Emergence of electrophilic alumination as the counterpart of established nucleophilic lithiation: an academic sojourn in organometallics with William Kaska as fellow traveler
Fundamental reactions of C–Al bonds in Ziegler's nobel research, alumination, carboalumination and hydroalumination, involve attack by tricoordinate aluminum electrophiles.
Dehydrogenation of hydrocarbons with metal-carbon multiple bonds and trapping of a titanium(II) intermediate
Reacting (PNP)Ti![[double bond, length as m-dash]](https://www.rsc.org/images/entities/char_e001.gif)
CHtBu(CH2tBu) with 2,2′-bipyridine (bipy) in cyclohexane or heptane results in dehydrogenation of the solvent, cleanly producing cyclohexene and 1-heptene, respectively, and a TiII intermediate that is trapped by bipy.
Zinc calixarene complexes for the ring opening polymerization of cyclic esters
A number of zinc calixarene complexes have been structurally characterized and screened for the ROP of ε-caprolactone and rac-lactide.
Addition of C–C and C–H bonds by pincer-iridium complexes: a combined experimental and computational study
Oxidative addition of the strained biphenylene C–C bond proceeds via a transition state wherein the biphenylene unit is severely “tilted”.
C–H activation and metalation at electrode surfaces: 2,3-dimethyl-1,4-dihydroxybenzene on Pd(pc) and Pd(111) studied by TLE, HREELS and DFT
The electrode-surface C–H activation and metalation of 2,3-dimethyl-1,4-dihydroxybenzene on Pd was investigated by electrochemistry, electron spectroscopy, and density functional theory. At high concentrations, formation of a (5,6-η)-o-phenylene organopalladium surface compound was indicated.
Synthesis and structures of tris(2-pyridyl)aluminate sandwich compounds [{RAl(2-py′)2}2M] (py′ = 2-pyridyl, M = Ca, Mn, Fe)
While neither the bridgehead group (R) nor remote ring Me-groups have any impact on metal coordination of tris(2-pyridyl) aluminate ligands [RAl(2-py′)3]−, Me groups adjacent to the donor pyridyl-N atoms have a large effect on their ability to form sandwich arrangements.
Iridium(III) catalyzed trifluoroacetoxylation of aromatic hydrocarbons
A tridentate, NNC-tb (where NNC-tb = 2-(pyridin-2-yl)benzo[h]quinoline) ligated IrIII complex (NNC-tb)Ir(Ph)(4-MePy)(TFA), 11 along with analogues are very active for CH activation as evidenced by rapid catalytic H/D exchange between benzene and trifluoroacetic acid – d1 (DTFA).
Copper-catalyzed hydrophosphinations of styrenes in water at room temperature
Copper-catalyzed hydrophosphinations of styrenyl systems in water, at room temperature is herein reported, enabled by our ‘designer’ surfactant TPGS-750-M.
Organometallic benzylidene anilines: donor–acceptor features in NCN-pincer Pt(II) complexes with a 4-(E)-[(4-R-phenyl)imino]methyl substituent
Inductively the Pt-moiety in these organometallic benzylidene anilines is a very strong electron-withdrawing group, but mesomerically a very strong electron-donating group.
Reaction of five-membered zirconacycloallenoids with the strong Lewis acid B(C6F5)3
Two alkyl and aryl substituted five-membered zirconacycloallenoids underwent a typical σ-alkyl metallocene reaction with B(C6F5)3, namely cleavage of the Zr–C(sp3) bond with formation of zwitterionic (η2-allenyl)zirconium/alkylborate products.
Benzo annulated cycloheptatriene PCP pincer iridium complexes
Chemical conversions of a cycloheptatriene iridium pincer complex were studied by NMR and MS techniques as well as DFT calculations.
Hemilability of P(X)N-type ligands (X = O, N–H): rollover cyclometalation and benzene C–H activation from (P(X)N)PtMe2 complexes
The hemilability of the pyridyl groups of (tBuP(O)N)PtMe2 and (tBuP(N–H)N)PtMe2 allows rollover cyclometalation to occur. In the case of (tBuP(N–H)N)PtMe2 intermolecular benzene C–H(D) activation is also competitive.
Differences in the cyclometalation reactivity of bisphosphinimine-supported organo-rare earth complexes
A novel yttrium complex [LnY(CH2SiMe3)2] is resistant to cyclometalation, while samarium variants undergo C–H activation, forming unique cyclometalated motifs.
Tuning coordination modes of pyridine/thioether Schiff base (NNS) ligands to mononuclear manganese carbonyls
Manganese carbonyls are ligated by pyridine/thioether Schiff base (NNS) ligands. Coordination of the thioether-S donor to the Mn(I) center is determined by subtle steric changes at the ligand periphery.
Generation of low-valent tantalum species by reversible C–H activation in a cyclometallated tantalum hydride complex
Ligand C–H activation leads to formation of a cyclometallated Ta(V) hydride complex, which can act as a Ta(III) synthon.
About this collection
This themed collection on the carbon‒metal bond and C‒H metalation is devoted to the career of Professor William (Bill) Kaska, who will celebrate his 80th birthday on May the 13th, 2015. Bill was a faculty member at The University of California at Santa Barbara for the entirety of his 41-year independent career (1964‒2004). During this time, he supervised many graduate students and post-doctoral scholars, a large number of whom are active in teaching, research, and in industry positions today.
Professor William (Bill) Charles Kaska
Throughout his career, Bill has been a true pioneer and adventurer in organometallic chemistry, bearing the innate synthetic flair and expertise to make unusual molecules where others had tried and failed. He has made several important (and perhaps under-recognized) impacts in the field of metal-mediated C‒H activation, as well as in several other areas of organometallic chemistry (see below). Perhaps most notably, Bill was one of the first researchers to realize the power of C‒H bond metalation using transition metals and his early work demonstrated some of the first reported instances of such chemistry.
During his career, Bill collaborated with many groups around the World, and was a visiting scientist at Monsanto in Zurich, at the Universities of Cambridge, Erlangen, Tübingen and Utrecht, and at the Max-Planck Institute in Mülheim. We celebrate the achievements of Bill, his mentors and co-workers in this themed collection: the publications kindly dedicated to this celebratory themed collection serve to illustrate how far the field has come since the publication of a number of seminal results over 40 years ago. Read the full commentary here.