Synthesis and Crystal Structure of （E）-ethyl 6-benzyl-2-[（cyclopropylmethylamino）（4-fluorophenylamino）-methyleneamino]-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate ethanol monosolvate

The crystal structure of the new title compound (E)-ethyl 6-benzyl-2-[(cyclopropylmethylamino)(4-fluorophenylamino)methyleneamino]-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate ethanol monosolvate (C28H31FN 4O2S·C2H6O, Mr=552.70) has been prepared and determined by single-crystal X-ray diffraction. The crystal is of monoclinic system, space group P21/c with a=13.806(10), b=10.850(7), c=19.938(14), β=98.842(9)° , V=2951(4)3 , Z=4, Dc=1.244g/cm 3 , F(000)=1176, μ=0.153 mm-1 , MoKα radiation (λ=0.71073), R=0.0758 and wR=0.2234 for 4262 observed reflections with I > 2σ(I). Intramolecular N-H…S and C-H…N interactions as well as intermolecular N-H…O and O-H…N hydrogen bonds help to stabilize the crystal structure. X-ray diffraction analysis reveals that the asymmetric unit contains one title molecule and one ethanol molecule.     

Hydrothermal Synthesis and Crystal Structure of a 2D Zinc（Ⅱ） Coordination Polymer with 5-Hydroxynicotinic Acid

The title compound,[Zn(5-hydroxynicotinate) 2 2H 2 O] n,has been synthesized by reacting zinc sulfate vitriol with 5-hydroxynicotinic acid under hydrothermal conditions,and its structure was determined by X-ray crystallography with the following data:monoclinic,space group C2/c,C 12 H 12 N 2 O 8 Zn,M r=377.61,a=10.223(3),b=10.319(3),c=13.613(4),β=105.922(6)°,Z=4,V=1380.9(8)3,F(000)=768,D c=1.816 g/cm 3,μ(MoKα)=1.826 mm-1,the final R=0.0401 and wR=0.1380 for 1157 observed reflections (I > 2σ(I)).In the structure of the title compound,the Zn II ion located in an inversion center lies in a distorted tetrahedral environment at a N 2 O 2 coordination mode,and the 5-hydroxynicotinic acid ligand links symmetry-related Zn II ions at a μ 2-N,O bridging way forming a two-dimensional covalent structure.In the crystal,solvent water molecules form intermolecular O-H O hydrogen bonds and pyridine rings of adjacent layers form π-π stacking (3.346),which connect adjacent two-dimensional sheets into a three-dimensional supramolecular network.     

Synthesis and Characterization of Chiral Mercury（II） and Cadmium（II） Complexes with 3,3＇-Bipyridine-5,5＇,6,6＇-tetramethyl-2,2＇-dimethoxy-1,1＇-biphenyl

Two homochiral mercury (1) and cadmium (2) complexes derived from chiral twisted biphenyl pyridine ligand (3,3'-bipyridine-5,5',6,6'-tetramethyl-2,2'-dimethoxy-1,1'-biphenyl) have been synthesized and characterized by IR, microanalysis, TGA, UV-Vis, powder and single-crystal X-ray crystallography. Both 1 and 2 crystallize in orthorhombic space group P21212 with Z = 2. For 1, a = 14.2038(16), b = 14.3630(17), c = 7.0257(8), V = 1433.3(3)3, Mr = 878.91, Dc = 2.037 g/cm3, μ = 7.549 mm-1, F(000) = 824, the final GOF = 1.017, R = 0.0296 and wR = 0.0645 for 2925 observed reflections with I > 2σ(I). For 2, a = 14.212(3), b = 14.392(3), c = 7.0498(14), V = 1442.0(5)3, Mr = 790.72, Dc = 1.821 g/cm3, μ = 2.924 mm-1, F(000) = 760, the final GOF = 1.075, R = 0.0340 and wR = 0.0834 for 3144 observed reflections with I > 2σ(I). The crystal structures of 1 and 2 are isostructural and each adopts a two-dimensional supramolecular network which contains the C-H···π interactions.     

Syntheses, Crystal Structures and Characterization of Two New Cadmium（II） Arsonates

Two cadmium arsonate coordination polymers, Cd(HL1)2 (1, H2L1 = 4-aminophenylarsonatic acid) and Cd(H2L2)2·2H2O (2, H3L2 = 2-(4-arsonphenylamino)acetic acid), have been synthesized and characterized by IR and single-crystal X-ray diffraction. Crystal data for 1: triclinic, space group P1 with a = 5.7559(12), b = 7.0903(14), c = 8.9925(18), α = 89.04(3), β = 80.79(3), γ = 85.09(3)o, Dc = 2.496 g·cm-3, μ = 6.095 mm-1, F(000) = 260, Z = 1, the final R = 0.0574 and wR = 0.1376 for 1489 observed reflections with I > 2σ(I). And those for 2: monoclinic, space group P21/c with a = 4.7595(10), b = 9.925(2), c = 22.609(5), β = 91.81(3)°, Dc = 2.167 g·cm-3, μ = 4.168 mm-1, F(000) = 684, Z = 2, the final R = 0.0335 and wR = 0.0815 for 2340 observed reflections with I > 2σ(I). The structure of 1 shows a two-dimensional layer consisting of inorganic chains of {CdN2(AsO3)2} along the a axis linking with the phenyl groups. These layers are further linked through strong interlayer hydrogen bonding interaction to form a three-dimensional hydrogen bond supramolecular architecture. Compound 2 has inorganic chains of {CdO2(AsO3)2} similar to 1, which connect with four adjacent inorganic chains forming a three-dimensional framework.     

Synthesis and Crystal Structure of a New Supramolecular Compound Constructed from Flexible 1,1＇-（1,4-Butanediyl）bis（imidazole） and 1,2,4,5-Benzenetetracarboxylic Acid

A new bis(imidazolium) compound,[H2L(H2btec)2]·H4btec(1,L=1,1'-(butane-1,4-diyl)bis(imidazole),H4btec=1,2,4,5-benzenetetracarboxylatic acid),has been synthesized and structurally characterized by single-crystal X-ray diffraction.The title compound crystallizes in the monoclinic system,space group Pnma,with a=13.3908(11),b=13.9249(12),c=16.2166(14),V=2957.6(4)3,Z=4,Mr=698.55,Dc=1.569 mg/m3,F(000)=1448,μ(MoKα)=0.130 mm-1,the final R=0.0584 and wR=0.1538 for 4295 observed reflections with I2σ(I).The compound consists of one 1,1'-(butane-1,4-diyl)bis(imidazolium) cation,one neutral H4btec and one H2btec2-(Only two para carboxyl groups are deprotonated,and two protonated ones remain free) anion.A one-dimensional hydrogen bonding chain and a 2D hydrogen bonding network are formed via intermolecular N-H…O and O-H…O hydrogen bonds.These adjacent chains are further stacked through intermolecular π-π and hydrogen bonding interactions to form a 3D supramolecular network.     

Synthesis and Crystal Structure of 3-（4-Chlorophenyl）-8-cyano-2-（di-isopropylamino）-5-methyl-7-（methylthio）-pyrido[4,3-d]pyrimidine-4（3H）-one

The crystal structure of the new title compound 3-(4-chlorophenyl)-8-cyano-2-(di-iso-propylamino)-5-methyl-7-(methylthio)-pyrido[4,3-d]pyrimidine-4(3H)-one(C22H24ClN5OS,Mr = 441.97)has been determined by single-crystal X-ray diffraction. The crystal is of orthorhombic,space group Pna21 with a = 7.6721(5),b = 18.9370(11),c = 15.6260(9),V = 2270.2(2)3,Z = 4,Dc = 1.293 g/cm3,F(000)= 928,μ = 0.283 mm-1,MoKa radiation(λ = 0.71073 ),R = 0.0494 and wR = 0.1062 for 3278 observed reflections with I > 2σ(I). X-ray diffraction analysis reveals that all ring atoms in the py-ridopyrimidinone moiety are almost coplanar. Intramolecular C(20)-H(20)···N(4),C(19)-H(19A)···N(3),C(18)-H(18C)···N(3)and C(16)-H(16B)···O(5)hydrogen bonds together with weak C···π interactions are found in the structure.     

Synthesis and Crystal Structure of Methyl 3-（5- Bromo-1-ethyl-1H-indole-3-carbonyl）aminopropionate

Methyl 3-(5-bromo-1-ethyl-1H-indole-3-carbonyl)aminopropionate has been syn-thesized by the acylation of 5-bromo-3-trichloroacetylindole with β-alanine methyl ester,followed by alkylation with ethyl iodide,in 82.6% yield.Its crystal structure was gotten and determined by X-ray diffraction method.The crystal is of monoclinic,space group P2 1 /c with a=11.7927(8),b=14.9342(8),c=9.0060(5),β=101.558(6)°,V=1553.93(16)3,Z=4,D c=1.510 g/cm 3,λ=0.71073,μ(MoKα)=2.656 mm-1,M r=353.22 and F(000)=720.The structure was refined to R=0.0401 and wR=0.0825 for 1704 observed reflections with I > 2σ(I).In the crystal structure,intermolecular N(2)-H(2)···O(1) hydrogen bond and weak intermolecular bonds (C(1)-H(1) O(1) and C(10)-H(10B) O(2)) are formed,and π-π stacking also exists.     

Ionothermal Syntheses and Crystal Structures of Two Cobalt（Ⅱ） Compounds：Co（2,2＇-bpy）_2Br_2 and Co（1,10-phen）_2Br_2

Two cobalt(Ⅱ) compounds,Co(2,2-bpy) 2 Br 2 (1,2,2-bpy=2,2-bipyridyl) and Co(1,10-phen) 2 Br 2 (2,1,10-phen=1,10-phenanthroline),have been prepared under ionothermal reactions using the 1-propyl-3-methylimidazolium bromide ionic liquid solvent.Single-crystal X-ray analyses reveal that 1 crystallizes in a monoclinic space group P2 1 /c,with a=8.5509(13),b=14.804(2),c=15.650(2),β=97.119(2) o,V=1965.8(5) 3,Z=4,C 20 H 16 Br 2 N 4 Co,M r=531.12,D c=1.795 g/cm 3,μ=4.950 mm-1,F(000)=1044,the final R=0.0467 and wR=0.0736 for 2291 observed reflections with I > 2σ(Ⅰ).Complex 2 crystallizes in a monoclinic space group P2 1 /n,with a=10.4237(8),b=16.8657(12),c=12.4945(9)b,β=102.110(1) o,V=2147.7(3) 3,Z=4,C 24 H 16 Br 2 N 4 Co,M r=579.16,D c=1.791 g/cm 3,μ=4.540 mm-1,F(000)=1140,the final R=0.0431 and wR=0.1042 for 3470 observed reflections with I > 2σ(Ⅰ).The mononuclear molecules of 1 are linked by the C-H···Br hydrogen bonds and π-π interactions to form a three-dimensional supramolecular framework structure.The C-H···Br hydrogen bonds and π-π interactions link the mononuclear molecules of 2 to give a two-dimensional layer structure.     

The Molybdenum（0）Complex [Et4N]2[Mo2（CO）6（pys）2]（pys=Pyrindine—2—thiol

The title compound tetraethylammonium hexacarbonylbis(μ-pyridine-2-thiolato-S∶S) dimolybdenum [Et4N]2[Mo2(CO)6(pys)2] crystallizes in the monoclinic, space group, P21/c with a=13.217(2), b=21.648(2), c=27.193(6)(), β=82.52(2)°, V=7714.6()3, Z=8, Mr=840.77, Dc=1.45 g/cm3, μ=7.8 cm-1, R=0.038 and Rw=0.040 for 6082 reflections with I≥3σ(I). X-ray crystal structure study reveals that the asymmetric unit of the title compound is comprised of two independent formulations of the molecular formula. Each dianion has approximate C2 symmetry and the dimetallic Mo2S2 core adopts a "butterfly" conformation with a dihedral angle between the halves of 139.3(1)° for the first independent anion and 142.8(1)° for the second one. The two pyridine rings lie on the same side of the molecule in a cis arrangement and the Mo...Mo separations are 3.76(1) and 3.838(1)().     

Synthesis and Crystal Structure of （S）-Ethyl-2-（2-methoxy-phenylsulfenamido）-3-（1H-indol-3-yl）propanoate

With an aim to discover novel AHAS inhibitors,the title compound (S)-ethyl-2(2-methoxy-phenylsulfenamido)-3-(1H-indol-3-yl)propanoate (C 21 H 22 N 2 O 4 S,M r=398.47) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis.The crystal belongs to orthorhombic,space group P2 1 2 1 2 1 with a=8.078(2),b=12.824(4),c=18.788(6),V=1946.2(10) 3,Z=4,F(000)=840,D c=1.360 mg/m 3,μ=0.197 mm-1,the final R=0.0433 and wR=0.1035 for 3075 observed reflections with I > 2σ(Ⅰ).The absolute structure Flack parameter X of this compound is 0.00(8).A total of 14375 reflections were collected,of which 3431 were independent (R int=0.0437).X-ray analysis reveals that the crystal structure involves two intermolecular N-H···O and one N-H···S intermolecular hydrogen bonds with the neighboring molecules.The crystal structure was compared with our previously reported (S)-methyl 2-(4-R-phenylsulfonamido)-3-(1H-indol-3-yl)propanoate (R=H(1) and Cl(2)),which provided some useful information of these compounds.     

Synthesis and Crystal Structure of N-[2-（4-Chlorophenyl）-1-（1-methylcarbamoyl-2-phenyl-ethylcarbamoyl）-3-phenyl-cyclopropyl]-benzamide

N-[2-(4-chlorophenyl)-1-(1-methylcarbamoyl-2-phenyl-ethylcarbamoyl)-3-phenyl-cyclopropyl]benzamide,C33H30ClN3O3,has been synthesized and characterized by IR,1H NMR,13C NMR and single-crystal X-ray diffraction.The crystal is of triclinic,space group P1 with a = 11.646(2),b = 13.795(3),c = 14.559(3),α = 76.422(4),β = 78.028(4),γ = 74.500(4)°,V = 2164.6(7)3,Z = 3,Mr = 552.05,Dc = 1.270 g/cm3,λ = 0.71073 ,μ(MoKα)= 0.171 mm–1,F(000)= 870,the final R = 0.0469 and wR = 0.0805 for 5554 observed reflections with I > 2σ(I).The N–H and oxygen atoms are involved in one-dimensional intermolecular hydrogen bonds,which further stabilize the structure.     

Synthesis and Crystal Structure of Tetra（（8-quinolyl）-amido-N）ytterbium Bi（tetrahydrofuran-O）lithium

The treatment of the mixture of n-BuLi with 1 equiv.8-aminoquinoline in THF in situ,which reacted further with 1/3 equiv.of YbCl3 in THF,to give the homoleptic lanthanide amide ate complex Yb(NH-C9H6N)4Li(C4H8O)2(1).The crystal structure was determined by X-ray diffraction and the following crystallographic data were obtained:C44H44N8O2YbLi,Mr = 896.85,monoclinic,space group C2/c,a = 7.8384(16),b = 22.294(5),c = 22.668(5),β = 97.614(5)°,V = 3926.3(14)3,Z = 4,Dc = 1.517 g/cm3,F(000)= 1812,μ(MoKα)= 2.431 mm-1,R = 0.0542 and wR = 0.1523 for 3372 observed reflections with I > 2σ(I).The structure of molecule 1 consists of one ytterbium atom,one lithium atom,four 8-aminoquinoline ligands and two THF molecules.The ytterbium atom is coordinated by eight nitrogen atoms of four 8-aminoquinoline ligands,forming a distorted dodecahedral geometry.     

Synthesis, Structure and Physical Properties of a Barium（II） Complex with 5-Sulfoisophthalic Acid Sodium

An alkaline earth metal-organic framework [Ba(Hsip)(H2O)4]n (1, NaH2sip = 5-sulfoisophthalic acid sodium) has been constructed, and characterized by single-crystal X-ray diffraction. In complex 1, each Ba(II) atom coordinates to one ligand Hsip3- and four water molecules with a distorted nine-coordinated monocapped tetragonal antiprism geometry. Each Hsip2- anion acts as a μ3-bridging ligand, in which two carboxylate groups adopt the same bidentate chelating coordinating model and the sulfonate group takes a monodentate coordinating model, resulting in a wave-like two-dimensional network with a (6, 3) topological structure. The two-dimensional networks are further linked by O-H···O to form a three-dimensional structure. Luminescent property and thermal stability of complex 1 are investigated. 1 belongs to the orthorhombic system, space group Pna21 with a = 7.3333(2), b = 16.7044(3), c = 10.4817(2), Z = 4, V = 1283.99(5)3, Mr = 453.58, Dc = 2.346 g/cm3, F(000) = 880, μ = 3.314 mm-1, the final R = 0.0261 and wR = 0.0592 for 2425 observed reflections with I > 2σ(I).     

Synthesis and Hydrogen-bonded Interpenetrating Grid Structure of 5,5＇-Bis [4- （2-hydroxyethyl）phenyl] diazo-dipyrromethane

A new 5,5'-bisdiazo-dipyrromethane compound 3 has been synthesized and cha- racterized. The crystal of 3 is of orthorhombic, space group Iba2 with a = 19.1914(17), b = 9.8396(8), c = 13.7643(12) , V = 2599.2(4)3, Z = 4, C29H34N6O2, Mr = 498.62, Dc = 1.274 g/cm3 , F(000) = 1064, μ(MoKα) = 0.083 mm-1, the final R = 0.0302 and wR = 0.0786 for 6361 observed reflections with I > 2σ(I), and R = 0.0320 and wR = 0.08006 for all data. It reveals that the molecules of compound 3 assemble into grid structures through a R22(7) type hydrogen bonding motif between azopyrrole and hydroxyl group. The grids interpenetrate each other with the assistance of C-H···π interaction.     

Synthesis and Crystal Structure of[Cu（dppb）（NO_3）]_2（dppb=1,4-Bis（diphenylphosphino）butane）

The synthesis and molecular structure of a new dinuclear copper(Ⅰ) complex [Cu(dppb)(NO 3)] 2 are reported.The compound crystallizes in the monoclinic system,space group P2 1 /n with a=12.830(3),b=10.899(2),c=19.666 (4),β=104.69(3)°,V=2660.1(9)3,Z=4,D c=1.378 g/cm 3,F(000)=1144,the final R=0.0600 and wR=0.0668 for 2951 observed reflections with I > 2σ(Ⅰ).The complex contains a folded Cu 2 P 4 core structure,with two Cu(Ⅰ) atoms being bridged by a pair of dppb ligands to form a 14-membered Cu 2 P 4 C 8 zigzag ring.The ligand sphere of each metal center is completed by a nitrate anion in a chelating fashion.     

Synthesis, Crystal Structure and Antibacterial Activity of a New Ternary Copper（Ⅱ） Complex with 2,6-Pyridinedicarboxylic Acid and 1,10-Phenanthroline

A new ternary copper(II) complex,[C 43 H 27 Cu 2 N 7 O 5 ]·[C 14 H 6 CuN 2 O 8 ]·6.5H 2 O,has been synthesized by the reaction of copper sulfate,2,6-pyridinedicarboxylic acid and 1,10-phenanthroline (phen),and characterized by elemental analysis,IR,UV and X-ray single-crystal diffraction.It crystallizes in triclinic,space group P1,with a=14.379(5),b=15.510(5),c=15.835(6),α=78.567(6),β=63.594(6),γ=81.287(6)°,V=3092.1(19)3,C 57 H 46 Cu 3 N 9 O 19.5,M r=1359.54,Z=2,D c=1.446 Mg/m 3,λ(MoKα)=0.71073,μ=1.101 mm-1,F(000)=1362,S=1.071,the final R=0.0718 and wR=0.11960 for 10705 observer reflections (I > 2σ(I)).The structure unit of the title complex consists of a mononuclear part and a di-nuclear part,and the three copper ions show three coordination modes.Each 6-coordinated geometry of the Cu atom is a distorted octahedral coordination geometry.The 3D supramolecular system is formed by the hydrogen bond O-H···O and π-π stacking interaction between neighboring single cells.The antibacterial activity of the title complex is also studied.     

Crystal and Molecular Structure of Ethyl 2-[（4-Hydroxy-phenyl）hydrazono]-3-oxobutanoate

The title compound,C 12 N 2 O 4 H 14 (M r=250.3),crystallizes in triclinic P1 space group with a=7.7709(9),b=8.7534(11),c=9.6958(12),α=77.103(2),β=80.496(2),γ=86.726(2)o,V=633.9(1) 3,Z=2,F(000)=264,D c=1.311 Mg/m 3,μ(MoKα)=0.1 mm-1,the final R=0.056,and wR=0.15 for 2239 observed reflections (I > 2σ(Ⅰ)).The molecules in the crystal are linked through O-H···O type of hydrogen bonding interaction forming an infinite chainlike structure.The phenylhydrazone ring and oxobutanoate groups are almost planar.The keto hydrazo group adopts a Z-configuration in the molecule and the torsion angle is-177.6(2)°.     

Synthesis, Crystal Structure and Properties of a Novel Vanadium（Ⅴ） Oxoperoxo Complex Incorporating a Tridentate Hydrazone Ligand

A novel vanadium(V) oxoperoxo complex [VOO2(APTCH)(CH3OH)] (HAPTCH = 2-acetylpyridine thiophene-2-carboxylic hydrazone) has been synthesized and characterized by IR, TGA and X-ray single-crystal structure determination. The complex crystallizes in the monoclinic system, space group P21/c with a = 11.232(2), b = 10.762(2), c = 112.613(3), β = 99.44(3)°, V = 1504.1(5)3, Dc = 1.657 g·cm-3, Z = 4, F(000) = 768, μ = 0.827 mm-1, the final R = 0.0392 and wR = 0.1073 for 2266 observed reflections with I > 2σ(I). Single-crystal X-ray diffraction studies reveal that the vanadium(V) is coordinated by a tridentate ligand, methanol molecule and peroxo group to form a pentagonal-bipyramidal geometry. The crystal structure is stabilized by intermolecular hydrogen bonds of O-H···N and C-H···O.     

Crystal Structures and Photoluminescence of Two Zinc（Ⅱ） and Silver（Ⅰ） Complexes with 6,7-Dicyanodipyridoquinoxaline

Two d10 metal-organic complexes, [ZnBr2(DICNQ)2] (1) and [AgCN(DICNQ)]2(2), were prepared from ZnBr2 and AgCN with 6,7-dicyanodipyridoquinoxaline (DICNQ) by solvothermal reactions, respectively, and characterized by single-crystal X-ray diffraction analyses, IR spectroscopy, and photoluminescent measurement. Compound 1 crystallizes in monoclinic, space group C2/c with a=8.436(2), b=13.011(3), c=27.565(6),β=97.90(3) , V=2997.0(1)3 , Z=4, Mr=789.73, Dc=1.750 g/cm3 ,μ=3.533 mm-1 , F(000)=1552, S=1.007 and T=293(2) K. The final R=0.0739 and wR=0.1380 for 1561 observed reflections with I > 2σ(I). Compound 2 crystallizes in monoclinic, space group P21/c with a=24.202(6), b=7.1619(17), c=18.339(5),β=111.8380(10) , V=2950.6(1)3 , Z=4, Mr=832.32, Dc=1.874 g/cm 3 ,μ=1.382 mm-1 , F(000)=1632, S=1.002 and T=293(2) K. The final R=0.0389 and wR=0.1257 for 4812 observed reflections with I > 2σ(I). Both compounds form packing structures by π…π stacking interactions and C-H…N or C-H…Br hydrogen-bonding interactions. Compounds 1 and 2 show similar photoluminescent spectra with emission maxima at ca. 430 nm in diluted acetonitrile solution (1×10-5 mol L-1 ) at room temperature.     

Structure and Luminescence Property of a Hexanuclear Thiosemicarbazone Silver（I） Cluster

A new hexanuclear silver(I) compound containing thiosemicarbazones with groups of 1-naphthalene was synthesized and structurally characterized by single-crystal X-ray diffraction,elemental analysis and fluorescence spectrum.The title compound crystallizes in monoclinic,space group P2 1 /c with a=16.101(4),b=24.855(7),c=14.492(4),β=109.730(5)°,V=5459(3)3,C 90 H 102 Ag 6 N 24 O 6 S 6,M r=2455.54,D c=1.494 g/cm 3,μ(MoKα)=1.228 mm-1,F(000)=2472,Z=2,the final R=0.0761 and wR=0.1507 for 5258 observed reflections (I > 2σ(I)).In the structure,the S atom of ligand L serves as a triply bridged chelator to connect the six silver atoms into a Ag 6 L 6 cluster.Luminescence investigation reveals that the compound exhibits two ligand-independent cluster-centered electron transfer bands and one ligand-dependent charge transfer band.