Metalation of a trialkylphosphine. Structure of bis(.mu.-chloro)bis[2-(di-tert-butylphosphino)-2-methylpropyl]dipalladium

Abstract

The structure of [P~C~((~-BU)~PCM~~CH~)]~ has been determined by single-crystal X-ray diffraction techniques. The compound crystallizes in the monoclinic space group P 2 J c with a = 7.709 (2) A, b = 15.187 (5) A, c = 13.383 (4) A, / 3 = 105.77 (2)', V = 1507.9 A3, and Z = 2. The structure was refined to R = 0.037 (0.043 for R,) for the 1838 unique reflections with I 1 3.0u(I). Metalation of a tri-tert-butylphosphine ligand has produced a saturated Pd-P-C-C four-atom chelate ring. The coordination about the palladium atom is square planar with the chloride ions cis to each other. Selected metrical details are Pd-P = 2.209 (2) A, Pd-C(u) = 2.052 (8) A, Pd-Cl(trans to P) = 2.429 (2) A, and Pd-Cl(trans to C) = 2.474 (2) A. The bond lengths are discussed in terms of trans influences and strain in the chelate ring. Metalation results in severely distorted Pd-P-C and P-C-C angles. The steric bulk of the tertiary phosphine ligand is described with a "ligand profile".. IntroductionIntramolecular metalation of aryl-substituted tertiary phosphine ligands to form metal-carbon bonds has been studied extensively in recent yearsS2 The reaction is facilitated by formation of five-and six-membered chelate rings and depends on the steric bulk of the phosphine ligand. In contrast, only a few examples of metalation of purely aliphatic phosphines have been reported.,"Recently, Goel and Clark7-lo reported intramolecular metalations of tri-tert-butylphosphine complexes to form

Syntheses and characterizations of methylpalladium complexes bearing a biphenyl-based bulky phosphine ligand: Weak interactions suggested by NBO and QTAIM analyses

“…The X-ray crystallographic analysis revealed that 8 has a Cl-bridged dinuclear structure where a half of the dinuclear structure is an asymmetric unit. In spite of the bulkiness of the ligands, bond lengths and angles around the central palladium atom in 8 are similar to those of previous Cl-bridged dinuclear complexes bearing a common triarylphosphine [41][42][43][44]. There is only one reported example of a neutral organopalladium(II) chloride complex, Pd(6)(allyl)Cl, bearing a biaryl-based phosphine ligand [20].…”

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

“…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.…”

Structure of di-μ-chlorobis(dicarbonylpalladium)

“…1)consists of two distorted square-planar C1Pd(CO)2 units, joined at a common edge via the bridging C1 atoms, which are shared equally between the Pd atoms. The Pd-C1 bond lengths of 2.387(3) and 2-371 (2)A are shorter than the values of 2.422 (7) and 2.426 (5)A in bis(2-neopentyl-r/-allylpalladium chloride).2CHC1 a (Murphy, Holt & Holt, 1981), and 2.492 (2) and 2.474 (2)A in bis(p-chloro)-bis- (Oliver, Mullica & Milligan, 1982). However, the bond angles Pd-CI-Pd(A) and Pd-CI(A)-Pd(A) are in good agreement with values in the literature cited above.…”

“…Copies may be obtained through The Executive Secretary, International Union of Crystallography, 5 Abbey Square, Chester CH 1 2HU, England. (Oliver, Mullica & Milligan, 1982), respectively. However, the mean C-O bond length of 1.089 (14)A is reasonably close to the mean C-O (1) 2289 (1) 4604 (1) 65 (1) C1 2035 (2) 3611 (2) 5926 (2) 76 (1) C (1) 1056 (7) 1206 (8) 3646 (10) 72 (3) O (1) 860 (7) 566 (8) 3139 (8) 103 (4) • C (2) 936 (7) 3013 (9) 3223 (8) 77 (4) 0(2) 590 (7) 3463 (9) 2401 (8) 122 (5) value of 1.17 (1)A, found in the isostructural [Rh 2-CI2(CO) 4] compound (Dahl, Martell & Wampler, 1961).…”