The syntheses, spectra and structures of five-coordinate cobalt(II) complexes of pyrazolyl-containing ligands

Slow Magnetic Relaxation in Cobalt(II) Field-Induced Single-Ion Magnets with Positive Large Anisotropy

“…The data demonstrate that the thiocyanate complexes with the pentacoordinate cobalt­(II) atom are bound to three nitrogen atoms of the terpy -like ligand, [Co­( terpy ) 2 ]­(NCS) 2 ]­·1.5H 2 O, [Co­( terpy ) 2 ­(NCO) 2 ], [Co­( mpzpy )­(SCN) 2 ], [Co­(4-Cl terpy )­(SCN) 2 ], [Co­( mpytrz )­(SCN) 2 ], and [Co­( bpp )­(NCS) 2 ], (where terpy = 2,2′:6′2′′-terpyridine; mpzpy = 2,6-bis­(3,5-dimethylpyrazolyl)­pyridine; 4-Cl- terpy = 4′-chloro-2,2′:6′2′′-terpyridine; mpytrz = 2,4-bis­(3,5-dimethyl-1 H -pyrazol-1-yl)-6-diethylamino-1,3,5-triazine, bpp = 2,6-bis­(2-benzimidazolyl)­pyridine) have a tendency to form intermediate structures between square pyramid and trigonal bipyramid with values in the range τ = 0.30–0.65. A similar trend is observed for the chloride complexes [Co­(L)­Cl 2 ] incorporating peripheral modified terpy -like ligands: [Co­( pyazatr )­Cl 2 ], [Co­( imterpy )­Cl 2 ], [Co­( pypzpy )­Cl 2 ], [Co­( pz3py )­Cl 2 ], [Co­(trimephpy)­Cl 2 ], [Co­(dimephpy)­Cl 2 ], [Co­(clmephpy)­Cl 2 ], and [Co­(isprpy)­Cl 2 ] where pyazatr -4,4′-(pyridine-2,6-diyl)­bis­(1′,1′-dimethyl-3-azatricyclo­[7.1.1.02,7]­undeca-2,4,6-triene; imterpy -6-iminoformyl-2,2′:6′,2′′-terpyridine-(2,6-diisopropylanil); pypzpy = 2,6-bis­(1-(pyridin-2-yl)­pyrazol-3-yl)­pyridine; pz3py – 2,6-bis­(pyrazol-3-yl)­pyridine, trimephpy = N , N ′-bis­(2,4,6-trimethylphenyl)­pyridine-2,6-dicarboximidoyl dichloride, dimephpy = N , N ′-bis­(2,6- dimethylphenyl)­pyridine-2,6-dicarboximidoyl dichloride, clmephpy = N , N ′-bis­(4-chloro-2,6-dimethyl- phenyl)­pyridine-2,6-dicarboximidoyl dichloride, isprpy = N , N ′-bis­(2,6-diisopropyl)­pyridine-2,6-dicarboximidoyl dichloride. In contrast, the planar bis­(imino)­pyridine pincer ligands in [Co­( isprpy )­(NCS) 2 ] and [Co­( pzam )­(NCS) 2 ] as well as terpy and terpy -like ligands [Co­( terpy )­Cl 2 ], , [Co­(4-Cl terpy )­Cl 2 ], and [Co­( hppzpy )­Cl 2 ] favor a square pyramidal over a trigonal bipyramidal coordination geometry (where isprpy = [2,6-bis­{1-[(2,6-diisopropylphenyl)­imino]­ethyl}­pyridine; pzam = bis­(ethyl-pyrazol-1 H -yl)­amine; 4-Cl- terpy = 4′-chloro-2,2′:6′,2″-terpyridine; hppzpy = 4-hept-1-ynyl-2,6-dipyrazol-1-ylpyridine).…”

“…to form intermediate structures between square pyramid and trigonal bipyramid with values in the range τ = 0.30−0.65. A similar trend is observed for the chloride complexes [Co(L)Cl 2 ] incorporating peripheral modified terpy-like ligands: [Co(pyazatr)Cl 2 ],60 [Co(imterpy)Cl 2 ],61 [Co(pypzpy)Cl 2 ],62 [Co(pz3py)Cl 2 ],62 [Co(trimephpy)Cl 2 ],63 [Co(dimephpy)Cl 2 ],63 [Co(clmephpy)Cl 2 ],63 and [Co-In contrast, the planar bis(imino)pyridine pincer ligands in [Co(isprpy)(NCS) 2 ] 65 and [Co(pzam)(NCS) 2 ] 66 as well as terpy and terpy-like ligands [Co(terpy)Cl 2 ], 38,67 [Co(4-Clterpy)Cl 2 ], 68 and [Co(hppzpy)Cl 2 ] 69 favor a square pyramidal over a trigonal bipyramidal coordination geometry…”

Benzenedicarbonyl and benzenetricarbonyl linker pyrazolyl complexes of palladium(ii): synthesis, X-ray structures and evaluation as ethylene polymerisation catalystsElectronic supplementary information (ESI) available: molecular structures and bond lengths and angles for L2, L3, L6 and 2. See http://www.rsc.org/suppdata/dt/b2/b208376k/

“…Another class † Electronic supplementary information (ESI) available: molecular structures and bond lengths and angles for L2, L3, L6 and 2. See http:// www.rsc.org/suppdata/dt/b2/b208376k/ of poly(1-pyrazolyl) linker compounds is comprised of pyridine, 2,6-bis(1-pyridin-2-ylpyrazol-3-yl)pyridine or benzene, 9 1,3-bis(pyrazol-1-ylmethyl)benzene, 10 and tri-substituted benzene. 11 Cyclophosphazenes can also be utilized in this role for poly(1-pyrazolyl) compounds as demonstrated by Chandrasekar et al 12 and others.…”

Pyridinium [2,6-bis(5-phenyl-1H-pyrazol-3-yl-κN2)pyridine-κN]tetranitrato-κ6O,O′;κO-samarium(III) pyridine monosolvate

“…For the synthesis of the ligand, see: Zhao et al (2009). For related transition metal and lanthanide complexes, see: Argent et al (2005); Bardwell et al (1997); Barrios et al (2008); Coronado et al (2003); Dong et al (1999); Dutta et al (1996); Gamez et al (2002); Gimenez-Lopez et al (2005); Scudder et al (2005); Wei et al (2008). (2) V = 1847.0 (6) Å 3 Z = 2 Mo K radiation = 1.67 mm À1 T = 296 K 0.18 Â 0.12 Â 0.10 mm…”