Liquid crystalline materials containing pyrimidine rings

Figures & data

The electron-withdrawing pyrimidine units containing two nitrogen atoms at C-3 and C-5 positions in six-membered aromatic rings play a vital role in constructing various liquid crystalline materials, such as calamitic, bent, discotic, taper-shaped, photopolymerised, oligomer and polymer, due to the presence of characteristic mesophases and opto-electronic properties compared with the traditional 1,4-phenylene rings. The heterocyclic pyrimidine-based liquid crystals with a reduced-symmetry structure, highly conjugated π-deficient aromatic rings, and good metal coordinating ability are often used as functional mesogens for application in some promising opto-electronic devices such as ferroelectrics, organic semiconductors, and sensors.

Figure 1. (Colour online) The schematic exhibition of the review article structure.

Figure 2. (Colour online) The schematic exhibition of structures and mesophases for pyrimidine liquid crystals based on geometric shape, flexible chains, molecular polarity and polarizability, etc.

Figure 3. (Colour online) The chemical structures, mesophase transition temperatures and POM textures of boron pyrimidine liquid crystals [11].

Figure 4. (Colour online) The chemical structures, mesophase transition temperatures and POM textures of cholesteric liquid crystals.

Table 1. The chemical structures and mesophase transition temperatures (^oC) of nitrogen-substituted 5CB derivatives.

Ref.	No.	R1	R2	X	Y	Mesophase Transition Temperatures (^oC)
[10]	LC1 (5CB)	C5H11	CN	CH	CH	Cr 22.5 N 35 I
	LC2	C5H11	CN	N	N	Cr 71 N (52) I
	LC3	CN	C5H11	N	N	Cr 96 N 109 I

Table 2. The chemical structures and mesophase transition temperatures (^oC) of discotic pyrimidine liquid crystals [12,13].

Ref.	No.	X1	X2	X3	Y1	Y2	Y3	Z1	Z2	Z3	Mesophase Transition Temperatures (^oC)
[12]	LC8	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	H	H	H	Cr1 29.8 Cr2 38.9 ColL 90.5 I; I 87.8 ColL −0.36 Cr
	LC9	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	H	NHSO2CF3	H	Cr 30.0 ColL 148.4 I; I 143.7 ColL 14.2 Cr
	LC10	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	H	F	H	Cr1 9.96 Cr2 21.4 ColL 128.2 I; I 125.8 ColL −19.5 Cr
	LC11	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	H	Cl	H	Cr1 1.66 Cr2 13.9 ColL 140.9 I; I 138.6 ColL −35.2 Cr
	LC12	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	H	Br	H	Cr1 −3.00 Cr2 9.39 ColL 144.4 I; I 142.3 ColL −39.4 Cr
	LC13	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	H	I	H	Cr 7.23 ColL 138.0 I; I 136.2 ColL −39.8 Cr
	LC14	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	H	OCH3	H	Cr 36.4 ColL 104.5 I; I 102.2 ColL −37.1 Cr
	LC15	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	H	CH3	H	Cr −2.89 ColL 104.9 I; I 102.2 ColL
	LC16	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	H	C2H5	H	Cr 12.5 ColL 101.5 I; I 99.5 ColL −35.9 Cr
	NLC1	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	NHSO2CF3	H	H	ColL 101.2 I; I 91.3 ColL
	LC17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	F	H	H	Cr 27.3 ColL 119.8 I; I 117.3 ColL −16.6 Cr
	LC18	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	Cl	H	H	Cr 5.23 ColL 119.0 I; I 116.1 ColL 1.94 Cr
	LC19	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	Br	H	H	Cr 19.4 ColL 117.0 I; I 114.5 ColL 13.1 Cr
	LC20	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OCH3	H	H	Cr 18.2 ColL 111.5 I; I 109.3 ColL −39.2 Cr
	LC21	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	OC8H17	CH3	H	H	Cr1 −16.3 Cr2 13.3 ColL 88.9 I; I 86.8 ColL −22.4 Cr
[13]	NLC2	H	OC8H17	H	H	OC8H17	H	H	OC8H17	H	Cr 74.8 I; I 31.5 Cr
	NLC3	H	OC12H25	H	H	OC12H25	H	H	OC12H25	H	Cr 64.5 I; I 33.8 Cr
	NLC4	H	OC8H17	OC8H17	H	OC8H17	OC8H17	H	OC8H17	OC8H17	Cr 101.3 I; I 80.0 Cr
	NLC5	H	OC12H25	OC12H25	H	OC12H25	OC12H25	H	OC12H25	OC12H25	Cr 106.7 I; I 83.5 Cr
	LC22	H	OC10H21	OC10H21	H	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	Cr 59.7 Colhd 105.0 I; I 97.7 Colhd 34.6 Cr
	LC23	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	H	H	H	Cr 45.7 Colhd 82.9 I; I 73.6 Colhd 37.9 Cr
	LC24	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	H	OC10H21	H	Cr 56.5 Colhd 114.0 I; I 104.0 Colhd 41.5 Cr
	LC25	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	H	OC10H21	OC10H21	Cr 36.2 Colhd 131.4 I; I 124.3 Colhd 5.92 Cr
	LC26	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	OC10H21	Cr 62.1 Colhd 140.5 I; I 134.4 Colhd 34.0 Cr

Figure 5. (Colour online) The chemical structures, mesophase transition temperatures and POM textures of laterally connected pyrimidine liquid crystals [16].

Table 3. The chemical structures and mesophase transition temperatures (^oC) of bipyrimidine discotic liquid crystals.

Ref.	No.	R1	R2	R3	Mesophase Transition Temperatures (^oC)
[17]	LC35	OC12H25	OC12H25	H	Cr 69.7 LamColrec 102.0 Colhex 126.8 I; I 120.5 Colhex 87.6 LamColrec 70.0 Cr
	LC36	OC16H33	OC16H33	H	Cr 43.0 Colhex 127.5 I; I 123.2 Colhex 29.6 Cr
	NLC6	OC12H25	H	OC12H25	G 13.7 I; I 3.9 G
	NLC7	OC16H33	H	OC16H33	Cr 24.7 I; I 14.7 Cr
	NLC8	OC12H25	OC12H25	OC12H25	Cr −18.6 I; I −20.3 Cr

Figure 6. (Colour online) The schematic exhibition of pyrimidine-based liquid crystalline structures and mesophases for ferroelectric application.

Table 4. The chemical structures and mesophase transition temperatures (^oC) of phenyl pyrimidine liquid crystals.

Ref.	No.	R1	R2	R3	R4	Mesophase Transition Temperatures (^oC)
[67]	LC37	OC9H19	OC7H15	H	H	Cr 57.4 SmC 95.3 SmA 98.4 I
[67]	LC38	OC9H19	OC9H19	H	H	Cr 61.5 SmC 95.5 SmA 99.2 I
[67]	LC39	OC8H17	OC8H17	H	H	Cr 50.1 SmC 91.1 SmA 89.3–100.3 I
[67]	LC40	OC7H15	OC9H19	H	H	Cr 57.0 SmC 79.7 SmA 91.2 N 94.7 I
[67]	LC41	C8H17	OC6H13	H	H	Cr 27.5 SmC 46.3 SmA 57.4 N 65.3 I
[67]	LC42	C8H17	OC8H17	H	H	Cr SmX 68.1 SmC 151.7 N 174.0 I
[68]	LC43	OC8H17	OC6H13	H	H	I 98 N 95.7 SmA 88 SmC 43 Cr
[20]	LC44	OC9H19	OCHFC6H13	H	H	Cr 64.2 SmC* 92.1 SmA 96.3 I
[21]	LC45	C8H17	OC10H21	H	H	Cr 32 SmC 60 SmA 66 N 70 I
[21]	LC46	C9H19	OC8H17	H	H	Cr 33 SmC 60 SmA 75 I
[21]	LC47	C10H21	OC10H21	H	H	Cr 36 SmC 73 SmA 77 I
[21]	LC48	C9H19	OC8H17	F	F	Cr 43 SmC 54 I
[21]	LC49	OC9H19	OC9H19	F	F	Cr 48 SmC 78 I
[21]	LC50	OC9H19	OC9H19	F	H	Cr 45 SmC 62 I
[21]	LC51	OC8H17	OCH2C6F13	F	F	Cr 65 SmC (64) SmA 138 I
[21]	LC52	OCH2C6F13	OC8H17	F	F	Cr 77 SmC 127 I
[21]	LC53	C7H15	OC8H17	H	H	Cr 51 SmC (45) N 72 I
[21]	LC54	C10H21	OCH2CHFC6H13	H	H	Cr 60 SmC (58) SmA* 68 I
[69]	LC55	OC8H17	OC4H9	H	H	Cr 58 SmC 85 SmA 95 N 98 I
[70]	LC56	C8H17	OCH2CF2OC2F4OC4F9	H	H	I 70 SmA 49 SmC 8 Cr
[71]	LC57	C6H13	OCH2C7F15	H	H	I 133 SmA 56 SmC 50 Cr
[71]	LC58	C7H15	OCH2C7F15	H	H	I 125 SmA 67 SmC 54 Cr
[71]	LC59	C8H17	OCH2C7F15	H	H	I 117 SmA 80 SmC 71 Cr
[71]	LC60	C9H19	OCH2C7F15	H	H	I 112 SmA 85 SmC 71 Cr
[71]	LC61	C10H21	OCH2C7F15	H	H	I 104 SmA 87 SmC 75 Cr
[71]	LC62	C10H21	OCH2C5F11	H	H	I 84 SmA 73 SmC 47 Cr
[71]	LC63	C10H21	OCH2C3F7	H	H	I 64 SmA 52 SmC 36 Cr
[72]	LC64	OC8H17	OCH2CHFC6H13	H	H	I 94.15 SmA 78.49 SmC 44.94 Cr

Table 5. The chemical structures and mesophase transition temperatures (^oC) of pyrimidine-based liquid crystals with epoxy [79], branched tricarbosilane [82], bent-core dimers [83], taper-shaped trimers [84].

Ref.	No.	Structures	Mesophase Transition Temperatures (^oC)
[79]	LC65 (adpc042)		Cr −5 SmC* 58 SmA* 82 I
[79]	LC66 (DR257)		Cr 60 SmA* 152 Iso
[82]	LC67 (QL30–6)		Cr 45 SmC 55 SmA 70 I
[82]	LC68 (QL29–6)		Cr 54 SmC 60 SmA 67 I
[83]	LC69		Cr 77 SmCA 81 SmA 115 N 131 I
[83]	LC70		Cr 78 SmCA 92 SmA 115 N 128 I
[84]	LC71		Cr 70 SmC 83.8 SmCanti 87.1 SmA 95.7 N 104.2 I
[84]	LC72		Cr 107.4 (SmX 97.0 SmCanti 101.9) SmA 113.4 I
[84]	LC73		Cr 105.1 SmC 105.2 N 110.2 I

Table 6. The chemical structures and mesophase transition temperatures (^oC) of biphenyl pyrimidine compounds with siloxane/carbosilane terminal chains.

Ref.	No.	X	m	n	A	R	Mesophase Transition Temperatures (^oC)
[60]	LC74 (DR118)	O	2	11		OCH(CH3)C6H13	Cr 60 SmC* 95 SmA* 113 I
[60]	LC75 (DR133)	O	2	11		OCH(CH3)C6H13	Cr 11 SmC* 94 SmA* 102 I
[81]	NLC9 (DR253)	CH2	2	11		OCH(CF3)C6H13	Cr 50.2 I
[81]	NLC10 (ADPD003)	CH2	2	11		OCH(CF3)C6H13	Cr 52 I
[81]	LC76 (DR276)	CH2	2	11		OCH(CH3)C6H13	Cr 14 SmX 48 SmC* 78.5 SmA* 87 I
[81]	LC77 (DR277)	CH2	3	11		OCH(CH3)C6H13	Cr 6 SmX 35 SmC* 65.5 SmA* 77 I

Figure 7. (Colour online) The chemical structures, mesophase transition temperatures (^oC) and POM textures of 2(n) and 3(n) series of liquid crystals [85].

Table 7. The chemical structures and mesophase transition temperatures (^oC) of phenyl-pyrimidine liquid crystals with siloxane/carbosilane terminal chains.

Ref.	No.	X	m	n	P	Q	Y	Z	R	Mesophase Transition Temperatures (^oC)
[69]	LC78	O	2	11	CH	CH	CH	N	OC8H17	Cr 66 SmC 76 SmA 80 I
[89]	LC79 (QL16–4)	CH2	2	11	CH	CH	CH	N	OC4H9	Cr 43 SmC 44 SmA 68 I
[89]	LC80 (QL16–5)	CH2	2	11	CH	CH	CH	N	OC5H11	Cr 34 Cr’ 40 SmC 55 SmA 66 I
[89]	LC81 (QL16–6)	CH2	2	11	CH	CH	CH	N	OC6H13	Cr 33 SmC 64 SmA 69 I
[89]	LC82 (QL16–7)	CH2	2	11	CH	CH	CH	N	OC7H15	Cr 64 SmC 65 SmA 67 I
[89]	LC83 (QL16–8)	CH2	2	11	CH	CH	CH	N	OC8H17	Cr 58 SmC 66 SmA 68 I
[89]	LC84 (QL16–9)	CH2	2	11	CH	CH	CH	N	OC9H19	Cr 67 SmC (65) SmA (66) I
[89]	LC85 (QL17–4)	CH2	2	11	N	CH	CH	CH	OC4H9	Cr 39 SmC 42 SmA 68 I
[89]	LC86 (QL17–5)	CH2	2	11	N	CH	CH	CH	OC5H11	Cr 44 SmC 48 SmA 66 I
[89]	LC87 (QL17–6)	CH2	2	11	N	CH	CH	CH	OC6H13	Cr 48 SmC 59 SmA 72 I
[89]	LC88 (QL17–7)	CH2	2	11	N	CH	CH	CH	OC7H15	Cr 51 SmC 61 SmA 70 I
[89]	LC89 (QL17–8)	CH2	2	11	N	CH	CH	CH	OC8H17	Cr 56 SmC 63 SmA 70 I
[89]	LC90 (QL17–9)	CH2	2	11	N	CH	CH	CH	OC9H19	Cr 57 Cr’ 60 SmC 63 SmA 69 I
[89]	LC91 (QL24–6)	CH2	1	11	CH	CH	CH	N	OC6H13	Cr 50 SmF (42) SmC 78 SmA 81 I
[82]	LC92 (QL26–6)	CH2	0	11	CH	CH	CH	N	OC6H13	Cr 68 SmX (54) SmC 70 SmA 93 I
[82]	LC93 (QL25–6)	CH2	1	11	N	CH	CH	CH	OC6H13	Cr 60 SmA 83 I
[90]	LC94 (QL32–6)	CH2	2	11	CH	CH	CH	N	OCH2(CHF)2C3H7	Cr 53 SmC* 62 SmA* 77 I
[90]	LC95	CH2	1	11	CH	CH	CH	N	OCH2(CHF)2C3H7	Cr 45 SmC* 55 SmA* 84 I
[90]	LC96	CH2	0	11	CH	CH	CH	N	OCH2(CHF)2C3H7	Cr 56 SmX (42) SmC* (52) SmA* 93 I
[86]	LC97	O	2	11	CH	CH	N	CH	O(CH2)7Cl	Cr 26 SmC 84 SmA 98 I
[88]	LC98	O	2	11	CH	CH	N	CH	O(CH2)7CH2Cl	Cr 48 SmC 89 SmA 98 I
[88]	LC99	O	2	6	CH	CH	N	CH	O(CH2)7CH2Cl	Cr 45 SmC 76 SmA 85 I
[88]	LC100	O	2	11	CH	CH	N	CH	OCH2(CHF)2C5H11	Cr 67 SmC* 97 SmA* 99 I
[88]	LC101	O	2	6	CH	CH	N	CH	OCH2(CHF)2C5H11	Cr 61 Cr’ 64 SmC* 80 SmA* 88 I
[87]	LC102	O	2	11	CH	CH	N	CH	OC8H17	Cr 42 SmC 92 I
[87]	LC103	O	2	11	CH	N	CH	CH	OC8H17	Cr 35 SmC 82 Iso
[87]	LC104	O	2	11	CH	N	CH	CH	OC8H16Cl	Cr 56 SmC 83 Iso

Table 8. Effect of halogen end-groups with fluoro-, bromo-, iodo-substitution on mesophases and their transition temperatures for phenyl-pyrimidine liquid crystals.

Ref.	No.	X	Y	R1	R2	Mesophase Transition Temperatures (^oC)
[87]	LC119	CH	N	OC12H25	O(CH2)4Cl	Cr 72 N 111 I
	LC120	CH	N	OC11H23	O(CH2)5Cl	Cr 73 N 112 I
	LC121	CH	N	OC10H21	O(CH2)6Cl	Cr 56 N 103 I
	LC122	CH	N	OC9H19	O(CH2)7Cl	Cr 51 N 107 I
	LC123	CH	N	OC8H17	O(CH2)8Cl	Cr 67 N 105 I
	LC124	CH	N	OC7H15	O(CH2)9Cl	Cr 48 N 98 I
	LC125	CH	N	OC6H13	O(CH2)10Cl	Cr 67 N 95 I
	LC126	CH	N	OC5H11	O(CH2)11Cl	Cr 93 SmA (85) I
	LC127	N	CH	OC12H25	O(CH2)4Cl	Cr 59 N 100 I
	LC128	N	CH	OC11H23	O(CH2)5Cl	Cr 65 N 101 I
	LC129	N	CH	OC10H21	O(CH2)6Cl	Cr 61 N 97 I
	LC130	N	CH	OC9H19	O(CH2)7Cl	Cr 66 N 94 I
	LC131	N	CH	OC8H17	O(CH2)8Cl	Cr 76 N 95 I
	LC132	N	CH	OC7H15	O(CH2)9Cl	Cr 66 SmA 82 N 85 I
	LC133	N	CH	OC6H13	O(CH2)10Cl	Cr 72 SmA 76 N 85 I
	LC134	N	CH	OC5H11	O(CH2)11Cl	Cr 65 SmA 61 N 76 I
	LC135	CH	N	OC8H17	O(CH2)8F	Cr 47 N 101 I
	LC136	CH	N	OC8H17	O(CH2)8Br	Cr 52 N 100 I
	LC137	CH	N	OC8H17	O(CH2)8I	Cr 49 N 97 I

Table 9. The chemical structures and mesophase transition temperatures (^oC) of tricarbosilane-terminated phenylpyrimidine with ethynyl spacer.

Ref.	No.	X	Y	R	Mesophase Transition Temperatures (^oC)
[96]	LC138	CH	N	OC4H9	Cr 31 SmC 61 SmA 64 I
	LC139	CH	N	OC5H11	Cr 45 SmC 60 SmA 62 I
	LC140	CH	N	OC6H13	Cr 55 SmC 65 I
	LC141	CH	N	OC7H15	Cr 69 SmC (62) I
	LC142	CH	N	OC8H17	Cr 74 SmA (64) I
	LC143	CH	N	OC9H19	Cr 79 Cr’ 51 SmC 47 SmA 63 I
	LC144	N	CH	OC4H9	Cr 41 Cr’ 52 SmC 58 SmA 69 I
	LC145	N	CH	OC5H11	Cr 35 SmC 63 SmA 68 I
	LC146	N	CH	OC6H13	Cr 42 SmC 67 SmA 71 I
	LC147	N	CH	OC7H15	Cr 11 SmC 68 SmA 71 I
	NLC11	N	CH	OC8H17	Cr 48 I
	NLC12	N	CH	OC9H19	Cr 64 I

Table 10. The chemical structures and mesophase transition temperatures (^oC) of pyrimidine-based liquid crystals with phenoxy end groups.

Ref.	No.	X	Y	n	R	Mesophase Transition Temperatures (^oC)
[65]	LC148 (QL11–4/12)	CH	N	12	OC4H9	Cr 83 SmA 78 I
	LC149 (QL11–5/11)	CH	N	11	OC5H11	Cr 74 SmA 70 I
	LC150 (QL11–6/10)	CH	N	10	OC6H13	Cr 86 SmA 85 I
	LC151 (QL11–7/9)	CH	N	9	OC7H15	Cr 72 SmC 61 SmA 76 I
	LC152 (QL11–8/8)	CH	N	8	OC8H17	Cr 79 SmC 80 SmA 95 I
	LC153 (QL11–9/7)	CH	N	7	OC9H19	Cr 81 SmC 75 SmA 84 I
	LC154 (QL11–10/6)	CH	N	6	OC10H21	Cr 85 Cr’ 95 SmC 83 SmA 106 I
	LC155 (QL11–11/5)	CH	N	5	OC11H23	Cr 80 SmA 86 I
	LC156 (QL11–12/4)	CH	N	4	OC12H25	Cr 127 SmA 116 I
	NLC13 (QL12–4/12)	N	CH	12	OC4H9	Cr 83 Cr’ 88 I
	NLC14 (QL12–5/11)	N	CH	11	OC5H11	Cr 80 I
	NLC15 (QL12–6/10)	N	CH	10	OC6H13	Cr 92 I
	NLC16 (QL12–7/9)	N	CH	9	OC7H15	Cr 79 Cr’ 82 I
	LC157 (QL12–8/8)	N	CH	8	OC8H17	Cr 93 SmA 81 N 86 I
	NLC17 (QL12–9/7)	N	CH	7	OC9H19	Cr 72 I
	LC158 (QL12–10/6)	N	CH	6	OC10H21	Cr 87 SmC 84 SmA 93 I
	LC159 (QL12–11/5)	N	CH	5	OC11H23	Cr 80 SmA 76 I
	LC160 (QL12–12/4)	N	CH	4	OC12H25	Cr 96 SmC 100 SmA 101 I

Table 11. The chemical structures and mesophase transition temperatures (^oC) of thienyl-phenyl-pyrimidine compounds.

Ref.	No.	R1	R2	Mesophase Transition Temperatures (^oC)
[110]	LC161	OC6H13	H	Cr 115.1 N (107.8) I
[110]	LC162	OC7H15	H	Cr 104.9 N (100.5) I
[110]	LC163	OC8H17	H	Cr 110.8 N (107.4) I
[110]	LC164	OC9H19	H	Cr 112.2 N (102.5) I
[110]	LC165	OC10H21	H	Cr 107.7 N (104.9) I
[110]	LC166	OC12H25	H	Cr 106.4 N (106.2) I
[110]	LC167	OC6H13	OC6H13	Cr 75.0 SmC 145.4 SmA 149.7 N 153.7 I
[110]	LC168	OC6H13	OC7H15	Cr 69.5 SmC 149.1 SmA 154.7 I
[110]	LC169	OC6H13	OC8H17	Cr 88.9 SmI 98.9 SmC 154.6 I
[110]	LC170	OC6H13	OC9H19	Cr 61.2 J/G 64.2 SmI 104.9 SmC 154.7 I
[110]	LC171	OC6H13	OC10H21	Cr 68.2 J/G 78.1 SmI 109.0 SmC 152.6 I
[110]	LC172	OC6H13	OC12H25	Cr 74.6 J/G 95.9 SmI 117.4 SmC 150.9 I
[110]	LC173	OC7H15	OC6H13	Cr 76.2 SmC 141.7 SmA 149.3 N 150.2 I
[110]	LC174	OC7H15	OC7H15	Cr 66.2 SmCalt 88.1 SmC 148.9 SmA 153.6 I
[110]	LC175	OC7H15	OC8H17	Cr 78.1 SmI 100.4 SmC 152.2 I
[110]	LC176	OC7H15	OC9H19	Cr 63.9 SmI 105.2 SmC 153.5 I
[110]	LC177	OC7H15	OC10H21	Cr 74.6 J/G 75.1 SmI 110.8 SmC 151.3 I
[110]	LC178	OC7H15	OC12H25	Cr 64.6 J/G 93.4 SmI 115.3 SmC 147.9 I
[110]	LC179	OC8H17	OC6H13	Cr 83.3 SmC 145.0 SmA 150.3 N 152.0 I
[110]	LC180	OC8H17	OC7H15	Cr 86.1 SmCalt 88.9 SmC 150.2 SmA 152.7 I
[110]	LC181	OC8H17	OC8H17	Cr 78.0 SmF 71.6 SmCalt 97.9 SmC 153.5 I
[110]	LC182	OC8H17	OC9H19	Cr 68.1 J/G 91.9 SmF 92.3 SmI 106.0 SmC 153.1 I
[110]	LC183	OC8H17	OC10H21	Cr 79.3 J/G 91.7 SmF 92.9 SmI 110.8 SmC 151.5 I
[110]	LC184	OC8H17	OC12H25	Cr 72.6 J/G 94.6 SmI 118.4 SmC 149.6 I
[110]	LC185	OC9H19	OC6H13	Cr 65.6 SmC 138.2 SmA 147.1 N 147.3 I
[110]	LC186	OC9H19	OC7H15	Cr 84.2 SmCalt 86.1 SmC 147.7 SmA 151.4 I
[110]	LC187	OC9H19	OC8H17	Cr 81.0 SmF 99.9 SmC 150.6 I
[110]	LC188	OC9H19	OC9H19	Cr 51.4 SmF 105.6 SmC 150.8 I
[110]	LC189	OC9H19	OC10H21	Cr 67.7 SmF 111.5 SmC 150.3 I
[110]	LC190	OC9H19	OC12H25	Cr 71.6 SmF 117.3 SmC 147.7 I
[110]	LC191	OC10H21	OC6H13	Cr 68.1 SmC 136.5 SmA 145.8 I
[110]	LC192	OC10H21	OC7H15	Cr 82.2 SmCalt 84.7 SmC 145.6 SmA 150.8 I
[110]	LC193	OC10H21	OC8H17	Cr 79.5 SmI 98.6 SmC 149.4 I
[110]	LC194	OC10H21	OC9H19	Cr 60.1 SmI 105.3 SmC 148.7 I
[110]	LC195	OC10H21	OC10H21	Cr 74.5 SmI 111.3 SmC 149.0 I
[110]	LC196	OC10H21	OC12H25	Cr 73.5 SmI 117.9 SmC 146.7 I
[110]	LC197	OC12H25	OC6H13	Cr 68.5 SmC 135.2 SmA 145.2 I
[110]	LC198	OC12H25	OC7H15	Cr 64.9 SmCalt 80.1 SmC 137.4 SmA 146.7 I
[110]	LC199	OC12H25	OC8H17	Cr 81.9 SmI 95.4 SmC 146.9 I
[110]	LC200	OC12H25	OC9H19	Cr 66.5 SmI 104.5 SmC 146.2 I
[110]	LC201	OC12H25	OC10H21	Cr 74.4 SmI 111.2 SmC 147.0 I
[110]	LC202	OC12H25	OC12H25	Cr 62.0 SmI 118.0 SmC 144.2 I
[105]	LC203	OC6H13		Cr 75.2 SmCA* 98.9 SmC* 99.8 I
[105]	LC204	OC7H15		Cr1 57.3 Cr2 73.4 SmCA* 97.2 SmC* 98.2 I
[105]	LC205	OC8H17		Cr1 64.1 Cr2 69.3 SmCA* 98.8 SmC* 99.8 I
[105]	LC206	OC9H19		Cr1 68.8 Cr2 77.2 SmCA* 86.5 SmC* 97.8 I
[105]	LC207	OC10H21		Cr1 72.4 Cr2 79.0 SmCA* 87.1 SmC* 97.6 I
[105]	LC208	OC11H23		Cr1 78.9 Cr2 84.7 SmC* 96.7 I
[105]	LC209	OC12H25		Cr1 80.7 Cr2 85.6 SmC* 95.3 I
[109]	NLC18		H	Cr 185.6 I
[109]	LC210		OC5H11	Cr 133.5 SmC 154.7 N 169.6 I
[109]	LC211		OC6H13	Cr 122.5 SmX 107.0 SmC 160.7 N 165.8 I
[109]	LC212		OC7H15	Cr 132.9 SmCalt 111.6 SmX 118.6 SmC 165.8 N 166.7 I
[109]	LC213		OC8H17	Cr 123.2 SmCalt 102.1 SmX 125.9 SmC 166.5 I
[109]	LC214		OC9H19	Cr 121.3 SmCalt 121.9 SmX 131.3 SmC 168.2 I
[109]	LC215		OC10H21	Cr 118.2 SmCalt 121.3 SmX 133.2 SmC 166.4 I
[109]	LC216		OC12H25	Cr 107.1 SmCalt 119.5 SmX 138.6 SmC 166.3 I

Table 12. The chemical structures and mesophase transition temperatures (^oC) of thienyl-pyrimidine liquid crystals.

Ref.	No.	R	Mesophase Transition Temperatures (^oC)
[111]	LC217	C5H11	Cr 72.8 (G 46.5) SmA 109.0 I
	LC218	C6H13	Cr 50.1 SmA 108.0 I
	LC219	C7H15	Cr 61.6 SmA 114.7 I
	LC220	C8H17	Cr 56.4 (G 35.7) (SmX1 51.2) (SmX2 58.7) SmC 111.6 I
	LC221	C9H19	Cr 68.7 (G 32.9) (SmX1 45.6) (SmX2 66.5) SmB 75.5 SmC 116.3 I
	LC222	C10H21	Cr 60.0 (G 37.2) (SmX1 67.0) SmB 90.9 SmC 115.9 I
	LC223	C12H25	Cr 71.8 (G 42.4) (SmX1 70.4) B 107.6 SmC 114.5 I

Table 13. The chemical structures and mesophase transition temperatures (^oC) of phenyl pyrimidine liquid crystals with chiral centres.

Ref.	No.	X	Y	Z	R1	R2	Mesophase Transition Temperatures (^oC)
[112]	LC224	N	CH	CH			Cr 102 SmX 122 SmC* 128 I
	LC225	CH	N	CH			Cr 98 SmC* 102 SmA 136 I
	LC226	CH	CH	N			Cr 102 SmX 122 SmC* 128 I
	LC227	N	CH	CH			Cr 148 (SmX 112) SmC* 151 I
	LC228	N	CH	CH			Cr 115 SmC* 149 I
	LC229	N	CH	CH			Cr 95 IsoX 127 I
	LC230	N	CH	CH			Cr 129 SmX 139 SmC* 191 SmA 216 I
	LC231	N	CH	CH			Cr 109 SmC* 130 I
	LC232	N	CH	CH			Cr 86 SmC* 126 I

Figure 8. (Colour online) The schematic exhibition of pyrimidine-based polycatenar oligomers, photopolymerisable liquid crystals and copolymers for application in organic semiconductors.

Table 14. The chemical structures of pyrimidine-based copolymers.

Ref.	No.	Structures
[132]	LC233
[133]	LC234
[134]	LC235 (n=1); LC236 (n=2); LC237 (n=3)
[135]	LC238 (m=1); LC239 (m=2); LC240 (m=3)
[136]	LC241 (m=1); LC242 (m=2);
[137]	LC243
[137]	LC244

Figure 9. (Colour online) The chemical structures, mesophase transition temperatures (^oC) and POM textures of photopolymerisable pyrimidine liquid crystals [145].

Table 15. The chemical structures and mesophase transition temperatures (^oC) of azobenzene pyrimidine compounds.

Ref.	No.	n	Mesophase Transition Temperatures (^oC)
[45]	NLC19	1	Cr 98.7 I; I 93.9 Cr
	NLC20	2	Cr 91.1 I; I 88.7 Cr
	LC247	3	Cr 71.1 SmA 96.5 I; I 92.7 SmA 67.1 Cr
	LC248	4	Cr1 64.0 Cr2 72.3 SmA 102.8 I; I 101.3 SmA 68.2 Cr
	LC249	5	Cr 65.7 SmA 100.4 I; I 98.2 SmA 62.8 Cr
	LC250	6	Cr1 62.1 Cr2 100.6 SmA 113.8 I; I 111.2 SmA 81.8 Cr

Table 16. The chemical structures and mesophase transition temperatures (^oC) of pyrimidine-based photopolymerisable liquid crystals.

Ref.	No.	R	Mesophase Transition Temperatures (^oC)
[146]	LC251		Cr 25 SmC 124 I
	LC252		Cr 58 SmC 175 I
	LC253		Cr 56 SmC 126 I
	LC254		Cr 73 SmC 108 I
	LC255		Cr 52 SmC 116 I
	LC256		Cr 78 SmC 123 I
	LC257		Cr 82 SmC 150 I
	LC258		Cr 55 SmC 123 I
	LC259		Cr 97 SmC 141 I

Table 17. The chemical structures and mesophase transition temperatures (^oC) of pyrimidine-based polycatenary oligomers.

Ref.	No.	Structures	Mesophase Transition Temperatures (^oC)
[150]	NLC21		Cr 180 I
	LC260		Cr 16 Col 53 I
	LC261		Cr 181 Col 250 I

Figure 10. (Colour online) The schematic exhibition of pyrimidine-based liquid crystals coordinated with palladium and platinum as metallomesogens and non-conventional functional mesomorphic materials for application in sensors.

Table 18. The chemical structures and mesophase transition temperatures (^oC) of pyrimidine-based organometallic calamitic/discotic liquid crystals.

Ref.	No.	M	R1	R2	R3	R4	R5	R6	Mesophase Transition Temperatures (^oC)
[163]	LC262	Pd	H	H	H	H	C7H15	OC10H21	Cr1 64 Cr2 113 SmC 117 SmA 133 I
	LC263	Pd	OC10H21	H	H	H	C7H15	OC10H21	Cr 117 (SmA 99 N 101) I
	NLC22	Pd	OC10H21	H	OC10H21	H	C7H15	OC10H21	Cr 115 I
	LC264	Pd	OC10H21	OC10H21	H	H	C7H15	OC10H21	Cr1 38 Cr2 59 Colh 76 I
	LC265	Pd	OC10H21	OC10H21	OC10H21	H	C7H15	OC10H21	Cr 72 Colh 134 I
	LC266	Pd	OC10H21	OC10H21	OC10H21	OC10H21	C7H15	OC10H21	Cr 79 Colh 163 I
	LC267	Pd	H	H	H	H	C10H21	OC8H17	Cr 129 SmA 136 I
	LC268	Pd	OC10H21	H	H	H	C10H21	OC8H17	Cr 114 (SmA 103 N 105) I
	NLC23	Pd	OC10H21	H	OC10H21	H	C10H21	OC8H17	Cr 117 I
	LC269	Pd	OC10H21	OC10H21	H	H	C10H21	OC8H17	Cr 61 Colh 74 NCol 76 X 79 I
	LC270	Pd	OC10H21	OC10H21	OC10H21	H	C10H21	OC8H17	Cr 78 Colh 146 I
	LC271	Pd	OC10H21	OC10H21	OC10H21	OC10H21	C10H21	OC8H17	Cr 79 Colh 169 I
	LC272	Pd	H	H	H	H		C9H19	Cr 178 SmA 196 I
	LC273	Pd	OC10H21	H	H	H		C9H19	Cr 113 SmC 122 SmA 140 N 147 I
	LC274	Pd	OC10H21	H	OC10H21	H		C9H19	Cr 131 (SmC 111 SmA 112) I
	LC275	Pd	OC10H21	OC10H21	H	H		C9H19	Cr 108 Colh 115 I
	LC276	Pd	OC10H21	OC10H21	OC10H21	H		C9H19	Cr 82 ColX 102 Colh 103 I
	LC277	Pd	OC10H21	OC10H21	OC10H21	OC10H21		C9H19	Cr 125 Colh 166 I
	LC278	Pt	H	H	H	H	C7H15	OC10H21	Cr 137 SmA 145 I
	LC279	Pt	OC10H21	H	H	H	C7H15	OC10H21	Cr 126 (SmA 107 N 109) I
	NLC24	Pt	OC10H21	H	OC10H21	H	C7H15	OC10H21	Cr 117 I
	LC280	Pt	OC10H21	OC10H21	H	H	C7H15	OC10H21	Cr 62 Colh 75 I
	LC281	Pt	OC10H21	OC10H21	OC10H21	H	C7H15	OC10H21	Cr 74 Colh 151 I
	LC282	Pt	OC10H21	OC10H21	OC10H21	OC10H21	C7H15	OC10H21	Cr 76 Colh 170 I

Table 19. The chemical structures and mesophase transition temperatures (^oC) of binuclear cyclopalladated phenylpyrimidine compounds.

Ref.	No.	X	R	R’	Mesophase Transition Temperatures (^oC)
[165]	NLC25	Cl	C6H13	CH3	Cr 215.0 I
	LC283	Cl	C9H19	CH3	Cr 100.0 Cr’ 128.9 SmA 137.2 SmX 168.3 I
	LC284	Cl	C6H13	C11H23	Cr 100.0 Cr’ 177.2 SmA 218.8 I
	NLC26	Cl	C9H19	C9H19	Cr 207.0 I
	NLC27	Br	C6H13	CH3	Cr 202.0 I
	LC285	Br	C9H19	CH3	Cr 115.8 Cr’ 129.8 SmA 174.5 I
	LC286	Br	C6H13	C11H23	Cr 112.0 Cr’ 171.3 SmA 202.1 I
	LC287	Br	C9H19	C9H19	Cr 105.9 SmA 196.6 I
	NLC28	I	C6H13	CH3	Cr 205.0 I
	NLC29	I	C9H19	CH3	Cr 195.0 I
	LC288	I	C6H13	C11H23	Cr 109.7 Cr’ 148.6 SmA 192.9 I
	LC289	I	C9H19	C9H19	Cr 105.1 SmA 128.1 SmX 202.5 I
	NLC30	OAc	C6H13	CH3	Cr 183.0 I
	NLC31	OAc	C9H19	CH3	Cr 128.0 I
	NLC32	OAc	C6H13	C11H23	Cr 139.6 I
	NLC33	OAc	C9H19	C9H19	Cr 135.0 I

Schilling C, Bauer A, Knöller JA, et al. Tailoring boron liquid crystals: mesomorphic properties of iminodiacetic acid boronates. J Mol Liq. 2022;367:120519. doi: 10.1016/j.molliq.2022.120519

 Web of Science ®Google Scholar

Upadhyay P, Rastogi MK, Kumar D. Polarizability study of nematic liquid crystal 4-cyano-4′-pentylbiphenyl (5CB) and its nitrogen derivatives. Chem Phys. 2015;456:41–46. doi: 10.1016/j.chemphys.2015.03.011

 Web of Science ®Google Scholar

Chien C-W, Liu K-T, Lai CK. Heterocyclic columnar pyrimidines: synthesis, characterization and mesomorphic properties. Liq Cryst. 2004;31(7):1007–1017. doi: 10.1080/02678290410001713342

 Web of Science ®Google Scholar

Lin Y-C, Lai CK, Chang Y-C, et al. Formation of hexagonal columnar phases by heterocyclic pyrimidine derivatives. Liq Cryst. 2002;29(2):237–242. doi: 10.1080/02678290110097800

 Web of Science ®Google Scholar

Nishiyama I, Tabe Y, Yamamoto J, et al. Pre-organization effects on chirality, polarity and biaxiality in liquid crystals: novel laterally connected mesogens showing anomalous properties. Mol Cryst Liq Cryst. 2011;549(1):174–183. doi: 10.1080/15421406.2011.581528

 Web of Science ®Google Scholar

Akdas-Kilig H, Godfroy M, Fillaut J-L, et al. Mesogenic, luminescence, and nonlinear optical properties of New Bipyrimidine-based multifunctional octupoles. J Phys Chem C. 2015;119(7):3697–3710. doi: 10.1021/jp511486y

 Web of Science ®Google Scholar

Tykarska M, Dąbrowski R, Czerwiński M, et al. The influence of the chiral terphenylate on the tilt angle in pyrimidine ferroelectric mixtures. Phase Transit. 2012;85(4):364–370. doi: 10.1080/01411594.2011.646274

 Web of Science ®Google Scholar

Pramanik A, Das MK, Das B, et al. Preparation and study of the electro-optical properties of binary mixtures of orthoconic anti-ferroelectric Esters and achiral phenyl pyrimidine liquid crystal. Soft Mater. 2015;13(4):201–209. doi: 10.1080/1539445X.2015.1063510

 Web of Science ®Google Scholar

Lapanik V, Lugovski A, Timofeev S. A new generation of ferroelectric liquid crystals with homogeneous and shock-stable orientation. Liq Cryst. 2023;50(2):203–209. doi: 10.1080/02678292.2022.2110956

 Web of Science ®Google Scholar

Hird M. Ferroelectricity in liquid crystals—materials, properties and applications. Liq Cryst. 2011;38(11–12):1467–1493. doi: 10.1080/02678292.2011.625126

 Web of Science ®Google Scholar

Roberts JC, Kapernaum N, Giesselmann F, et al. Design of liquid crystals with “de vries-like” properties: organosiloxane Mesogen with a 5-Phenylpyrimidine Core. J Am Chem Soc. 2008;130(42):13842–13843. doi: 10.1021/ja805672q

 PubMed Web of Science ®Google Scholar

Radcliffe MD, Brostrom ML, Epstein KA, et al. Smectic a and C materials with novel director tilt and layer thickness behaviour. Liq Cryst. 1999;26(6):789–794. doi: 10.1080/026782999204471

 Web of Science ®Google Scholar

Rieker TP, Janulis EP. Enhanced thermal response of the SAd1 layer thickness in highly fluorinated thermotropic liquid crystals. Liq Cryst. 1994;17(5):681–687. doi: 10.1080/02678299408037339

 Web of Science ®Google Scholar

Romero-Hasler PN, Kurihara LK, Mair LO, et al. Nanocomposites of ferroelectric liquid crystals and FeCo nanoparticles: towards a magnetic response via the application of a small electric field. Liq Cryst. 2020;47(2):169–178. doi: 10.1080/02678292.2019.1633429

 Web of Science ®Google Scholar

Sreenilayam SP, Rodriguez-Lojo D, Panov VP, et al. Design and investigation of de vries liquid crystals based on 5-phenyl-pyrimidine and (RR)-2,3-epoxyhexoxy backbone. Phys Rev E. 2017;96(4):042701. doi: 10.1103/PhysRevE.96.042701

 PubMed Web of Science ®Google Scholar

Schubert CPJ, Müller C, Bogner A, et al. Design of liquid crystals with ‘de vries-like’ properties: structural variants of carbosilane-terminated 5-phenylpyrimidine mesogens. Soft Matter. 2017;13(18):3307–3313. doi: 10.1039/C7SM00355B

 PubMed Web of Science ®Google Scholar

Furue H, Furutani M, Ito A, et al. Alignment structure of dimeric liquid crystal molecules having bent molecular structure. Ferroelectrics. 2010;394(1):22–31. doi: 10.1080/00150191003677569

 Web of Science ®Google Scholar

Kashima S, Takanishi Y, Yamamoto J, et al. Flexible taper-shaped liquid crystal trimer exhibiting a modulated smectic phase. Liq Cryst. 2014;41(12):1752–1761. doi: 10.1080/02678292.2014.950353

 Web of Science ®Google Scholar

Swaminathan V, Panov VP, Panov A, et al. Design and electro-optic investigations of de vries chiral smectic liquid crystals for exhibiting broad temperature ranges of SmA* and SmC* phases and fast electro-optic switching. J Mater Chem C. 2020;8(14):4859–4868. doi: 10.1039/C9TC04405A

 PubMed Web of Science ®Google Scholar

Sreenilayam SP, Rodriguez-Lojo D, Agra-Kooijman DM, et al. de Vries liquid crystals based on a chiral 5-phenylpyrimidine benzoate core with a tri- and tetra-carbosilane backbone. Phys Rev Mater. 2018;2(2):025603. doi: 10.1103/PhysRevMaterials.2.025603

 Web of Science ®Google Scholar

Roberts JC, Kapernaum N, Song Q, et al. Design of liquid crystals with “de vries-like” properties: frustration between SmA- and SmC-promoting elements. J Am Chem Soc. 2010;132(1):364–370. doi: 10.1021/ja9087727

 PubMed Web of Science ®Google Scholar

Schubert CPJ, Bogner A, Porada JH, et al. Design of liquid crystals with ‘de vries-like’ properties: carbosilane-terminated 5-phenylpyrimidine mesogens suitable for chevron-free FLC formulations. J Mater Chem C. 2014;2(23):4581–4589. doi: 10.1039/C4TC00393D

 Web of Science ®Google Scholar

Schubert CPJ, Müller C, Giesselmann F, et al. Chiral 5-phenylpyrimidine liquid crystals with ‘de vries-like’ properties: dependence of electroclinic effect and ferroelectric properties on carbosilane nanosegregation. J Mater Chem C. 2016;4(36):8483–8489. doi: 10.1039/C6TC03120J

 Web of Science ®Google Scholar

Song Q, Nonnenmacher D, Giesselmann F, et al. Tuning the frustration between SmA- and SmC-promoting elements in liquid crystals with ‘de vries-like’ properties. Chem Commun. 2011;47(16):4781–4783. doi: 10.1039/C1CC10344J

 PubMed Web of Science ®Google Scholar

Roberts JC, Kapernaum N, Giesselmann F, et al. Fast switching organosiloxane ferroelectric liquid crystals. J Mater Chem. 2008;18(43):5301–5306. doi: 10.1039/B810209K

 Web of Science ®Google Scholar

Rupar I, Mulligan KM, Roberts JC, et al. Elucidating the smectic A-promoting effect of halogen end-groups in calamitic liquid crystals. J Mater Chem C. 2013;1(23):3729–3735. doi: 10.1039/C3TC30534A

 Web of Science ®Google Scholar

Ahmed Z, Müller C, Johnston JJ, et al. Design of liquid crystals with ‘de vries-like’ properties: the effect of an ethynyl spacer in the core structure. Liq Cryst. 2019;46(6):896–904. doi: 10.1080/02678292.2018.1536810

 Web of Science ®Google Scholar

Thompson M, Carkner C, Bailey A, et al. Tuning the mesogenic properties of 5-alkoxy-2-(4-alkoxyphenyl)pyrimidine liquid crystals: the effect of a phenoxy end-group in two sterically equivalent series. Liq Cryst. 2014;41(9):1246–1260. doi: 10.1080/02678292.2014.913721

 Web of Science ®Google Scholar

Sharma S, Lacey D, Wilson P. Synthesis and characterization of a range of heterocyclic liquid crystalline materials incorporating the novel thiophene-pyrimidine moiety. Liq Cryst. 2003;30(4):451–461. doi: 10.1080/0267829031000091138

 Web of Science ®Google Scholar

McDonald R, Lacey D, Watson P, et al. Synthesis and evaluation of some novel chiral heterocyclic liquid crystalline materials exhibiting ferro‐ and antiferro‐electric phases. Liq Cryst. 2005;32(3):319–330. doi: 10.1080/02678290500033711

 Web of Science ®Google Scholar

Sharma S, Lacey D, Wilson P. The SYNTHESIS and THERMAL PROPERTIES of NOVEL HETEROCYCLIC LIQUID CRYSTALLINE MATERIALS. Mol Cryst Liq Cryst. 2003;401(1):111–121. doi: 10.1080/744815207

 Google Scholar

Wilson P, Lacey D, Sharma S, et al. The synthesis and characterisation of novel thienyl-pyrimidine liquid crystalline materials. Mol Cryst Liq Cryst. 2001;368(1):279–292. doi: 10.1080/10587250108029957

 Google Scholar

Hori K, Matsunaga Y, Yoshizawa A, et al. Diversity in the packing modes of mesogenic diphenylpyrimidines with two chiral centres in their crystal structures: the role of interactions between the pyrimidine rings. Liq Cryst. 2004;31(6):759–766. doi: 10.1080/02678290410001697576

 Web of Science ®Google Scholar

Tong F, Chen S, Chen Z, et al. Mesogen-co-polymerized transparent polyimide as a liquid-crystal alignment layer with enhanced anchoring energy. RSC Adv. 2018;8(20):11119–11126. doi: 10.1039/C8RA00479J

 PubMed Web of Science ®Google Scholar

Wang A, Kawabata K, Goto H. Synthesis of isothianaphthene (ITN) and 3,4-Ethylenedioxy-thiophene (EDOT)-based low-bandgap liquid crystalline conjugated polymers. Materials. 2013;6(6):2218–2228. doi: 10.3390/ma6062218

 PubMed Web of Science ®Google Scholar

Ito R, Goto H. Synthesis of aromatic liquid crystal π-conjugated copolymers bearing three-ring pyrimidine-based mesogens, and optical texture observations. Mol Cryst Liq Cryst. 2021;723(1):33–44. doi: 10.1080/15421406.2021.1897943

 Web of Science ®Google Scholar

Kawabata K, Goto H. Liquid crystalline π-conjugated copolymers bearing a pyrimidine type mesogenic group. Materials. 2009;2(1):22–37. doi: 10.3390/ma2010022

 Web of Science ®Google Scholar

Ohkawa S, Ohta R, Kawabata K, et al. Polymerization in liquid crystal medium: preparation of polythiophene derivatives bearing a bulky pyrimidine substituent. Polymers. 2010;2(4):393–406. doi: 10.3390/polym2040393

 Web of Science ®Google Scholar

Otaki M, Kumai R, Sagayama H, et al. Synthesis of polyazobenzenes exhibiting photoisomerization and liquid crystallinity. Polymers. 2019;11(2):348. doi: 10.3390/polym11020348

 PubMed Web of Science ®Google Scholar

Ye Y, He R, Oh E, et al. Syntheses and properties of new smectic reactive mesogens and their application in guest-host polarizer. Macromol Res. 2020;28(10):910–918. doi: 10.1007/s13233-020-8121-1

 Web of Science ®Google Scholar

Rahman ML, Hegde G, Yusoff MM, et al. New pyrimidine-based photo-switchable bent-core liquid crystals. New J Chem. 2013;37(8):2460–2467. doi: 10.1039/C3NJ00359K

 Web of Science ®Google Scholar

Aldred MP, Vlachos P, Dong D, et al. Heterocyclic reactive mesogens: synthesis, characterisation and mesomorphic behaviour. Liq Cryst. 2005;32(8):951–965. doi: 10.1080/02678290500248400

 Web of Science ®Google Scholar

Sultana NH, Kelly SM, Mansoor B, et al. Polycatenar oligophenylene liquid crystals. Liq Cryst. 2007;34(11):1307–1316. doi: 10.1080/02678290701682357

 Web of Science ®Google Scholar

Hegmann T, Kain J, Diele S, et al. Molecular design at the calamitic/discotic cross-over point. Mononuclear ortho-metallated mesogens based on the combination of rod-like phenylpyrimidines and -pyridines with bent or half-disc-shaped diketonates. J Mater Chem. 2003;13(5):991–1003. doi: 10.1039/B210250A

 Web of Science ®Google Scholar

Ghedini M, Pucci D, De Munno G, et al. Transition metals complexed to ordered mesophases. Part 7. Synthesis, characterization and mesomorphic properties of binuclear cyclopalladated phenylpyrimidine species. Crystal structure of bis{(5-(1-hexyl)-2-[(4’-methoxy)phenyl-2’-ato]pyrimidine-N’,C2’)-.Mu.-acetato}dipalladium(II). Chem Mater. 1991;3:65–72. doi: 10.1021/cm00013a018

 Web of Science ®Google Scholar