Bis(μ4-adamantane-1,3-di-carboxyl-ato-1κO 1:2κO 1':3κO 3:4κO 3')octa-carbonyl-1κ2 C,2κ2 C,3κ2 C,4κ2 C-tetra-kis-[tris-(4-methyl-phen-yl)phosphane]-1κP,2κP,3κP,4κP-tetra-osmium(I)(2 Os-Os).

Eric W. Reinheimer,Gregory L. Powell,Diego F. Zometa Paniagua,Cynthia B. Powell

doi:10.1107/s2414314620012043

Abstract

The title complex, [{Os2(CO)4(C21H21P)2}2(C12H14O4)2], is a centrosymmetric mol-ecular loop consisting of two Os-Os sawhorse units linked by two adamantane di-carboxyl-ato bridges. It was synthesized by the microwave-mediated reaction between Os3(CO)12 and adamantane-1,3-di-carb-oxy-lic acid. In contrast to the related complex [{Os2(CO)6}2(μ4-adamantane-1,3-di-acetate)2], the metal-metal axes within each mol-ecule are oriented parallel rather than perpendicular to one another. The crystal structure exhibits cavities that contain residual electron density peaks, but it was not possible to unambiguously identify the solvent therein. The contribution of the disordered solvent mol-ecules to the scattering was removed using the SQUEEZE (Spek (2015 ▸). Acta Cryst. C71, 9-18) routine in PLATON [Spek (2020 ▸). Acta Cryst. E76, 1-11]. These solvent mol-ecules are not considered in the given chemical formula and other crystal data.

Highlights

The title complex, [{Os2(CO)4(C21H21P)2}2(C12H14O4)2], is a centrosymmetric molecular loop consisting of two Os—Os sawhorse units linked by two adamantane dicarboxylato bridges
The CSD contains six Os2 carboxylato sawhorse assemblies: five are molecular loops of two sawhorse units and one is a molecular triangle consisting of three sawhorse units (Fikes et al, 2014; Gwini et al, 2017)
The cluster entity resides on an inversion center and consists of a molecular loop in which two Os2(CO)4(phosphine)2 sawhorse units are bridged by two adamantane-1,3-dicarboxylato ligands

Summary

Structure description

Group VIIIB sawhorse units with metal–metal bonds may have potential as building blocks for larger framework compounds including metal–organic frameworks (Koberl et al, 2011; Therrien & Suss-Fink, 2009). Like Ru2 sawhorse carboxylato macrocycles in which the Ru—Ru axes are parallel to one another, the two Os—Os axes in this structure are parallel This is in contrast to the related molecular loop [Os2(CO)6]2(4-adamantane-1,3-diacetate) in which the metal–metal axes within each molecule are oriented perpendicular to one another (Fikes et al, 2014). The cavity in the center of the title compound is a distorted rhombus with unique edge lengths of 4.684 (1) and 4.976 (1) Aas measured from the Os—Os midpoints to the central adamantane carbon atom C58 This cavity is smaller than that in [Os2(CO)6]2(4-adamantane-1,3diacetate) in which these distances average 5.2 A (Fikes et al, 2014). Despite the differences in dimensions and spacing for the adamantane-based ligands in these two complexes, the distances between Os—Os centroids are remarkably similar at 8.983 (2) and 8.964 (2) A , respectively

Synthesis and crystallization

No of parameters

Data collection

Special details