Partial conversion of thio­amide into nitrile in a copper(II) complex of 2,6-di­acetyl­pyridine bis­(thio­semicarbazone), a drug prototype for Alzheimer's disease

This work reports the crystal structure of [(Z)-2-((E)-1-{6-[1-({[amino­(sul­fani­dyl-κS)methyl­idene]amino}­imino-κN)eth­yl]pyridin-2-yl-κN}ethyl­idene)-1-cyano­hydrazinido-κN¹]copper(II), [Cu(C₁₁H₁₁N₇S)], the first description of a copper(II) complex of 2,6-di­acetyl­pyridine bis­(thio­semicarbazone) showing partial conversion of a thio­amide group to a nitrile group. The asymmetric ligand coordinates to the metal centre in an N,N′,N′′,S-tetra­dentate manner via the pyridine N atom, an imine N atom, the hydrazinide N atom and the sul­fanidyl S atom, displaying a square-planar geometry. Ligand coordination results in two five-membered chelate rings and one six-membered chelate ring, and in crystal packing based on N—H...N hydrogen bonds of the cyano­hydrazinide and hydrazinecarbo­thio­amidate arms of the ligand. The correlation between the partial conversion upon metal complexation, H₂S release and possible effects on the activity of bis­(thio­semicarbazone)s as drug prototypes for Alzheimer's disease is also discussed.

Computing details

Data collection: APEX2 (Bruker, 2014); cell refinement: SAINT (Bruker, 2013); data reduction: SAINT (Bruker, 2013); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b) and Shelxle (Hübschle et al., 2011); molecular graphics: Mercury (Macrae et al., 2008) and POV-RAY (https://www.povray.org); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015b).

[(Z)-2-((E)-1-{6-[1-({[Amino(sulfanidyl-κS)methylidene]amino}imino-κN)ethyl]pyridin-2-yl-κN}ethylidene)-1-cyanohydrazinido-κN¹]copper(II)

Crystal data

[Cu(C11H11N7S)]	F(000) = 684
Mr = 336.87	Dx = 1.691 Mg m^−3
Monoclinic, P21/c	Cu Kα radiation, λ = 1.54178 Å
a = 7.2358 (1) Å	Cell parameters from 8522 reflections
b = 10.5895 (2) Å	θ = 4.2–68.7°
c = 17.2664 (3) Å	µ = 3.82 mm^−1
β = 90.6740 (11)°	T = 296 K
V = 1322.92 (4) Å^3	Plate, orange
Z = 4	0.16 × 0.16 × 0.06 mm

Data collection

Bruker APEXII CCD diffractometer	2153 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.036
φ and ω scans	θmax = 68.7°, θmin = 4.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −8→8
Tmin = 0.617, Tmax = 0.753	k = −12→12
16824 measured reflections	l = −20→20
2437 independent reflections

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.035	H-atom parameters constrained
wR(F^2) = 0.096	w = 1/[σ^2(Fo^2) + (0.0479P)^2 + 0.8241P] where P = (Fo^2 + 2Fc^2)/3
S = 1.09	(Δ/σ)max = 0.002
2437 reflections	Δρmax = 0.76 e Å^−3
183 parameters	Δρmin = −0.22 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cu1	0.21025 (5)	0.42580 (3)	0.54573 (2)	0.03932 (15)
S1	0.13271 (10)	0.28767 (6)	0.63790 (4)	0.04741 (19)
C1	0.2613 (4)	0.4392 (3)	0.38702 (16)	0.0479 (6)
N1	0.2750 (3)	0.5146 (2)	0.44956 (13)	0.0452 (5)
C6	0.2065 (4)	0.3072 (3)	0.40317 (15)	0.0497 (6)
C3	0.3423 (5)	0.6089 (4)	0.3045 (2)	0.0696 (9)
H3	0.3643	0.6415	0.2555	0.084*
N3	0.1117 (3)	0.1689 (2)	0.49791 (12)	0.0430 (5)
C8	0.0899 (3)	0.1646 (2)	0.57373 (14)	0.0398 (5)
N2	0.1706 (3)	0.28604 (19)	0.47503 (12)	0.0400 (5)
C2	0.2936 (4)	0.4840 (3)	0.31314 (19)	0.0633 (8)
H2	0.2826	0.4311	0.2703	0.076*
C7	0.1982 (7)	0.2100 (3)	0.34233 (18)	0.0844 (13)
H7A	0.0722	0.1980	0.3259	0.127*
H7B	0.2465	0.1320	0.3623	0.127*
H7C	0.2705	0.2366	0.2990	0.127*
N4	0.0319 (4)	0.0556 (2)	0.60451 (13)	0.0528 (6)
H4A	0.0103	−0.0084	0.5751	0.063*
H4B	0.0163	0.0496	0.6537	0.063*
C4	0.3582 (4)	0.6845 (3)	0.3677 (2)	0.0681 (10)
H4	0.3925	0.7686	0.3616	0.082*
N5	0.3066 (3)	0.6940 (2)	0.58342 (17)	0.0549 (6)
C5	0.3235 (3)	0.6374 (3)	0.44223 (18)	0.0510 (7)
N7	0.1961 (5)	0.5646 (3)	0.74737 (18)	0.0823 (10)
N6	0.2514 (3)	0.5739 (2)	0.60608 (15)	0.0519 (6)
C9	0.3378 (4)	0.7183 (3)	0.5114 (2)	0.0565 (8)
C10	0.3968 (5)	0.8552 (3)	0.4991 (2)	0.0756 (11)
H10A	0.5143	0.8571	0.4739	0.113*
H10B	0.4069	0.8969	0.5483	0.113*
H10C	0.3063	0.8976	0.4674	0.113*
C11	0.2233 (5)	0.5723 (3)	0.6824 (2)	0.0590 (8)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0371 (2)	0.0323 (2)	0.0486 (2)	−0.00366 (14)	0.00031 (15)	0.00392 (14)
S1	0.0596 (4)	0.0426 (4)	0.0401 (3)	−0.0136 (3)	0.0031 (3)	0.0001 (3)
C1	0.0430 (13)	0.0489 (15)	0.0516 (15)	−0.0044 (12)	−0.0027 (11)	0.0155 (12)
N1	0.0366 (10)	0.0411 (12)	0.0577 (13)	−0.0034 (9)	−0.0022 (9)	0.0167 (10)
C6	0.0570 (15)	0.0478 (15)	0.0441 (14)	−0.0077 (13)	−0.0019 (12)	0.0093 (12)
C3	0.0644 (19)	0.073 (2)	0.072 (2)	−0.0051 (17)	0.0085 (16)	0.0356 (19)
N3	0.0521 (12)	0.0346 (11)	0.0423 (11)	−0.0084 (10)	0.0005 (9)	0.0041 (9)
C8	0.0392 (12)	0.0381 (13)	0.0421 (13)	−0.0037 (11)	0.0013 (10)	0.0035 (10)
N2	0.0427 (11)	0.0347 (11)	0.0426 (11)	−0.0058 (9)	−0.0011 (8)	0.0063 (8)
C2	0.0628 (18)	0.069 (2)	0.0576 (17)	−0.0062 (16)	0.0030 (14)	0.0222 (16)
C7	0.146 (4)	0.066 (2)	0.0409 (16)	−0.032 (2)	0.0092 (19)	0.0001 (15)
N4	0.0752 (16)	0.0416 (12)	0.0417 (11)	−0.0169 (12)	0.0039 (11)	0.0049 (9)
C4	0.0509 (16)	0.0549 (19)	0.099 (3)	−0.0067 (15)	0.0026 (16)	0.0364 (19)
N5	0.0491 (13)	0.0316 (11)	0.0840 (18)	−0.0051 (10)	0.0007 (12)	0.0054 (11)
C5	0.0312 (11)	0.0425 (15)	0.0794 (19)	−0.0008 (11)	−0.0004 (11)	0.0223 (14)
N7	0.122 (3)	0.0545 (17)	0.071 (2)	−0.0129 (17)	0.0288 (18)	−0.0202 (14)
N6	0.0547 (13)	0.0339 (12)	0.0671 (15)	−0.0065 (10)	0.0057 (11)	−0.0019 (10)
C9	0.0376 (13)	0.0325 (14)	0.099 (2)	−0.0026 (11)	−0.0040 (14)	0.0109 (14)
C10	0.0625 (19)	0.0381 (17)	0.126 (3)	−0.0101 (15)	0.0008 (19)	0.0206 (18)
C11	0.0669 (19)	0.0369 (15)	0.074 (2)	−0.0051 (14)	0.0090 (16)	−0.0120 (14)

Geometric parameters (Å, º)

Cu1—N6	1.904 (2)	C2—H2	0.9300
Cu1—N2	1.938 (2)	C7—H7A	0.9600
Cu1—N1	1.970 (2)	C7—H7B	0.9600
Cu1—S1	2.2379 (7)	C7—H7C	0.9600
S1—C8	1.736 (3)	N4—H4A	0.8600
C1—N1	1.346 (4)	N4—H4B	0.8600
C1—C2	1.383 (4)	C4—C5	1.405 (4)
C1—C6	1.481 (4)	C4—H4	0.9300
N1—C5	1.353 (4)	N5—C9	1.293 (4)
C6—N2	1.290 (3)	N5—N6	1.391 (3)
C6—C7	1.472 (4)	C5—C9	1.472 (5)
C3—C4	1.357 (5)	N7—C11	1.144 (4)
C3—C2	1.378 (5)	N6—C11	1.336 (4)
C3—H3	0.9300	C9—C10	1.527 (4)
N3—C8	1.321 (3)	C10—H10A	0.9600
N3—N2	1.371 (3)	C10—H10B	0.9600
C8—N4	1.341 (3)	C10—H10C	0.9600
N6—Cu1—N2	174.13 (9)	C6—C7—H7A	109.5
N6—Cu1—N1	91.77 (10)	C6—C7—H7B	109.5
N2—Cu1—N1	82.45 (9)	H7A—C7—H7B	109.5
N6—Cu1—S1	100.83 (8)	C6—C7—H7C	109.5
N2—Cu1—S1	84.97 (6)	H7A—C7—H7C	109.5
N1—Cu1—S1	167.36 (8)	H7B—C7—H7C	109.5
C8—S1—Cu1	94.65 (8)	C8—N4—H4A	120.0
N1—C1—C2	121.7 (3)	C8—N4—H4B	120.0
N1—C1—C6	115.2 (2)	H4A—N4—H4B	120.0
C2—C1—C6	123.1 (3)	C3—C4—C5	120.8 (3)
C1—N1—C5	120.8 (2)	C3—C4—H4	119.6
C1—N1—Cu1	112.15 (18)	C5—C4—H4	119.6
C5—N1—Cu1	127.0 (2)	C9—N5—N6	120.4 (3)
N2—C6—C7	123.9 (3)	N1—C5—C4	118.4 (3)
N2—C6—C1	113.7 (2)	N1—C5—C9	119.9 (3)
C7—C6—C1	122.3 (3)	C4—C5—C9	121.6 (3)
C4—C3—C2	120.0 (3)	C11—N6—N5	109.6 (2)
C4—C3—H3	120.0	C11—N6—Cu1	120.34 (19)
C2—C3—H3	120.0	N5—N6—Cu1	130.0 (2)
C8—N3—N2	111.0 (2)	N5—C9—C5	130.8 (3)
N3—C8—N4	117.6 (2)	N5—C9—C10	112.0 (3)
N3—C8—S1	125.74 (19)	C5—C9—C10	117.2 (3)
N4—C8—S1	116.61 (19)	C9—C10—H10A	109.5
C6—N2—N3	120.1 (2)	C9—C10—H10B	109.5
C6—N2—Cu1	116.31 (18)	H10A—C10—H10B	109.5
N3—N2—Cu1	123.62 (16)	C9—C10—H10C	109.5
C3—C2—C1	118.3 (3)	H10A—C10—H10C	109.5
C3—C2—H2	120.8	H10B—C10—H10C	109.5
C1—C2—H2	120.8	N7—C11—N6	176.4 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N4—H4A···N3^i	0.86	2.29	3.133 (3)	168
N4—H4B···N7^ii	0.86	2.32	3.061 (4)	145

Symmetry codes: (i) −x, −y, −z+1; (ii) −x, y−1/2, −z+3/2.