CBS-Q were used to obtain reliable values for these reactions. Although the obtained results can not be taken as absolute, the relative ordering of the stabilities of all WCAs will undoubtedly be correct, since a single methodology was chosen for the investigation. To include media effects the decomposition reactions of a subset of 14 WCAs with the SiMe3+ and [Cp2ZrMe]+ ions were also calculated in PhCl and 1,2-F2C6H4 (COSMO solvation model). We found that in most cases gas-phase calculations and solution calculations give comparable results for the stability of the anion. Applications of the LA and FIA that allow one to decide, on thermodynamic grounds, which WCA or Lewis acid is the most suitable for a given problem are sketched.