title: Gold(I) and silver(I) mixed-metal trinuclear complexes: dimeric products from the reaction of gold(I) carbeniates or benzylimidazolates with silver(I) 3,5-diphenylpyrazolate.
abstract: Trinuclear mixed-metal gold-silver compounds are obtained by the reaction of gold(I) carbeniate [Au(mu-C(OEt)=NC6H4-p-CH3)]3, TR(carb), or gold(I) imidazolate [Au-mu-C,N-1-benzyl-2-imidazolate]3, TR(bzim), with silver(I) pyrazolate [Ag(mu-3,5-Ph2pz)]3. The crystalline products are mixed-ligand, mixed-metal dimeric products [Au(carb)Ag2(mu-3,5-Ph2pz)2], [Au2(carb)2Ag(mu-3,5-Ph2pz)].CH2Cl2, [Au(bzim)2Ag2(mu-3,5-Ph2pz)], and [Au2(bzim)2Ag(mu-3,5-Ph2pz)]. They have been characterized by elemental analysis and 1H NMR and mass spectrometry. The X-ray structure of [Au(carb)Ag2(mu-3,5-Ph2pz)2] shows it to be a dimer with two Ag...Au contacts between the trinuclear units of 3.083(2) and 3.310(2) A and with average intramolecular Ag...Ag and Au...Ag distances of approximately 3.3 and 3.2 A, respectively. The structure of [Au2(carb)2Ag(mu-3,5-Ph2pz)].CH2Cl2 is a dimer with one intermolecular Au...Au attraction of 3.3354(10) A and a short Ag...Au distance of approximately 3.42 A and intramolecular Ag...Au and Au...Au contacts of approximately 3.2 and approximately 3.3 A, respectively. Packing diagrams of both complexes show that the dimeric units are independent, similar to their parent molecules. The dimers of trinuclear [Au(carb)Ag2(mu-3,5-Ph2pz)2] and [Au2(carb)2Ag(mu-3,5-Ph2pz)].CH2Cl2 crystallize in the triclinic space group P (Z = 2), a = 9.688(3) A, b = 15.542(4) A, c = 23.689(6) A, alpha = 82.560(5) degrees , beta = 87.887(6) degrees , gamma = 78.060(5) degrees , and the orthorhombic space group Pca2(1) (Z = 4), a = 29.644(4) A, b = 7.4582(10) A, c = 30.473(4) A, respectively. The structure of [Au(bzim)Ag2(mu-3,5-Ph2pz)2] is a dimer with two metallophilic Ag...Au interactions of 3.14 A. The complex crystallizes in the monoclinic space group C2/c (Z = 4), a = 26.368(5) A, b = 15.672(3) A, c = 17.010(3) A, beta = 102.206(3) degrees .
authors.affiliation: Laboratory for Molecular Structure & Bonding, Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, USA.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Mohamed
authors.forename: Rossana
authors.initials: R
authors.lastname: Galassi
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Papa
authors.forename: Alfredo
authors.initials: A
authors.lastname: Burini
authors.forename: John P
authors.initials: JP
authors.lastname: Fackler
mesh_terms: D018360:Crystallography, X-Ray; D019281:Dimerization; D006046:Gold / Q000737:chemistry*; D017612:Gold Compounds / Q000737:chemistry*; D006838:Hydrocarbons / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D011720:Pyrazoles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D018030:Silver Compounds / Q000737:chemistry*
chemical_list: D017612:Gold Compounds; D006838:Hydrocarbons; D007093:Imidazoles; D011720:Pyrazoles; D018030:Silver Compounds; C030011:carbene; D012834:Silver; C031280:pyrazole; D006046:Gold; C029899:imidazole; D008697:Methane