Markku R. Sundberg

Comparison of the structural parameters in copper(II) acetate-type dimers containing distorted square pyramidal CuO4O and CuO4N chromophores

Abstract A survey of 123 of copper(II) acetate-type dimeric complex units, determined by X-ray diffraction in the crystal structures containing either a CuO 4 O or CuO 4 N chromophore, gave the following results. All the distorted square pyramidal coordination spheres contain a copper atom displaced 0.165–0.225 and 0.184–0.322 A from the basal O 4 plane in CuO 4 O and CuO 4 N chromophores, respectively. The Cu-Cu distances were in the range of 2.575–2.702 and 2.603–2.886 A for the CuO 4 O and CuO 4 N chromophores, respectively. The apical ligand atoms show large coefficients of variation for the distortion from the perpendicular to the basal O 4 plane. There is highly significant propensity for the copper(II) atoms to move out from the basal O 4 plane upon elongation of the Cu-Cu distance. Strong negative correlations were found between the CuOC and OCO angles. The most marked deviations for the observed parameters are caused by the bridges containing a halogenoacetate anion, leading to distorted trigonal bipyramidal geometry.

Copper(II) salicylideneglycinate complexes as potential antimicrobial agents

Abstract The reaction of an ethanolic solutions of N-salicylideneglycinatoaquacopper(II) hemihydrate with urea, pyridine, 2,4-dimethylpyridine, 3,5-dimethylpyridine, quinoline, 4-methylquinoline, isoquinoline, or 3-methylisoquinoline in an equimolar ratio resulted in solid products containing complexes of the type Cu(salgly)L with distorted square pyramidal coordination polyhedra. The products were characterized by elemental analysis, electronic and EPR spectra, and magnetic susceptibility measurements. Moreover, the crystal and molecular structure of N-salicylideneglycinatoureacopper(II) dimer was determined by single crystal X-ray diffraction methods. The copper(II) atoms are bridged by two phenolic oxygen atoms with a CuCu distance of 3.1093(11) A and CuOCu angle of 94.47(12)°. The antimicrobial effects have been tested on various strains of bacteria, yeasts and filamentous fungi.

Chemical structures from the analysis of domain-averaged fermi holes. Nature of the Mn-Mn bond in bis(pentacarbonylmanganese).

Because of conflicting and contradictory classification based on traditional AIM characteristics, the nature of the MnMn bond has been and still is the subject of continuing discussions. To overcome the existing inconsistencies in the interpretation of the nature of this bond, the bonding in Mn2(CO)10 has been analyzed and discussed in terms of new recently proposed methodology known as the analysis of domain‐averaged Fermi holes. It has been shown that this analysis is able to reconcile the conflicting conclusions of earlier AIM‐based studies with traditional anticipations based on simple electron counting rules. According to Fermi hole analysis, the MnMn bond has the character of the more or less ordinary covalent single σ bond, but the analysis also brings clear evidence in favor of Mn · · · (CO) intramolecular interactions between the metal atom and the ligands bonded to the other metal atom. These interactions could be responsible for the observed decrease of electron density at the bond critical point detected in AIM studies.

Conformational flexibility of the di(1,3-diaminopropane)copper(II) cation Part 3. Structure determination for trans-diaquabis(1,3-diaminopropane-N,N′)copper(II)trans-di(ortho-phthalato-O)bis(1,3-diaminopropane-N,N′)cuprate(II) monohydrate and DFT calculations for the trans-diaquabis(1,3-diaminopropane-N,N′)copper(II) cation2

Abstract The structure of trans-diaquabis(1,3-diaminopropane-N,N′)copper(II)trans-di(ortho-phthalato-O)bis(1,3-diaminopropane-N,N′)-cuprate(II) dihydrate was determined by single crystal X-ray diffraction methods. The compound crystallises in the triclinic system, space group P 1 (No. 2) with a = 7.233(2), b = 10.187(2), c = 12.905(2) A , α = 81.70(2), β = 82.08(2) and γ = 81.03(2)°, and V = 922.8(3) A 3 . The structure consists of cationic and anionic monomeric coordination units and a crystal water molecule. Both of the coordination units contain a centrosymmetric [Cu(tn)2]2γ moiety (tn = 1,3-diaminopropane). In the cationic unit the axial sites are occupied by water molecules, whereas in the anionic unit there are doubly deprotonated ortho-phthalate anions in the axial positions. The respective CuO bond lengths are quite long, 2.618(2) and 2.622(2) A. The six-membered chelate rings formed by the CuII ion and in display a chair conformation. In the anionic complex unit the rings are less puckered. The geometry of the cationic species was optimised by DFT methods and it was found to be more stable than a five-coordinated species with a non-coordinated water by 77.4 kJ mol−1.

Effect of hydrogen bonding on coordination in trans-di(Z-animobenzoato-O)di(1,3-diaminopropane-N,N′)copper(II) (Z = 2, 3 or 4) complex units

Abstract The crystal structures of the series of compounds containing the di(Z-aminobenzoato-O)di(1,3-diaminopropane-N,N′)copper(II) (Z = 2, 3 or 4) coordination units were determined by single-crystal X-ray methods. In the ortho- and meta-aminobenzoate analogues the structures are composed of monomeric complex units, where a copper(II) cation is located at a centre of symmetry and the chelate rings display a chair conformation. The benzoate anions in the axial positions are coordinated via one oxygen only. In the para-aminobenzoate analogue the complex units are similar, but there are two additional crystal water molecules in the asymmetric unit. The main differences between the three coordination units are seen in the bite angle of a chelate ring and the declination value of a benzoate anion. The differences are likely due to variation in the participation of an amine group of a chelate ring and a carboxylate group of a benzoate anion to form a hydrogen bonding network. Intramolecular hydrogen bonding seems to be correlated with inclination of a benzoate anion. Small inclination and absolute declination values for a benzoate anion seem to be related with bifurcated intramolecular hydrogen bonding and narrowing of a bite angle NCuN. The hydrogen bonding to the coordinated oxygen atom changes its hybridisation from approximate sp2 towards sp4. The existence of hydrogen bonding is supported by IR spectra. The crystallographic data are as follows (tn: 1,3-diaminopropane: bzO: a benzoate anion): [Cutn2(2NH2b/O)2], C20H42CuN6O4, monoclinic, space group P24/a No. 14, a = 10.513(2), b = 9.1789(12), c = 12.126(2) A , β = 99.82(2)° , V = 1153.0(4) A 1 : [Cutn2(3NH2bzO)2], C20H2CuN6O4, monoclinic, space group P21/n No. 14, a = 6.7128(12), b = 16.503(4), c = 10.268(2) A , β = 92.022(15)°, V = 1136.8(1) A : [Cutn2(4NH2bzO)2] · 2H2O, C20H30CuN40O6, monoclinic, space group P2/n No. 14, a = 9.484(2), b = 8.938(2), c = 16.30(3) A , β = 103.910(14)°, V = 1334.6(5) A 1 .

Unexpected five-coordination in di(1,3-diaminopropane)-3,5-dinitrobenzoatocopper(II) 3,5-dinitrobenzoate. Comparison between the coordinated and non-coordinated anions

Abstract The crystal and molecular structure of di(1,3-diaminopropane)-3,5-dinitrobenzoatocopper(II) 3,5-dinitrobenzoate (C 13 H 23 CuN 6 O 6 ) + (C 7 H 3 N 2 O 6 ) − was determined by single crystal X-ray methods. The compound crystallizes in the monoclinic system, space group P 2 1 / c , a =19.378(9), b =6.358(2), c =22.549(9) A, β=107.48(3)°, Z =4, D c =1.59, D m =1.60(1) g/cm 3 . The final R value for 2746 reflections was 0.037 ( R w =0.035, 1/σ 2 weights). Only one of the two 3,5-dinitrobenzoate anions is coordinated via one carboxylate oxygen with the bond length of 2.252(3) A. Thus the coordination around the central Cu II ion is 4 + 1 and the site symmetry approximately C 2v . The coordination mode 4+1 is the first reported among the series consisting of variously substituted benzoates and bis(1,3- diaminopropane)copper(II) cations. The non-coordinated 3,5-dinitrobenzoate anion is bonded by hydrogen bonds to the neighbouring amines. The v as (CO 2 ) vibrations for both anions appear at about 1609 cm −1 , whereas the v s (CO 2 ) is seen at 1335 and 1527 cm −1 for the coordinated and non-coordinated anions, respectively. Ab initio calculations with the 3-21G* basis set for 3,5-dinitrobenzoic acid and its anion reveal elongation of the bond between the carboxylate group and aromatic ring upon deprotonation of the acid. The complexation of the anion does not cause any clear difference in the bond length. The charge densities obtained by the STO-3G* basis set show that the oxygen coordinated to the copper(II) cation carries more negative charge than the non- coordinated oxygen. In the non-coordinated anion the charge densities are more evenly distributed.

Structure of the first polymeric catena-µ-tris[oxalato(2–)-O1,O2;O3,O4]-dicopper complex with interlocked helical chains

Oxidation of a mixture of copper(II), vitamin C and 2-diethylaminoethanol in the presence of H2O2 yielded a polymeric catena-µ-tris(oxalato)-copper(II) compound with the CuII ion surrounded by six oxygen atoms of three oxalate ions, each one starting a helical chain.

A new class of oxazaborolidine derivatives discovered. Ketones and aldehydes as bidentate ligands

Abstract Novel adducts ( 5′a-f ) of H 2 CO Me 2 CO and H 2 BOR (R = H, Me) to aminoborane ( 1′a ), aminohydroxy-borane ( 1′b ) and 1,3,2-oxazaborolidine ( 1′c ) were studied by means of ab initio MO (RHF) methods. Energies of the formation of the adducts were clearly exothermic [e.g. −140 and −134 kJ mol −1 (MP2/6–31G∗MP2/6–31G∗) in the case of H 2 CO - H 2 BOH adduct of 1′a and 1′c ]. All the Me 2 CO adducts were found to be slightly less stable than the corresponding H 2 CO adducts. In all the adducts ( 5′a-f ) studied the carbonyl system was found to behave as a bidentate ligand. All the bidentate adducts were found to be significantly more stable than the related monodentate adducts ( 4′a-c ). Activation of the carbonyl moiety of the bidentate adducts resembles that of the related adducts of N -sulfonylated oxazaborolidines ( 7 ).

Spectroscopic, magnetic and structural characterization of bis(dimethyl sulfoxide) tetrakis(μ-2-nitrobenzoato-O,O' dicopper (II)

Abstract The title compound, Cu2(2-NO2C6H4COO)4(DMSO)2, crystallizes in the monoclinic space group P21/n, with a=10.621(4), b=10.480(3), c=17.5 67(10) A, β=96.15(8)°. Single crystal X-ray data of 2534 independent reflections converged to a conventional R factor of 0.043. The complex has dimeric structure (copper acetate type), in which two copper(II) atoms are separated by 2.702(1) A and bridged by four bidentate carboxylate groups with CuO (average) distance of 1.984(3) A. The apical CuO bond to the DMSO molecule is 2.167(3) A. There is a centre of symmetry at the middle of the CuCu bond. Fitting of the modified Bleaney-Bowers equation to the magnetic susceptibility data yielded a singlet-triplet separation of 2J = −334 cm−1. The main properties of IR, EPR and electronic spectra at room temperature and the magnetic properties down to 4.2 K are reported.

Structure and bonding in binuclear metal carbonyls from the analysis of domain averaged Fermi holes. 2. Fe2(CO)8 2- and Fe2(CO)8

The nature of the bonding interactions in individual isomeric structures of the above carbonyls was studied using the analysis of domain averaged Fermi holes (DAFH). The main focus was directed on the confrontation of the picture of the bonding resulting from this analysis with the predictions of empirical 18-electron rule. This rule assumes, namely, the presence of direct metal-metal bond(s) for both carbonyls, but the detailed insights provided by the DAFH analysis show that the straightforward association of metal-metal bond with the favorable electron count only is too simplistic, and provided the actual structure of individual isomeric species is not taken into account, the predictions of this rule may fail. This is, e.g., the case of the C(2v) isomer of the carbonylate anion [Fe2(CO)8](2-) where the DAFH analysis denies the existence of direct metal-metal bond similarly as in the case the isoelectronic Co2(CO)8. Similar discrepancies between the predictions of the 18-electron rule and DAFH analysis were found also in the case of the C(2v) isomer of the neutral Fe2(CO)8 carbonyl, where the DAFH analysis detects the presence of a single bent Fe-Fe bond rather than the double bond anticipated by the 18-electron rule.