Terphenyl ligand systems in lanthanide chemistry: use of the 2,6-di(1-naphthyl)phenyl ligand for the synthesis of kinetically stabilized complexes of trivalent ytterbium, thulium, and yttrium

The molecular structures of terphenyl derivatives of trivalent ytterbium, thulium, and yttrium of general composition DnpLnCl(2)(THF)(2) [Dnp = 2,6-di(1-naphthyl)phenyl] are reported. The complexes (Ln = Yb: 1; Ln = Tm: 2; Ln = Y: 3) are synthesized by reaction of 1 equiv of DnpLi with 1 equiv of LnCl(3) (Ln = Yb, Tm, or Y) in tetrahydrofuran at room temperature in 50% yield. Attempts to prepare a Dnp scandium compound gave heterobimetallic [(THF)(3)Sc(2)OCl(5)Li(THF)](2) (4) in low yield. 1 crystallizes in the monoclinic space group C2/c. Crystal data for 1 at 203 K: a = 14.333(3) A, b = 16.353(3) A, c = 12.427(2) A, beta = 91.021(4) degrees, Z = 4, D(calcd) = 1.637 g cm(-3), R(1) = 4.44%. 2 crystallizes in the monoclinic space group C2/c. Crystal data for 2 at 203 K: a = 14.333(1) A, b = 16.374(2) A, c = 12.404(1) A, beta = 90.934(2) degrees, Z = 4, D(calcd) = 1.628 g cm(-3), R(1) = 3.00%. 3 crystallizes in the monoclinic space group C2/c. Crystal data for 3 at 203 K: a = 14.348(3) A, b = 16.476(3) A, c = 12.356(2) A, beta = 90.987(4) degrees, Z = 4, D(calcd) = 1.441 g cm(-3), R(1) = 5.62%. 4 crystallizes in the monoclinic space group P2(1)/n. Crystal data for 4 at 203 K: a = 11.0975(9) A, b = 11.0976(9) A, c = 21.3305(18) A, beta = 94.718(2) degrees, Z = 2, D(calcd) = 1.051 g cm(-3), R(1) = 3.45%. Complexes 1-3 represent examples of novel chiral (racemic) organometallic complexes of the lanthanide elements ytterbium and thulium and the group 3 element yttrium, respectively. The molecular structures of monomeric 1-3 exhibit distorted trigonal-bipyramidal coordination environments at the metal center, with the two oxygen atoms of the tetrahydrofuran ligands occupying the axial positions of a trigonal-bipyramidal coordination polyeder. The molecular structure of the scandium compound 4 shows a complex polynuclear heterobimetallic arrangement.     

Novel square planar copper(II) complexes with imino or nitronyl nitroxide radicals exhibiting large ferro- and antiferromagnetic interactions

This paper reports the synthesis, crystal structures, and magnetic properties of two copper(II) complexes (1, 2) of general formula Cu(tfac)2(radical)2 (tfac = trifluoroacetate; radical = (1) 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (NITPh) or (2) 2-phenyl-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazoline-1- oxyl (IMPh)). They crystallize in the monoclinic P2(1)/n space group with the following parameters: (1) a = 13.212(2) A, b = 9.136(1) A, c = 15.587(2) A, beta = 114.61(1) degrees, Z = 2; (2) a = 11.059(2) A, b = 15.289(1) A, c = 10.694(2) A, beta = 114.20(1) degrees, Z = 2. In both complexes the copper(II) ion is coordinated to two radicals in a slightly distorted square planar surrounding. The copper(II)-radical exchange couplings are antiferromagnetic for the nitronyl nitroxide (NITPh) complex (1) and ferromagnetic in the case of the imino nitroxide (IMPh) analogue (2). The ground state has been found to be a spin-doublet for 1 and the spin-quartet for 2. No thermal population of the highest states has been observed, indicating copper(II)-radical couplings of magnitude of J > 500 cm-1.     

Novel metal-organic frameworks with specific topology from new tripodal ligands: 1,3,5-tris(1-imidazolyl)benzene and 1,3-bis(1-imidazolyl)-5-(imidazol-1-ylmethyl)benzene

Reactions of two new tripodal ligands 1,3,5-tris(1-imidazolyl)benzene (4) and 1,3-bis(1-imidazolyl)-5-(imidazol-1-ylmethyl)benzene (5) with metal [Ag(I), Cu(II), Zn(II), Ni(II)] salts lead to the formation of novel two-dimensional (2D) metal-organic frameworks [Ag(2)(4)(2)][p-C(6)H(4)(COO)(2)].H(2)O (6), [Ag(4)]ClO(4) (7), [Cu(4)(2)(H(2)O)(2)](CH(3)COO)(2).2H(2)O (8), [Zn(4)(2)(H(2)O)(2)](NO(3))(2) (9), [Ni(4)(2)(N(3))(2)].2H(2)O (10), and [Ag(5)]ClO(4) (11). All the structures were established by single-crystal X-ray diffraction analysis. Crystal data for 6: monoclinic, C2/c, a = 23.766(3) A, b = 12.0475(10) A, c = 13.5160(13) A, beta = 117.827(3) degrees, Z = 4. For compound 7: orthorhombic, P2(1)2(1)2(1), a = 7.2495(4) A, b = 12.0763(7) A, c = 19.2196(13) A, Z = 4. For compound 8: monoclinic, P2(1)/n, a = 8.2969(5) A, b = 12.2834(5) A, c = 17.4667(12) A, beta = 96.5740(10) degrees, Z = 2. For compound 9: monoclinic, P2(1)/n, a =10.5699(3) A, b = 11.5037(3) A, c = 13.5194(4) A, beta = 110.2779(10) degrees, Z = 2. For compound 10: monoclinic, P2(1)/n, a = 9.8033(3) A, b = 12.1369(5) A, c = 13.5215(5) A, beta = 107.3280(10) degrees, Z = 2. For compound 11: monoclinic C2/c, a = 18.947(2) A, b = 9.7593(10) A, c = 19.761(2) A, beta = 97.967(2) degrees, Z = 8. Both complexes 6 and 7 are noninterpenetrating frameworks based on the (6, 3) nets, and 8, 9 and 10 are based on the (4, 4) nets while complex 11 has a twofold parallel interpenetrated network with 4.8(2) topology. It is interesting that, in complexes 6,7, and 11 with three-coordinated planar silver(I) atoms, each ligand 4 or 5 connects three metal atoms, while in the case of complexes 8, 9, and 10 with six-coordinated octahedral metal atoms, each ligand 4 only links two metal atoms, and another imidazole nitrogen atom of 4 did not participate in the coordination with the metal atoms in these complexes. The results show that the nature of organic ligand and geometric needs of metal atoms have great influence on the structure of metal-organic frameworks.     

Synthesis and characterization of six new quaternary actinide thiophosphate compounds: Cs(8)U(5)(P(3)S(10))(2)(PS(4))(6)(,) K(10)Th(3)(P(2)S(7))(4)(PS(4))(2), and A(5)An(PS(4))(3), (A = K, Rb, Cs; An = U, Th)

Six new actinide metal thiophosphates have been synthesized by the reactive flux method and characterized by single-crystal X-ray diffraction: Cs(8)U(5)(P(3)S(10))(2)(PS(4))(6) (I), K(10)Th(3)(P(2)S(7))(4)(PS(4))(2) (II), K(5)U(PS(4))(3) (III), K(5)Th(PS(4))(3) (IV), Rb(5)Th(PS(4))(3) (V), and Cs(5)Th(PS(4))(3) (VI). Compound I crystallizes in the monoclinic space group P2(1)/c with a = 33.2897(1) A, b = 14.9295(1) A, c = 17.3528(2) A, beta = 115.478(1) degrees, Z = 8. Compound II crystallizes in the monoclinic space group C2/c with a = 32.8085(6) A, b = 9.0482(2) A, c = 27.2972(3) A, beta = 125.720(1) degrees, Z = 8. Compound III crystallizes in the monoclinic space group P2(1)/c with a = 14.6132(1) A, b = 17.0884(2) A, c = 9.7082(2) A, beta = 108.63(1) degrees, Z = 4. Compound IV crystallizes in the monoclinic space group P2(1)/n with a = 9.7436(1) A, b = 11.3894(2) A, c = 20.0163(3) A, beta = 90.041(1) degrees, Z = 4, as a pseudo-merohedrally twinned cell. Compound V crystallizes in the monoclinic space group P2(1)/c with a = 13.197(4) A, b = 9.997(4) A, c = 18.189(7) A, beta = 100.77(1) degrees, Z = 4. Compound VI crystallizes in the monoclinic space group P2(1)/c with a = 13.5624(1) A, b = 10.3007(1) A, c = 18.6738(1) A, beta = 100.670(1) degrees, Z = 4. Optical band-gap measurements by diffuse reflectance show that compounds I and III contain tetravalent uranium as part of an extended electronic system. Thorium-containing compounds are large-gap materials. Raman spectroscopy on single crystals displays the vibrational characteristics expected for [PS(4)](3)(-), [P(2)S(7)](4-), and the new [P(3)S(10)](5)(-) building blocks. This new thiophosphate building block has not been observed except in the structure of the uranium-containing compound Cs(8)U(5)(P(3)S(10))(2)(PS(4))(6).     

Synthesis and structure of a complex having a quartet ground state with three entirely different spin carriers: nitronyl nitroxide, o-semiquinone, and CuII

A "spin diverse" S = 3/2 ground-state complex, NN-SQCuTpCum,Me, has been prepared. The three S = 1/2 spin carriers are nitronyl nitroxide (NN), o-semiquinone (o-SQ), and cupric ion. The solid-state structure of the ZnII derivative, NN-SQZnTpCum,Me (C56H69BN8O4Zn), was determined: monoclinic, P2(1)/c, a = 12.5781(12) A, b = 17.7408(17) A, c = 24.440(2) A, alpha = 90.00 degrees, beta = 98.240(2) degrees, gamma = 90.00 degrees, Z = 4. The results of X-ray structural characterization of the ZnII derivative suggest substantial interaction between the two spin carriers NN and o-SQ. Indeed, strong intramolecular exchange coupling has been determined by variable-temperature magnetic susceptibility studies. Intraligand ferromagnetic exchange is considerably greater than kT, such that only the triplet state is populated at 300 K, and CuII-ligand exchange is ferromagnetic, with J = +75 cm-1.     

A homologous series of alkaline earth phosphanides: syntheses,crystal structures,and unusual dynamic behavior of (THF)(n)M[P(CH(SiMe(3))(2))(C(6)H(4)-2-CH(2)NMe(2))](2) (M = Mg,Ca, Sr,Ba)

The secondary phosphine R(Me(2)NCH(2)-2-C(6)H(4))PH reacts with Bu(2)Mg to give the homoleptic complex Mg[PR(C(6)H(4)-2-CH(2)NMe(2))](2) (1) [R = CH(SiMe(3))(2)]. The analogous heavier alkaline earth metal complexes (THF)(n)Ae[PR(C(6)H(4)-2-CH(2)NMe(2))](2) [Ae = Ca (2), n = 0; Ae = Sr (3), Ba (4), n = 1] have been synthesized by metathesis reactions between K[PR(C(6)H(4)-2-CH(2)NMe(2))] and 0.5 equiv of the respective alkaline earth metal diiodide. Compounds 1-4 have been characterized by X-ray crystallography and multielement NMR spectroscopy. In the solid state, compounds 1-4 are monomeric, complexes 1 and 2 adopting a distorted tetrahedral geometry and complexes 3 and 4 adopting a distorted square pyramidal geometry (1: orthorhombic, P2(1)2(1)2(1), a = 11.413(3) A, b = 12.072(3) A, c = 32.620(11) A, Z = 4. 2: monoclinic, P2(1)/c, a = 9.5550(4) A, b = 17.4560(7) A, c = 24.5782(10) A, beta = 91.673(2) degrees, Z = 4. 3: monoclinic, C2/c, a = 15.0498(9) A, b = 13.0180(8) A, c = 24.3664(14) A, beta = 104.593(2) degrees, Z = 4. 4: monoclinic, C2/c, a = 15.2930(10) A, b = 13.0326(9) A, c = 24.6491(17) A, beta = 105.542(2) degrees, Z = 4). In toluene solution, compounds 2-4 are subject to dynamic processes which are attributed to a monomer-dimer equilibrium for which bridge-terminal exchange of the phosphanide ligands in the dimer may be frozen out at low temperatures.     

Mixed-metal uranium(VI) iodates: hydrothermal syntheses,structures, and reactivity of Rb[UO(2)(CrO(4))(IO(3))(H(2)O)], A(2)[UO(2)(CrO(4))(IO(3))(2)] (A = K,Rb, Cs), and K(2)[UO(2)(MoO(4))(IO(3))(2)

The reactions of the molecular transition metal iodates A[CrO(3)(IO(3))] (A = K, Rb, Cs) with UO(3) under mild hydrothermal conditions provide access to four new, one-dimensional, uranyl chromatoiodates, Rb[UO(2)(CrO(4))(IO(3))(H(2)O)] (1) and A(2)[UO(2)(CrO(4))(IO(3))(2)] (A = K (2), Rb (3), Cs (4)). Under basic conditions, MoO(3), UO(3), and KIO(4) can be reacted to form K(2)[UO(2)(MoO(4))(IO(3))(2)] (5), which is isostructural with 2 and 3. The structure of 1 consists of one-dimensional[UO(2)(CrO(4))(IO(3))(H(2)O)](-) ribbons that contain uranyl moieties bound by bridging chromate and iodate anions as well as a terminal water molecule to create [UO(7)] pentagonal bipyramidal environments around the U(VI) centers. These ribbons are separated from one another by Rb(+) cations. When the iodate content is increased in the hydrothermal reactions, the terminal water molecule is replaced by a monodentate iodate anion to yield 2-4. These ribbons can be further modified by replacing tetrahedral chromate anions with MoO(4)(2)(-) anions to yield isostructural, one-dimensional [UO(2)(MoO(4))(IO(3))(2)](2)(-) ribbons. Crystallographic data: 1, triclinic, space group P(-)1, a = 7.3133(5) A, b = 8.0561(6) A, c = 8.4870(6) A, alpha = 88.740(1) degrees, beta = 87.075(1) degrees, gamma = 71.672(1) degrees, Z = 2; 2, monoclinic, space group P2(1)/c, a = 11.1337(5) A, b = 7.2884(4) A, c = 15.5661(7) A, beta = 107.977(1) degrees, Z = 4; 3, monoclinic, space group P2(1)/c, a = 11.3463(6) A, b = 7.3263(4) A, c = 15.9332(8) A, beta = 108.173(1) degrees, Z = 4; 4, monoclinic, space group P2(1)/n, a = 7.3929(5) A, b = 8.1346(6) A, c = 22.126(2) A, beta = 90.647(1) degrees, Z = 4; 5, monoclinic, space group P2(1)/c, a = 11.3717(6) A, b = 7.2903(4) A, c = 15.7122(8) A, beta = 108.167(1) degrees, Z = 4.     

Aminomethyl-bipyridine bearing two flexible nitronyl-nitroxide arms: a new podand for complexation of transition metals in a facial or meridional conformation

Transition metal complexes of 6-aminomethyl-bis[methyl-2-(4,5-dihydro-4,4,5,5- tetramethylimidazolinyl-3-oxide-l-oxy)]-2,2'-bipyridine, bpyN(NIT)(2), 1, have been synthesized and characterized by FAB-MS, UV-vis, FT-IR, and EPR spectroscopies, elemental analysis, and susceptibility measurements. Single-crystal X-ray diffraction studies have been performed on all compounds giving the following crystal data: bpyN(NIT)(2), 1, triclinic, P(-)1, Z = 2, a = 10.7224(4) A, b = 11.0995(4) A, c = 13.1134(3) A, alpha = 114.101(9) degrees, beta = 97.476(9) degrees, gamma = 99.667(9) degrees; ZnbpyN(NIT)(2), 2, hexagonal, P3(2), Z = 3, a = 15.4545(3) A, b = 15.4545(3) A, c = 13.5594(3) A; NibpyN(NIT)(2), 3, hexagonal, P3(2), Z = 3, a = 15.2867(1) A, b = 15.2867(1) A, c = 13.7160(1) A; CubpyN(NIT)(2), 4, triclinic, P(-)l, Z = 2, a = 11.8640(4) A, b = 13.2023(4) A, c = 13.2661(5) A, alpha = 90.539(9) degrees, beta = 104.983(9) degrees, gamma = 113.252(9) degrees. The two radicals of the free ligand 1 are almost perpendicular to one another in the solid state, favoring a weak ferromagnetic interaction (J/k(B) = 8.8 K). The complexes obtained by wrapping the ligand around a single metal center gave rise to two different coordination schemes where the two radicals of 1 adopt a ON(3)O meridional (with Ni and Zn) or a ON(3)O facial conformation (with Cu), which strongly affects the magnetic and electronic properties (O accounts for the coordinated oxygen atoms of the nitroxide radicals and N(3) accounts for the tertiary amine). For 2, a model of a dimer has been used giving rise to a weak antiferromagnetic interaction between the radicals (J/k(B) = -5.3 K). For 3, a very strong intramolecular antiferromagnetic coupling has been found and estimated at J/k(B) = -230 K and J'/k(B) = -110 K between the nickel and each radical using an asymmetric model of a trimer. For 4, an unusual magnetic behavior is observed, dominated by antiferromagnetic interactions with a residual plateau at chiT = 0.63 emu.K.mol(-)(1). Molecular modeling at the CASSCF level is in keeping with an antiferromagnetic coupling of the radical bound with the Cu(II) in the equatorial position. The combined structural, electronic, and magnetic characteristics suggest that the use of a flexible molecule provide an additional approach for fine-tuning magnetic interactions.     

Ion-Bearing Propellers: Alkali Metal Complexes of Tris(2-alkoxyphenyl)amine Ionophores

NMR spectroscopic studies reveal that binding of Na(+) by tris(2-methoxyphenyl)amine (3) brings two of these tripod ethers together about the metal ion; the related double-tripod-ether ionophore 1,2-bis[2-(bis(2-methoxyphenyl)amino)phenoxy]ethane (4), in which two triarylamines are covalently attached, binds LiI, LiBPh(4), NaI, NaBPh(4), and KB(4-ClPh)(4). Dynamic NMR puts lower limits on binding free energies of 4 for Na(+) (71.8 kJ mol(-)(1)) and K(+) (66.8 kJ mol(-)(1)) ions. X-ray studies of 3(2).NaBPh(4), 4.NaBPh(4), 4.NaB(4-ClPh)(4), and 4.KB(4-ClPh)(4).CH(3)NO(2) show eight-coordinate M(+) ions bound between crystallographically independent, homochiral triarylamine tripod ethers in structures reminiscent of alkali metal [2.2.2] cryptates. Complexes crystallize as follows: 3(2).NaBPh(4), monoclinic, P2(1)/c, Z = 4, a = 10.701(3) ?, b = 37.593(3) ?, c = 13.774(2) ?, and beta = 98.24(2) degrees; 4.NaBPh(4), triclinic, P&onemacr;, Z = 2, a = 12.157(1) ?, b = 14.811(1) ?, c = 15.860(2) ?, alpha = 105.400(8) degrees, beta = 91.594(9) degrees, and gamma = 95.354(8) degrees; 4.NaB(4-ClPh)(4), monoclinic, P2(1)/n, Z = 4, a = 13.652(5) ?, b = 18.75(1) ?, c = 22.805(5) ?, and beta = 92.21(5) degrees; 4.KB(4-ClPh)(4).CH(3)NO(2), monoclinic, Pn, Z = 2, a = 13.663(4) ?, b = 12.228(3) ?, c = 18.712(8) ?, and beta = 91.45(3) degrees. They show variable N-M-N angles; 3(2).NaBPh(4) is surprisingly bent ( angleN-Na-N = 154.5 degrees ), while the 4.M(+) complexes are normal: nearly linear for Na(+) ( angleN-Na-N = 178.6, 178.1 degrees ) and again bent with the larger K(+) ( angleN-K-N = 164.5 degrees ). Finally, free 4 is structurally similar to 3; it crystallizes in the triclinic space group P&onemacr;, with Z = 2, a = 8.068(1) ?, b = 14.599(2) ?, c = 16.475(3) ?, alpha = 115.43(1) degrees, beta = 92.51(1) degrees, and gamma = 90.40(1) degrees.     

(Eta5-pentamethylcyclopentadienyl)rhodium and -iridium complexes with weakly and strongly coordinating anions: isolation and first X-ray molecular structures of the tris(solvent) complexes [(C5Me5)M(acetone)2(H2O)][BF4]2 (M = Rh, Ir)

Several novel pentamethylcyclopentadienyl complexes of general formula [(C5Me5)IrL3][BF4]2 were prepared including the tris(solvent) precursors [(C5Me5)M(acetone)2(H2O)][BF4]2 (M = Rh, Ir) (1a,b). The X-ray molecular structures of 1a,b were determined at low temperature. Complexes 1a,b are isostructural, and both compounds crystallize in the monoclinic space group P2(1)/c with a = 10.157(3) A, b = 14.038(9) A, c = 16.335(2) A, beta = 99.73(2) degrees, and Z = 4 for 1a and with a = 10.107(9) A, b = 13.994(16) A, c = 15.996(34) A, beta = 99.61(12) degrees, and Z = 4 for 1b. The coordinated water molecule is hydrogen bonded to both BF4(-) anions. Reaction of 1a,b with pyridine (py) afforded the related tris(pyridine) complexes [(C5Me5)M(eta1-(N)-py)3][BF4]2 (M = Rh, Ir) (2a,b). Complex 2b was characterized by X-ray crystallography, monoclinic space group P2(1)/c with a = 8.665(3) A, b = 19.687(7) A, c = 18.408(5) A, beta = 94.17(3) degrees, and Z = 4. Moreover, we prepared the novel neutral compounds (C5Me5)M(eta2-NO3)(eta1-NO3) (M = Rh, Ir) (4a,b) where the anions are bonded to the metal center instead of a coordinating solvent as confirmed by X-ray study on the iridium complex 4b. The latter crystallizes in the orthorhombic space group Pcab with a = 13.032(4) A, b = 14.370(11) A, c = 14.839(18) A, and Z = 8.     

The synthesis and characterization of compounds of the type Hg[1-C(6)H(4)-2-C(H)=NC(6)H(5-n)R(n)](2)

The organomercurial compounds Hg[1-C(6)H(4)-2-C(H)=NC(6)H(5-n)R(n)](2) (R = 4-NMe(2), 6a; 4-Me, 6b; 4-I, 6c; 4-NO(2), 6d; 2-(i)Pr, 6e; 2-Me, 6f; 2,6-(i)Pr(2), 6g; 2,6-Me(2), 6h) have been prepared in good overall yield from 2-bromobenzaldehyde. All of the compounds have been characterized by elemental analysis, (1)H NMR, (13)C[(1)H] NMR, and infrared spectroscopy. In addition, compounds 6a [C(30)H(30)HgN(4), triclinic, P, a = 6.20000(10) A, b = 9.2315(2) A, c = 10.9069(3) A, alpha = 85.8510(10) degrees, beta = 89.3570(10) degrees, gamma = 87.206(2) degrees, Z = 1], 6b [C(28)H(24)HgN(2), monoclinic, P2(1)/c, a = 12.8260(5) A, b = 14.0675(4) A, c = 6.1032(2) A, beta = 90.0990(10) degrees, Z = 2], 6g [C(38)H(44)HgN(2), triclinic, P, a = 8.2626(2) A, b = 9.8317(2) A, c = 11.8873(3) A, alpha = 103.6650(10) degrees, beta = 109.3350(10) degrees, gamma = 104.627(2) degrees, Z = 1], and 6h [C(30)H(28)HgN(2), monoclinic, P2(1)/c, a = 12.5307(2) A, b = 10.9852(2) A, c = 18.2112(2) A, beta = 104.0190(10) degrees, gamma = 87.206(2) degrees, Z = 4] have been characterized by low-temperature single-crystal X-ray diffraction studies, and two different molecular geometries about the central mercury atom have been observed; intramolecular contacts suggest a van der Waals radius for Hg of 2.1-2.2 A.     

A novel group of alkaline earth metal amides: syntheses and characterization of M[N(2,6-(i)Pr(2)C(6)H(3))(SiMe(3))](2)(THF)(2) (M = Mg,Ca, Sr,Ba) and the linear,two-coordinate Mg[N(2,6-(i)Pr(2)C(6)H(3))(SiMe(3))](2)

Novel alkaline earth metal aryl-substituted silylamides were prepared using alkane (Mg) and salt elimination reactions (Mg, Ca, Sr, and Ba). The salt elimination regime involved the treatment of the alkaline earth metal iodides with 2 equiv of the respective potassium amide KNDiip(SiMe(3)), (Diip = 2,6-i-Pr(2)C(6)H(3)). The organomagnesium source for the alkane elimination was ((n)()Bu/(s)()Bu)(2)Mg. All compounds were characterized using (1)H, (13)C NMR, and IR spectroscopy, in addition to X-ray crystallography (except Mg[NDiip(SiMe(3))](2)THF(2)). Crystal data with Mo Kalpha (lambda = 0.710 73 A) are as follows: Mg[NDiip(SiMe(3))](2), 1, a = 9.4687(6) A, b = 9.6818(6) A, c = 17.9296(1) A, alpha = 96.487(1) degrees, beta = 94.537(1) degrees, gamma = 89.222(1) degrees, V = 1608.8(2) A(3), Z = 2 (two independent molecules), triclinic, space group P(-)1, R1 (all data) = 0.0508; (n)()BuMg[NDiip(SiMe(3))]THF(2), 2, a = 9.5413(1) A, b = 16.493(2) A, c = 9.8218(1) A, beta = 108.149(2) degrees, V = 1468.7(4) A(3), Z = 2, monoclinic, space group P2(1), R1(all data) = 0.1232; Ca[NDiip(SiMe(3))](2)THF(2), 4, a = 9.7074(1) A, b = 20.9466(4) A, c = 21.6242(3) A, alpha = 73.573(1) degrees, beta = 78.632(1) degrees, gamma = 89.621(1) degrees, V = 4129.1(1) A(3), Z = 4 (two independent molecules), triclinic, space group P(-)1, R1 (all data) = 0.0902; Sr[NDiip(SiMe(3))](2)THF(2), 5, a = 20.5874(5) A, b = 9.8785(2) A, c = 20.8522(5) A, beta = 102.035(2) degrees, V = 4147.6(2) A(3), Z = 4 (two independent molecules), monoclinic, space group P2/n, R1 (all data) = 0.0756; Ba[NDiip(SiMe(3))](2)THF(2), 6, a = 20.5476(2) A, b = 10.0353(2) A, c = 20.9020(4) A, beta = 101.657(1) degrees, V = 4221.0(1) A(3), Z = 4 (two independent molecules), monoclinic, space group P2/n, R1 (all data) = 0.0573.     

Tuning the electronic structures of platinum(II) complexes with a cyclometalating aryldiamine ligand

Triflate salts of four platinum(II) pyridyl complexes with a mer-coordinating tridentate pincer ligand, pip(2)NCN(-) (pip(2)NCNH = 1,3-bis(piperidylmethyl)benzene), are reported: Pt(pip(2)NCN)(L)(+) (2, L = pyridine; 3, L = 4-phenylpyridine; 5, L = 2,6-pyridinedimethanol) and [(Pt(pip(2)NCN))(2)(micro-4,4'-bipyridine)](2+) (4). The complexes have been fully characterized by (1)H NMR spectroscopy, elemental analysis, and X-ray crystallography. Compound 2(CF(3)SO(3)(-)): triclinic, P1, a = 9.7518(6) A, b = 12.0132(8) A, c = 12.6718(9) A, alpha = 114.190(2) degrees, beta = 100.745(3) degrees, gamma = 103.545(2) degrees, V = 1247.95(14) A(3), Z = 2. Compound 3(CF(3)SO(3)(-)): monoclinic, P2(1)/c, a = 15.550(2) A, b = 9.7386(11) A, c = 18.965(3) A, beta = 92.559(7) degrees, V = 2869.1(6) A(3), Z = 4. Compound 4(CF(3)SO(3)(-))(2).1/2(CH(3))(2)CO: monoclinic, I2/a, a = 21.3316(5) A, b = 9.6526(2) A, c = 26.1800(6) A, beta = 96.4930(10) degrees, V = 5356.0(2) A(3), Z = 4. Compound 5(CF(3)SO(3)(-)).3/2CHCl(3): monoclinic, P2(1)/n, a = 17.1236(10) A, b = 9.3591(5) A, c = 21.3189(11) A, beta = 96.11(3) degrees, V = 3397.2(3) A(3), Z = 4. The accumulated data indicate that the phenyl group of pip(2)NCN(-) labilizes the trans pyridyl ligand. The electronic structures were investigated using cyclic voltammetry, as well as UV-visible absorption and emission spectroscopies. Red emission from 2 in rigid media originates from a lowest triplet ligand field excited state, whereas yellow-green emissions from 3 and 4 originate from a lowest pyridyl ligand-centered triplet pi-pi state, indicating that substitution of the pyridyl ligand results in a dramatic change in the orbital character of the emissive state.     

Robust, alkali-stable, triscarbonyl metal derivatives of hexametalate anions, [M6O19[M'(CO)3]n](8-n)- (M = Nb, Ta; M' =Mn, Re; n = 1, 2)

Ten 1:1 and 2:1 complexes of [Mn(CO)(3)](+) and [Re(CO)(3)](+) with [Nb(6)O(19)](8)(-) and [Ta(6)O(19)](8)(-) have been isolated as potassium salts in good yields and characterized by elemental analysis, (17)O NMR and infrared spectroscopy, and single-crystal X-ray structure determinations. Crystal data for 1 (t-Re(2)Ta(6)): empirical formula, K(4)Na(2)Re(2)C(6)Ta(6)O(35)H(20), monoclinic, space group, C2/m, a = 17.648(3) A, b = 10.056(1) A, c = 13.171(2) A, beta = 112.531(2) degrees, Z = 2. 2 (t-Re(2)Nb(6)): empirical formula, K(6)Re(2)C(6)Nb(6)O(38)H(26), monoclinic, space group, C2/m, a = 17.724(1) A, b = 10.0664(6) A, c = 13.1965(7) A, beta = 112.067(1) degrees, Z = 2. 3 (t-Mn(2)Nb(6)): empirical formula, K(6)Mn(2)C(6)Nb(6)O(37)H(24), monoclinic, space group, C2/m, a = 17.812(2) A, b = 10.098(1) A, c = 13.109(2) A, beta = 112.733(2) degrees, Z = 2. 4 (c-Mn(2)Nb(6)): empirical formula, K(6)Mn(2)C(6)Nb(6)O(50)H(50), triclinic, space group, P1, a = 10.2617(6) A, b = 13.4198(8) A, c = 21.411(1) A, alpha = 72.738(1) degrees, beta = 112.067(1) degrees, gamma = 83.501(1) degrees, Z = 2. 5 (c-Re(2)Nb(6)): empirical formula, K(6)Re(2)C(6)Nb(6)O(54)H(58), monoclinic, space group, P2(1)/c, a = 21.687(2) A, b = 10.3085(9) A, c = 26.780(2) A, beta = 108.787(1) degrees, Z = 4. The complexes contain M(CO)(3) groups attached to the surface bridging oxygen atoms of the hexametalate anions to yield structures of nominal C(3)(v)() (1:1), D(3)(d)() (trans 2:1), and C(2)(v)() (cis 2:1) symmetry. The syntheses are carried out in aqueous solution or by aqueous hydrothermal methods, and the complexes have remarkably high thermal, redox, and hydrolytic stabilities. The Re-containing compounds are stable to 400-450 degrees C, at which point CO loss occurs. The Mn compounds lose CO at temperatures above 200 degrees C. Cyclic voltammetry of all complexes in 0.1 M sodium acetate show no redox behavior, except an irreversible oxidation process at approximately 1.0 V vs. Ag/AgCl. In contrast to the parent hexametalate anions that are stable only in alkaline (pH >10) solution, the new complexes are stable, at least kinetically, between pH 4 and pEta approximately 12.     

Structural Chemistry of Poly(ethylene glycol) Complexes of Lead(II) Nitrate and Lead(II) Bromide

The reaction of 1:1 stoichiometries (1:1.5 for the nitrate/tetraethylene glycol (EO4) and pentaethylene glycol (EO5) complexes) of PbX(2) (X = NO(3), Br) with five- to eight-donor poly(ethylene glycols) (PEGs) in 3:1 CH(3)CN/CH(3)OH (CH(3)CN only for the nitrate/EO5 complex) followed by solvent evaporation resulted in six crystalline materials upon which X-ray structural analyses were carried out: [Pb(NO(3))(2)(EO4)](n)(), [Pb(NO(3))(2)(EO5)], [Pb(NO(3))(2)(EO6)], [PbBr(EO5)(&mgr;-Br)PbBr(2)].H(2)O, [PbBr(NCMe)(EO6)](2)[PbBr(2)(EO6)][PbBr(3)](2), and [PbBr(EO7)][PbBr(3)]. The nitrates crystallize as tight ion pairs with the PEG ligands coordinating in an equatorial plane around the Pb(2+) ions. Because EO4 has only five oxygen donors, this complex exhibits steric unsaturation which is overcome by a monodentate interaction with a third nitrate anion that is also coordinated to a neighboring Pb(2+) ion. The six donors of EO5 coordinate in an equatorial plane resulting in a 10-coordinate complex with trans, twisted, bidentate nitrate anions. The seven-donor hexaethylene glycol (EO6) only uses six of its oxygen donors to coordinate Pb(2+). [Pb(NO(3))(2)(EO4)](n)() is monoclinic, P2(1)/c, with a = 7.902(3) ?, b = 22.136(6) ?, c = 8.910(2) ?, beta = 90.96(3) degrees, and Z = 4. [Pb(NO(3))(2)(EO5)] is triclinic P&onemacr;, with a = 9.332(3) ?, b = 10.025(3) ?, c = 11.688(4) ?, alpha = 68.41(3) degrees, beta = 68.39(3) degrees, gamma = 68.58(3) degrees, and Z = 2. [Pb(NO(3))(2)(EO6)] is monoclinic P2(1)/c, with a = 16.289(4) ?, b = 10.773(4) ?, c = 12.329(4) ?, beta = 106.77(2) degrees, and Z = 4. Lead(II) bromide complexes with PEGs tend to crystallize as PEG complexed cations with polymeric lead(II) bromide anions. In the EO5 complex, bromide anions in the polymer also coordinate to the PEG-wrapped Pb(2+) cations. The hexa- and heptaethylene glycol (EO6 and EO7, respectively) complexes contain discreet ions. In these halide complexes, EO7 is the only PEG to expand the Pb(2+) coordination number from eight to nine. [PbBr(EO5)(&mgr;-Br)PbBr(2)].H(2)O is triclinic P&onemacr;, with a = 7.922(6) ?,b = 15.802(9) ?, c = 19.001(9) ?, alpha = 73.19(8) degrees, beta = 88.91(9) degrees, gamma = 87.22(9) degrees, and Z = 4. [PbBr(NCMe)(EO6)](2)[PbBr(2)(EO6)][PbBr(3)](2) is monoclinic P2(1)/c, with a = 14.389(4) ?, b = 31.931(9) ?, c = 8.029(2) ?, beta = 97.76(3) degrees, and Z = 2. [PbBr(EO7)][PbBr(3)] is monoclinic Cc, with a = 13.165(3) ?, b = 24.732(5) ?, c = 8.007(1) ?, beta = 94.58(2) degrees, and Z = 4.     

Utility of Arylamido Ligands in Yttrium and Lanthanide Chemistry(1)

The reactivity of KNHAr reagents (Ar = C(6)H(5), C(6)H(3)Me(2)-2,6, C(6)H(3)(i)Pr(2)-2,6) with lanthanide and yttrium trichlorides has been investigated. With the larger metals Nd and Sm and the smaller 2,6-dimethyl-substituted ligand, the bimetallic dianionic complexes [K(THF)(6)](2)[Ln(&mgr;-NHC(6)H(3)Me(2)-2,6)(NHC(6)H(3)Me(2)-2,6)(3)](2) (Ln: Sm, 1a; Nd, 1b) are isolated as the potassium salts. Under the same reaction conditions YCl(3) forms a bimetallic anion which retains chloride: [K(DME)(2)(THF)(3)][Y(2)(&mgr;-NHC(6)H(3)Me(2)-2,6)(2)(&mgr;-Cl)(NHC(6)H(3)Me(2)-2,6)(4)(THF)(2)], 2. With the larger 2,6-diisopropyl ligands, neutral complexes are isolated in both solvated monometallic and unsolvated bimetallic forms. With Nd, a distorted octahedral trisolvate, Nd(NHC(6)H(3)(i)Pr(2)-2,6)(3)(THF)(3), 3, was obtained, whereas with Yb and Y the trigonal bipyramidal disolvates, Ln(NHC(6)H(3)(i)Pr(2)-2,6)(3)(THF)(2) (Ln: Yb, 4a; Y, 4b), were isolated. THF-free complexes of the NHC(6)H(3)(i)Pr(2)-2,6 ligand are available by reacting the amine NH(2)C(6)H(3)(i)Pr(2)-2,6 with Ln[N(SiMe(3))(2)](3) complexes. By this route, the dimers [Ln(&mgr;-NHC(6)H(3)(i)Pr(2)-2,6)(NHC(6)H(3)(i)Pr(2)-2,6)(2)](2) (Ln: Yb, 5a; Y, 5b) were isolated. The reaction of the unsubstituted arylamido salt KNHC(6)H(5) with NdCl(3) produced an insoluble material which was characterized as [Nd(NHC(6)H(5))(3)(KCl)(3)], 6. 6 reacted with Al(2)Me(6) in hexanes and produced a heteroleptic mixed-metal complex {[Me(2)Al(&mgr;-Me(2))](2)Nd(&mgr;(3)-NC(6)H(5))(&mgr;-Me)AlMe}(2), 7, and the trimeric aluminum arylamido complex [Me(2)Al(&mgr;-NHC(6)H(5))](3), 8. The solvent of crystallization and relevant crystallographic data for the compounds identified by X-ray analysis follow: 1a,THF, 156 K, P2(1)/n, a = 12.985(2) ?, b = 27.122(5) ?, c = 17.935(3) ?, beta = 100.19(1) degrees, V = 6216(1) ?(3), Z = 2, 6148 reflections (I > 3sigma(I)), R(F)() = 7.1%; 1b,THF, 156 K, P2(1)/n, a = 12.998(2) ?, b = 27.058(3) ?, c = 17.962(2) ?, beta = 99.74(1) degrees, V = 6225(1) ?(3), Z = 2; 2,DME/hexanes, P2(1)/n, a = 23.335(2) ?, b = 12.649(1) ?, c = 27.175(3) ?, beta = 96.36(1) degrees, V = 7971(1) ?(3), Z = 4, 2788 reflections (I > 3sigma(I)), R(F)() = 9.5%; 3, THF, P2(1), a = 12.898(1) ?, b = 16.945(1) ?, c = 13.290(1) ?, beta = 118.64(2) degrees, V = 2549.3(3) ?(3), Z = 2, 3414 reflections (I > 3sigma(I)), R(F)() = 4.3%; 4a, hexanes, P2(1), a = 9.718(2) ?, b = 19.119(3) ?, c = 12.640(2) ?, beta = 112.08(1) degrees, V = 2176.3(6) ?(3), Z = 2, 2933 reflections (I > 3sigma(I)), R(F)() = 4.3%; 4b, hexanes, 158 K, a = 9.729(2) ?, b = 19.095(5) ?, c = 12.744(1) ?, beta = 112.11(1) degrees, V = 2193.4(6) ?(3); 5b, hot toluene, 158 K, P2(1), a =19.218(9) ?, b = 9.375(3) ?, c = 19.820(5) ?, beta = 110.25(2) degrees, V = 3350(2)?(3), Z = 2, 1718 reflections (I > 2sigma (I)), R1 = 9.7%; 7, hexanes, 156 K, P&onemacr;, a = 9.618(3) ?, b = 12.738(4) ?, c = 9.608(3) ?, alpha = 99.32(1) degrees, beta = 108.87(1) degrees, gamma = 94.23(1) degrees, V = 1089.1(6) ?(3), Z = 2, 2976 reflections (I > 3sigma(I)), R(F)() = 3.9%; 8, hexanes, 156 K, Pcab, a = 23.510(5) ?, b = 25.462(5) ?, c = 8.668(2) ?, V = 5188(1) ?(3), Z = 8, 1386 reflections (I > 3sigma(I)), R(F)() = 5.7%.     

Niobium-arsenic Zintl phases: A(6)NbAs(5) (A = K,Rb, Cs), K(6)NbTlAs(4), and K(8)NbPbAs(5) with edge-bridged niobium-centered tetrahedra of arsenic, [NbAs(4)M](n-) where M = As,Tl, Pb

The five title compounds were prepared by direct reactions of the corresponding elements at high temperature. Their structures contain isolated anions of tetrahedral NbAs(4) where one of the edges of the tetrahedron is bridged by a third atom. The bridging atom is arsenic in A(6)NbAs(5) (monoclinic, P2(1)/c, Z = 8; with a = 25.774(3) A, b = 9.335(1) A, c = 13.012(1) A, beta = 101.05(1) degrees for A = K; a = 27.629(1) A, b = 9.925(1) A, c = 14.111(1) A, beta = 101.63(1) degrees for A = Rb; and a = 27.405(1) A, b = 9.9447(6) A, c = 13.9964(8) A, beta = 101.210(1) degrees for A = Cs), thallium in K(6)NbTlAs(4) (orthorhombic, Pnma, Z = 4, a = 18.786(1) A, b = 10.4442(4) A, c = 7.715(1) A), and lead in K(8)NbPbAs(5) (monoclinic, C2/c, Z = 8, a = 31.597(9) A, b = 9.353(1) A, c = 13.427(2) A, beta = 95.25(1) degrees ). The lead atom in the latter is bonded to a third arsenic atom as well. Magnetic measurements showed diamagnetic behavior, and therefore, the compounds are electronically balanced, closed-shell type compounds and can be described as transition-metal Zintl phases. The bonding in the anion NbAs(5)(6-) is discussed in detail.     

Bis(pyrazol-1-yl)acetates as tripodal heteroscorpionate ligands in iron chemistry: syntheses and structures of iron(II) and iron(III) complexes with bpza, bdmpza, and bdtbpza ligands

The molecular structure of the previously reported species "[Fe(bdtbpza)Cl]" has been revealed by X-ray structure determination to be a ferrous dimer [Fe(bdtbpza)Cl](2) (2c) [bdtbpza = bis(3,5-di-tert-butylpyrazol-1-yl)acetate]. The syntheses of ferrous 2:1 complexes [Fe(bpza)(2)] (3a) and [Fe(bdtbpza)(2)] (3c) as well as ferric 1:1 complexes [NEt(4)][Fe(bpza)Cl(3)] (4a) and [NEt(4)][Fe(bdmpza)Cl(3)] (4b) [bpza = bis(pyrazol-1-yl)acetate, bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate] are reported. Complexes 3a, previously reported [Fe(bdmpza)(2)] (3b), and 3c are high-spin. No spin crossover to the low-spin state was observed in the temperature range of 5-350 K. 4a and 4b are synthesized in one step and in high yield from [NEt(4)](2)[Cl(3)FeOFeCl(3)]. 4a and 4b are iron(III) high-spin complexes. Crystallographic information: 2c (C(24)H(39)ClFeN(4)O(2).CH(2)Cl(2).CH(3)CN) is triclinic, P1, a = 12.171(16) A, b = 12.851(14) A, c = 13.390(13) A, alpha = 98.61(9) degrees, beta = 113.51(11) degrees, gamma = 108.10(5) degrees, Z = 2; 3a (C(8)H(7)Fe(0.5)N(4)O(2)) is monoclinic, P2(1)/n, a = 7.4784(19) A, b = 7.604(3) A, c = 16.196(4) A, beta = 95.397(9) degrees, Z = 4; 3c (C(24)H(39)Fe(0.5)N(4)O(2)) is monoclinic, P2(1)/n, a = 9.939(6) A, b = 18.161(10) A, c = 13.722(8) A, beta = 97.67(7) degrees, Z = 4; 4b (C(20)H(35)Cl(3)FeN(5)O(2)) is monoclinic, C2/c, a = 30.45(6) A, b = 12.33(2) A, c = 16.17(3) A, beta = 118.47(5) degrees, Z = 8.     

Crystal structures and solution behavior of paramagnetic divalent transition metal complexes (Fe, Co) of the sterically encumbered tridentate macrocycles 1,4,7-R3-1,4,7-triazacyclononane: coordination numbers 5 (R = i-Pr) and 6 (R = i-Bu)

The coordination chemistry of the sterically hindered macrocyclic triamines, 1,4,7-R3-1,4,7-triazacyclononane (R = i-Pr, i-Pr3tacn, and R = i-Bu, i-Bu3tacn) with divalent transition metals has been investigated. These ligands form a series of stable novel complexes with the triflate salts MII(CF3SO3)2 (M = Fe, Co, or Zn) under anaerobic conditions. The complexes Fe(i-Pr3tacn)(CF3SO3)2 (2), [Co(i-Pr3tacn)(SO3CF3)(H2O)](CF3SO3) (3), [Co(i-Pr3tacn)(CH3CN)2](BPh4)2 (4), Zn(i-Pr3tacn)(CF3SO3)2 (5), [Fe(i-Bu3tacn)(CH3CN)2(CF3SO3)](CF3SO3) (6), Fe(i-Bu3tacn)-(H2O)(CF3SO3)2 (7), and Co(i-Bu3tacn)(CF3SO3)2 (8) have been isolated. The behavior of these paramagnetic complexes in solution is explored by their 1H NMR spectra. The solid-state structures of four complexes have been determined by X-ray single-crystal crystallography. Crystallographic parameters are as follows. 2: C17H33F6FeN3O6S2, monoclinic, P2(1)/n, a = 10.895(1) A, b = 14.669(1) A, c = 16.617(1) A, beta = 101.37(1) degrees, Z = 4. 3: C17H35CoF6N3O7S2, monoclinic, P2(1)/c, a = 8.669(2) A, b = 25.538(3) A, c = 12.4349(12) A, beta = 103.132(13) degrees, Z = 4. 6: C24H45F6FeN5O6S2, monoclinic, P2(1)/c, a = 12.953(6) A, b = 16.780(6) A, c = 15.790(5) A, beta = 96.32(2) degrees, Z = 4. 7: C20H41F6FeN3O7S2, monoclinic, C2/c, a = 22.990(2) A, b = 15.768(2) A, c = 17.564(2) A, beta = 107.65(1) degrees, Z = 8. The ligand i-Pr3tacn leads to complexes in which the metal ions are five-coordinate, while it's isobutyl homologue affords six-coordinate complexes. This difference in the stereochemistries around the metal center is attributed to steric interactions involving the bulky alkyl appendages of the macrocycles.     

Diverse solid-state and solution structures within a series of hexaamine dicopper(II) complexes

Mono- and dicopper(II) complexes of a series of potentially bridging hexaamine ligands have been prepared and characterized in the solid state by X-ray crystallography. The crystal structures of the following Cu(II) complexes are reported: [Cu(HL3)](ClO4)(3), C11H31Cl3CuN6O12, monoclinic, P2(1)/n, a = 8.294(2) A, b = 18.364(3) A, c = 15.674(3) A, beta = 94.73(2) degrees, Z = 4; ([Cu2(L4)(CO3)](2))(ClO4)(4).4H2O, C40H100Cl4Cu4N12O26, triclinic, P1, a = 9.4888(8) A, b = 13.353(1) A, c = 15.329(1) A, alpha = 111.250(7) degrees, beta = 90.068(8) degrees, gamma = 105.081(8) degrees, Z = 1; [Cu2(L5)(OH2)(2)](ClO4)(4), C13H36Cl4Cu2N6O18, monoclinic, P2(1)/c, a = 7.225(2) A, b = 8.5555(5) A, c = 23.134(8) A, beta = 92.37(1) degrees, Z = 2; [Cu2(L6)(OH2)(2)](ClO4)(4).3H2O, C14H44Cl4Cu2N6O21, monoclinic, P2(1)/a, a = 15.204(5) A, b = 7.6810(7) A, c = 29.370(1) A, beta = 100.42(2) degrees, Z = 4. Solution spectroscopic properties of the bimetallic complexes indicate that significant conformational changes occur upon dissolution, and this has been probed with EPR spectroscopy and molecular mechanics calculations.