Carbon Dioxide Fixation by an Unprecedented Hydroxo Lead−Chromium Carbonyl Complex:  Synthesis, Reactivity, and Theoretical Calculations

Abstract

The novel hydroxo-bridged dimeric lead-chromium carbonyl complex [Et4N]2[{PbCr2(CO)10}2(mu-OH)2] ([Et4N]2[1]) was synthesized from the reaction of PbCl2 and Cr(CO)6 followed by metathesis with [Et4N]Br in a KOH/MeOH solution. The X-ray crystallographic structure shows that dianion 1 consists of two Pb{Cr(CO)5}2 units bridged by two hydroxo fragments in which the Pb atoms are further coordinated with two Cr(CO)5 groups, resulting in a distorted tetrahedral geometry. A CO2 molecule can insert itself into dianion 1 to form two new carbonate complexes, [Et(4)N]2[{PbCr2(CO)10}(CO3)] ([Et4N]2[2]) and [Et4N]2[{PbCr2(CO)10}2(CO3)] ([Et4N]2[3]), depending on the reaction conditions. In addition, complex 2 can be transformed into 3 in CH2Cl2 solution at an elevated temperature. While the carbonate group in dianion 2 is bonded to one Pb atom, which is coordinated with two Cr(CO)5 fragments, the carbonate group in 3 bridges the two Pb centers in a mu-1kappa2OO':2kappa2OO' fashion in which each Pb atom is further bonded to two Cr(CO)5 moieties. Complexes 2 and 3 can be converted back the hydroxo complex 1 under appropriate conditions. All three unprecedented lead-chromium compounds, 1-3, were fully characterized by spectroscopic methods and single-crystal X-ray diffraction analyses. The nature and formation of complexes 1-3 were also examined by molecular orbital calculations using the B3LYP method of the density functional theory.

Construction of Copper Halide-Triiron Selenide Carbonyl Complexes: Synthetic, Electrochemical, and Theoretical Studies

“…To further describe the electronic structures of clusters 1a − 4a and their relevant reactions, a hybrid density functional, B3LYP, , method with a modest basis set LanL2DZ was employed for computations. This level of calculation has been reported to work quite well for many charged inorganic and organometallic systems. ,, The geometries of complexes [SeFe 3 (CO) 9 ] 2− , 1a − 1c , 2a , 2b , 3a , 3b , and 4a were taken from single-crystal diffraction data, and the proposed intermediate 2a′ and 4a′ were fully optimized with the same level of theory. In addition, Wiberg bond indices and natural population analyses (NPA) for these complexes were also calculated and compared in Table .…”

Efficient and Reversible Fixation of Carbon Dioxide by NCN-Chelated Organoantimony(III) Oxide

“…The most interesting feature of the molecular structure of 3 is coordination of the carbonate moiety as a terminal ligand in a chelating fashion. This coordination mode of the carbonate entity is, to our knowledge, very rare for main-group-metal compounds, and among organoantimony and organobismuth compounds, characterized in the solid state by X-ray diffraction, only those with the carbonate group in a bridging position are known. , This coordination of the CO 3 moiety to the central Sb(1) atom leads to the formation of a four-membered SbCO 2 ring, and the coordination of the carbonate is nearly symmetrical (Sb(1)−O(1) = 2.126(3) and Sb(1)−O(2) = 2.151(3) Å, indicating an Sb−O covalent bond, ∑ cov (Sb,O) = 2.14 Å). The bonding angle at the antimony center is significantly more acute (O(1)−Sb(1)−O(2) = 61.17(10)°) than the angle at the carbon atom (O(1)−C(13)−O(2) = 112.0(3)°).…”

Lead−Chromium Carbonyl Complexes Incorporated with Group 8 Metals: Synthesis, Reactivity, and Theoretical Calculations

“…The class of Pb−Cr−CO complexes has previously been rare because of the lack of a feasible methodology and their reactive nature. ,− By varying of the sources of lead(II) and the bases, as well as the concentration of the bases applied, we have discovered a facile route to the known lead−chromium carbonyl complex [Pb{Cr(CO) 5 } 3 ] 2− ( 1 ) from the reaction of PbCl 2 with Cr(CO) 6 in a KOH/MeOH solution. In pursuit of novel heteronuclear clusters, group 8 metals were introduced into the lead−chromium carbonyl system.…”

“…Our research group has an ongoing interest in chromium, iron, and ruthenium carbonyl clusters and has recently explored the lead-containing chromium system . Although group 14-incorporated, group 6 and/or group 8 metal carbonyl complexes have been reported, their lead-incorporated complexes remain rare, mainly because of a lack of applicable synthetic routes. ,,− Furthermore, the effect and nature of homo- or heteronuclear metal−metal interactions on the formation of such carbonyl complexes remain little explored. , The study and comparison of lead-containing homo- or heterometallic complexes are, therefore, of great interest and are challenging in view of their cooperative chemical properties and potential applications.…”