Walter (W.) Dean Harman is an American chemist,academic,author and researcher. He is the William R. Kenan,Jr. Professor of Chemistry at the University of Virginia. [1]
Harman's research primarily focuses on organic,inorganic,and organometallic chemistry. He has also worked extensively in the area of dearomatization,and has developed new chemical tools based on tungsten,osmium,rhenium,and molybdenum that are designed to manipulate organic molecules in new ways. [2] He is also the co-author of a textbook for general chemistry with Professor Gordon Yee,entitled Thinkwell Chemistry.
Harman is the son of Willis Harman. He was born on November 4,1960,in Stanford,California. He studied at Stanford University and received his bachelor's degree in chemistry in 1983,and a doctoral degree in chemistry in 1987. He then served there as a research associate with Henry Taube until 1989. [3]
Harman held a brief appointment as an instructor at Stanford University before joining the University of Virginia as assistant professor of chemistry in 1989. He was promoted to associate professor in 1994,and became a full professor in the department of chemistry in 1997. He also held an administrative appointment in his career. From 2011 till 2019,he served as the chair of the department of chemistry at the University of Virginia. In 2023,he became the William R. Kenan,Jr. Professor of Chemistry. [1]
Harman specializes in organic,inorganic,and organometallic chemistry. [4] He focuses on the development of a new generation of dearomatization agents based on a matching of the d5/d6 reduction potential of rhenium(I),tungsten(0),and molybdenum(0) complexes with that of pentaammineosmium(II). He is the first to demonstrate the step by step conversion of benzene to cyclohexene with varying degrees of deuterium incorporation while binding to a tungsten complex. He also described the formation of stereoselectively deuterated building blocks for pharmaceutical research. [5]
Harman prepared and explored a series of novel bridgehead CF3-substituted isoquinuclidines from decomplexed dihydropyridines,and suggested that dihapto-coordinate complex can be isolated as a single diastereomer,methylated,and reacted with a number of nucleophiles. [6] In 2017,he reviewed a series of his papers published between 2005 and 2017 that focused on the organic reactions of aromatic ligands η2-coordinated to tungsten,and the usage of these reactions in the synthesis of novel organic substances. [7] Furthermore,in collaboration with Daniel Ess,he conducted experiments and directed dynamics simulations to investigate η2-arene/aryl hydride equilibria of tungsten benzene complexes in which the arene is held more loosely than in the ground state,primarily through dispersion forces. [8]
Cyclohexa-1,3-diene (also known as Benzane) is an organic compound with the formula (C2H4)(CH)4. It is a colorless,flammable liquid. Its refractive index is 1.475 (20 °C,D). A naturally occurring derivative of cyclohexa-1,3-diene is terpinene,a component of pine oil.
An alkyne trimerisation is a [2+2+2] cycloaddition reaction in which three alkyne units react to form a benzene ring. The reaction requires a metal catalyst. The process is of historic interest as well as being applicable to organic synthesis. Being a cycloaddition reaction,it has high atom economy. Many variations have been developed,including cyclisation of mixtures of alkynes and alkenes as well as alkynes and nitriles.
Alkyne metathesis is an organic reaction that entails the redistribution of alkyne chemical bonds. The reaction requires metal catalysts. Mechanistic studies show that the conversion proceeds via the intermediacy of metal alkylidyne complexes. The reaction is related to olefin metathesis.
Titanocene dichloride is the organotitanium compound with the formula (η5-C5H5)2TiCl2,commonly abbreviated as Cp2TiCl2. This metallocene is a common reagent in organometallic and organic synthesis. It exists as a bright red solid that slowly hydrolyzes in air. It shows antitumour activity and was the first non-platinum complex to undergo clinical trials as a chemotherapy drug.
In organometallic chemistry,a sandwich compound is a chemical compound featuring a metal bound by haptic,covalent bonds to two arene (ring) ligands. The arenes have the formula CnHn,substituted derivatives and heterocyclic derivatives. Because the metal is usually situated between the two rings,it is said to be "sandwiched". A special class of sandwich complexes are the metallocenes.
Tungsten hexacarbonyl (also called tungsten carbonyl) is the organometallic compound with the formula W(CO)6. This complex gave rise to the first example of a dihydrogen complex.
In organic chemistry,carbon–hydrogen bond functionalization is a type of organic reaction in which a carbon–hydrogen bond is cleaved and replaced with a C−X bond. The term usually implies that a transition metal is involved in the C−H cleavage process. Reactions classified by the term typically involve the hydrocarbon first to react with a metal catalyst to create an organometallic complex in which the hydrocarbon is coordinated to the inner-sphere of a metal,either via an intermediate "alkane or arene complex" or as a transition state leading to a "M−C" intermediate. The intermediate of this first step can then undergo subsequent reactions to produce the functionalized product. Important to this definition is the requirement that during the C−H cleavage event,the hydrocarbyl species remains associated in the inner-sphere and under the influence of "M".
Bis(benzene)chromium is the organometallic compound with the formula Cr(η6-C6H6)2. It is sometimes called dibenzenechromium. The compound played an important role in the development of sandwich compounds in organometallic chemistry and is the prototypical complex containing two arene ligands.
Deuterated benzene (C6D6) is an isotopologue of benzene (C6H6) in which the hydrogen atom ("H") is replaced with deuterium (heavy hydrogen) isotope ("D").
Organochromium chemistry is a branch of organometallic chemistry that deals with organic compounds containing a chromium to carbon bond and their reactions. The field is of some relevance to organic synthesis. The relevant oxidation states for organochromium complexes encompass the entire range of possible oxidation states from –4 (d10) in Na4[Cr–IV(CO)4] to +6 (d0) in oxo-alkyl complexes like Cp*CrVI(=O)2Me.
(Cymene)ruthenium dichloride dimer is the organometallic compound with the formula [(cymene)RuCl2]2. This red-coloured,diamagnetic solid is a reagent in organometallic chemistry and homogeneous catalysis. The complex is structurally similar to (benzene)ruthenium dichloride dimer.
(Benzene)chromium tricarbonyl is an organometallic compound with the formula Cr(C6H6)(CO)3. This yellow crystalline solid compound is soluble in common nonpolar organic solvents. The molecule adopts a geometry known as “piano stool”because of the planar arrangement of the aryl group and the presence of three CO ligands as "legs" on the chromium-bond axis.
Organomolybdenum chemistry is the chemistry of chemical compounds with Mo-C bonds. The heavier group 6 elements molybdenum and tungsten form organometallic compounds similar to those in organochromium chemistry but higher oxidation states tend to be more common.
(Mesitylene)molybdenum tricarbonyl is an organomolybdenum compound derived from the aromatic compound mesitylene (1,3,5-trimethylbenzene) and molybdenum carbonyl. It exists as pale yellow crystals,which are soluble in organic solvents but decompose when in solution. It has been examined as a catalyst and reagent.
Peter Michael Maitlis,FRS was a British organometallic chemist.
Half sandwich compounds,also known as piano stool complexes,are organometallic complexes that feature a cyclic polyhapto ligand bound to an MLn center,where L is a unidentate ligand. Thousands of such complexes are known. Well-known examples include cyclobutadieneiron tricarbonyl and (C5H5)TiCl3. Commercially useful examples include (C5H5)Co(CO)2,which is used in the synthesis of substituted pyridines,and methylcyclopentadienyl manganese tricarbonyl,an antiknock agent in petrol.
(Benzene)ruthenium dichloride dimer is the organoruthenium compound with the formula [(C6H6)RuCl2]2. This red-coloured,diamagnetic solid is a reagent in organometallic chemistry and homogeneous catalysis.
Metal arene complexes are organometallic compounds of the formula (C6R6)xMLy. Common classes are of the type (C6R6)ML3 and (C6R6)2M. These compounds are reagents in inorganic and organic synthesis. The principles that describe arene complexes extend to related organic ligands such as many heterocycles (e.g. thiophene) and polycyclic aromatic compounds (e.g. naphthalene).
Jonas C. Peters is the Bren Professor of Chemistry at the California Institute of Technology and Director of the Resnick Sustainability Institute. He has contributed to the development of catalysts and photocatalysts relevant to small molecule activation.
Arene complexes of univalent gallium,indium,and thallium are complexes featuring the centric (η6) coordination of the metal to the arene. Although arene complexes of transitional metals have long been reported,arene complexes of the main group elements remain scarce. This might be partly explained by the difference in energy of the d and p orbitals.