Protease-catalyzed Synthesis of Bz-Arg-Gly-Asp-OMe in Full Aqueous Medium

Synthesis of N-benzoyl-argininylglycylasparagine methyl ester(Bz-Arg-Gly-Asp-OMe),a precursor tripeptide of Arg-Gly-Asp)was catalyzed by papain under kinetic control,at alkaline pH,in a full aqueous medium.The substrates were N-benzoyl-argininylglycine ethyl ester and asparagine dimethyl ester.An aqueous solution of 0.1 mol/L KCl/NaOH containing 8 mmol/L EDTA and 2 mmol/L DTT was selected as the reaction medium.The synthesized hydrophilic tripeptide was soluble in the reaction medium during the reaction process,however,the secondary hydro-lysis of the tripeptide product was not considerable.The effects of different factors,including water content,temperature,reaction time,and molar ratio of the substrates,on the yield of Bz-Arg-Gly-Asp-OMe were examined.The optimal reaction conditions were 0.05 mol/L Bz-Arg-Gly-OEt and 0.15 mol/L Asp(-OMe)2·HCl in 0.1 mol/L KCl/NaOH solution(pH 8.5),at 40 ℃,and a reaction time of 60 min,with a maximum conversion yield of 62.4%.     

Enzymatic Synthesis of a CCK-8 Tripeptide Fragment

A process for the synthesis of CCK-8 tripeptide H-Gly-Trp-Met-OH catalyzed by immobilized enzyme was reported. Enzymes were used for the formation of peptide bonds and the removal of protecting group. Starting with phenylacetyl (PhAc) glycin, N-protected dipeptide PhAc-Gly-Trp-OMe was obtained by coupling PhAc-protected glycine carboxamidomethyl ester (OCam) with Trp-OMe catalyzed by immobilized papain in buffered ethyl acetate. Then the condensation between PhAc-Gly-Trp-OMe and Met-OEtoHC1 was carried out by immobilized α-chymotrypsin catalysis in solvent free system. Basic hydrolysis was followed getting PhAc-Gly-Trp-Met-OH. The PhAc-group was removed with penicillin G amidase and H-Gly-Trp-Met-OH was obtained in an overall yield of 43.9%. The reaction conversion of tripeptide in solvent free system was strongly affected by the system of basic salts added. The influence of the support materials used to deposit enzymes and structures of acyl donor and nucleophile on the reaction was also investigated.     

Sterically hindered electron-withdrawing ligands: the reactions of N-carbazolyl phosphines with rhodium and palladium centres

The series of N-carbazolyl phosphines PPh(3-n)(NC(12)H(8))(n)(n= 1, L1; n= 2, L2; n= 3, L3) has been synthesised using BuLi to generate the N-carbazolyl lithium salt, followed by reaction with the appropriate chlorophosphine. The reactions between [Rh(mu-Cl)(CO)(2)](2) and four equivalents of L1 or L2 gave [RhCl(CO)(L1)(2)] 1 and [RhCl(CO)(L2)(2)] 2, though attempts to synthesise the analogous complex using L3 resulted in the formation of [Rh(mu-Cl)(CO)(L3)](2) 3 instead. The inability of L3 to cleave the chloride bridges can be related to its considerable steric requirements. The electronic properties of L1-3 were assessed by comparison of the nu(CO) values of the [Rh(acac)(CO)(L1-3)] complexes 4-6. The increase in number of N-carbazolyl substituents at the phosphorus atom results in a decrease of the sigma-donor and increase in the pi-acceptor character in the order L1 < L2 < L3. In the reactions of L1-3 with [PdCl(2)(cod)] only L1 was able to displace cod from the metal centre and form [PdCl(2)(L1)(2)] 7. The use of [PdCl(2)(NCMe)(2)] instead of [PdCl(2)(cod)] resulted in the formation of the complexes [PdCl(2)(L1)(2)] 7 from L1, the cyclometallated complex [Pd(mu-Cl)[P(NC(12)H(8))(2)(NC(12)H(7))-kappa(2)P,C]](2) 8 from L3 , and a mixture of [PdCl(2)(L2)(2)] 9 and [Pd(mu-Cl)[PPh(NC(12)H(8))(NC(12)H(7))-kappa(2)P,C]](2) 10 from L2 . The reaction of L3 with [Pd(OAc)(2)] produced the cyclometallated complex [Pd(mu-O(2)CCH(3))[P(NC(12)H(8))(2)(NC(12)H(7))-kappa(2)P,C]](2) 11. The reaction of L3 with [Pd(2)(dba)(3)].CHCl(3) produced the 14-electron complex [Pd(L3)(2)] 12. The X-ray crystal structures of six complexes are reported, all of which show the presence of C-H...Pd hydrogen bonding.     

Enzymatic Synthesis of a CCK-8 Tripeptide Derivative

The enzymatic synthesis of CCK-8 tripeptide derivative Phae-Met-Asp(OMe)-Phe-NH2 is reported.Starting with Phac-Met-OCam,we have successfully synthesized the target tripeptide with three free or immobilized enzymes, α-chymotrypsin,papain and thermolysin in reasonable yields.The key steps in this synthesis were the coupling of Phac-Met-OCam and H-Asp(OMe)2 to from Met-Asp peptide bond catalyzed by α-chymotrypsin and the selective hydrolysis of α-ester of Phac-met-Asp(OMe)2 catalyzed by papain.     

Photoreduction of carbon dioxide to carbon monoxide with hydrogen catalyzed by a rhenium(i) phenanthroline-polyoxometalate hybrid complex

A phenanthroline ligand decorated at the 5,6-position with a 15-crown-5 ether was used to prepare a metalorganic-polyoxometalate hybrid complex Re(I)(L)(CO)(3)CH(3)CN-MHPW(12)O(40) (L = 15-crown-5-phenanthroline, M = Na(+), H(3)O(+)). X-ray diffraction, (1)H and (13)C NMR, ESI-MS, IR, and elemental analysis were used to characterize this complex. In the presence of Pt/C, the polyoxometalate moiety in Re(I)(L)(CO)(3)CH(3)CN-MHPW(12)O(40) can oxidize H(2) to two protons and two electrons which in the presence of visible light can catalyze the photoreduction of CO(2) to CO with H(2) as the reducing agent instead of the universally used amines as sacrificial reducing agents. An EPR spectrum of a stable intermediate species under reaction conditions shows characteristics of a PW(V)W(VI)(11)O(40) and a Re(0) species with a tentative assignment of the intermediate as Re(0)(L)(CO)(3)(S)-MH(3)PW(V)W(VI)(11)O(40).     

Microwave-assisted construction of ferromagnetic coordination polymers of [W(V)(CN)8]3- with Cu(II)-pyrazole synthons

The microwave-mediated self-assembly of [W(V)(CN)(8)](3-) with Cu(II) in the presence of pyrazole ligand resulted in the formation of three novel assemblies: Cu(II)(2)(Hpyr)(5)(H(2)O)[W(V)(CN)(8)](NO(3))·H(2)O (1), {Cu(II)(5)(Hpyr)(18)[W(V)(CN)(8)](4)}·[Cu(II)(Hpyr)(4)(H(2)O)(2)]·9H(2)O (2), and Cu(II)(4)(Hpyr)(10)(H(2)O)[W(V)(CN)(8)](2)(HCOO)(2)·4.5H(2)O (3) (Hpyr =1H-pyrazole). Single-crystal X-ray structure of 1 consists of cyanido-bridged 1-D chains of vertex-sharing squares topology. The structure of 2 reveals 2-D hybrid inorganic layer topology with large coordination spaces occupied by {Cu(Hpyr)(2)(H(2)O)(4)}(2+) ions. Compound 3 contains two types of cyanido-bridged 1-D chains of vertex-sharing squares linked together by formate ions in two directions forming hybrid inorganic-organic 3-D framework (I(1)O(2)). The magnetic measurements for 1-3 reveal a weak ferromagnetic coupling through Cu(II)-NC-W(V) bridges.     

Hybrid polymeric iodoplumbates constructed from morpholine and its derivatives: structures and properties

Three hybrid polymeric iodoplumbates constructed from morpholine and its derivatives, {(Pb(4)I(15))[(Mph·H)(3)(Mph·1.5H)(2)]}(n)(1), {(edm-H(2))(Pb(3)I(8))]·2DMF}(n)(2), {(edm-H(2))[(dmp)(Pb(4)I(12))]˙2DMF}(n) (3) (Mph = morpholine, edm = ethylenedimorpholine, dmp(2+) = N,N'- dispiromorpholinopiperazonium) have been synthesized and structurally determined. In these compounds, morpholine and its derivatives weakly interact with or covalently bond to polymeric iodoplumbates. In 1, hydrogen bonds between (Pb(4)I(15))(7-) clusters and protonized Mph contribute to the formation of a 1-D hybrid chain. In 2, the 1-D [(Pb(3)I(8))](n)(2n-) chain is extended to be a 2-D layer via the edm(2+) ligand by means of Pb-O covalent bonds. Interestingly, the 2-D [(Pb(4)I(12))](n)(4n-) inorganic layer in 3 is concertedly templated by two kinds of organic cations. The above compounds exhibit a semiconductor nature, and third-order nonlinear optical (NLO) activities can be detected in 1 and 3.     

New family of silver(I) complexes based on hydroxyl and carboxyl groups decorated arenesulfonic acid: syntheses, structures, and luminescent properties

Self-assembly of silver(I) salts and three ortho-hydroxyl and carboxyl groups decorated arenesulfonic acids affords the formation of nine silver(I)-sulfonates, (NH(4))·[Ag(HL1)(NH(3))(H(2)O)] (1), {(NH(4))·[Ag(3)(HL1)(2)(NH(3))(H(2)O)]}(n) (2), [Ag(2)(HL1)(H(2)O)(2)](n) (3), [Ag(2)(HL2)(NH(3))(2)]·H(2)O (4), [Ag(H(2)L2)(H(2)O)](n) (5), [Ag(2)(HL2)](n) (6), [Ag(3)(L3)(NH(3))(3)](n) (7), [Ag(2)(HL3)](n) (8), and [Ag(6)(L3)(2)(H(2)O)(3)](n) (9) (H(3)L1 = 2-hydroxyl-3-carboxyl-5-bromobenzenesulfonic acid, H(3)L2 = 2-hydroxyl-4-carboxylbenzenesulfonic acid, H(3)L3 = 2-hydroxyl-5-carboxylbenzenesulfonic acid), which are characterized by elemental analysis, IR, TGA, PL, and single-crystal X-ray diffraction. Complex 1 is 3-D supramolecular network extended by [Ag(HL1)(NH(3))(H(2)O)](-) anions and NH(4)(+) cations. Complex 2 exhibits 3-D host-guest framework which encapsulates ammonium cations as guests. Complex 3 presents 2-D layer structure constructed from 1-D tape of sulfonate-bridged Ag1 dimers linked by [(Ag2)(2)(COO)(2)] binuclear units. Complex 4 exhibits 3-D hydrogen-bonding host-guest network which encapsulates water molecules as guests. Complex 5 shows 3-D hybrid framework constructed from organic linker bridged 1-D Ag-O-S chains while complex 6 is 3-D pillared layered framework with the inorganic substructure constructing from the Ag2 polyhedral chains interlinked by Ag1 dimers and sulfonate tetrahedra. The hybrid 3-D framework of complex 7 is formed by L3(-) trianions bridging short trisilver(I) sticks and silver(I) chains. Complex 8 also presents 3-D pillared layered framework, and the inorganic layer substructure is formed by the sulfonate tetrahedrons bridging [(Ag1O(4))(2)(Ag2O(5))(2)](∞) motifs. Complex 9 represents the first silver-based metal-polyhedral framework containing four kinds of coordination spheres with low coordination numbers. The structural diversities and evolutions can be attributed to the synthetic methods, different ligands and coordination modes of the three functional groups, that is, sulfonate, hydroxyl and carboxyl groups. The luminescent properties of the nine complexes have also been investigated at room temperature, especially, complex 1 presents excellent blue luminescence and can sensitize Tb(III) ion to exhibit characteristic green emission.     

Studies of the ligand effect on the synthesis of dialuminoxanes by various β-diketiminato ligands

Reactions of LH (L = HC[C(Me)N(2,6-Me(2)C(6)H(3))](2)) with Me(n)AlCl(3-n) in diethyl ether afforded the adducts LH·AlMe(n)(Cl)(3-n) (n = 2, 3; 1, 4; 0, 5) in good yields. Treatment of 3 at elevated temperatures in toluene resulted in LAlMeCl (2) by intramolecular elimination of methane. The controlled hydrolysis of LAlMeCl (2) with equimolar amounts of water in the presence of N-heterocyclic carbene (NHC) gave a mixture of [LAl(Me)](2)(μ-O) (7) and dimeric [LAlMe(μ-OH)](2) (8). A convenient route for the preparation of [LAlMe(μ-OH)](2) (8) was the NHC-assisted controlled hydrolysis of LAlMeI (9). Stepwise hydrolysis of LAlH(2) (11) gave dialuminoxane hydride [LAl(H)](2)(μ-O) (12) and dialuminoxane hydroxide [LAl(OH)](2)(μ-O) (13), respectively. Anhydrous treatment of LAlCl(2) (1) or LAlMeCl (2) with Ag(2)O afforded chlorinated dialuminoxane [LAl(Cl)](2)(μ-O) (14) and [LAl(Me)](2)(μ-O) (7), respectively.     

Chelation-assisted hydroesterification of alkenes catalyzed by rhodium complex

[reaction: see text] The hydroesterification of alkenes with 2-pyridylmethanol (1) catalyzed by Rh(4)(CO)(12) is described. The reaction is accelerated by the presence of a pyridine ring in the alcohol 1. The reaction is applicable to various alkenes, both terminal and internal alkenes.     

An effective metallohydrolase model with a supramolecular environment: structures, properties, and activities

A supramolecular inclusion complex, [Zn(L1)(H2O)2(beta-CD)](ClO4)2.9.5 H2O (1) was synthesized and characterized structurally and its first-order active species for hydrolysis of esters, [Zn(L1)(H2O)(OH)(beta-CD)](ClO4) (2), was isolated (L1=4-(4'-tert-butylbenzyl)diethylenetriamine; beta-CD=beta-cyclodextrin). The apparent inclusion stability constant of the host and the guest measured in aqueous solution was (5.91+/-0.03)x10(3) for 1. The measured values of the first- and second-order pK(a) values of coordinated water molecules were 8.20+/-0.08 and 10.44+/-0.08, respectively, and were assigned to water molecules occupying the plane and remaining axial positions in a distorted trigonal bipyramid of the [Zn(L1)(H2O)2(beta-CD)]2+ sphere according to the structural analysis of [Zn(L2)(H2O)}2(mu-OH)](ClO4)3 (3) (L2=4-benzyldiethylenetriamine). p-Nitrophenyl acetate (pNA) hydrolysis catalyzed by 1 at pH 7.5-9.1 and 25.0+/-0.1 degrees C exhibited a first-order reaction with various concentrations of pNA and 1, but the pH profile did not indicate saturated kinetic behavior. Second-order rate constants of 0.59 and 24.0 M(-1) s(-1) were calculated for [Zn(L1)(H2O)(OH)(beta-CD)]+ and [Zn(L1)(OH)2(beta-CD)], respectively; the latter exhibited a potent catalytic activity relative to the reported mononuclear and polynuclear Zn(II) species.     

A sodalite-type porous metal-organic framework with polyoxometalate templates: adsorption and decomposition of dimethyl methylphosphonate

A sodalite-type porous metal-organic framework with polyoxometalate templates, H(3)[(Cu(4)Cl)(3)(BTC)(8)](2)[PW(12)O(40)]·(C(4)H(12)N)(6)·3H(2)O (NENU-11; BTC = 1,3,5-benzenetricarboxylate), was obtained by a hydrothermal reaction. As a reasonable candidate for eliminating nerve gas, NENU-11 displays good adsorption behavior for dimethyl methylphosphonate (15.5 molecules per formula unit). In virtue of the catalytic activity of polyoxometalate guests, this nerve gas mimic could be facilely decomposed by a hydrolysis reaction.     

Molybdenum(VI) catalysts obtained from η3-allyl dicarbonyl precursors: synthesis, characterization and catalytic performance in cyclooctene epoxidation

The oxidative decarbonylation of the η(3)-allyl dicarbonyl complexes [Mo(η(3)-C(3)H(5))Cl(CO)(2)(L)] (L = 2,2'-bipyridine (bipy) (1), 4,4'-di-tert-butyl-2,2'-bipyridine (di-tBu-bipy) (2)) by reaction with aqueous tert-butylhydroperoxide (TBHP) or H(2)O(2) gave the following compounds in good to excellent yields: the oxo-bridged dimers [MoO(2)Cl(L)](2)O (L = bipy (3), di-tBu-bipy (6)) using TBHP(10 equiv.)/CH(3)CN/r.t.; the molybdenum oxide/bipyridine hybrid material {[MoO(3)(bipy)][MoO(3)(H(2)O)]}(n) (4) and the octanuclear complex [Mo(8)O(24)(di-tBu-bipy)(4)] (7) using TBHP(50 equiv.)/H(2)O/70 °C; the oxodiperoxo complexes MoO(O(2))(2)(L) (L = bipy (5), di-tBu-bipy (8)) using H(2)O(2)(10 equiv.)/CH(3)CN/r.t. The structure of 7·x(solvent) (where solvent = CH(2)Cl(2) and/or diethyl ether) was determined by single crystal X-ray diffraction. Despite possessing the same windmill-type complex as that described previously for 7·10CH(2)Cl(2), the crystal structure of 7·x(solvent) is unique due to differences in the crystal packing. Compounds 1-8 were examined as catalysts or catalyst precursors for the epoxidation of cyclooctene using aqueous TBHP or H(2)O(2) as oxidant at 55 or 70 °C. Reactions were performed without co-solvent or with the addition of water, ethanol or acetonitrile. Cyclooctene oxide was always the only reaction product. Solids recovered after 24 h reaction at 70 °C were identified by FT-IR spectroscopy as the hybrid 4 from (1,3-5)/TBHP, complex 5 from (1,3-5)/H(2)O(2), and complex 8 from (2,6-8)/H(2)O(2). With TBHP as oxidant, the highest epoxide yields (for 24 h reaction at 70 °C) were obtained using excess H(2)O as solvent (28-38% for 1,3-5; 87-98% for 2,6-8), while with H(2)O(2) as oxidant, the highest epoxide yields were obtained using CH(3)CN as solvent (54-81% for 3-8).     

Temperature-dependent in situ ligand cyclization via C═C coupling and formation of a spin-crossover iron(II) coordination polymer

The reaction of N(1),N(2)-bis(pyridin-4-ylmethylene)ethane-1,2-diamine (L) with Fe(NCS)(2) under various temperatures gave rise to three iron(II) coordination polymers, namely, one-dimensional [Fe(L')(NCS)(2)] (1), two-dimensional [Fe(L)(2)(NCS)(2)]·H(2)O (2), and one-dimensional [Fe(L)(2)(NCS)(2)]·2CH(2)Cl(2)·4MeOH (3). The formation of 1 involved an in situ C═C coupling reaction, L to L' [L' = 5,6-di(pyridin-4-yl)-1,2,3,4-tetrahydropyrazine], which was catalyzed by cyanide ions decomposed from thiocyanates; the manganese(II) (1a) and zinc(II) (1b) analogues of 1 were also synthesized for comparison. Magnetic studies showed that complex 1 underwent a pressure-dependent one-step incomplete spin transition whereas complexes 2 and 3 were paramagnetic in the whole temperature range.     

固定化酶催化合成CCK-8C-端三肽衍生物

报道胆囊收缩素（CCK-8）C-末端片段三肽衍生物外Hpac-Met_Asp(Cam为起始 原料，采用三种固定化酶--α-糜蛋白酶／Celite-545、木瓜蛋白酶／VA-Epoxy、 步酶促反应得到目标三肽化合物．对酶的专一性、酶的固定化、溶剂选择和合成条 件等进行了研究，比较了自由酶法与固定化酶法的结果．     

Synthesis and structures of gold perfluorophthalimido complexes

Compounds of the new tetrafluorophthalimido anion, [C(6)F(4)(CO)(2)N](-), are readily accessible by treatment of tetrafluorophthalimide with either LiNPr(i)(2) or mixtures of NEt(3) and Me(3)ECl (E = Si or Sn), to give C(6)F(4)(CO)(2)N-X (X = Li 3, SiMe(3)4, and SnMe(3)5). The reaction of the trimethylsilyl derivative 4 with AgF leads cleanly to the ion pair complex [Ag(NCMe)(2)][Ag(N(CO)(2)C(6)F(4))(2)] (6·2MeCN), which contains a linear [Ag{N(CO)(2)C(6)F(4)}(2)](-) anion and a tetracoordinate Ag(+) cation. Compound 6 reacts with iodine to give the N-iodo compound C(6)F(4)(CO)(2)NI 7, which crystallises as an acetonitrile adduct. Treatment of 6 with LAuCl affords LAu{N(CO)(2)C(6)F(4)} (L = Ph(3)P 8a, Cy(3)P 8b, or THT 9), whereas the reaction with AuCl in acetonitrile affords the heterobinuclear compound [Ag(MeCN)(2)][Au{N(CO)(2)C(6)F(4)}(2)]·MeCN (10·3MeCN). The tetrafluorophthalimido ligand is not readily displaced by donor ligands; however, the addition of B(C(6)F(5))(3)(Et(2)O) to a diethyl ether solution of 8a leads to the salt [Au(PPh(3))(2)][N{COB(C(6)F(5))(3)}(2)C(6)F(4))] 11. The analogous reaction of (THT)Au{N(CO)(2)C(6)F(4)} with B(C(6)F(5))(3) in toluene in the presence of excess norbornene (nb) gives [Au(nb)(3)][N{COB(C(6)F(5))(3)}(2)C(6)F(4))] 12. Compounds 11 and 12 contain a new non-coordinating phthalimido-bridged diborate anion with O-bonded boron atoms. The crystal structures of compounds 2-11 are reported.     

C-H activations at iridium(I) square-planar complexes promoted by a fifth ligand

In the presence of ligands such as acetonitrile, ethylene, or propylene, the Ir(I) complex [Ir(1,2,5,6-eta-C8H12)(NCMe)(PMe3)]BF4 (1) transforms into the Ir(III) derivatives [Ir(1-kappa-4,5,6-eta-C8H12)(NCMe)(L)(PMe3)]BF4 (L = NCMe, 2; eta2-C2H4, 3; eta2-C3H6, 4), respectively, through a sequence of C-H oxidative addition and insertion elementary steps. The rate of this transformation depends on the nature of L and, in the case of NCMe, the pseudo-first-order rate constants display a dependence upon ligand concentration suggesting the formation of five-coordinate reaction intermediates. A similar reaction between 1 and vinyl acetate affords the Ir(III) complex [Ir(1-kappa-4,5,6-eta-C8H12){kappa-O-eta2-OC(Me)OC2H3}(PMe3)]BF4 (7) via the isolable five-coordinate Ir(I) compound [Ir(1,2,5,6-eta-C8H12){kappa-O-eta2-OC(Me)OC2H3}(PMe3)]BF4 (6). DFT (B3LYP) calculations in model complexes show that reactions initiated by acetonitrile or ethylene five-coordinate adducts involve C-H oxidative addition transition states of lower energy than that found in the absence of these ligands. Key species in these ligand-assisted transformations are the distorted (nonsquare-planar) intermediates preceding the intramolecular C-H oxidative addition step, which are generated after release of one cyclooctadiene double bond from the five-coordinate species. The feasibility of this mechanism is also investigated for complexes [IrCl(L)(PiPr3)2] (L = eta2-C2H4, 27; eta2-C3H6, 28). In the presence of NCMe, these complexes afford the C-H activation products [IrClH(CH=CHR)(NCMe)(PiPr3)2] (R = H, 29; Me, 30) via the common cyclometalated intermediate [IrClH{kappa-P,C-P(iPr)2CH(CH3)CH2}(NCMe)(PiPr3)] (31). The most effective C-H oxidative addition mechanism seems to involve three-coordinate intermediates generated by photochemical release of the alkene ligand. However, in the absence of light, the reaction rates display dependences upon NCMe concentration again indicating the intermediacy of five-coordinate acetonitrile adducts.     

PH-controlled construction of Cu(I) coordination polymers: in situ transformation of ligand, network topologies, and luminescence and UV-vis-NIR absorption properties

Two new complexes [Cu(I)(3)(L1)I(3)](n) (1, L1 = 2,5-bis(4-pyridyl)-1,3,4-oxadiazole) and [Cu(I)(3)(L2)I(2)](n) (2, L2 = 2,5-bis(4-pyridyl)-1,2,4-triazolate) are controllably formed by using aqueous ammonia to regulate the pH value of the reaction involving CuI and L1. Interestingly, L2 of 2 is in situ generated from the ring transform of L1 when increase the pH value of the reaction. 1 exhibits 2-D layer, while 2 shows 3-D MOFs with a novel 3-nodal 4,4,5-connected net topology of an unprecedented Point (Schlafli) symbol: (4·5(2)·6(2)·7)(5(4)·8(2))(4(3)·5·6(6)). Although both 1 and 2 are built of CuI and similar ligands, different arrangements of CuI chains and ligands endow them with different physical properties. 1 displays a strong pure red luminescence emission, while 2 is nonluminescent and shows a broad absorption band covering the whole UV-vis-NIR spectrum range. The emissive excited states of 1 and the charge transitions of the optical absorption for 2 are solved by DFT calculations.     

(Fluoren-9-ylidene)methanedithiolato complexes of platinum: synthesis, reactivity, and luminescence

Platinum(II) complexes with (fluoren-9-ylidene)methanedithiolato and its 2,7-di-tert-butyl- and 2,7-dimethoxy-substituted analogues were obtained by reacting different chloroplatinum(II) precursors with the piperidinium dithioates (pipH)[(2,7-R2C12H6)CHCS2] [R = H (1a), t-Bu (1b), or OMe (1c)] in the presence of piperidine. The anionic complexes Q2[Pt{S(2)C=C(C12H6R(2)-2,7)}2] [R = H, (Pr(4)N)(2)2a; R = t-Bu, (Pr4N)(2)2b, (Et4N)(2)2b; R = OMe, (Pr4N)(2)2c] were prepared from PtCl(2), piperidine, the corresponding QCl salt, and 1a-c in molar ratio 1:2:2:2. In the absence of QCl, the complexes (pipH)(2)2b and [Pt(pip)(4)]2b were isolated depending on the PtCl(2):pip molar ratio. The neutral complexes [Pt{S2C=C(C12H6R(2)-2,7)L(2)] [L = PPh(3), R = H (3a), t-Bu (3b), OMe (3c); L = PEt(3), R = H (4a), t-Bu (4b), OMe (4c); L(2) = dbbpy, R = H (5a), t-Bu (5b), OMe (5c) (dbbpy = 4,4'-di-tert-butyl-2,2'-bipyridyl)] were similarly prepared from the corresponding precursors [PtCl2L2] and 1a-c in the presence of piperidine. Oxidation of Q(2)2b with [FeCp2]PF6 afforded the mixed Pt(II)-Pt(IV) complex Q2[Pt2{S2C=C[C12H6(t-Bu)(2)-2,7]}4] (Q(2)6, Q = Et4N+, Pr4N+). The protonation of (Pr4N)(2)2b with 2 equiv of triflic acid gave the neutral dithioato complex [Pt2{S2CCH[C12H6(t-Bu)(2)-2,7]}4] (7). The same reaction in 1:1 molar ratio gave the mixed dithiolato/dithioato complex Pr4N[Pt{S2C=C[C12H6(t-Bu)(2)-2,7]}{S2CCH[C12H6(t-Bu)(2)-2,7]}] (Pr(4)N8) while the corresponding DMANH+ salt was obtained by treating 7 with 2 equiv of 1,8-bis(dimethylamino)naphthalene (DMAN). The crystal structures of 3b and 5c.CH2Cl2 have been solved by X-ray crystallography. All the platinum complexes are photoluminescent at 77 K in CH2Cl2 or KBr matrix, except for Q(2)6. Compounds 5a-c and Q8 show room-temperature luminescence in fluid solution. The electronic absorption and emission spectra of the dithiolato complexes reveal charge-transfer absorption and emission energies which are significantly lower than those of analogous platinum complexes with previously described 1,1-ethylenedithiolato ligands and in most cases compare well to those of 1,2-dithiolene complexes.     

Coordination polymers assembled from angular dipyridyl ligands and CuII, CdII, CoII salts: crystal structures and properties

Six new metal-organic coordination networks based on linking unit 2,5-bis(4-pyridyl)-1,3,4-thiadiazole (L(1)) or 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L(3)) and inorganic Cu(II), Cd(II), and Co(II) salts have been prepared and structurally characterized by single-crystal X-ray analysis. Using L(1) to react with three different Cu(II) salts, Cu(OAc)(2).H(2)O, Cu(NO(3))(2).3H(2)O, and CuSO(4).5H(2)O, respectively, two different one-dimensional (1-D) coordination polymers, [[Cu(2)L(1)(mu-OAc)(4)](CHCl(3))(2)](n) (1) [triclinic, space group P1, a = 7.416(3) A, b = 8.207(3) A, c = 14.137(5) A, alpha = 100.333(7) degrees, beta = 105.013(6) degrees, gamma = 94.547(6) degrees, Z = 1] and [[CuL(1)(NO(3))(2)](CHCl(3))(0.5)](n) (2) [monoclinic, space group C2/c, a = 28.070(8) A, b = 9.289(3) A, c = 15.235(4) A, beta = 113.537(5) degrees, Z = 8], and a chiral 3-D open framework, [[CuL(1)(H(2)O)(SO(4))](H(2)O)(2)](n) (3) [orthorhombic, space group P2(1)2(1)2(1), a = 5.509(2) A, b = 10.545(4) A, c = 29.399(11) A, Z = 4], were obtained. Reaction of L(1) and Cd(ClO(4))(2).6H(2)O or Co(ClO(4))(2).6H(2)O, in the presence of NH(4)SCN, yielded another 3-D open framework, [[CdL(1)(NCS)(2)](CH(3)OH)(1.5)](n) (4) [monoclinic, space group C2/c, a = 28.408(10) A, b = 9.997(5) A, c = 7.358(4) A, beta = 99.013(8) degrees, Z = 4], or a 2-D network, [[Co(L(1)())(2)(NCS)(2)](H(2)O)(2.5)](n) (5) [orthorhombic, space group Pnna, a = 22.210(5) A, b = 12.899(3) A, c = 20.232(4) A, Z = 4]. When L(1) was replaced by L(3) to react with Co(ClO(4))(2).6H(2)O and NH(4)SCN, another 2-D coordination polymer, [Co(L(3))(2)(NCS)(2)](n) (6) [monoclinic, space group P2(1)/c, a = 8.120(3) A, b = 9.829(4) A, c = 17.453(6) A, beta = 103.307(6) degrees, Z = 2], was constructed. These results indicate that the nature of the ligands, metal centers, or counteranions plays the critical role in construction of these novel coordination polymers. The interesting porous natures of two 3-D open frameworks 3 and 4 were investigated by TGA and XPRD techniques, and the magnetic properties of the Cu(II) and Co(II) complexes were studied by variable-temperature magnetic susceptibility and magnetization measurements.