The synthesis of cationic trimetallic clusters with AuW bonds. Crystal structure of [AuW2(μ-CR)2(CO)4(bipy)2Cl2]·PF6 (R = C6H4Me-4)

Side-on coordination of boryl and borylene complexes to cationic coinage metal fragments

“…29 The Mn-B and Au-B distances of 5c are 2.113(5) Å and 2.320(5) Å, noticeably shorter than those observed in 5a and 5b. The B-N distance of 1.532 (7) Å falls between those established for aminoboranes R 2 B]NR 2 and amine-borane adducts R 3 B-NR 3 , indicating signicant p-donation from the nitrogen to boron. This is also reected by the linear geometry (B-N-C 177.0(5) and N-C-S 178.3(5) ) of the BNCS moiety.…”

“…From this we proposed that the formation of [8][BAr x 4 ] (Ar x ¼ Ar Cl and Ar F ) proceeds via the expected cationic halide abstraction intermediate, followed by a ligand exchange, a route that has been reported for the analogous alkylidyne complexes (see Chart 1). 7,35 Similar reactions have also been carried out with silver and copper salts. The reaction of 1 with [AgCl(PPh 3 )] in toluene led ) and the by-product [Ag(PPh 3 ) 3 ][BAr Cl 4 ] (Scheme 6(i)).…”

“…From this we proposed that the formation of [ 8 ][BArx4] (Ar x = Ar Cl and Ar F ) proceeds via the expected cationic halide abstraction intermediate, followed by a ligand exchange, a route that has been reported for the analogous alkylidyne complexes (see Chart 1 ). 7 , 35…”

“…1 One remarkable demonstration of their application can be found in Stone's studies of unsaturated systems containing metal-carbon multiple bonds, where the alkylidene and alkylidyne metal fragments were compared to their isolobal organic fragments CR 2 and CR respectively to rationalize alkylidene-and alkylidyne-derived bi-and multi-metallic frameworks, such as those shown in Chart 1. [2][3][4][5][6][7][8] Transition metal boryl complexes, by virtue of their weak p-back bonding interactions, are isolobal with alkenes and alkylidenes in the same way that transition metal borylene complexes are isolobal with alkynes and alkylidyne complexes. 9,10 Following the guidance of these concepts, one may postulate analogous molecular motifs by invoking the isolobal and isoelectronic fragment pairs alkylidene [CR 2 ]/boryl [BR 2 ] À and alkylidyne [CR] + /borylene [BR] as shown in Chart 2.…”

Gold–Heterometal Interactions and Bonds

“…In contrast, dinuclear complexes with an unsupported Au-W bond are much rarer[113,129], a recent example being the tungsten analog 139 of compound 136 [Au-W 2.7121(5)/2.7060(5) Å][113]. Much more common are dinuclear and polynuclear compounds in which the metal centers of an Au-W bond are bridged by m-arylmethylidene[130,131], m-arylmethylidyne[132][133][134][135][136][137][138][139][140], m-C:C t Bu[141], m-CN (Et)Me[142], m-CO or m-CS ligands[127,[143][144][145].A recent example, (Ph 3 P)AuW(m-CO)(m-C:C t Bu)(h 5 -Cp)(NO) 140, features both alkynyl and carbonyl groups supporting the Au-W bond [2.803(3) Å] (Figure 4.36a)…”