Synthesis and reactivity of bis-alkynyl appended metallocenes of Ti, Fe, and Co

2010 ◽  
Vol 88 (12) ◽  
pp. 1213-1221 ◽  
Author(s):  
Preeti Chadha ◽  
Jason L. Dutton ◽  
Paul J. Ragogna

(Dimethyl)(phenylethynyl)silyl-substituted cyclopentadiene C5H5SiMe2C2Ph (1) was synthesized by the reaction of in situ generated C5H5SiMe2Cl with LiC2Ph. Metallation of 1 with nBuLi or KN(SiMe3)2 gave the corresponding Li (2) and K (3) salts. Transmetallation of 2 with transition metal halides MCl2 (M = TiCl2, Fe, and Co) generated the corresponding early and late transition metal metallocenes (4, 5, and 6) with pendant alkynyl substituents. Compounds 4 and 6 are the first examples of bis alkyne appended Ti and Co metallocenes. Complexes 5 and 6 undergo alkyne dimerization in the presence of CpCo(CO)2 generating metallocenophanes 7 and 8 incorporating two metal atoms. Compounds 3, 4Cl2, 6, and [8][OTf] have been characterized by single crystal X-ray structure analysis.

2011 ◽  
Vol 89 (12) ◽  
pp. 1506-1511 ◽  
Author(s):  
Jenkins Yin Ki Tsang ◽  
Kin Shing Chan

A synthetic route for iridium porphyrin amido complexes has been established. Treatment of a THF solution of Ir(ttp)(CO)Cl (1) (ttp = 5,10,15,20-tetrakis(p-tolyl)porphyrinato dianion) with an aqueous mixture of NaOH and NaBH4, followed by 2-iodoethanol leads to the clean formation of the β-hydroxyethyl complex Ir(ttp)(C2H4OH) (2) in 92% yield. Heating a pyridine solution of complex 2 in the presence of ca. 5–10 equiv. of phthalimide (HNC8H4O2; HPhth) leads to the formation of Ir(ttp)(C5H5N)(CH2CH2Phth) (3). The replacement of pyridine by THF as the reaction solvent leads to the formation of the THF adduct Ir(ttp)(THF)(Phth) (4), which has been characterized spectroscopically. Heating a solution of 4 in pyridine leads to the formation of Ir(ttp)(C5H5N)(Phth) (5), which has been isolated in 72% yield. Complexes 3 and 5 have been characterized by X-ray crystallographic studies. Complexes 4 and 5 are rare examples of monomeric late transition metal-amido complexes and are the first examples of iridium-amido complexes featuring a porphyrin as a supporting ligand.


2014 ◽  
Vol 43 (22) ◽  
pp. 7536-7547 ◽  
Author(s):  
Jason F. Weaver ◽  
Can Hakanoglu ◽  
Abbin Antony ◽  
Aravind Asthagiri

Late transition-metal oxide surfaces that expose coordinatively-unsaturated metal atoms promote the formation and bond activation of alkane σ-complexes.


2012 ◽  
Vol 90 (1) ◽  
pp. 108-117 ◽  
Author(s):  
Dongmei Liu ◽  
Zaozao Qiu ◽  
Hoi-Shan Chan ◽  
Zuowei Xie

Late transition-metal complexes bearing linked cyclopentadienyl/indenyl–carboranyl ligands were synthesized and their reactivities were examined. Reaction of Li2[Me2C(L)(C2B10H10)] (L = C5H4, C9H6, Me2NCH2CH2C5H3) with MCl2(PPh3)2 in Et2O afforded [η5:σ-Me2C(C5H4)(C2B10H10)]M(PPh3) (M = Co (4), Ni (5)), [η5:σ-Me2C(C9H6)(C2B10H10)]M(PPh3) (M = Co (6), Ni (7)), and [η5:σ-Me2C(Me2NCH2CH2C5H3)(C2B10H10)]Ni(PPh3) (8). Treatment of 4 or 5 with 2,6-dimethylphenylisocyanide, N-heterocyclic carbene (NHC), PCy3, or 1,2-bis(diphenylphosphino)ethane (dppe) gave the corresponding PPh3 displacement complexes [η5:σ-Me2C(C5H4)(C2B10H10)]M(2,6-Me2C6H3NC) (M = Co (9), Ni (10)), [η5:σ-Me2C(C5H4)(C2B10H10)]M[1,3-(2,6-i-Pr2C6H3)2C3N2H2] (M = Co (11), Ni (12)), [η5:σ-Me2C(C5H4)(C2B10H10)]Ni(PCy3) (13), or {[η5:σ-Me2C(C5H4)(C2B10H10)]Co}2(dppe) (14), respectively. These complexes were characterized by various spectroscopic techniques and elemental analyses. The molecular structures of 4–14 were further confirmed by single-crystal X-ray analyses.


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