Insertion of isocyanides and carbon monoxide into metal-metal bonds. Preparation and structure of [Pd2(CNCH3)3[(C6H5)2PCH2P(C6H5)2]2][PF6]2

Abstract

Sir:Recent suggestions' that polynuclear metal complexes may e,xhibit heretofore unobserved modes of catalytic activity have stimulated interest in the behavior of such complexes and particularily those complexes (e.g., Os3H2(CO)la2 and ($-containing unsaturated metal-metal bonds. Here we report some addition reactions of two coordinatively unsaturated palladium( I) dimers. The most conspicuous feature of these reactions is the expansion of the palladium-palladium distance which occurs upon formation of an isocyanide or carbon monoxide bridge. In contrast, with most other complexes containing monohapto, doubly bridging carbon monoxide or isocyanide ligands, these ligands span two metal centers which are generally thought to be connected by a direct metal-metal bond.4When a dichloromethane solution of the phosphine bridged palladium(1) dimer Pd2(dpm)2Xzs (1, X = Cl, Br) (dpm, Ph2PCHzPPh2) is exposed to 1 atm of carbon monoxide, 1 equiv of carbon monoxide is absorbed and the dark red crystalline complex Pd2(dpm)z(CO)X2 (2) may be isolated. This product contains only a bridging carbonyl (UCO 1704 cm-I, X [Pd2(CNCH3)3[(C6H5)2PCHzP(C6H5)2]2][pF6]2 Scheme I Ph 2 I 1 + CNR I +zcm t 2 x -3 RNC, 2 +2 5 N C ' + -3CNR

Palladium carbonyl complexes

“…When [Pd(m-dppm)X] 2 (X = Cl, Br) is treated with CO in dihloromethane, [Pd(m-dppm)X] 2 (m-CO) (n C0 = 1704 cm 71 ) is formed; 106 ; it liberates CO reversibly on heating in solution in dichloromethane. The complex Pd 2 (m-CO)(m-dppm) 2 Cl 2 has been obtained as a result of the addition of oxalyl chloride ClC(=O)-C(=O)Cl to Pd 2 (dppm) 3 in dichloromethane.…”

PdII–PdII bonding interaction in dinuclear PdII complex with non-macrocyclic (O&N) chelates: Characterization, kinetics and DFT study

“…A few selected bond angles are given in Table 2 (and for other resolved important bond distances and angles refer to SI, Tables S3-S5). Pd-O and Pd-N interaction in distorted square pyramidal geometry support the metal-metal (d 8 -d 8 …”

“…In the last several years, different research groups have targeted to synthesize Pd I and Pd II complexes persisting with metal-metal bonding interaction with different types of ligands by tuning the steric and electronic factors [2][3][4] using bridging or without bridging supports [5][6][7][8][9][10][11][12][13][14][15][16][17]. However, only a few Pd II dinuclear complexes with metal-metal [18][19][20][21][22][23][24][25] interactions have been described so far.…”

“…However, only a few Pd II dinuclear complexes with metal-metal [18][19][20][21][22][23][24][25] interactions have been described so far. In these cases, the weak d 8 -d 8 bonding interaction has been explained by symmetry allowed mixing of the Pd(5p z ) and (5s) orbitals into the 4dz 2 orbital of the Pd center [26][27][28][29], and DFT analysis have revealed Pd-Pd bond orders [22,24] of 0.10-0.15. Theoretically explained Pd II dimers, stabilized by metal-metal (d 8 -d 8 ) interaction have been recently reported by H.B.…”

Properties of [Pd2X2(dppm)2] (X = Cl, SnCl3, dppm = Bis(diphenylphosphino)methane) complexes on porous vycor glass

“…15 These compounds take part in different types of reactions, such as additions, substitutions and insertions, owing to the presence of a single metal-metal bond, which acts as a nucleophilic center. 16 The structure of the molecules comprises two Pd-Cl 641 Properties of [Pd 2 X 2 (dppm) 2 ] (X = Cl, SnCl 3 , dppm = Bis(diphenylphosphino)methane) Vol. 15, No.…”