RSC Publishing


Publishing

 

Cover image for Dalton Transactions, select for current issue

Dalton Transactions

The international journal for inorganic, organometallic and bioinorganic chemistry



Subscribers

Non-subscribers

Free access



Paper

Dalton Trans., 2009, 10601 - 10608, DOI: 10.1039/b917377c

1,1,3,3-Tetramethylguanidine solvated lanthanide aryloxides: pre-catalysts for intramolecular hydroalkoxylation

Thomas E. Janini, Robert Rakosi III, Christopher B. Durr, Jeffrey A. Bertke and Scott D. Bunge

The synthesis and structural characterization of six 1,1,3,3-tetramethylguanidine (H-TMG) solvated lanthanide aryloxide complexes are reported. Ln[N{Si(CH3)3}2]3 (Ln = Nd, La) was reacted with two equivalents of both H-TMG and HOAr {HOAr = HOC6H2(CMe3)2-2,6 (H-DBP) or HOC6H2(CMe3)2-2,6-CH3-4 (H-4MeDBP)} and one equivelent of ethanol (HOEt) to yield the corresponding [Nd(H-TMG)2(4MeDBP)2(OEt)] ( 1) and [La(H-TMG)2(DBP)2(OEt)] ( 2). Compounds 1 and 2 were further reacted with 4-pentyn-1-ol {HO(CH2)3CCH} to isolate [Nd(H-TMG)2(4MeDBP)2{O(CH2)3CCH}] ( 3) and [La(H-TMG)2(DBP)2{O(CH2)3CCH}] ( 4), respectively. Three equivalents of HOAr and one equivalent of H-TMG were additionally reacted with Ln[N{Si(CH3)3}2]3 to generate [Nd(4MeDBP)3(H-TMG)] ( 5) and [La(DBP)3(H-TMG)] ( 6). In order to examine the formation of 1–6, the interaction of H-TMG and HOAr was further examined in solution and the hydrogen bonded complexes (H-TMG:HOAr), 7 and 8, were isolated. Upon successful isolation of 1–6, the utility of 1, 2, 4 and 5 as pre-catalysts for the intramolecular hydroalkoxylation of 4-pentyn-1-ol was investigated. The bulk powders for all complexes were found to be in agreement with the crystal structures based on elemental analyses, FT-IR spectroscopy, and 1H and 13C NMR investigations.

Graphical abstract image for this article (ID: b917377c)