Dirhenium decacarbonyl and Rome, Watertown and Ogdensburg Railroad

Contents 1 History 2 Structure and properties 3 Synthesis 4 Reactions 5 Applications 6 See also 7 References

History

In the 1930s Robert Mond developed methods which used increased pressure and temperature to produce various forms of metal carbonyl . A prominent scientist of the twentieth century, Walter Hieber was crucial to the further development of specifically the dirhenium decacarbonyl. Initial efforts produced mononuclear metal complexes, but upon further evaluation, Hieber discovered that by using Re2O7 as a starting material with no solvent, a dirhenium complex could be achieved producing a Re-Re interaction. Structure and properties

The crystal structure of Re2(CO)10 is relatively well known. The compound consists of a pair of square pyramidal Re(CO)5 units linked by a Re-Re bond. There are two different conformations that can occur: staggered and eclipsed. The eclipsed conformation occurs about 30% of the time, producing a D4h point group, but the staggered form, with point group D4d, is more stable. The Re-Re bond length was experimentally found to be 3.04Å.

The Re atom exists in a slightly distorted octahedral configuration with the C axial-Re-C equatorial angle equal to 88°. The mean Re-C bond length of 2.01 Å is the same for the axial and equatorial positions. The mean C-O distance is 1.16 Å.

This compound has a broad IR absorption band at 1800 cm−1 region can be assigned to two components centered at 1780 and 1830 cm−1, resulting from CO adsorption. The remaining nine CO groups in Re2(CO)10 give the complex IR absorption in the 1950–2150 cm−1 region. Free Re2(CO)10 (point symmetry D4d ) has a CO stretch representation of 2A1+E2 + E3+ 2B2 +E1, where 2B2 + E1 are IR active. For an axially perturbed (C4v) Re2(CO)10 molecule, the CO stretch representation was found to be 2E+B1+B2+3A1, where the IR active modes are 2E+3A1.

Its identity can also be confirmed by mass spectrometry, using the isotopic pattern of rhenium (185Re and 187Re). Synthesis

Dirhenium decacarbonyl may be obtained by reductive carbonylation of rhenium(VII) oxide (Re2O7) at 350 atm and 250 °C. Re2O7 + 17 CO → Re2(CO)10 + 7 CO2 Reactions

The carbonyl ligands may be displaced by other ligands such as phosphines and phosphites (denoted L). Re2(CO)10 + 2 L → Re2(CO)8L2

This compound may also be "cracked" to mononuclear Re(I) carbonyl complexes by halogenation: Re2(CO)10 + X2 → 2 Re(CO)5X (X = Cl, Br, I)

When bromine is used, bromopentacarbonylrhenium(I) is formed, which is an intermediate for many more rhenium complexes.

This compound may also be hydrogenated to form various polyrhenium complexes, eventually giving elemental rhenium. Re2(CO)10 → H3Re3(CO)12 → H5Re4(CO)12 → Re (metal)

In the presence of water, photolysis of Re2(CO)10 yields a hydroxide complex: Re2(CO)10 → HRe(CO)5 + Re4(CO)12(OH)4

This reaction includes the cleavage of Re-Re bond and the synthesis of HRe(CO)5, which can be used to prepare surface structures designed to incorporate isolated surface-bound Re carbonyl complexes.

Loss of a carbonyl ligand by photolysis generates a coordinatively unsaturated complex that undergoes oxidative addition of Si-H bonds, for example: Re2(CO)10 + HSiCl3* → (CO)5ReHRe(CO)4SiCl3 + CO Applications

Rhenium-based catalysis have been used in metathesis, reforming, hydrogenation and various hydrotreating processes such as hydrodesulfurization. Re2(CO)10 can be used to promote the silation of alcohols and prepare the silyl ethers, and its reaction: RSiH3 + R’OH → RH2SiOR’ + H2 See also Metal carbonyl

Rome, Watertown and Ogdensburg Railroad and Dirhenium decacarbonyl

Contents 1 History 2 Legacy 3 Hojack nickname 4 See Also 5 References 6 External links

History

The Rome, Watertown & Ogdensburg Railroad (RW&O) began in 1842 as the Watertown & Rome Railroad (W&R) to link Watertown with Rome, New York on the Syracuse & Utica Railroad, later consolidated as part of the New York Central Railroad (NYC). The Potsdam & Watertown Railroad was formed at this time to link Watertown with Potsdam, New York in St. Lawrence County near Massena. In 1861 these two railroads merged as the RW&O.

A branch line from DeKalb Junction (near Canton, New York) to Ogdensburg was later built. In 1864 the RW&O constructed a line from Pulaski to Oswego and merged with the Syracuse & Northern Railroad. In 1858 the Lake Ontario Shore Railroad (LOS) was chartered from Oswego to Suspension Bridge, New York (now Niagara Falls, New York). RW&O merged LOS in 1875; by that time it was bankrupt.

The RW&O was nicknamed "Rotten Wood & Old Rusty Rails" due to its crumbling infrastructure. By 1878 the RW&O had been merged into the Delaware, Lackawanna & Western Railroad (DL&W). DL&W built the Ontario Secondary in 1882 (Beebee line) from Charlotte, New York (where the Genesee River flows into Lake Ontario) to Rochester, New York. By 1891 RW&O became a subsidiary of NYC. On April 12, 1913 the RW&O was formally merged into the NYC. Legacy

Former RW&O trackage is operated by CSX (CSXT), Ontario Midland Railroad (OMID) and the Mohawk, Adirondack & Northern Railroad. Several disconnected sections of the former line have also been converted to the Webster Hojack Trail, Cayuga Hojack Trail, and additional sections in Hamlin, Hilton and Rochester, New York.

The RW&O had terminals in Suspension Bridge, Rochester, Syracuse, Rome, Utica, Natural Bridge, Massena, Ogdensburg, Clayton, Cape Vincent and Sacket's Harbor. Hojack nickname

The RW&O was nicknamed the Hojack, but its origins have multiple explanations. Hojack originated from the engineer of the first train, who was named Jack Welch (often called "Big Jack"). Welch used to be a farmer and was more familiar with horses than steam locomotives. When he stopped the trains he would shout "Whoa Jack!". This became Hojack over time. Many people fondly called the RW&O by its nickname, "Hojack." In the early days of the railroad, a farmer in his buckboard drawn by a bulky mule was caught on a crossing at train time. When the mule was halfway across the tracks, he stopped. The train was fast approaching and the farmer naturally got excited and began shouting, "Ho-Jack, Ho-Jack." Amused by the incident, the trainmen began calling their line the "Ho-Jack."

Author Richard Palmer attributes it to a slang term for a slow local passenger train or way freight. The Port Jervis Evening Gazette reported, "hile the Hojack was backing down to the depot Wednesday afternoon a horse in a team attached to a wagon from the country got its foot fast between the rail and the bed of the track in a manner similar to that which a horse belonging to Thomas Cuddeback was ruined some time ago. It was with great difficulty that the horse Wednesday was saved from a similar fate. The foot was got out just in time to get out of the way of the train."

A subsequent story in the same newspaper supports that explanation, saying "he name Hojack, which the Gazette gave to the way train leaving here for the west at 1:30 in the afternoon, sticks closer than a brother, and the train is now generally known by that name." NYC attempted to ban the name by way of an edict released in 1906. See Also Ontario Midland Railroad Ontario Eastern Railroad
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