Magnetic exchange interactions in some novel .mu.-azido-bridged copper(II) dimers. Crystal structures of [L2Cu2(.mu.-N3)(N3)2](ClO4).cntdot.H2O, LCu(N3)2, [L2Cu2(.mu.-N3)2(ClO4)2], and L'Cu(N3)2 (L = N,N',N"-trimethyl-1,4,7-triazacyclononane and L' = 1,4,7-triazacyclononane)

Abstract

reaction coordinate. The rate of the spin-change reaction has in all cases which have been investigated found to be of the order of magnitude of 101 23456-107 s"1, so the rate of the racemization reaction will not be restricted by any spin-change bottleneck.Acknowledgment. We are grateful for support from the Na-tional Institutes of Health (Grant HL 13652).Supplementary Material Available: Listings of thermal parameters, hydrogen atom positions, and bond distances and angles for [Fe-(tptcn)](C104)2 and Figure 4, a stereoview of the unit cell (4 pages).Ordering information is given on any current masthead page.

The Encapsulation of Ferrocyanide by Copper(II) Complexes of Tripodal Tetradentate Ligands. Novel H-Bonding Networks Incorporating Heptanuclear and Pentanuclear Heterometallic Assemblies

“…In each case, a high energy shoulder is observed at ca. 680 nm which is typical of Cu II complexes with TBP geometry. , However, it should be recognized that these less intense shoulders can also arise from d−d transitions in copper(II) complexes with square pyramidal (SP) geometries. − The solid-state reflectance spectra of 1 − 3 show good correspondence to the solution spectra in the 600−900 nm region, indicating little stereochemical change on dissolution. The high energy shoulders have shifted to slightly lower λ (665 nm for 1 , 652 nm for 2 , and 670 nm for 3 ) and are slightly more prominent than in the solution spectra.…”

Mechanistic Studies of Dichloro(1,4,7-triazacyclononane)copper(II)-Catalyzed Phosphate Diester Hydrolysis

“…A bis(μ-hydroxo)-bridged copper(II) dimer of the 1,4,7-trimethyl derivative of [9]aneN 3 has been structurally characterized, providing precedent for the formulation of the dimeric species in solution. Additional dimeric compounds of the form [LCu(μ-X) 2 CuL] n+ , where L = 1,4,7-(CH 3 ) 3 -[9]aneN 3 and X = OH or N 3 , have been characterized by X-ray structure analysis and by ESR spectroscopy. We have structurally characterized [Cu 2 ([9]aneN 3 ) 2 Cl 3 ]PF 6 with a single μ-Cl bridge as well as the bis(μ-hydroxide)-bridged dimer [Cu 2 ([10]aneN 3 ) 2 (μ-OH) 2 ]Br 2 , demonstrating that dimeric copper(II) complexes of the nonalkylated [9]aneN 3 ligand are also stable.…”

Role of the Coordination of the Azido Bridge in the Magnetic Coupling of Copper(II) Binuclear Complexes

“…The two models either have two azido ligands in the basal plane (Figure 1 a; ete‐m1) or one azido ligand in the apical position (Figure 1 b; ete‐m2). The second set of calculations was performed on five distorted bridging geometries, taken from to the crystallographically determined structures of the compounds 1 to 5 : [L 2 Cu 2 ( μ ‐1,3‐N 3 ) 2 ](ClO 4 ) 2 ( 1 ;29 L= N , N ′, N ″‐trimethyl‐1,4,7‐triazacyclononane), [(Me 5 dien) 2 Cu 2 ( μ ‐1,3‐N 3 ) 2 ](BPh 4 ) 2 ( 2; 30 Me 5 dien=1,1,4,7,7‐pentamethyldiethylenetriamine), [(Et 5 dien) 2 Cu 2 ( μ ‐1,3‐N 3 ) 2 ](ClO 4 ) 2 ( 3; 30, 31 Et 5 dien=1,1,4,7,7‐pentaethyldiethylenetriamine), [(EtMe 4 dien) 2 Cu 2 ( μ ‐1,3‐N 3 ) 2 ](ClO 4 ) 2 ( 4; 31 EtMe 4 dien=4‐ethyl‐1,1,7,7‐tetramethyldiethylenetriamine) and [(Me 5 dien) 2 Cu 2 ( μ ‐1,3‐N 3 ) 2 ](ClO 4 ) 2 ( 5 ) 30, 31. Hereafter, the corresponding [(NH 3 ) 6 Cu 2 ( μ ‐1,3‐N 3 ) 2 ] 2+ structures are labelled ete‐ 1 to ete‐ 5 .…”