Novel intercluster compounds consisting of pentakis[(triphenylphosphane)gold]ammonium(2+) cation (1) and Keggin polyoxometalate (POM) anions, i.e., {[Au(PPh)](μ-N)}[α-PMO] (1-PW for M = W; 1-PMo for M = Mo), were synthesized in 30-36% yield by one-pot reaction of the protonic acid form of the Keggin POMs, H[α-PMO]·nHO (n = 13 for M = W; n = 15 for M = Mo) with monomeric (triphenylphosphane)gold(I) carboxylate [Au(RS-pyrrld)(PPh)] [RS-Hpyrrld = (RS)-2-pyrrolidone-5-carboxylic acid] in the presence of aqueous NH at a molar ratio of 2:15:x (x = 3 for 1-PW; x = 7.5 for 1-PMo). These compounds resulted from the nitrogen-centered phosphanegold(I) clusterization of in situ generated monomeric phosphanegold(I) units, [Au(PPh)] or [Au(L)(PPh)] (L = NH or solvent), during the carboxylate elimination of [Au(RS-pyrrld)(PPh)] in the presence of the Keggin POMs and aqueous NH. The products 1-PW and 1-PMo were characterized by elemental analysis, Fourier transform infrared, thermogravimetric and differential thermal analyses (TGA/DTA), X-ray crystallography, and solid-state cross-polarization magic-angle-spinning (CPMAS) (P and N) and solution (P{H} and H) NMR spectroscopy. The lattice contained three independent {[Au(PPh)](μ-N)} cations, of which two took regular trigonal-bipyramidal (TBP) geometries and the third took a distorted, square-pyramidal (SP) geometry. These geometries are in contrast to those reported by Schmidbaur's group for {[Au(PPh)](μ-N)} cations as BF salts. Density functional theory and ONIOM calculations for {[(LP)Au]N} (L = H or Ph; n = 4-6) showed that the pentacoordinate cluster is energetically most stable and its TBP structure is only 1.6 kcal mol more stable than its SP structure, in accordance with the experimental facts.

The present paper is the Supplemental materials for our original paper entitled “highly active, homogeneous catalysis by polyoxometalate-assisted N -heterocyclic carbene gold(I) complexes for hydration of diphenylacetylene. The present article refers to the preparations of several monomeric, N -heterocyclic (NHC) carbene/carboxylate ( RS -pyrrld)/gold(I) complexes, [Au( RS -pyrrld)(NHC)] (NHC = IMes ( 6 ), BIPr ( 7 ), IF 3 ( 8 ), I t Bu ( 9 )), which were used for homogenous catalysis of the hydration reaction of diphenylacetylene to afford deoxybenzoin. The article also includes the preparations of the precursor complexes, [AuCl(NHC)] (NHC = IPr, IMes, BIPr, IF 3 , I t Bu), and novel X-ray crystallography of the separately prepared [Au(IPr)(H 2 O)] 3 [α-PW 12 O 40 ]·7Et 2 O ( 2 ), summary of crystal data of ( 2 ), and selected bond distances (Å) and angles (deg) of ( 2 ). Also presented are Cartesian coordinates of the optimized structures in the quantum-mechanical calculations.