Methyl methylphenylphosphinate,MePh(MeO)PO complexes of the first row transition metals

Summary Methyl methylphenylphosphinate (L) complexes with 3d metal perchlorates were synthesized by interaction of L and metal salt solutions in triethyl orthoformate (61 molar ratio) and characterized by means of spectral, magnetic and conductance studies. In most cases (Mⁿ⁺ = Cr³⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺ or Zn²⁺), complexes involving 41 L: metal ratios, similar to those obtained with bulky triorganophosphine oxides and neutral phosphonate or phosphate esters, were formed. These complexes contain exclusively terminal L groups and were characterized as monomeric of the types [CrL₄(OClO₃)₂](ClO₄), [ML₄(OH₂)](ClO₄)₂ (M = Mn or Ni), [ML₄(OClO₃)](ClO₄) (M = Co or Zn) and [CuL₄](ClO₄)₂. In contrast, Fe²⁺ and Fe³⁺ perchlorates formed, rather unexpectedly, complexes involving 21 L: Fe ratios. These compounds appear to be binuclear and of the type [(O₃ClO)(H₂O)₂LFeL₂FeL(OH₂)₂(OClO₃)](ClO₄)_n (n=2 for Fe²⁺; n=4 for Fe³⁺), containing both terminal and bridging coordinated L ligands. The bridging L groups in the iron complexes seem to be exclusively coordinated through the P=O oxygen, which acts as a bridging group between two adjacent Fe²⁺ or Fe³⁺ions, rather than functioning as bidentate bridging O,O-ligands, with both the P=O and methoxy oxygens involved in coordination. Spectral evidence suggests that L is a weaker ligand than triorganophosphine oxides and a stronger ligand than neutral phosphonate and phosphate esters, as anticipated.     

ADDUCTS OF THEOBROMINE WITH 3d METAL PERCHLORATES

Abstract

Adducts of theobromine (tbH) with 3d metal perchlorates (Mⁿ⁺ = Cr^3-. Mn²⁺, Fe²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn^2- I here prepared by refluxing mixtures of the Iigand and a metal salt in ethyl acetate-triethyl orthoformate. The new complexes invariably involve 2: 1 molar ratios of tbH to metal ion and are apparently monomeric with terminal tbH ligands binding riaa ring nitrogen (N9 or Nl). The Mn²⁺, Cu²⁺ and Zn^2- complexes are distorted tetrahedral, involving tuo tbH and two unidentate perchlorato ligands in the first coordination sphere of the metal ion. The remaining metal(II) complexes (Fe, Co, Ni) were obtained as monohydrates. These compounds are pentacoordinated of the [M(tbH)₂(OClO₃)₂(OH₂)] type, containing one aqua ligand in addition to the tbH and perchlorato ligands. The Cr³⁺ and Fe³⁺ complexes are low-symmetry hexacoordinated, with two tbH ligands. two unidentate and one bidentate chelating perchlorate Iigands.     

Allopurinol complexes with first row transition metal perchlorates

Summary Complexes of allopurinol (apH) with Fe^III and several 3d metal(II) (e.g. Fe, Co, Ni and Cu) perchlorates were prepared. The solid complexes isolated included two monomeric hexacoordinated adducts of the type [Fe(apH)₃-(OClO₃) (OH₂)₂]ClO₄ and [Fe(apH)₃(OClO₃)₂(OH₂)]ClO₄, involving N(8)-bound neutral apH ligands, and polymeric Co, Ni or Cu complexes containing both neutral apH and monoanionic ap^- ligands. The latter three complexes involved both N(8)-bound terminal apH and N(1), N(8)- or N(1), N(9)-bound bridging ap^- ligands, and were of the following types: [(apH)₂Cu(ap)] _n (ClO₄) _n , tetrahedral; [(apH)(H₂O)(OClO₃)Co(ap)] _n , pentacoordinated; and [(apH)₂(H₂O)(OClO₃)Ni(ap)] _n , hexacoordinated.Presented in part at the 203rd. American Chemical Society National Meeting; see Ref. 1.     

Thiocarbonyl rhodium complexes with tricyclohexylphosphine and other nitrogen and phosphorus donor ligands

Summary The preparation of the covalent Rh(OCIO₃)(CS)(PCy₃)₂ and Rh(OClO₃)(CS)(PPh₃)(PCy₃) perchlorato complexes is described, These complexes react with mono- or bidentate nitrogen donor ligands to give new cationic complexes of the [Rh(CS)(PCY₃)₂L]ClO4 and [Rh(CS)(PPh,)(PCy₃)L]ClO₄ types,     

Effect of auxiliary ligand on the crystalline architectures of copper(II)-sparfloxacin complexes via coordinative and supramolecular interactions

Reactions of sparfloxacin (Hsf) with Cu(II), in the absence or presence of auxiliary ligands (bpy, 2,2′-bipyridine; dmbpy, 4,4′-dimethyl-2,2′-bipyridine) under similar conditions, afforded three coordination complexes, [Cu(Hsf)₂(ClO₄)](ClO₄)(CH₃OH)₂(H₂O)_3.75 (1), [Cu(Hsf)(bpy)(ClO₄)](ClO₄)(H₂O) (2), and [Cu₂(Hsf)₂(dmbpy)₂(ClO₄)₃](ClO₄)(C₂H₅OH)₃(H₂O)_0.75 (3). All three complexes have been structurally characterized by single-crystal X-ray diffraction. In their crystal structures, distinct extended metallosupramolecular architectures, specifically 3D (for 1), 2D (for 2), and 2D + 1D (for 3), are constructed with the aid of secondary interactions involving H-bonding and aromatic stacking.     

Structural characterisation of mononuclear zinc(ii) complexes of 4-methyl-3,5-di(2-pyridyl)-4H-1,2,4-triazole with three-atom co-ligands: [ZnII(medpt)2X]ClO4 (X?=?NCS?, N3?, NO2?)

The reaction of 4-methyl-3,5-di(2-pyridyl)-4H-1,2,4-triazole (medpt) with Zn(ClO₄)₂·6H₂O and NaSCN, NaN₃ or NaNO₂ in a 2:1:1 molar ratio in MeOH/H₂O (9:1) affords the mononuclear complexes [Zn^II(medpt)₂(NCS)]ClO₄, [Zn^II(medpt)₂(N₃)]ClO₄ and [Zn^II(medpt)₂(NO₂)]ClO₄, respectively. All three complexes have been structurally characterised and found to feature unusual coordination polyhedra for 3,5-di(2-pyridyl)-4H-1,2,4-triazole complexes. In [Zn^II(medpt)₂(NCS)]ClO₄ and [Zn^II(medpt)₂(N₃)]ClO₄, the zinc atom resides within a distorted square-pyramidal N₅ coordination sphere [τ = 0.22 and 0.04, respectively] with two bidentate medpt ligands bound equatorially and the pseudohalide ion coordinating as a unidentate co-ligand in the apical position. In contrast, the NO₂ ⁻ ion in [Zn^II(medpt)₂(NO₂)]ClO₄ acts as a bidentate ligand, which leads to a strongly distorted N₄O₂ coordination environment about the metal centre.     

Three copper(II) complexes of 4-formylbenzoate obtained from degradation of the Schiff base

A 1-D copper(II) coordination polymer and two mononuclear copper(II) complexes of 4-formylbenzoate, [Cu(L)₂(H₂O)₂] _n (1), [Cu(L)₂(D,L-cam)] (2), and [Cu(L)(bpy)₂]?·?(ClO₄)(H₂O) (3) (HL?=?4-formylbenzoic acid, D,L-cam?=?D,L-camphoric diamine, bpy?=?2,2′-bipyridine), have been obtained from cleavage of C=N double bonds of a bis-Schiff-base compound. 4-Formylbenzoate exhibits bidentate chelating and bidentate μ ₂-bridging modes by terminal carboxylic and aldehydic groups in 1-D coordination polymer 1. In contrast, it shows bidentate chelating in 2 and monodentate and bidentate bonding in 3 by its terminal carboxylic group where the aldehydic group does not coordinate. Offset π–π stacking interactions and two types of 8-membered hydrogen-bonding rings are found between neighboring molecules of the copper(II) complexes.     

Yttrium(III) and lanthanide(III) perchlorate complexes with the 2,2,6,6- tetramethylpiperidine nitroxide free radical

Summary 2,2,6,6-Tetramethylpiperidine nitroxide free radical (TMPNO) complexes with Y³⁺ and Ln³⁺ (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er or Yb) perchlorates were synthesized and characterized by means of i.r. and e.s.r. spectral, magnetic susceptibility and molar conductance studies. The new complexes are of the general type [M(TMPNO-)₂(OH₂)₃(OCIO₃)](ClO₄)₂ (M = Y or Ln), involving two TMPNO;, three aqua and one unidentate perchlorato ligand in the complex cation, and two anionic C10₄ groups. The NO bond-order in coordinated TMPNO is apparently two, as suggested by the i.r. evidence. The magnetic susceptibility and e.s.r. data were interpreted in terms of partial spin-spin coupling interaction between the unpaired electrons of the two TMPNO- ligands, as well as unpaired f electrons, in the case of paramagnetic lanthanide(Ill) ions. Severe steric hindrance, introduced during coordination of the free radical ligand through the NO oxygen atom, does not seem to allow accommodation of more than two TMPNO molecules in the inner coordination sphere of the central Y³⁺, or Ln³⁺ ion.To whom all correspondence should be directed.     

Urate complexes of dipositive first row transition metal ions

Summary The following complexes were prepared by reacting uric acid (uaH₂) with 3d metal(II) perchlorates in non-aqueous media: trans-[Mn(uaH)₂(OH₂)₄], octahedral, and [Co-(uaH)₂(OH₂)₂] tetrahedral, both involving O(8)-bound hydrogenurate; [Cu(ua)(OH₂)₃], tetrahedral, with the urate dianion binding via a ring nitrogen; and [Ni₂(uaH)₂-(uaH₂)(ClO₄)₂(H₂O)₃] formulated as a pentacoordinated linear polymetric species, involving bidentate bridging hydrogenurate, binding through O(8) and a ring nitrogen.Presented in part at the 4th Chemical Congress of North America (Ref. 1).     

Thiosemicarbazone complexes of the platinum metals. A story of variable coordination modes

Salicylaldehyde thiosemicarbazone (H₂saltsc) reacts with [M(PPh₃)₃X₂] (M = Ru, Os; X = Cl, Br) to afford complexes of type [M(PPh₃)₂(Hsaltsc)₂], in which the salicylaldehyde thiosemicarbazone ligand is coordinated to the metal as a bidentate N,S-donor forming a four-membered chelate ring. Reaction of benzaldehyde thiosemicarbazones (Hbztsc-R) with [M(PPh₃)₃X₂] also affords complexes of similar type, viz. [M(PPh₃)₂(bztsc-R)₂], in which the benzaldehyde thiosemicarbazones have also been found to coordinate the metal as a bidentate N,S-donor forming a four-membered chelate ring as before. Reaction of the Hbztsc-R ligands has also been carried out with [M(bpy)₂X₂] (M = Ru, Os; X = Cl, Br), which has afforded complexes of type [M(bpy)₂(bztsc-R)]⁺, which have been isolated as perchlorate salts. Coordination mode of bztsc-R has been found to be the same as before. Structure of the Hbztsc-OMe ligand has been determined and some molecular modelling studies have been carried out determine the reason for the observed mode of coordination. Reaction of acetone thiosemicarbazone (Hactsc) has then been carried out with [M(bpy)₂X₂] to afford the [M(bpy)₂(actsc)]ClO₄ complexes, in which the actsc ligand coordinates the metal as a bidentate N,S-donorformingafive-membered chelate ring. Reaction of H₂saltsc has been carried out with [Ru(bpy)₂Cl₂] to prepare the [Ru(bpy)₂(Hsaltsc)]ClO₄ complex, which has then been reacted with one equivalent of nickel perchlorate to afford an octanuclear complex of type [Ru(bpy)₂(saltsc-H)₄Ni₄](ClO₄)₄.     

5′-DEOXYADENOSINE COMPLEXES WITH DIVALENT 3d METAL PERCHLORATES

Abstract

5′-deoxyadenosine (LH) complexes with divalent 3d metal perchlorates were prepared by refluxing mixtures of LH and salt in triethylorthoformate-ethylacetate. With one exception (M = Co), adducts of the types M(LH)₂(ClO₄)₂.3EtOH (M = Mn, Fe, Ni, Zn) and Cu(LH)₃(ClO₄)₂.EtOH were obtained. Ethanol is introduced to the system by hydrolysis of triethylorthoformate during the dehydration of the metal salts. Co(II) perchlorate yielded a complex involving both neutral LH and monoanionic L^? ligands, i. e., Co₂(LH)L₂(ClO₄)₂.4EtOH. An analogous Cu(II) complex, Cu₂(LH)L₂(ClO₄)₂.EtOH.3H₂O, was also obtained by refluxing substantially more dilute suspensions of LH and Cu salt, relative to the standard preparative method employed. The new complexes were characrerized as dimers or linear polymers, involving bridging bidentate N1,N7-bound LH ligands between adjacent metal ions and coordination number six. The new adducts also involve terminal N7-bound LH and EtOH ligands and ionic perchlorate, and the Co and Cu complexes a chelating N6,N7-bound L^? (monodeprotonation of the exocyclic NH₂ group) per metal ion and terminal -OClO₃ and ROH (R = Et or H) ligands.     

X-ray structure and spectroscopic characterization of doubly-bridged binuclear copper(II) complexes in symmetric and asymmetric coordination environments

μ-1,3-Acetamide or acetate bridged, symmetric and asymmetric dicopper(II) complexes viz [Cu₂(P1-O⁻)(NHAc⁻)](ClO₄)₂ (1), [Cu₂(P2-O⁻)(OAc⁻)](ClO₄)₂ (2) and [Cu₂(P2′-O⁻)(OAc⁻)(H₂O)](ClO₄)₂ (3) were synthesized by employing classic dinucleating ligands; P1-OH, P2-OH (symmetric), and P2′-OH (asymmetric) having trivial differences in their ligand frame work. Solid state structures of these complexes were determined by X-ray crystallography. In solution, they were also characterized by various spectroscopic techniques, which includes ESI-MS, FT-IR, optical, solution magnetic moment, paramagnetic ¹H NMR and EPR. The solution magnetic moment of these complexes at room temperature suggests a weak magnetic interaction between the two Cu(II) centers.     

Heterodinukleare Cobalt(II)‐, Nickel(II)‐, Kupfer(II)‐, Zink(II)und Palladium(II)‐Komplexe mit einem makrocyclischen Liganden vom Schiff‐Basen‐Typ: Synthesen und Strukturen

Complexes with Macrocyclic Ligands. IV. Heterodinuclear Cobalt(II), Nickel(II), Copper(II), Zinc(II) and Palladium(II) Complexes with a Macrocyclic Ligand of Schiff‐Base Type: Syntheses and Structures The synthesis and properties of nickel(II), copper(II), and palladium(II) complexes, [ML^Ph] ( 3 ; L^Ph = N,N′‐phenylene‐bis(3‐formyl‐5‐tert.‐butyl‐salicylaldimine)), are described. These neutral mononuclear complexes react with metal(II) perchlorate and 1,3‐propylenediamine to form heterodinuclear, macrocyclic, cationic complexes of the type [MM′(L^Ph,3)]²⁺ ( 4 ; M = Ni, Cu, Pd; M′ = Co, Cu, Zn). The structures of the five new compounds [NiCo(L^Ph,3)](ClO₄)₂, [NiCu(L^Ph,3)](ClO₄)₂, [CuCu(L^Ph,3)](ClO₄)₂, [CuZn(L^Ph,3)](ClO₄)₂, and [PdCu(L^Ph,3)](ClO₄)₂ were determined by X‐ray diffraction.     

Different Types of Coordinated Urea Molecules in its Complexes with Rare‐Earth Iodides and Perchlorates

An earlier reported series of the [Ln(Ur)₄(H₂O)₄]I₃ (Ln = Y, La, Nd, Eu, Gd, Dy, Ho, Er; Ur = urea) complexes was completed with seven new compounds (Ln = Ce, Pr, Sm, Tb, Tm, Yb, Lu); one of them, [Ce(Ur)₄(H₂O)₄]I₃, was studied by X‐ray diffraction. The most striking feature of the [Ln(Ur)₄(H₂O)₄]I₃ structures is the presence of two types of coordinated urea molecules. There are two planar symmetric and two non‐planar asymmetric urea molecules. The Ln–O–C bond angles vary in the ranges 163.06–165.71° and 148.42–152.42° for symmetric and asymmetric urea ligands, respectively, correlating with the ionic mode of urea coordination. To elucidate the role of aqua ligands for the urea coordination mode, two water‐free perchlorate complexes, [La(Ur)₈](ClO₄)₃ · 2Ur and [La(Ur)₇(OClO₃)](ClO₄)₂ were synthesized and structurally characterized. In these complexes, all urea molecules are planar symmetric; however, both covalent and ionic types of urea coordination with the La–O–C bond angles varying in the 132.4–142.3° and 145.5–159.1° ranges, respectively can be observed.     

Cyclooctenyl complexes of palladium(II) with multidentate N-heterocycles

[Pd(cod)(cotl)]ClO₄ (cod = 1,5-cyclooctadiene, cotl = cyclooctenyl, C₈H₁₃ ^–) undergoes substitutions with multidentate N-heterocycles: 1,3-bis(benzimidazolyl)benzene (L¹), 1,3-bis(1-methylbenzimidazol-2-yl)benzene (L²), 2,6-bis(benzimidazolyl)pyridine (L³) and 2,6-bis(1-methylbenzimidazol-2-yl)pyridine (L⁴) to yield mono/binuclear complexes: [Pd(cotl)(L¹)(OClO₃)], [Pd(cotl)(L)]ClO₄ (L = L² or L³) and [Pd(cotl)₂(L⁴)](ClO₄)₂. Dihalobridged binuclear complexes [PdX(cotl)]₂ (X = Cl or Br) undergo halogen bridge cleavages with the multidentate N-heterocycles to form binuclear complexes of the type [PdX(cotl)₂L] (X = Cl or Br; L = L¹, L², L³ or L⁴). The complexes were characterized by elemental analyses, ¹H-, ¹³C-n.m.r., i.r., far-i.r. and FAB-mass spectral studies.     

Synthesis,Crystal Structures,and Properties of Copper(II), Zinc(II), and Cadmium(II) Coordination Polymers Based on 5‐Nitro‐isophthalate and 1,2‐(2‐Pyridyl)‐1,2,4‐triazole

Three coordination polymers, namely {[Cu(5‐nipa)(L²²)](H₂O)₂}_n ( 1 ), [Zn(5‐nipa)(L²²)(H₂O)]_n ( 2 ), and {[Cd₂(5‐nipa)₂(L²²)(H₂O)₃](H₂O)_3.6}_n ( 3 ), were prepared under similar synthetic method based on 1,2‐(2‐pyridyl)‐1,2,4‐triazole (L²²) and ancillary ligand 5‐nitro‐isophthalic acid (5‐H₂nipa) with Cu^II, Zn^II, and Cd^II perchlorate, respectively. All the complexes were characterized by IR spectroscopy, elemental analysis, and powder X‐ray diffraction (PXRD) patterns. Single‐crystal X‐ray diffraction indicates that complexes 1 and 2 show similar 1D chain structures, whereas complex 3 exhibits the 2D coordination network with hcb topology. The central metal atoms show distinct coordination arrangements ranging from distorted square‐pyramid for Cu^II in 1 , octahedron for Zn^II in 2 , to pentagonal‐bipyramid for Cd^II in 3 . The L²² ligand adopts the same (η³,μ₂) coordination fashion in complexes 1 – 3 , while the carboxyl groups of co‐ligand 5‐nipa^2– adopt monodentate fashion in 1 and 2 and bidentate chelating mode in 3 . These results indicate that the choice of metal ions exerts a significant influence on governing the target complexes. Furthermore, thermal stabilities of complexes 1 – 3 and photoluminescent properties of 2 and 3 were also studied in the solid state.     

Complexes of palladium(II) and platinum(II) with 2-hydrazinopyridine and 8-hydrazinoquinoline

The square planar complexes cis-[MCl₂(hypy)], cis-[MCl₂(hyqu)], [Pt(hypy)₂] [PtCl₄], [Pd(hypy)₂][ClO₄]₂ and [Pd(hyqu)₂][ClO₄]₂ (M = Pd or Pt, hypy = 2-hydrazinopyridine, hyqu = 8-hydrazinoquinoline), in which hypy and hyqu act as bidentate chelating ligands, have been prepared and characterized. Complexes containing hyqu do not appear to have been isolated previously.     

Two hetero-spin metal–radical complexes exhibiting strong antiferromagnetic interactions between the metal ions and nitroxide radicals

Two hetero-spin metal–radical complexes [Cu(NIT2Py)₂Cl] · ClO₄ · H₂O ( 1 ) and [Co(NIT2Py)₂(H₂O)(CH₃OH)] · (ClO₄)₂ ( 2 ) (NIT2Py = 2-(2′-pyridinyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), were synthesized and characterized structurally and magnetically. The two complexes crystallize in mononuclear structures where two radical ligands coordinate to the metal ion through the nitroxide oxygen atoms directly via the bidentate chelating mode. The magnetic measurements show that two complexes exhibit strong antiferromagnetic interactions between the metal ions and the nitroxide radicals.     

Solvothermal synthesis and crystal structures of two new copper(II) terephthalates

Two new copper(II) complexes, [Cu₂(bipy)₂(H₂O)₃(tp)(NO₃)](NO₃) · H₂O (1) and [Cu₂(bipy)₂(tp)₂(H₂O)] _n (2), (tp = terephthalato, bipy = 2,2-bipyridine), have been synthesized and their crystal structures determined by single-crystal X-ray diffraction methods. Complex (1) contains a non-coordinated nitrate anion and an asymmetric binuclear cation in which each copper ion has a distorted square pyramidal coordination geometry with the axial Cu—O distance elongated. The crystal structure of (2) features a zigzag 1D polymeric chain along the diagonal axis of the (0 0 1) plane. Tp adopts two types of coordination mode. In the first mode, both carboxylate groups are unidentate, as in complex (1). In addition to the first mode, the tp ligand in complex (2) also adopts the second coordination mode, in which one carboxylate group is unidentate and the other is bidentately chelating with a copper(II) ion. The magnetic properties of complex (2) have also been studied.     

Hydrogen-bonded networks based on manganese(II), nickel(II), copper(II) and zinc(II) complexes of N,N′-dimethylurea

A project related to the crystal engineering of hydrogen-bonded coordination complexes has been initiatied and some of our first results are presented here. The compounds [Mn(DMU)₆](ClO₄)₂ (1), [Ni(DMU)₆](ClO₄)₂ (2), [Cu(OClO₃)₂(DMU)₄] (3) and [Zn(DMU)₆](ClO₄)₂ (4) have all been prepared from the reaction of N,N-dimethylurea (DMU) and the appropriate hydrated metal perchlorate salt. Crystal structure determinations of the four compounds demonstrate the existence of [M(DMU)₆]²⁺ cations and ClO₄ ^– counterions in (1), (2) and (4), whereas in (3) monodentate coordination of the perchlorate groups leads to molecules. The [M(DMU)₆]²⁺ cations and ClO₄ ^– anions self-assemble to form a hydrogen-bonded one-dimensional (1D) architecture in (1) and different 2D hydrogen-bonded networks in (2) and (4). The hydrogen bonding functionalities on the molecules of (3) create a 2D structure. The complexes were also characterised by room-temperature effective magnetic moments and i.r. studies. The data are discussed in terms of the nature of bonding and the known structures.