INTRODUCTION. Tetraazamacrocyclic compounds I and II having two double bonds in the six-membered rings demonstrate high reactivity of the carbon atoms

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1 Journal of Structural Chemistry, Vol. 45, No. 6, pp , 2004 Original Russian Text Copyright 2004 by V. A. Afanasieva, I. V. Mironov, L. A. Glinskaya, R. F. Klevtsova, and L. A. Sheludyakova INVESTIGATION OF PROTONATION OF THE TETRAAZAMACROCYCLIC COMPLEX OF GOLD(III) [Au(C 14 H 22 N 4 )] + IN WATER. SYNTHESIS AND CRYSTAL AND MOLECULAR STRUCTURES OF [Au(C 14 H 23 N 4 )]( lo 4 ) 2 V. A. Afanasieva, I. V. Mironov, L. A. Glinskaya, R. F. Klevtsova, and L. A. Sheludyakova UDC The equilibrium of protonation of tetraazamacrocyclic complex of gold(iii) [AuL] + (L = 5,7,12,14- tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,13-tetraenato(2-)) in a water solution has been investigated. A monoprotonated tetraazamacrocyclic metallocomplex with two inequivalent (iminate and imine) six-membered chelate cycles and charge 1- was obtained and isolated for the first time. The compound [Au L]( lo 4 ) 2 was characterized by chemical analysis, IR and UV-VIS spectroscopy, powder and single crystal X-ray diffraction. The proton was shown to be attached to the -carbon of one of the two sixmembered chelate rings of the macrocycle. Crystal data for [Au L]( lo 4 ) 2 are: = 7.693(1) Å, b = (2) Å, c = (2) Å; = 96.82(1), V = (4) Å 3, Z =4, d calc = g/cm 3, space group P2 1 /c. The structure is built from practically planar [Au(C 14 H 23 N 4 )] 2+ cations and perchlorate anions [ClO 4 ]. Keywords: gold, tetraazamacrocyclic complexes, protonation, equilibrium, synthesis, crystal and molecular structure, UV-VIS spectra, IR spectra. INTRODUCTION Tetraazamacrocyclic compounds I and II having two double bonds in the six-membered rings demonstrate high reactivity of the carbon atoms in the -positions of the six-membered chelate rings resulting in facile electrophilic substitution and addition. The addition of the simplest electrophiles such as + to the central carbon atoms of the unsaturated six-membered rings of the macrocycle A. V. Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk; imir@che.nsk.su. Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp , November-December, Original article submitted September 5, /04/ Springer Science+Business Media, Inc.

2 causes the rearrangement of the multiple bonds; the complexes formed do not contain negatively charged iminate ligands but have neutral imine ones [1]. Bases promote the reverse process. The acidity of the -proton strongly depends on the nature of the central atom and only slightly on the size of the macrocycle. Both iminate and imine complexes of transition metals (Cu, Ni, Co, Fe) were isolated as solids and characterized by physical methods [2-6]. It should be noted that treatment of complexes II with mineral acids results in simultaneous addition of two protons in the -position of both six-membered rings [1, 5, 6]. Monoprotonated complexes having both diiminate and diimine sixmembered rings were not observed in solution nor as solids; in [6] it was suggested that there is an intermediate iron(ii) complex containing partially ionized singly charged negative ligands formed by an electrophilic attack of acetonitrile on the -carbon. The only known compound with a tetraazamacrocycle containing both delocalized diiminate (C N) and localized imine bonds (C=N) and having ligand charge 1 is a nickel(ii) complex reported in [7]. However, in this case the =N bonds belong to the five-membered (but not six-membered) chelate rings. We investigated [8] water solution protonation equilibrium involving 14-membered macrocyclic bis-diiminate complex 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,13-tetraenatogold(III), [Au(C 14 H 22 N 4 )] +, [AuL] +. It was shown that with + concentrations of up to 3 M the deprotonated ([AuL] + ) and monoprotonated ([AuHL] 2+ ) forms are present in the equilibrium. The present work studies the behavior of the [AuL] + complex in concentrated ( + >3 M) water solutions of acids (HClO 4, HCl); a tetraazamacrocyclic complex containing both delocalized bonds C N and localized C=N bonds in the six-membered rings is isolated for the first time. The complex was characterized by elemental analysis, IR and UV-VIS spectroscopy, powder and single crystal X-ray diffraction data. EXPERIMENTAL The acids HCl, HClO 4 were chemical grade. The solution containing the macrocyclic complex cation [AuL] + was obtained by condensation of the bis-ethylendiamine complex of gold(iii) [Au(en) 2 ] 3+ with acetylacetone according to [9]; the perchlorate salt [AuL]ClO 4 was obtained as described in [8]. The bis-perchlorate of monoprotonated tetraazamacrocyclic complex of gold(iii), 5,7,12,14-tetramethyl-1,4,8,11- tetraazacyclotetradeca-4,7-diene-11,13-dienatogold(iii) bis-perchlorate, [Au(C 14 H 23 N 4 )](ClO 4 ) 2, was obtained as follows. 0.8 ml of concentrated perchloric acid was added to 0.2 g of [AuL](ClO 4 ). Gradually the precipitate dissolved to give a brownish-green solution which shortly yielded large colorless crystals (the perchlorate of the diprotonated form of the complex; yield 10%-15%), the mother liquor slowly gaining light-orange color. The colorless crystals were separated from the mother liquor. After a few droplets of water had been added to the mother liquor it immediately turned bright-orange. Cooling of the solution to 0 C resulted in precipitation of orange crystals of the monoprotonated form. The crystals were filtered off and gently dried with a filter paper. Found, %: 25.8; 3.5; N 8.5; Cl For AuN 4 C 14 H 23 Cl 2 O 8 calculated, %: 26.14; 3.60; N 8.71; Cl Yield 40%. Solution processes were studied by spectrophotometry (Specord UV-VIS spectrophotometer). IR spectra were recorded with a Specord 75IR spectrophotometer in the range 3800 cm cm 1 ; the samples were prepared as suspensions in vaseline and fluorinated oil. Determination of C, H, N, Cl content was performed in the laboratory of microanalysis at Institute of Organic Chemistry SB RAS. 1015

3 Prismatic orange-colored transparent crystals were picked for an X-ray diffraction study. Experimental reflections were obtained from a single crystal mm in size. The intensities of 3333 independent nonzero reflections were collected with an Enraf-Nonius CAD-4 automated diffractometer (MoK radiation, graphite monochromator, /2 scanning, maximum 2 =50 ). An empirical absorption correction was applied using azimuthal scans, reflections 111, 222, 324, (MoK ) = cm 1. The crystals were attributed to the monoclinic crystal system with the following unit cell parameters: = 7.693(1) Å, b = (2) Å, c = (2) Å; = 96.82(1), V = (4) Å 3, Z =4, d calc = g/cm 3, space group P2 1 /c. The structure was solved by direct methods and refined in a full-matrix anisotropic approximation for the nonhydrogen atoms using the SHELX-97 package [10]. During refinement of the oxygen positions in the [Cl(2)O 4 ] perchlorate anion the O O distances were restrained (because of unstable refinement), resulting in large thermal parameters of these atoms, which can indicate possible disorder of this perchlorate anion. The positions of H atoms were set geometrically and the atoms were refined isotropically. The final R-factor value (H atoms included) for 2240 independent F(hkl) with I >2 (I ) equals (273 refined parameters) and R = for all 3106 F(hkl). Corresponding positional and equivalent isotropic thermal parameters of the independent atoms are reported in Table 1, selected bond lengths and angles in Table 2. The tables of positional parameters of hydrogen atoms, anisotropic thermal parameters as well as structure factors can be requested from the authors. TABLE 1. Positional ( 10 4 ) and Equivalent Isotropic Thermal Atomic Parameters (Å , U eq =1/3(U 11 + U 22 + U 33 )) in the Structure of [Au(C 14 H 23 N 4 )](ClO 4 ) 2 Atom x y z U eq Atom x y z U eq Au(1) 7383(1) 6(1) 1822(1) 36(1) C(10) 7158(12) 254(6) 3706(6) 41(2) N(1) 7777(9) 561(4) 727(4) 38(2) C(11) 7926(14) 723(6) 866(6) 59(3) N(2) 6946(10) 1007(4) 1260(5) 43(2) C(12) 6674(16) 1932(6) 53(6) 65(3) N(3) 6943(10) 548(4) 2925(4) 37(2) C(13) 8106(16) 1953(5) 3611(7) 63(3) N(4) 7759(10) 1034(4) 2399(5) 40(2) C(14) 6766(14) 695(6) 4503(6) 57(3) C(1) 7730(17) 1658(6) 1712(7) 60(3) Cl(1) 11332(3) 1395(1) 3711(2) 52(1) C(2) 8359(17) 1362(6) 894(7) 59(3) O(1) 11369(13) 1433(5) 2757(5) 90(3) C(3) 6171(14) 1315(5) 2721(6) 50(2) O(2) 11027(11) 620(4) 3972(5) 79(2) C(4) 6903(15) 1625(6) 1916(6) 50(3) O(3) 9983(10) 1881(4) 3956(5) 78(2) C(5) 7600(13) 234(6) 68(6) 45(2) O(4) 12949(10) 1674(5) 4158(5) 81(3) C(6) 7185(13) 542(6) 213(6) 51(3) Cl(2) 3062(4) 1183(2) 2858(2) 61(1) C(7) 6950(13) 1127(6) 378(6) 46(2) O(5) 3627(15) 1713(5) 2221(5) 108(3) C(8) 7899(12) 1158(6) 3217(6) 46(2) O(6) 3861(15) 446(6) 2729(10) 206(8) C(9) 7870(14) 533(5) 3887(6) 51(3) O(7) 3770(20) 1450(8) 3707(4) 347(16) O(8) 1282(8) 1120(9) 2767(13) 450(20) TABLE 2. Selected Bond Lengths d, Å and Angles, deg for [Au(C 14 H 23 N 4 )](ClO 4 ) 2 Bond d Bond d Bond d Bond d Au(1) N(2) 1.967(7) N(2) C(4) 1.47(1) C(5) C(6) 1.40(1) Cl(1) O(3) 1.420(8) Au(1) N(1) 1.975(6) N(3) C(10) 1.28(1) C(5) C(11) 1.52(1) Cl(1) O(2) 1.431(7) Au(1) N(4) 1.993(7) N(3) C(3) 1.48(1) C(6) C(7) 1.38(1) Cl(1) O(1) 1.452(8) Au(1) N(3) 1.994(6) N(4) C(8) 1.25(1) C(7) C(12) 1.49(1) Cl(1) O(4) 1.429(8) N(1) C(5) 1.33(1) N(4) C(1) 1.50(1) C(8) C(9) 1.49(1) Cl(2) O(8) 1.364(6) N(1) C(2) 1.47(1) C(1) C(2) 1.48(1) C(8) C(13) 1.50(1) Cl(2) O(6) 1.443(9) N(2) C(7) 1.35(1) C(3) C(4) 1.50(1) C(9) C(10) 1.49(1) Cl(2) O(5) 1.439(8) C(10) C(14) 1.49(1) Cl(2) O(7) 1.415(5) 1016

4 TABLE 2 (Continued) Angle, deg Angle, deg Angle, deg N(2) Au(1) N(1) 96.1(3) C(8) N(4) Au(1) 125.5(7) C(8) C(9) C(10) 125.5(8) N(2) Au(1) N(4) 178.5(3) C(1) N(4) Au(1) 110.6(6) N(3) C(10) C(14) 122.0(9) N(1) Au(1) N(4) 84.5(3) C(2) C(1) N(4) 110.6(8) N(3) C(10) C(9) 122.7(8) N(2) Au(1) N(3) 84.0(3) N(1) C(2) C(1) 110.5(8) C(14) C(10) C(9) 115.3(8) N(1) Au(1) N(3) 179.0(3) N(3) C(3) C(4) 108.3(8) O(3) Cl(1) O(2) 109.7(5) N(4) Au(1) N(3) 95.4(3) N(2) C(4) C(3) 109.3(8) O(3) Cl(1) O(1) 109.6(5) C(5) N(1) C(2) 123.8(7) N(1) C(5) C(6) 123.6(8) O(2) Cl(1) O(1) 110.0(5) C(5) N(1) Au(1) 123.2(6) N(1) C(5) C(11) 118.4(9) O(3) Cl(1) O(4) 107.2(5) C(2) N(1) Au(1) 112.9(5) C(6) C(5) C(11) 118.0(8) O(2) Cl(1) O(4) 110.5(5) C(7) N(2) C(4) 124.1(8) C(7) C(6) C(5) 130.8(9) O(1) Cl(1) O(4) 109.7(6) C(7) N(2) Au(1) 123.1(6) N(2) C(7) C(6) 122.9(9) O(8) Cl(2) O(6) 110.7(6) C(4) N(2) Au(1) 112.1(6) N(2) C(7) C(12) 117.0(8) O(8) Cl(2) O(5) 111.3(9) C(10) N(3) C(3) 123.8(8) C(6) C(7) C(12) 120.0(8) O(6) Cl(2) O(5) 108.0(7) C(10) N(3) Au(1) 124.6(6) N(4) C(8) C(9) 123.0(9) O(8) Cl(2) O(7) 113.0(6) C(3) N(3) Au(1) 111.3(5) N(4) C(8) C(13) 123.0(9) O(6) Cl(2) O(7) 106.9(5) C(8) N(4) C(1) 123.8(8) C(9) C(8) C(13) 114.1(8) O(5) Cl(2) O(7) 106.7(6) RESULTS AND DISCUSSION Solution equilibrium. A water solution of the tetraazamacrocyclic complex [AuL] + has three absorption bands in its electronic spectra (Table 3). The spectra of acidic (0.01 M < + < 3 M) solutions (H l, H 2 SO 4 ) on acidification demonstrate a hypsochromic shift of the band at 27,200 cm 1 accompanied by shape distortion and substantial decrease of absorption above 33,000 cm 1, isobestic point being at 28,500 cm 1. The spectra of solutions containing more than 3 M hydrogen ions have only one absorption band at 29,200 cm 1. These evolutions were shown to originate from normal protonation of [AuL] + [8 ]: [AuL] + + = [AuHL] 2+. (1) The protonation constant (1) is logk = (I = 1 mol/l, NaCl, HCl), i.e., the [AuHL] 2+ complex is not a weak acid and can be obtained only in rather acidic solutions. Naturally, the second step protonation requires even higher acidity. Further acidification results in a decreased absorption band of the monoprotonated form [AuHL] 2+ (29,200 cm 1 ) until its disappearance in concentrated (9 M) perchloric acid (Fig. 1); concentrated hydrochloric acid (12 M) does not bleach the band completely. We believe that in water media at high acid concentration ( + > 3 M) the monoprotonated complex [Au L] 2+ undergoes further protonation to form the diprotonated form which does not absorb in the (40-25) 10 3 cm 1 range: 2 [AuHL] + + =[AuH 2 L] 3+. (2) It is known [1] that protonation of iminate tetraazamacrocyclic complexes of transition metals results in migration of multiple bonds and formation of =N double bonds. The bleaching observed by us in strongly acidic solutions originates from complete vanishing of conjugation of double bonds in the six-membered fragments of the [AuH 2 L] 3+ macrocycle upon addition of two protons to the -carbon atoms. Naturally, at such high concentrations the equilibrium constant (2) must strongly depend on the ionic strength and electrolyte type (acid type). The dependence of the equilibrium constant (2), derived as K 2 =(D 0 D)/(D D )[H + ], on C HClO4 is shown in Fig. 2. Almost linear dependence of logk 2 on acid concentration is in accord with known behavior of equilibrium constants at high ionic strength. In perchloric acid the monoprotonated form dominates ([AuHL]/[AuH 2 L] > 1) in the concentration range 0.5 M-7 M; the diprotonated form dominates at 7 M-9 M. At 1017

5 TABLE 3. Characteristics of the Main Absorption Bands in the Electronic Spectra of [AuL] + and [AuHL] 2+ Complexes in Water Complex max 10 3, cm 1 max, l mol 1 cm 1 [AuL] sh 5800 [Au L] 2+ * *HCl or H 2 SO 4 (C H + = 3 M). Fig. 1. Spectra of [AuL](ClO 4 ) solutions at different concentrations of perchloric acid. Au = M, HClO 4 : 1 4.1; 2 5.5; 3 6.2; 4 6.6; 5 6.9; 6 7.3; 7 7.6; M, l = 1 cm. Fig. 2. Dependence of the equilibrium constant of the process (2) on HClO 4 the same time in hydrochloric acid, even concentrated, the diprotonated form never dominates indicating that the protonation constant K 2 in perchloric acid is much larger than in hydrochloric. The process (2) is reversible: on dilution with water the colorless solution of the complex in concentrated perchloric 1018

6 acid turns yellow and the electronic spectrum demonstrates the appearance and growth (until M) of the absorption band at 29,200 cm 1. Further dilution results in a decrease of the band at 29,200 cm 1 and appearance of a shoulder at 27,200 cm 1 : this range of hydrogen ion concentrations corresponds to equilibrium (1). Synthesis. The synthesis of the protonated forms of the [AuL] + complex resides on the results of the spectrophotometry studies of protonation in water media. On dissolution of [AuL](ClO 4 ) in concentrated perchloric acid the equilibrium (2) takes over, the dominating form being [AuH 2 L] 3+ which does not absorb within (40-25) 10 3 cm 1 (weak orange color of the solution indicates the presence of a small concentration of the monoprotonated form [AuHL] 2+ ). The large colorless crystals which precipitate from the solution are the perchlorate of the diprotonated form [AuH 2 L](ClO 4 ) 3 (the results of the structural study of this complex are to be published elsewhere). After addition of a few droplets of water to the mother liquor, the hydrogen ion concentration diminishes, shifting the equilibrium (2) to the left (the solution color changes from light-orange to deep-orange) and crystallization of orange crystals of the monoprotonated complex [AuHL](ClO 4 ) 2 occurs (on cooling). Properties. The monoprotonated complex [AuHL](ClO 4 ) 2 is stable in air in a closed vessel at least for four months. The diprotonated complex [AuH 2 L](ClO 4 ) 3 is explosive and degrades in air, the crystals turning orange. When exposed to air, the heterogeneous mixture of the colorless crystals of the diprotonated complex and the mother liquor undergoes orange coloring of both the crystals and the liquor: on absorption of atmospheric moisture the equilibrium (2) shifts backwards and the monoprotonated complex [AuHL](ClO 4 ) 2 crystallizes. On dissolution in water both complexes immediately undergo deprotonation to give sparingly soluble yellow precipitate of [AuL](ClO 4 ) which is easy to identify by chemical analysis, IR and UV-vis spectroscopy. The IR spectrum of the monoprotonated complex [AuHL](ClO 4 ) 2 in general resembles the spectrum of the deprotonated complex [AuL](ClO 4 ): the bands at 470 cm 1 and 430 cm 1 in the ligand-metal vibration area are attributed to the Au N vibrations [11], the bands at 1550 cm 1 and 1525 cm 1 correspond to N bonds, and ( H) are observed at 3000 cm cm 1, the absorption bands of the outer sphere anions [ClO 4 ] are observed at 1105, 1080 ( 3 ) cm 1, and 620 ( 4 ) cm 1. The IR spectrum of [AuHL](ClO 4 ) 2 reveals, as compared to that of [AuL](ClO 4 ), along with the vibrations of the delocalized N bond, a sharp band of the localized double bond =N (1680 cm 1 ) indicating the imine-iminate nature of the structure. The splitting of the 3 (ClO 4 ) observed in the spectrum, apparently, is due to hydrogen bonding in the structure. Structure of [AuHL](ClO 4 ) 2. The stereochemistry of the monoprotonated complex [AuHL](ClO 4 ) 2 was investigated by single crystal X-ray diffraction. The results of the structural investigation entirely support the conclusions derived from the studies on protonation of [AuL] + in water solutions and analytical and IR spectroscopy data obtained for the solid. The structure of the [AuHL](ClO 4 ) 2 complex is formed by [Au(C 14 H 23 N 4 )] 2+ complex cation and two crystallographically independent perchlorate ions [ClO 4 ]. The structure of the cation is given in Fig. 3; all the atoms occupy general positions. The cation contains two five-membered and two six-membered rings (A and B). Four carbons of the sixmembered rings (5), (7), (8), (10) are connected to four methyl groups, while (6) and (9) atoms are connected to one and two hydrogen atoms correspondingly. In general the [AuHL] 2+ macrocycle can be considered as practically planar, mean deviation of atoms from the rms plane being Å. Four nitrogen atoms of the macrocyclic ligand make vertices of a planar square centered with the gold atom. The largest deviation of the atoms from the AuN 4 rms square is Å for the gold atom. Average bond lengths Au N for the and rings are Å and Å, respectively, i.e., the square is slightly distorted, the angles N(1)Au(1)N(2), N(3)Au(1)N(4) are equal to 96.1(3) and 95.4(3), the angles N(1)Au(1)N(4), N(2)Au(1)N(3) are equal to 84.5(3) and 84.0(3). The six-membered -diiminate ring is practically planar; the protonated ring has a conformation close to 1019

7 Fig. 3. Structure of acentric complex cation [Au(C 14 H 23 N 4 )] 2+ including atomic labeling. Unlabeled circles hydrogen atoms. distorted boat, dihedral angles made by N(3)N(4)C(8)C(10) plane to (8) (9) (10) and N(3)N(4)Au(1) planes being equal to 16.8 and 7.3, respectively. The largest deviation of atoms from the rms planes of the and rings is Å for (9) and Å for (6). The C C and C N distances in the six-membered rings reveal significant variation. So, in the ring the N C and C C distances are 1.33(1) Å, 1.35(1) Å and 1.40(1) Å, 1.38(1) Å typical for delocalized N C and C C bonds. Average N C and C C bond lengths (1.265 Å and Å) of ring protonated at the -carbon (9) indicate localization of electrons resulting in the formation of the -diimine bonds. In the protonated ring the angle at the vertex carbon is 5.3 smaller than in the deprotonated ring. The five-membered rings have usual gauche-conformation typical for complexes involving ethylendiamine bridges [12]. In the metallocycle Au(1)N(1)C(2)C(1)N(4) atoms (1) and (2) deviate from the AuN 4 plane by Å and Å, in the other ring Au(1)N(2)C(4)C(3)N(3) the deviations of (3) and (4) are Å and Å indicating almost similar conformation of both rings. Both perchlorate anions with Cl(1) and Cl(2) as the central atoms are tetrahedral. The Cl(1) O distances vary within 1.420(8) Å-1.429(8) Å; the Cl(2) O ones, within 1.364(6) Å-1.415(5) Å. The packing of the complex down the b axis is given in Fig. 4, clearly illustrating the isolated cations and anions. The six-membered ring of the macrocyclic cation and the perchlorate anions make short contacts: N(4) O(8) = 2.706(9) Å, C(8) O(8) = 2.77(1) Å, N(3) O(6) = 2.92(1) Å, C(1) O(8) = 3.14(1) Å, C(1) O(4) = 3.20(1) Å. It is noteworthy that the central carbon atom (9) of the diimine ring is bound by weak hydrogen bonds (3.14(1) Å and 3.26(1) Å) to O(2) oxygen of the l(1) perchlorate anion, while the shortest contact (6) O(5) is equal to 3.65(1) Å. Comparison of the structures of the deprotonated and the monoprotonated complexes [AuL](ClO 4 ) and [AuHL](ClO 4 ) 2 revealed that, in general, the structural features of both complexes are similar: in each of them the ligand is planar; the bond lengths and angles of the six-membered diiminate ring and the five-membered chelate rings of the [AuHL] 2+ macrocycle are in accord to that found [13] in the starting deprotonated complex [AuL] + which contains two delocalized diiminate rings. The specific feature of the structure of the protonated complex is inequivalence of the sixmembered rings of the ligand. In particular, a) the neutral diimine ring has localized double bounds =N, possesses a distorted boat conformation with bending angles 16.8 and 7.3 at (8) (10) and N(3) N(4) lines while the diiminate ring is planar, it is negatively charged, and it has delocalized bonds N and C C; b) the distances Au N in the diiminate ring are somewhat shorter (by 0.03 Å) than the distances in the diimine ring, and substantially shorter than in systems with 1020

8 Fig. 4. Projection of the [Au(C 14 H 23 N 4 )](ClO 4 ) 2 structure onto (010) plane. Dashed lines denote the shortest cation-anion contacts. saturated six-membered rings [14] (2.02 Å-2.08 Å), which can be the result of nonsaturation; c) the vertex angle (8) (9) (10) of the six-membered diimine ring involving the localized bonds C = N is 5.3 smaller than that of the diiminate ring but strongly deviates (by 15 ) from the theoretical sp 3 -value (109.4 ). REFERENCES 1. K. B. Yatzimirskii, A. G. Kolchinskii, V. V. Pavlischuk, V. V. Talanova, and G. G. Talanova, Synthesis of Macrocyclic Compounds [in Russian], Naukova Dumka, Kiev (1987). 2. S. C. Cummings and R. E. Sievers, J. Am. Chem. Soc., 92, No. 1, (1970). 3. W. H. Elfring and N. J. Rose, Inorg. Chem., 14, No. 11, (1975). 4. G. W. Roberts, S. C. Cummings, and J. A. Cunningham, ibid., 15, No. 10, (1976). 5. C. J. Hipp and D. H. Busch, J. Chem. Soc. Chem. Comm., 737/738 (1972). 6. D. P. Riley, J. A. Stone, and D. H. Busch, J. Am. Chem. Soc., 99, No. 3, (1977). 7. J. J. Wilker, A. Gelasco, M. A. Pressler, et al., ibid., 113, No. 16, 6342/6343 (1991). 8. V. A. Afanasieva and I. V. Mironov, Koordinats. Khim., 27, No. 12, (2001). 9. J.-H. Kim and G. W. Everett, Inorg. Chem., 18, No. 11, 3145 (1979). 10. G. M. Sheldrick, SHELX-97, Rel. 97-2, Univ. Göttingen, Germany (1998). 11. R. Puddephatt, Chemistry of Gold [Russian translation], Mir, Moscow (1982). 12. V. A. Afanasieva, I. A. Baidina, I. V. Mironov, et al., Zh. Strukt. Khim., 41, No. 5, (2000). 13. L. A. Glinskaya, V. A. Afanasieva, and R. F. Klevtzova, ibid., 45, No. 1, (2004). 14. M. Rossignoli, P. V. Bernhardt, G. A. Lawrance, and M. Maeder, J. Chem. Soc. Dalton Trans., No. 2, (1997). 1021