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1,1,1,1 -Tetrakis[triorganylphosphineaurio(I)]ethanium(+) Tetrafluoroborates - Hypercoordinated Species Containing [H3C -C (A uL )4I+ CationsOliver Steigeimann, Peter Bissinger, and H ubert Schm idbaur*Anorganisch-chemisches Institut der Technischen Universität München,Lichtenbergstraße 4, D-W-8046 GarchingZ. Naturforsch. 48b, 72-78 (1993); received September 10, 1992Auriophilicity, Gold(I) Phosphine Complexes, Ethane-tetraaurio(I) Compounds, X-Ray

Hypercoordinate, tetraaurated carbon-complexes of the type [H3C -C (A u P R 3)4]+BF4~, R = Ph (1), R = C6H u (2), (PR3) 2 = l,2-C 6H4(CH 2CH 2PPh2) 2 (3) have been prepared by the reac­tion of the appropriate (phosphane)gold(I) chlorides with l,l,l-tris(dim ethoxyboryl)ethane H 3C -C [B (O M e ) 2]3 in the presence of CsF. The products have been characterized by standard analytical and spectroscopic methods, including single crystal X-ray analyses of 1 and 2. In each case the pentacoordinated carbon atoms have been located at the centre of a square pyr- amide built up by a methyl group at the apex and four gold atoms forming the base with short Au ••• Au distances of about 2.85 A, which strongly contribute to the formation and stability of these species.

Introduction

The special position o f gold in the Periodic Table is largely based on relativistic effects [1], which modify significantly the properties o f the valence electrons o f Post-Lanthanide elements. The relativistic contraction o f the 6 s orbitals o f the heavy elements reaches a pronounced local m axi­mum for gold and leads to a break-up o f the 5 d 10 closed shell o f electrons in the Au(I) oxidation state. A wealth o f evidence has been obtained from structural and spectroscopic studies o f both mono- and polynuclear gold(I) com pounds for the exist­ence o f the resulting metal-metal bonding between A u + centers [2], In tra- and interm olecular metal- metal interactions give rise not only to the aggre­

gation o f complex units L - A u - X o f phosphane gold com pounds [3], but also to a clustering of gold(I) atom s at or around a main group element like carbon, nitrogen, phosphorus, arsenic, oxy­gen, sulfur, and selenium [4-10]. A part from spe­cies with a m ore conventional stoichiometry [(AuL)3E]+ (E = O [8], S [9a], Se [10a]), [(AuL)4N ]+ [5 a -c ,7 ] , [(AuL)3N R ]+ [5e-g], [(AuL)3PR ]+ [6 ] , or C (A uL )4 [ 6 c] , novel cations [(AuL)4A s]+ [7] with a nonclassical square-pyram i- dal structure and the unprecedented hypercoor­dinated cations [(AuL)5C]+ [4d], [(AuL)6C]2+ [4c, e -h ] , [(AuL)5N]2+ [5d], and [(AuL)5P]2+ [6 a] have been discovered.

r— — 2 + — _ n+ —LAu Au R

1 ..-A u L 1 ,,-A u L 1

L A u ^ | " '^ A u LLAu — X ' '

| ^ * A u Lx

L A u '" ^ \^" 'A uL

AuL

Au LAu AuL_ _ _ _

B: X = C, n = 1

C: X = N, n = 2

D: X = P, n = 2

E: X = C, n = 1

F: X = P, n = 2

* Reprint requests to Prof. Dr. H. Schmidbaur.Verlag der Zeitschrift für Naturforschung,D-W-7400 Tübingen0932-0776/93/0100-0072/$ 01.00/0

While the num ber o f hom oleptic species A -D with the interstitial atom in the center o f trigonal bipyram ids or octahedra o f gold atom s has been steadily increasing, only two examples are known

O. Steigeimann et al. • Tetraaurio(I) Complexes 73

to date where the coordination sphere around the hypercoordinate central atom contains also a non­gold substituent (E ,F): These two dications [RP(A uL)4]2+ [6 b] (R = o-tolyl) and (dimeric) [RC(A uL)4]+ [4 b] (R = oxazolinyl) feature square pyram idal structures with, respectively, phospho­rus or carbon at the center, the R substituent at the apex, and the four gold atom s at the base o f the polyhedron, with short Au-- Au contacts, indica­tive o f the origin o f this unusual clustering o f gold in both cases.

We now report on simple com pounds with five-coordinated carbon atom s in cationic C H 3-C [A u P R 3]4 units.

Results

In preceding w ork tetrakis(dim ethoxyboryl)- m ethane C[B(OM e)2]4 and bis(dimethoxyboryl)- m ethane H 2C[B(OM e)2]2 were found to be excel­lent starting m aterials for the synthesis o f highly aurated hom oleptic carbon centered clusters [4 c, d, e -h ] . Thus, the reactions o f C[B(OM e)2]4 with (triorganylphosphine)gold(I) chlorides LAuCl in the presence o f CsF lead to the form ation o f hy­percoordinated hexakis(phosphineaurio(I))-m eth- anium (2+) dications o f the type [(AuL)6C]2+. The degree o f au ra tion could be reduced from six to five and four by the use o f gold chloride complexes with bulky phosphanes [6 c],

W hen l,l,l-tris(d im ethoxybory l)e thane was chosen as the precursor, which is readily obtained

from the reaction o f 1, 1, 1-trichlorom ethane and ClB(OM e)2 w ith lithium pow der in tetrahydro- furan, as described by M atteson et al. [11], the analogous reaction led to the title com pounds. The gold(I) chloride complexes o f PPh3, P(C 6H ,,)3 andl,2-C 6H 4(C H 2C H 2PPh2)2 required, were readily available via published m ethods [12, 13, 4 e].

Treatm ent o f the individual (phosphine)gold(I) chloride w ith l,l,l-tris(d im ethoxybory l)e thane in the presence o f cesium fluoride in hexamethyl- phosphoric triam ide (H M PT ) produced yellow solutions. A fter filtration and precipitation with pentane/benzene crystalline complexes [H3C -C (A u P P h 3)4]+BF4- (1), [H3C -C (A u P { C 6H u }3)4]+BF4- (2) and [H3C -C ({ A u P P h 2C H 2C H 2}2C 6H 4)2]+BF4- (3) were obtained.

The products 1, 2 (yellow) and 3 (colourless) are airstable, hygroscopic substances, insoluble in non-polar solvents like pentane, slightly soluble in benzene and readily soluble in dichlorom ethane or H M PT. The com pounds decom pose on melting. Characterization is achieved by elemental analysis, mass spectrom etry and N M R spectroscopy. The data are sum m arized in the Experim ental Section.

The existence o f the hypercoordinated species [CH3-C (A u P R 3)4]+ was first established by high- resolution field desorption (FD ) mass spectrosco­py. In the m ass spectral studies the parent peaks at m /z = 1864.7 (1), 1936.1 (2), and 1821.1 (3) can readily be assigned to the appropriate cations.

H3C-C[B (O M e)2]3

+ 4 CsF

- 4 CsCI

- 2 (MeO)3B

CH+ 4 RjPAuCI. + 4 CsF

- 4 CsCI, - 2 (MeO)jB R p ^ A u " - / \~ " A u .3 Au Au

/ \RjP PR3

b f 4-‘ PR-i

Ph2PAuCIocx.Ph,

1 : R = Ph

2 : R = c—C6H„

b f 4~

74 Q. Steigeimann et al. • Tetraaurio(I) Complexes

Table I. { 'H}3IP NMR chemical shifts 6 [ppm] for com­pounds R3PAuCl and [CH3-C (A uP R 3)4]BF4.

p r 3 R3PAuC1 [CH3C(AuPR3)4]BF4

PPh-, 33.4 32.1P(C6H n ) 3 54.9 49.5'/2(Ph,PCH,CH,)2C6H4 29.2 27.5

The { 'H } 3IP -N M R spectra at room tem perature of com pounds 1 -3 in dichlorom ethane-d2 show one sharp singlet resonance in each case, which is not only indicative o f a virtual fourfold symmetry of the cations o f 1 and 2, but also dem onstrates the equivalence o f the ligand halves in the chelated cation o f 3. W hen com pared to the data o f the co r­responding (phosphine)gold(I) chlorides, upfield shifts can be stated (Table I), as already reported for the conversion o f (phosphine)gold(I) com ­pounds to hom oleptic hypercoordinated species [(AuL)5C]+ [4d], [(AuL)6C]2+ [ 4 c , e -h ] . The equi­valence o f the LAu units is further established by the num ber and multiplicity o f the signals in the ’H N M R spectra. Besides the resonances o f the (phos- phine) ligands, symmetrical 1 :4 :6 :4 :1 quintets could be observed for the methyl hydrogen atom s at ö = 3.55 (1), 3.22 (2) and 3.65 ppm (3) due to a V HP coupling with the phosphorus atom s of the phos- phines (Fig. 1). The signals appear in a region down- field from the resonances o f /^-hydrogen atoms in al- kylgold(I) complexes like (H 3C)3CA uPPh3 (ö = 1.97 ppm) [14] attesting a deshielding with an increas­ing degree o f auration. The absolute values o f the coupling constants V HP (between 4.3 and 4.7 Hz)

are also in good agreement with that found for (H 3C)3C -A u P P h 3 (V HP = 6.5 Hz).

In the { 'H }13C N M R spectrum of [H3C -C (A u P P h 3)4]BF4 the resonances o f the phenyl carbon atom s show a pattern also com m on for homoleptic carbon centered gold cluster cations. The doublet for the ipso C atom is shifted downfield as com pared to the corresponding reso­nance in Ph3PAuCl, whereas the o ther phenyl sig­nals are largely unchanged. The o- and w -carbon atoms give rise to centered doublets caused by long range P - P ' coupling. The resonance o f the term i­nal H 3C group appears as a singlet at Ö = 28.2 ppm. The signal o f the interstitial carbon could not be detected, and partial enrichm ent with ,3C will probably be necessary for a direct observation of the nucleus, a procedure already successfully ap ­plied for the [C(AuL)6]:+ species [4f],

Crystal Structure Determinations

Because o f strong crystal d isorder in all samples of 1 so far investigated, only the C - C ( A u - P )4 skeleton could be determ ined for the cation in [H3C -C (A u P P h 3)4]BF4, which crystallizes in the triclinic space group P i with two stoichiom etric equivalents in the unit cell excluding any crystallo- graphical symmetry for the individual cation. N ev­ertheless, by using a split m odel and refining A u -P moieties at two positions, the coordination geometry at the interstitial carbon atom could be established beyond any doubt. The penta-coordi- nated cluster C atom is capping a square o f gold atom s and is associated with an apical methyl group (Fig. 2). The structure solution is a prelim i­nary result.

Fig. 1. Quintet CH 3 resonance in th e 'H NM R spectrum Fig. 2. Structure of the C -C [A uP ]4 framework in the of[H 3C -C (A uP P h 3)4]BF4 (l) in CD 2C12. cation of 1 (ORTEP. arbitrary radii).

O. Steigeimann et al. • Tetraaurio(I) Complexes 75

The resulting tetragonal-pyram idal environ­ment o f the central carbon atom was fully con­firmed, however, for the[H3C -C (A u P { C 6H n }3)4]+ cation in 2, which crys­tallizes in the triclinic space group P i with two for­m ula units in the unit cell. The carbon-carbon bond distance center-apex corresponds to a stand­ard C - C single bond. The average A u - C - A u an ­gle o f 83° and gold-carbon distances between 2.14 and 2.19Ä give rise to short intram olecular A u -"A u contacts o f 2.816Ä (average). The local geometrical situation at the interstitial cluster atom is thus com parable to that found for the cen­tral carbon atom in the[Au(oxazolinyl)C(A uPPh3)3]22̂ dication [4b], The increasing sterical dem and o f the tricyclohexyl- phosphine ligands in 1 as com pared to the PPh3 substituents in the oxazolinyl complex is reflected in an elongation o f the A u - P bonds (average 2.30Ä vs. 2 .26Ä) and in larger deviations o f the C - A u - P angles (average 169.9° vs. 175.0°) from linearity.

F ractional atom ic coordinates and equivalent isotropic displacem ent param eters for 2 are given in Table II, selected structural param eters in the cation to Fig. 3 [15].

Table II. Fractional atomic coordinates and equivalent isotropic displacement parameters for 2. (U(eq.) = (U 1 ■ U 2 ■ U 3)1-'3, where U 1, U 2, U 3 are the eigenvalues of the U(ij) matrix. E.s.d.'s in parentheses).

Atom x a y /b z/c U(eq.

A ul 0 .0 2 2 1 0 (8 ) 0.73650(9) 0.28863(8) 0.043Au2 -0.16285(8) 0.75131(9) 0.27675(8) 0.042Au3 0.00806(8) 0.92282(9) 0.28321(8) 0.044Au4 -0.17795(8) 0.93017(9) 0.29693(8) 0.044PI 0.1352(5) 0.6352(6) 0.2753(5) 0.046P2 -0.2551(6) 0.6595(6) 0.2423(6) 0.047P3 0 . 1 0 0 0 (6 ) 1.0356(6) 0.2499(6) 0.049P4 -0.2894(6) 1.0388(6) 0.2863(6) 0.053C l -0.079(2) 0.821(2) 0.326(2) 0.035C2 -0.082(2) 0.793(2) 0.401(2) 0.054c m 0.113(2) 0.526(2) 0.323(2) 0.048C 112 0.100(3) 0.526(3) 0.405(2) 0.072C 113 0.080(3) 0.427(3) 0.446(2) 0.072C 114 0.000(4) 0.394(4) 0.417(3) 0.107C 115 0.016(3) 0.393(3) 0.342(3) 0.097C 116 0.035(3) 0.491(3) 0.296(2) 0.078C 121 0.156(3) 0.625(3) 0.186(2) 0.068C 122 0.224(3) 0.540(3) 0.173(3) 0 . 1 0 0C 123 0.219(5) 0.541(5) 0.093(4) 0.146C 124 0.251(4) 0.626(4) 0.047(3) 0.124C 125 0.185(4) 0.700(4) 0.060(3) 0.123C 126 0.187(3) 0.711(4) 0.142(3) 0.103

Table II. (Fortsetzung).

Atom x /a y /b z/c U(eq.)

C 131 0.237(3) 0.668(3) 0.301(2) 0.072C 132 0.309(2) 0.592(3) 0.323(2) 0.062C 133 0.392(3) 0.630(3) 0.337(3) 0.092C 134 0.375(3) 0.680(3) 0.399(3) 0.087C 135 0.304(3) 0.756(3) 0.382(2) 0.084C l 36 0.218(3) 0.719(3) 0.365(2) 0.081C 211 -0.194(2) 0.581(3) 0.194(2) 0.062C212 -0.129(3) 0.636(3) 0.136(3) 0.097C213 -0.067(4) 0.570(4) 0.098(3) 0.114C214 -0.134(4) 0.507(4) 0.078(3) 0.118C215 -0.183(4) 0.456(4) 0.130(3) 0.113C216 -0.242(3) 0.523(3) 0.162(3) 0.097C 2 2 1 -0.302(2) 0.590(2) 0.319(2) 0.059C 2 2 2 -0.354(3) 0.654(3) 0.361(2) 0.083C223 -0.398(2) 0.586(3) 0.429(2) 0.063C224 -0.319(3) 0.549(3) 0.477(3) 0.099C225 -0.266(3) 0.481(3) 0.435(3) 0.093C226 -0.225(3) 0.534(3) 0.362(2) 0.070C231 -0.348(3) 0.721(3) 0.195(2) 0.067C232 -0.421(3) 0.657(3) 0.189(2) 0.083C233 -0.501(4) 0.725(4) 0.150(3) 0 . 1 1 1C234 -0.465(4) 0.775(4) 0.088(3) 0.119C235 -0.402(4) 0.841(4) 0.104(3) 0 . 1 1 1C236 -0.319(4) 0.775(4) 0.132(3) 0.108C311 0.143(3) 1.065(3) 0.326(2) 0.066C312 0.188(3) 0.986(3) 0.372(2) 0.074C313 0.224(3) 1.017(3) 0.432(3) 0.099C314 0.134(4) 1.041(4) 0.480(3) 0.129C315 0.088(4) 1.113(4) 0.440(3) 0.115C316 0.061(3) 1.101(3) 0.372(3) 0.088C321 0.195(2) 1.018(3) 0.193(2) 0.063C322 0.276(2) 1.067(3) 0.203(2) 0.063C323 0.347(5) 1.064(5) 0.129(4) 0.145C324 0.373(4) 0.956(4) 0.142(3) 0 . 1 1 2

C325 0.295(4) 0.908(4) 0.126(3) 0.109C326 0.224(4) 0.923(4) 0.191(3) 0.104C331 0.044(3) 1.135(3) 0.205(2) 0.068C332 -0.004(3) 1.120(3) 0.141(2) 0.078C 333 -0.068(4) 1.196(4) 0.106(3) 0.114C 334 -0.005(4) 1.273(4) 0.083(4) 0.134C335 0.034(4) 1.300(4) 0.140(3) 0 . 1 2 1

C 336 0.092(3) 1.215(3) 0.172(2) 0.085C411 -0.390(3) 0.989(3) 0.329(2) 0.076C412 -0.471(5) 1.047(5) 0.338(4) 0.139C413 -0.559(6) 0.990(6) 0.379(5) 0.189C414 -0.478(6) 0.878(7) 0.428(6) 0 . 2 2 1

C415 -0.494(6) 0.872(6) 0.354(5) 0.175C416 -0.419(5) 0.918(5) 0.306(4) 0.153C421 -0.273(3) 1.132(3) 0.326(3) 0.090C422 -0.259(5) 1.097(5) 0.401(4) 0.154C423 -0.285(8) 1.244(8) 0.424(6) 0.279C424 -0.163(5) 1.226(5) 0.383(4) 0.145C425 -0.206(6) 1.283(6) 0.323(5) 0.181C426 -0.188(5) 1.176(5) 0.297(4) 0.159C431 -0.308(3) 1.091(4) 0.195(3) 0.096C432 -0.386(5) 1.154(5) 0.177(4) 0.159C433 -0.380(6) 1.191(6) 0.099(5) 0.180C434 -0.375(6) 1.128(6) 0.059(5) 0.183C435 -0.288(5) 1.080(5) 0.063(4) 0.145C436 -0.301(5) 1.034(5) 0.147(4) 0.154

76 O. Steigeimann et al. • Tetraaurio(I) Complexes

Fig. 3. Molecular structure of the[H3C -C (A uP{C 6H m}3]+ cation of 2 (SCHAKAL, only the a-carbon atoms of the cyclohexyl groups are shown). - Selected bond distances [A] and angles [°]: A u l - C l 2.17(3). A u 2 -C l 2.14(3), A u 3 -C l 2.14(3), A u 4 -C 1 2.19(3), A u l - P l 2.30(1), A u 2 -P 2 2.31(1), A u 3 -P 3 2.28(1), A u 4 -P 4 2.30(1), A u l- A u 2 2.849(2), Au 1 - Au3 2.865(2), A u 4 -A u 2 2.883(2), A u 4 -A u 3 2.846(2), C 1- C 2 1.44(5), Au 1 - C 1 -A u 2 83(1),Au 1 - C 1 - Au 3 83(1), A u 4 -C 1 - Au2 83(1),A u 4 -C 1 - Au 3 82( 1), A u l - C l - C 2 106(1),A u 2 -C 1 —C2 114(1), A u 3 - C l - C 2 116(1),A u 4 -C 1 —C2 109(1), C l - A u l - P l 166.8(8),C 1 - A u 2 -P 2 169.8(8), C 1 - A u 3 - P 3 173.1(9),C 1 - A u 4 -P 4 169.9(9).

Conclusions

The present study has shown that partially di- m ethoxyboryl substituted alkanes can be used as starting m aterials for the syntheses o f poly- aurio(I)alkanes in much the same way like tetra- kis(dim ethoxyboryl)m ethane for the synthesis o f aurated m ethanes [4c, e -h ] . The reaction does not come to a halt at the triaurated [H3C -C (A u P R 3)3] stage, but proceeds to novel penta-coordinated cationic species [H3C -C (A u P R 3)4]+. This result again dem onstrates the tendency o f polyaurio-car- bon aggregates to accept further L A u+ units. In this context it is quite rem arkable tha t for carbon- centered clusters precursors like C (A uL )4 or H 3C -C (A u L )3 are transient species for smaller li­gands L, whereas in the case o f the am m onium and phosphonium analogues [N (A uL)5]2+ [5 d] and [RP(AuL)4]2+ [6 b] the auration can be carried out in well defined steps [16].

According to X-ray analyses the m onocations [H3C -C (A u P R 3)4]+ feature a square-pyram idal geometry with an interstitial carbon, four gold a t­oms at the base and the methyl group at the apex. The short Au -A u contacts o f ca. 2.8 Ä along the edges of a distorted square reflect bonding in terac­

tions between neighbouring gold atom s, which are im portant for the stabilization o f the system. N e­glecting the Au - Au bonding, the electron-defi­cient nature of the hypercoordinated pentagonal- pyram idal framework with eight valence electrons for five covalent bonds can be illustrated by a sim­plified molecular orbital diagram under idealized C4v symmetry. Symmetry allowed linear com bina­tions o f the three donor electron pairs o f the (for­mal) m ethylcarbide trianion H 3C~C13~ and the a acceptor orbitals (sp hybrids) o f the four LAu* units lead to three bonding states, which are filled by the six electrons available to give a diam agnetic ground state. Therefore the bond order for each of the A u -C bonds is 3/4.

The synthesis o f the novel com pounds shows the way to the preparation o f o ther polyaurio(I) alkane species starting from m aterials like R 2C[B(OM e)2]2. Preliminary results have ind icat­ed, however, that the auration sometimes is ac­com panied by dealkylation of the boryl ester, which parallels the dealkylation o f alkylam ines observed in analogous auration reactions. F urther work will be necessary to m ark scope and lim ita­tions of the hyperauration process.

Experimental Part

All experiments were carried out in an atm os­phere o f dry and purified nitrogen. Solvents and glassware were dried and saturated/filled w ith n i­trogen. - N M R : [D2]dichlorom ethane as solvent, tetram ethylsilane and phosphoric acid as reference com pounds, measurem ent tem perature 25 °C, Jeol JN M G X 270 and GX 400 spectrom eters. - MS: V arian M A T 311 (FD). - l,l,l-T ris(d im ethoxy- boryl)ethane was prepared as described [11]. P h3PAuCl, (C6H n)3PAuCl and C 6H 4(C H 2C H 2PPh2A uC l)2 were synthesized fol­lowing literature procedures [12, 13, 4e]. All o ther reagents were obtained commercially and used w ithout further purification.

1,1,1,1-Tetrakis( triphenylphosphineaurio ( I) )- ethanium( + ) tetrafluoroborate (1)

(Triphenylphosphine)gold(I) chloride (1.00 g,2.0 mmol) and CsF (3.42 g, 22.6 mmol) in H M PT (30 ml) were treated with a solution of H 3C -C [B (O M e )2]3 (0.17 g, 0.70 mmol) in the same solvent (5 ml) for 24 h at 25 °C under nitrogen.

O. Steigeimann et al. • Tetraaurio(I) Complexes 77

The yellow solution was filtered and the product precipitated with pentane. Repeated extraction with C H 2C12 and reprecipitation with pentane/ benzene afforded yellow crystals o f 1: yield 0.41 g (42%); m.p. 154 °C (decomp.). - 'H N M R (CD,Cl-,): S = 3.55 (quin, V HP = 4.9 Hz, 3 H, H 3C), 7.12 (m, 24H, m -Q H j), 7 .31 -7 .36 (m, 36H , o/p- Q H s). - { 'H }31P N M R (CD ,Cl,): Ö = 32.1 (s). - { 'H } 13C N M R (CD ,Cl,): Ö = 28.2 (s, C C H 3), 131.5 (d, lJ cp = 51.8 Hz, C -l), 134.4 (d(cent.), 2/ CP - N = 13.0 Hz, C-2), 129.3 (d(cent.), V CP ~ N =11.4 Hz, C-3), 131.5 (s, C-4). - MS (FD , C H 2C12): m /z (% ) = 1864.7(17), M + (cation).Analysis fo r C74H 63A u4BF4P4 (1950.89)

Calcd C 45.56 H 3.25%,Found C 44.93 H 3.40%.

1,1,1,1-Tetrakis( tricyclohexylphospliineaurio( I ) ) - ethanium( + ) tetrafluoroborate (2)

Procedure as described for com pound 1, tricyclo- hexylphosphine gold(I) chloride (0.51 g, 1.0 mmol), CsF (2.02 g, 13.4 mmol), H 3C -C [B (O M e)J3 (0.09 g,0.40 mmol): yield 0.18 g (36%); m.p. 162 °C (de­comp.). - 'H N M R (CD,C1,): ö = 3.22 (quin, V HP = 4.3 Hz, 3H , H 3C), 1 .15-2 .00 (m, 132H, C6H n ).- { 'H }31P N M R (CD ,Cl,): Ö = 49.5 (s). - MS (FD , CH,C1,): m /z (% ) =" 1936.1 (100), M + (cat­ion).Analysis for C74H n5Au4BF4P4 (2023.45)

' Calcd C 43.93 H 6.72% ,Found C 43.07 H 6.59%.

1,1,1,1-Bis[ 1,2-bis( 2-diphenylphosphinylethyl) - benzene-diaurio(I) ]-ethanium ( + ) tetrafluoroborate (3)

Procedure as described for com pound 1, [1,2- bis(2-diphenylphosphinylethyl)benzene] digold(I) dichloride (1.23 g, 1.3 mmol), CsF (3.83 g, 25.4 mmol), H 3C -C [B (O M e ),]3 (0.16 g, 0.70 mmol): yield 0.28 g (23%). - ‘H N M R (C D ,C l,): S = 3.65 (quin, V HP = 4.9 Hz, 3 H, H 3C), 2 .6 6 -2 .7 0 (m, 8 H, C H ,C H ,P), 3 .02-3 .05 (m, 8 H, C H ,P), 7 .10-7 .76 (m, 4 8 H, C6H 4, C 6H 5). - {‘H }31P N M R (CD ,Cl,): S = 27.5 (s). - MS (FD , CH,C1,): m /z (% ) =1821.1 (100), M + (cation).Analysis fo r C7nH 67Au4BF4P4 (1906.88)

' Calcd C 44.09 H 3.54%,Found C 43.62 H 3.42%.

Crystal structure determination o f compound 1, [H 3C ~ C (A uP P h3) 4]BF4

Enraf-N onius C A D 4 diffractom eter, M o ~ K a radiation, X - 0.71069 Ä, graphite m onochrom a­tor, T = -2 7 °C. jg

Crystal data: C 74H 63A u4BF4P4, M r = 1950.89, triclinic, space group P I , a = 15.167(2), b = 16.669(3), c = 19.119(3)Ä, a = 112.62(2), ß = 96.46(1), y = 90.61(1)°, V = 4425.8Ä3, Z = 2, D caicd. = 1-464 g e m '3, / / ( M o - K J = 66.99 c m '1, F(000) = 1848, 13800 reflections, 13800 unique, and 6234 “observed” with F 0 > 4cr(F0), da ta cor­rected for Lorentz polarization and adsorption ef­fects (empirically, T = 0.73-1 .00). The structure was solved by direct m ethods (SHELXS 86 [16]), com pleted by difference Fourier syntheses, and re­fined by full-matrix, least-squares techniques (SH ELX 76 [17]). Au, P were refined anisotropi- cally as a split model (s.o. f. 0.6: 0.4), C 1, C 2 iso- tropically, phenyl-C, B, F, H were neglected.

Crystal structure determination o f compound 2,[ H 3C — C (A uP { C6H 1j) 3) 4]BF4

E nraf-N onius C A D 4 diffractom eter, M o —K a radiation, A = 0.71069 A, graphite m onochrom a­tor, T = - 4 0 °C.

Crystal Data: C 74H 135A u4BF4P4, M r = 2023.45, triclinic, space group P i , a = 15.334(6), b = 15.229(6), c = 19.783(6)Ä, a = 77.36(3), ß = 86.56(3), y = 86.00(2)°, V = 4492.1 A 3, Z = 2, Dcaicd. = 1469 gem “3, /z (M o -K J = 66.02, F(000) = 1992, 15820 reflections, 15820 unique, and 9691 “observed” with F 0 > 4<r(F0), data corrected for Lorentz polarization and adsorption effects (em­pirically, T = 0.71-1 .00). The structure was solved by direct m ethods (SHELXS 86 [16]), com pleted by difference Fourier syntheses, and refined by full-m atrix least-squares techniques (SH ELX 76 [17]). H ydrogen atom s were neglected. All heavy atom s (Au, P) were refined anisotropically, C iso- tropically, BF4 neglected because of disorder p ro b ­lems (R ( R J = 0.115 (0.133), w = l/er2(F 0), Agrm (m ax/m in) = 5 .5 1 /-5 .8 4 eA “3) [15].

This w ork was supported by Deutsche F o r­schungsgemeinschaft (Leibniz-Program m ), by the Fonds der Chemischen Industrie and by H oechst A G , Degussa A G , and Heraeus AG. J. Riede is thanked for collecting the crystallographic data and Prof. F. R. Kreißl for mass spectrom etric m easurem ents.

78 O. Steigeimann et al. • Tetraaurio(I) Complexes

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