Crystal structure of [NBu4]2[Pd2{C4(COOMe)4}2(μ-OH)2] determined ab initio by charge flipping

The crystal structure of bis(tetra-n-butylammonium)bis(μ2-hydroxo)-bis(1,2,3,4-tetrakis(methoxycarbonyl)-1,3-butadiene-1,4-diyl)-di-palladium, [NBu4]2[Pd2{C4(COOMe)4}2 (μ-OH)2], was determined ab initio by X-ray single-crystal diffractometry using the charge flipping method. The compound crystallizes in the monoclinic system with P21/c as space group and the following cell parameters: a = 12.8481(6) Å, b = 63.744(3) Å, c = 16.6102(8) Å, β = 111.943(10). The asymmetric unit is formed by two molecules, and the unit cell contains eight molecules (Z = 8) giving a density of 1.369 g cm−3. The coordination around the Pd(II) atoms is approximately planar, the methoxycarbonyl groups at the α and β positions relative to Pd are perpendicular and parallel to the palladacycle ring, respectively, and the {Pd(μ-O)}2 core has a bent conformation. The structure closely resembles the features reported previously for other palladacyclopentadiene complexes.