Crystal and molecular structure of bis[(1,2-dihapto-3,5-dimethyl-pyrazolido)-?-allylpalladium(II)]

Abstract

The crystal and molecular structure of bis[(1,2-dihapto-3,5-dimethylpyrazolido)-nallylpalladium(II)], C16H24N4Pd v has been determined by X-ray diffraction techniques. The crystals are monoclinic, P2Jc (No. 14), with a=8.752(1), b= 18.932(2), c= 11.780(3) •, and fl= 109.78(1) ~ The observed crystal density (1.746 gcm -3) agrees well with that calculated on the basis of four molecules per unit cell (1.754 g cm-3). The structure has been refined by full-matrix least-squares techniques to a final R 1 value of 0.045 (R2----0.056) for 2974 unique reflections with ./net)7 counts sec -1. The Pd2N 4 ring is in a boat conformation in which the two palladium atoms are 1.113 and 1.064 A out of the plane defined by the four nitrogen atoms. The Pd-C bond distances to the terminal atoms of the 7r-allyl groups (2.12 A) are longer than those to the central carbon atoms (2.06 A). The molecule possesses approximate mm2(C2, ) symmetry.

Oxidative Addition Reactions to Novel Heterotrinuclear Iridium Complexes with Mixed Bridging Ligands. Crystal Structure of [{Ir(.mu.-pz)(.mu.-StBu)I2(CO)[P(OMe)3]}2Pd]

“…Figure 2. Alternative view of the complex ]{ (µ-)(µ-8 )-I2(CO)[P(OMe)a] }2Pd] (6), showing the step conformation of the metal coordination planes.Rh-Pd-Rh complex10 and in other related pyrazolate palladium compounds [23][24][25]. Regarding the Ir coordination sphere, the Ir-donor-atom bond distances are analogous to those reported in similar dinuclear Ir(III) complexes containing pyrazolate and/or butanethiolate bridging ligands and terminal iodide, carbonyl and phosphinegroups, i.e.…”

The Counterion Effect on the Assembly of Coordination Networks of Cationic (η3‐Allyl)palladium Complexes Containing 3,5‐Dimethyl‐4‐nitro‐1H‐pyrazole

“…In this context and for comparative purposes, we took into account the structural data of some allyl palladium derivatives containing pyrazolyl groups. These exhibited dihedral angles between the allyl ligand and the coordination plane PdÀNÀN of 908 [11], 111.38 [7], or 1138 and 1088 [12], but all of them presented restricted positions on the pyrazole rings because of the characteristics of the polydentate ligands in which the pyrazolyl group was included, i.e., in 4,6-bis(1H-pyrazol-1-yl)pyrimidine [11] and 4,6-bis(4-methyl-1H-pyrazol-1- (4) 1.32(1) ± N(7)ÀO(5) ± 1.219(5) N(7)ÀO(6) ± 1.249(4) N(7)ÀO (7) ± 1.249 (5) yl)1,3,5-triazin-2-olate [7], or by the coordinative form as bridging group in bis(h 3 -allyl)bis[m-(3,5-dimethyl-1H-pyrazolato-)kN 1 :kN 2 )]palladium(II) [12]. In our complexes, the position of the pyrazole ligands was constrained only by the H-bonding interactions with the corresponding counterion BF À 4 in 1 and NO À 3 in 2, this fact, therefore, being related with the lower dihedral angles between the allyl and coordination planes (28(3)8 and 61.0(7)8 for 1 and 2, resp.…”

Structure of trans-bis(dimethylphenylphosphine)bis(pyrazole)platinum, [Pt(C3H4N2)2{P(CH3)2(C6H5)}2]

“…Oliver & Rice, 1976) and coordinated pyrazolide ions (e.g. Henslee & Oliver, 1977).The structural analysis of PTPP serves to extend our previous investigations (Smith & Oliver, 1978;Oliver, Mullica & Milligan, 1982) of the steric requirements of coordinated phosphine ligands. To define quantitatively the steric bulk of these ligands, several authors (Alyea, Dias, Ferguson & Restivo, 1977; Richardson & Payne, 1977;Smith & Oliver, 1978) have expanded Tolman's (1970) concept of a ligand cone angle by using crystallographic coordinates to generate a series of half-cone angles (0/2) as a function of the angle of rotation about the metal-P bond, which is termed a ligand profile.…”