Search

The title structure consists of [Ni(CN)4]2– square-planar anions separated by layers of (C10H10N3)+ cations. The crystal packing features N—H⋯N hydrogen bonds, which generate [101] chains., In the title mol­ecular salt, (C10H10N3)2[Ni(CN)4], the dihedral angle between the pyridine rings in the cation is 1.92 (13)° and the complete anion is generated by a crystallographic centre of symmetry. An intra­molecular N—H⋯N hydrogen bond occurs in the cation, which closes an S(6) ring. In the crystal, the components are linked by N—H⋯N and weak C—H⋯N hydrogen bonds, which generate chains propagating in the [101] direction. Weak aromatic π–π stacking inter­actions are also observed. A Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the most important contact types in the crystal packing are N⋯H/H⋯N, C⋯H/H⋯C and H⋯H with contributions of 37.2, 28.3 and 21.9%, respectively.

Two new complexes [Cu(bcen)Ni(CN) 4 ] 2 ( 1 ) and [Ni(bcen)Ni(CN) 4 ] ( 2 ) where bcen is 4,7-diazadecanediamide, were synthesized by reaction of equimolar amounts of M(NO 3 ) 2 (M = Cu and Ni), bcen ligand and K 2 [Ni(CN) 4 ]. Single-crystal X-ray diffraction analysis of compound 1 , shows that the bcen ligand acts as a tridentate chelate, coordinating to the Cu(II) ion via the two nitrogen atoms of the amine groups and one oxygen atom of one amide group, and the other amide unit is left uncoordinated. The coordination geometry around the Cu(II) ions is five coordinate with a distorted square pyramid geometry, comprising two nitrogen atoms and one oxygen atom belonging to the bcen ligand and two nitrogen atoms of the cyano groups of two Ni(CN) 4 2– units. The distance between the copper ion and the amide oxygen of the dangling arm of an adjacent tetranuclear species is within the expected range for an axial Cu–O bond, and hence suggests that the amide oxygen of an adjacent tetranuclear complex may weakly coordinate to the copper ion in an axial position. These contacts link the tetranuclear species into infinite chain polymers.

M(PZA) 2 Ni(CN) 4 {where M=Mn, Co, Fe, Ni or Cd; PZA=pyrazinamide} complexes have been prepared for the first time and their FT-IR spectra are reported in the 400–4000 cm −1 region. The spectral features suggest that the compounds are similar in structure to the Hofmann type two dimensional coordination polymer compounds, formed with Ni(CN) 4 −2 ions bridged by M(PZA) 2 +2 cations. PZA is coordinated to M(II) through the oxygen atom of the carbonyl group.

The coordination polymeric compounds, M(2APM)2Ni(CN)4 (where M=Mn, Co, Ni or Cd; 2APM=2-aminopyrimidine) have been prepared for the first time and their FT-IR spectra are reported in the 400–4000 cm−1 region. The spectral features suggest that the compounds are similar in structure to the Hofmann type two dimensional coordination polymeric compounds, formed with Ni(CN)4−2 ions bridged by M(2APM)2+2 cations. 2APM is coordinated to M(II) through one of the pyrimidine ring nitrogen atoms; the amino group is not involved in the complex formation. The coordination effect on the 2APM vibrational wavenumbers is analysed. The coordination polymeric compounds, M(2-Aminopyrimidine)2Ni(CN)2 (M=Mn, Co, Ni, Cd) have been prepared and their FT-IR spectra are reported.

A series of Hofmann-type clathrate host molecules containing two 2-aminopyridine (2-Apy) groups attached to transition metal (II) (M) tetracyanonickelate frame, with the formula: M(2Apy) 2 Ni(CN) 4 (where M=Mn, Co, Cu or Zn), have been synthesised for the first time. Their FT-IR spectra are reported in the 400–4000 cm −1 region. The spectral features suggest that the compounds are substantially isostructural to that of already known Hofmann type pyridine complex; M(py) 2 Ni(CN) 4 . Moreover, 2Apy pyridine molecules are found to involve coordination through the ring nitrogen. The coordination effect on the 2Apy modes was analysed.

WOS: 000305562300002, The first synthesis of benzonitrile tetracyanonickelate complexes, represented by the general formula M(benzonitrile)(2)Ni(CN)(4) (M = Ni, Zn, Cd, and Hg), is reported. Fourier transform infrared spectroscopy and Raman spectroscopic data in the region of 4,000-400 cm(-1) are presented, and the vibrational frequencies are assigned and explained in detail. The thermal behavior of these complexes was also investigated by thermogravimetric analysis, differential thermal analysis, and derivative thermal gravimetric analysis. The spectral and thermal analysis results of the newly synthesized complexes suggest that these complexes are new examples of Hofmann-type complexes. The spectral data obtained show that the complexes consist of |M-Ni(CN)(4)|(infinity) polymeric layers with the ligand (benzonitrile) molecules bound to metal through the N-donor atom of the cyanide group., Dumlupinar UniversityDumlupinar University [46], The author wishes to thank in particular Anadolu University for providing technical assistance and Dumlupinar University for the technical and financial support with the project number 46. The author is also indebted to Prof. Dr. Mustafa, SENYEL for the use of the Bruker Senterra Dispersive Raman Microscope.

Bu çalışmada, [Cu(dmen)2Ni(μ-CN)2(CN)2] (1), [Zn4(dmen)8Ni4(CN)16] (2), [Cd4(dmen)8Ni4(CN)16] (3), [Cu(dmen)2Pd(μ-CN)2(CN)2] (4), [Zn(dmen)2Pd(μ-CN)2(CN)2] (5), [Cd(deten)2Ni(μ-CN)2(CN)2] (6), [Zn(deten)2Pd(μ-CN)2(CN)2] (7) ve [Cd(deten)2Pd(μ- CN)2(CN)2] (8) formülleri ile verilen siyano köprülü polimerik komplekslerin tek kristalleri elde edilmiştir. Komplekslerin yapıları element analiz ve titreşim spektroskopisi ile belirlenmiştir. Komplekslerin titreşim spektrumlarında 2200-2000 cm-1 dalga sayısı aralığındaki şiddetli ve keskin ν(CN) titreşim bandı, [Ni(CN)4]2- tabaka yapısına sahip 1-3 ve 5 komplekslerinde 28-15 cm-1, [Pd(CN)4]2- tabaka yapısına sahip 4 ve 6-8 komplekslerinde ise 17-9 cm-1 yüksek frekans bölgelerine kaymıştır. Serbest ligantların (dmen veya deten) ve komplekslerin spektrumları karşılaştırıldığında ise ligant moleküllerinin 3365-3193 cm-1 dalga sayısı aralığındaki ν(NH) titreşimlerinin komplekslerde 3345-3160 cm-1 dalga sayısına, 2972-2770 cm-1 dalga sayısı aralığındaki etil ve metil gruplarına ait ν(CH) titreşimlerinin ise 2988-2792 cm-1 dalga sayısına kaydığı gözlenmiştir. Tek kristalleri elde edilen 1-8 komplekslerinin X-ışınları kırınımı tekniği ile yapı analizleri gerçekleştirilmiştir. 2,2-TT zincir yapısındaki 1, 4, 5, 7 ve 8 kompleksleri P21/c, 6 kompleksi P21/n uzay grubuna sahip ve monoklinik yapıda, 2,2-CC zincir yapısına sahip, 2 ve 3 kompleksleri ise I41/a uzay grubuna sahip tetragonal yapıdadır. 1, 4-8 komplekslerinin yapılarında bulunan nikel(II) veya paladyum(II) iyonuna, dört tane siyano ligantının (iki siyano grubu uç, diğer iki siyano grubu köprü) karbon atomları üzerinden koordine olmasıyla kare düzlem geometrili, Cu(II), Zn(II) ve Cd(II) iyonlarının ise ikisi siyano ve çift dişli iki dmen veya deten ligantlarıyla koordine olmasıyla bozulmuş sekiz yüzlü geometri oluşmuştur. Elde edilen komplekslerin termal analiz bozunmaları statik havada 30-700 °C sıcaklık aralığında incelenmiştir.. Yapılan incelemelerde ilk bozunma basamağında komplekslerin yapısında bulunan dmen veya deten ligantlarının endotermik olarak uzaklaştığı, takip eden basamakta ise siyano ligantının ekzotermik olarak bozulduğu belirlenmiştir. Son bozunma ürünlerine karşılık gelen metal oksitlerdir. In this study, cyano-bridged heteronuclear polymeric complexes with formulas given by [Cu(dmen)2Ni(μ-CN)2(CN)2] (1), [Zn4(dmen)8Ni4(CN)16] (2), [Cd4(dmen)8Ni4(CN)16] (3), [Cu(dmen)2Pd(μ-CN)2(CN)2] (4), [Zn(dmen)2Pd(μ-CN)2(CN)2] (5), [Cd(deten)2Ni(μ- CN)2(CN)2] (6), [Zn(deten)2Pd(μ-CN)2(CN)2] (7) and [Cd(deten)2Pd(μ-CN)2(CN)2] (8) have been synthesized and their single crystals have been obtained. The structures of complexes were characterized by using elemental analysis and vibrational spectroscopy. Intensive and sharp ν(CN) vibration band between 2200-2000 cm-1 in the vibration spectra of complexes, was shifted through high frequency regions as 28-15 cm-1 for [Ni(CN)4]2- layer type 1-3 and 5 complexes and 17-9 cm-1 for [Pd(CN)4]2- layer type 4 and 6-8 complexes. When the spectra of free ligands (dmen or deten) and complexes compared, it was seen that ν(NH) vibrations of ligand molecules between 3365-3193 cm-1 were shifted to 3345-3160 cm-1 in complexes and ν(CH) vibrations which belong to ethyl and methyl groups between 2972-2770 cm-1 were shifted to 2988-2792 cm-1. Structural analysis of single crystalline 1-8 complexes were performed by x-ray diffraction technique. 1, 4, 5, 7 and 8 complexes with chain structure 2,2-TT belong to P21/c, 6 complex belongs to P21/n space group and both have monoclinic structure, while 2 and 3 complexes with chain structure 2,2-CC belong to I41/a space group and has tetragonal structure. Square plane geometry was formed via the coordination of 4 cyano ligand (two cyano groups as end, other two cyano groups as bridge) to nickel (II) and palladium (II) ions, which present in the structure of 1, 4-8 complexes, through carbon atoms and distorted octahedral geometry was formed by the coordination of Cu(II), Zn(II) ve Cd(II) ions with dmen or deten ligands (two of them are cyano and double-geared). Thermal analysis decompositions of complexes were investigated between the temperature ranges of 30-700 oC in static air atmosphere. It was determined that dmen or deten ligands in the structure of complexes were removed endothermically in the first stage, and cyano ligand was decomposed exothermically in the subsequent stage. Resultant decomposition products are metal oxides.

Tez (doktora) - Anadolu Üniversitesi, Anadolu Üniversitesi, Fen Bilimleri Enstitüsü, Fizik Anabilim Dalı, Kayıt no: 179005, Bu çalışmanın ilk aşamasında, 3-fenil-1-propilamin (3-fenilpropilamin: 3PPA) ligand molekülünün iç dönmelerine bağlı olarak en kararlı formu, deneysel ve teorik titreşim spektroskopisi yardımıyla belirlenmiştir. Son aşamasında, 3PPA molekülü kullanılarak M(C?H??N)?Ni(CN)? (M=Ni, Co, Cd veya Pd) ve M (C?H??N)?Ni(CN)?.2G (M=Ni veya Co ve G=1,2-diklorobenzen veya 1,3- diklorobenzen) baz bileşik formülüne sahip Hofmann-3PPA tipi kompleks ve klatratlar ilk kez kimyasal yollardan elde edilmiştir. Bütün bileşiklerin yapılarını aydınlatmak için infrared ve Raman spektrumları (4000-100 cm-1), elementel analizleri, termal davranışları ve manyetik duygunlukları incelenmistir. Yapılan bu incelemeler sonucunda, 3PPA ligand molekülünün serbest halde en kararlı hali trans-trans-gauche (TTG) formudur. Bu form Hofmann-3PPA tipi komplekslerde gözlenirken, bir diger kararlı formu olan trans-gauche-gauche (TGG) formu Hofmann-3PPA tipi klatratlarda gözlemlenmiştir. Bunun sebebinin ligand molekülü ile konuk molekülünün ? elektronları arasındaki zayıf konak-konuk etkileşiminden olduğu sonucuna varılmıştır.

Bu çalışmada [Mx(L)yM'(CN)4].zH2O [M= NiII, CuII, ZnII, CdII; M'= NiII, PdII, PtII; L= N,N?-bis(2-hidroksietil)etilendiamin (bishydeten) ve 2,2?-(etilendioksi)bis(etilamin) (edbea); x= 1 veya 2; y= 1 veya 2; z= 0, 1/2 veya 1] genel formüllerine sahip yeni homo ve heterobimetalik siyano köprülü kompleksler sentezlendi ve elementel analizleri, spektroskopik (IR, EPR) ve termik özellikleri incelendi. Ayrıca uygun kristallere sahip komplekslerin X-ışını tek kristal yapı analizleri gerçekleştirildi ve paramanyetik merkez bulunduranların sıcaklığa bağlı manyetik duyarlılıkları ölçüldü. Tuğla-harç metodu kullanılarak sentezlenen komplekslerin, elementel analiz sonuçlarına göre [M(L)M'(CN)4], [M(L)2M'(CN)4] ve [M2(L)2M'(CN)4] genel formüllerine sahip oldukları anlaşıldı. Ayrıca elementel analiz ve termik analiz sonuçlarının değerlendirilmesiyle [Ni(edbea)Ni(CN)4].1/2H2O ve [Cu(edbea)Ni(CN)4].H2O komplekslerinde örgü sularının bulunduğu belirlendi. Havada kararlılığını koruyan tüm kompleksler sık kullanılan çözücülerde (etil alkol, metil alkol, izopropil alkol, asetonitril ve su) çözünmemektedir. Siyano köprülü polimerik kompleks yapısındaki yirmi bir kompleksin kızılötesi spektrumlarında benzer titreşim bandları gözlemlendi. Bünyesinde CuII (d9) merkezler bulunduran komplekslerin EPR çalışmaları yapıldı. EPR sonuçlarına göre, oktahedral geometrideki CuII iyonları [Cu(edbea)Ni(CN)4].H2O kompleksinde rombik olarak bozulmaya uğrarken, kalan tüm komplekslerde tetragonal olarak bozulmaktadır. Tüm CuII komplekslerinde paramanyetik elektronun temel halinin olduğu belirlendi. Komplekslerin termik analiz çalışmaları azot atmosferinde gerçekleştirildi. Komplekslerin termik bozunmaları, ilk olarak varsa örgü sularının, daha sonra nötral ligantların (bishydeten ve edbea) ve son olarak siyano gruplarının yapıdan uzaklaştığı özdeş mekanizmayı takip etti. Analiz sonucunda ortamda metal veya metal oksit karışımları kaldı. Uygun kristallere sahip sekiz kompleksin kristal yapıları X-ışını tek kristal yöntemiyle aydınlatıldı. Bu komplekslerden [Zn(bishydeten)M?(CN)4] (M?= NiII, PdII, PtII) genel formüllü olanlar, bishydeten'in üç dişli (N-, N?-, O-) ligant olarak davrandığı siyano köprülü polimer yapısına sahiptir. Yine polimerik yapıya sahip [Cd(bishydeten)M?(CN)4] (M?= NiII, PdII, PtII) komplekslerinde bishydeten farklı olarak CdII'ye iki dişiyle (N-, N?-) koordine olmaktadır. Farklı yapılara sahip [Cu(edbea)Ni(CN)4] ve [Zn2(edbea)2Pd(CN)4] polimerik komplekslerinde edbea ligantının da siyano ligantı gibi köprü oluşumuna katıldığı anlaşıldı. edbea ligantı [Cu(edbea)Ni(CN)4] kompleksinde dört dişli davranarak zincirler arası köprü oluştururken; [Zn2(edbea)2Pd(CN)4] kompleksinde ise üç dişli (N-, O-, O?-) davranarak zincir içinde komşu ZnII iyonlarını bağlamaktadır. Tuğla bileşeninde paramanyetik metal merkezler bulunduran komplekslerin, 10 ve 300 K'de manyetik duyarlılıkları ölçüldü. [Ni(edbea)Pd(CN)4] kompleksi çalışma aralığında zayıf ferromanyetik etkileşimler sergilerken, kalan komplekslerde ise zayıf antiferromanyetik etkileşimler gözlemlendi. In this study, new homo and heterobimetallic cyano bridged complexes with [Mx(L)yM'(CN)4].zH2O [M= NiII, CuII, ZnII, CdII; M'= NiII, PdII, PtII; L= N,N'-bis(2-hydroxyethyl)ethylenediamine (bishydeten) and 2,2'-(ethylenedioxy)bis(ethylamine) (edbea); x= 1 or 2; y= 1 or 2; z= 0, 1/2 or 1] general formula were synthesized and their elemental analysis, spectroscopic (IR, EPR) and thermal properties were investigated. Besides, X-ray single crystal structure analyses of complexes having proper crystals were performed and magnetic susceptibilities of the ones having paramagnetic sites were measured upon temperature. It was understood that complexes synthesized by used brick and mortar method have [M(L)M'(CN)4], [M(L)2M'(CN)4] and [M2(L)2M'(CN)4] general formula according to results of elemental analysis. Besides, it was determined that lattice water exist in [Ni(edbea)Ni(CN)4].1/2H2O and [Cu(edbea)Ni(CN)4].H2O complexes by evaluating elemental analysis and thermal analysis results. Whole complexes keeping up with stability do not dissolve in common solvents (ethanol, methanol, isopropyl alcohol, acetonitrile and water). Similar vibration bands were observed in infrared spectra of twenty one complexes, structures of which are cyano bridged polymeric complexes. EPR studies of the complexes containing CuII (d9) centers were carried out. According to EPR results, while CuII ion with octahedral geometry undergoes rhombic distortion in [Cu(edbea)Ni(CN)4].H2O complex, they distort as tetragonal in the rest of the complexes. It was determined that ground state of the paramagnetic electron in all of the CuII complexes is . Thermal analyze studies of complexes were carried out in nitrogen atmosphere. Thermal decompositions of complexes follow identical mechanism in which firstly hydrate waters if there is, then neutral ligands (bishydeten and edbea) and finally cyano ligands leave from structure. Mixture of metal or metal oxides remained at the end of the analysis. Structures of eight complexes having proper crystals were determined with X-ray single crystal method. Complexes with [Zn(bishydeten)M?(CN)4] (M?=NiII, PdII, PtII) general formula have cyano bridged polymeric structure in which bishydeten acts as threedentate ligand (N-, N?-, O-). bishydeten is differently coordinated to CdII ion as bidentate (N-, N?-) in [Cd(bishydeten)M?(CN)4] (M?=NiII, PdII, PtII) complexes having polymeric structure. It was understood that edbea ligand forms bridge like cyano in [Cu(edbea)Ni(CN)4] and [Zn2(edbea)2Pd(CN)4] polymeric complexes having different structure. While edbea ligand forms interchain bridge by acting tetradentate in [Cu(edbea)Ni(CN)4] complex, it bonds intrachain neighbour ZnII ions by acting tridentate (N-, O-, O?-) in [Zn2(edbea)2Pd(CN)4] complex. Magnetic susceptibilities of the complexes having paramagnetic metal centres in themortar component were measured at 10 and 300 K. While [Ni(edbea)Pd(CN)4] exhibits weak ferromagnetic interaction in studying interval; weak antiferromagnetic interactions were observed at the rest of the complexes. 208

In this study, the Raman and far-IR spectra of the two dimensional coordination polymer compounds, M(PZA) 2 Ni(CN) 4 {where M = Mn, Ni, Zn or Cd; PZA = pyrazinamide} and mid-IR spectrum of Zn(PZA) 2 Ni(CN) 4 were reported for the first time. Far-IR spectroscopic study allowed us to make correction in the bonding mode of PZA. PZA molecules are found to involve coordination through one of the pyrazine ring nitrogen atoms. The spectral features suggest that the compounds are similar in structure to the Hofmann type two dimensional coordination polymer compounds, formed with Ni(CN) 4 - 2 ions bridged by M(PZA) 2 + 2 cations. Vibrational bands originated from both PZA and Ni(CN) 4 group were assigned.

4-Aminopyrimidine tetracyanonickelate, M(4APM)(2)Ni(CN)(4) {where M = Mn, Co, Ni, Zn or Cd; 4APM = 4-aminopyrimidine}, coordination polymer compounds have been prepared for the first time and their FT-IR (400-4000 cm(-1)) and FT-Raman (704000 cm(-1)) spectra are reported. 4APM is coordinated to M(II) through one of the pyrimidine ring nitrogen atoms as a monodentate ligand; the amino group is not involved in the complex formation. Vibrational bands arising from both 4APM and the Ni(CN)(4) group, were assigned. The effect of coordination on 4APM vibrational wavenumbers is analysed by comparison with isostructural compounds. (C) 2006 Elsevier B.V. All rights reserved.

Bu çalışmada, Hofmann tipi M(C₆H₁₆N₂)Ni(CN)₄.nG (M= Ni, Cd veya Co; G= Toluen, Bifenil veya Anilin; n= konuk sayısı) konak-konuk bileşikleri kimyasal yollardan elde edilmiştir. Elde edilen bu bileşiklerin kırmızı altı spektrumları 4000 cm⁻¹-400 cm⁻¹spektroskopik bölgesinde kaydedilmiş, ligand molekülün Ni(CN)₄²⁻- iyonunun ve konuk moleküllerin titreşim dalga sayıları belirlenmiştir. Ayrıca elde edilen konak-konuk bileşiklerinin elementel analizleri yapılarak moleküler yapının desteklendiği görülmüştür. Yapılan bu incelemeler ile elde edilen konak-konuk bileşiklerinin Hofmann tipine benzer yapıda oldukları, ligand molekül 1,6-diaminohekzanın azot atomundan M metal atomuna bağlı olduğu, konuk moleküllerin ise tabakalar arasında oluşan yapısal boşluklara hapsedildikleri sonucuna varılmıştır., In this study, Hofmann type M(C₆H₁₆N₂)Ni(CN)₄.nG (M= Ni, Cd or Co; G= Toluene, Biphenyl or Aniline; n= the number of guest) host-guest compounds were obtained chemically. The infrared spectra of these compounds were recorded in the spectroscopic region of 4000 cm⁻¹-400 cm⁻¹, and the vibrational wave numbers of ligand molecule, Ni(CN)₄²⁻ ion and guest molecules were determined. In addition, elemental analysis of the compounds were performed and the results were found to support given formula. The results indicated that the structure of the host-guest compounds was similar to those of Hofmann-type compounds, ligand molecule diaminohexane was coordinated to M metal atom through its nitrogen, the guest molecules were trapped in the structural cavities between the sheets.

The Raman spectra of the two dimensional layered polymer compounds, M(2APM)(2)M' (CN)(4) {where M = Mn or Cd; and M' = Ni or Pt; 2APM = 2-aminopyrimidine} are reported in the 70-4000 cm(-1) region. Vibrational data suggests that compounds are similar in structure to the Hofmann type two dimensional coordination polymer compounds, formed with M'(CN)(4)(-2) ions bridged by M(2APM)(2)(+2) cations. 2-Aminopyrimidine was coordinated to M(II) through one of the nitrogen atom of its heterocycle ring. Vibrational assignments are given for the bands arising from the tetracyanometallate layers and coordinated 2APM. (c) 2005 Elsevier B.V. All rights reserved.

WOS: 000231361100011, New Hofmann-type complexes in the form of M(4-Chpy)(2)Ni(CN)(4) [where 4-Chpy = 4-(3-cyclohexen-1-yl)pyridine and M = Ni, Co] were prepared in powder form, and their infrared spectra are reported in the range of 4000-400 cm(-1). The spectral findings suggest that these compounds are similar in structure to the Hofmann-type complexes, and their structure consists of polymeric layers vertical bar M-Ni(CN)(4)vertical bar(infinity) with the 4-(3-cyclohexen-1-yl)pyridine molecule bound to the metal atom(M).

WOS: 000167780000027, Three Hofmann-diaminododecane-type clathrates of the form M(1,12-diaminododecane) Ni(CN)(4).G (M = Co, Ni or Cd; G = benzene, naphthalene, anthracene, phenanthrene or biphenyl) have been prepared in powder form. The 1,12-diaminododecane molecules in the host lattice permit the inclusion of bulky guest molecules. The spectral features suggest that these compounds are similar in structure to the other Hofmann-diam-type clathrates.

FT-IR spectra of M(4Apy) 2 Ni(CN) 4 {where M=Mn, Co, Ni, Cu or Cd; 4Apy=4-aminopyridine} complexes are reported for the first time in the 400–4000 cm −1 range. The spectral features suggest that the compounds are similar in structure to the Hofmann-type complexes with infinite polymeric layers formed with Ni(CN) 4 −2 ions bridged by M(4Apy) 2 +2 cations and the ring nitrogen of the 4Apy is only involved in complex formation. However in some cases host complexes include H 2 O molecules as guest species which are found to be H-bonded to hydrogens of the amino group of 4Apy (N–H⋯OH 2 ). The coordination effect on the 4Apy modes is analysed.